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STARGAZING by Tony Flanders
Stargazing Blogs
On and off from 2007 through early 2011, I wrote a blog entitled Stargazing for the S&T website.
I had a lot of fun doing this, because I got to write about any old topic I wanted, as long as it was in any way connected to astronomy. But when I started working on the SkyWeek TV show, I simply ran out of available hours per week. I also get to talk about anything I want in SkyWeek, but video emphasizes presentation over content. I can reach a broader audience with SkyWeek, but I can't cover nearly as wide a range of subjects, or delve as deeply into them.
I find myself still referring back to those old Stargazing blogs quite frequently; there's a lot of good stuff in there. I may start writing meta-blogs calling attention to old blogs or groups of blogs that I find particularly interesting. Meanwhile, in case anybody's interested, is a complete list of all Stargazing blogs from 2007 through 2011:
2011
2010
2009
2007
Many of the Stargazing blogs talk about the relationship between stargazing and other nature activities, notably hiking. Here, Jupiter sets over Sphinx Col in New Hampshire's White Mountains, as viewed from The Bluff.
Tony Flanders
I find myself still referring back to those old Stargazing blogs quite frequently; there's a lot of good stuff in there. I may start writing meta-blogs calling attention to old blogs or groups of blogs that I find particularly interesting. Meanwhile, in case anybody's interested, is a complete list of all Stargazing blogs from 2007 through 2011:
2011
| Sept 1, 2011 | Lots Going On in the Sky |
| June 24, 2011 | Is Asteroid 2011 MD Space Junk? |
| Feb 14, 2011 | Measuring Skyglow with Digital Cameras |
| Jan 10, 2011 | SkyScanner 100 vs. 4.5-inch StarBlast |
| Jan 7, 2011 | The Joy of Small Instruments |
2010
2009
| Nov 25, 2009 | More on Scopes and Binoculars |
| Nov 9, 2009 | Paradoxical Messier 33 |
| Nov 4, 2009 | Chainsaw Astronomy |
| Oct 13, 2009 | Doing Deep-Sky Wonders |
| Sept 29, 2009 | Hiking Under the Stars |
| July 10, 2009 | Light Pollution in North America |
| June 25, 2009 | Light Pollution Per Capita |
| June 14, 2009 | Is the U.S. Bright or Dark? |
| June 5, 2009 | Ground Truth for the Light Pollution Atlas |
2007
Posted by Tony Flanders, February 21, 2010
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STARGAZING by Tony Flanders
Lots Going On in the Sky
The northeastern U.S. has had wonderful weather ever since Hurricane Irene. So I went out a couple of nights ago to check up on the celestial events that we've been covering on our website. I was delighted that all of them exceeded my expectactions.
First there's the supernova in M101. If you own a telescope, live at mid-northern latitudes, and haven't seen this yet, get out now and do it! It's little exaggeration to call this a chance of a lifetime. At magnitude 11, this is the brightest supernova since SN 1993J in M81. And it's still brightening, so it may well exceed that supernova.
I've been following Comet Garradd since the last new-Moon period, and I'm pleased to report that it's coming along nicely. It's now a rival for the northern sky's best deep-sky objects, it shares a binocular field of view with the wonderful Coathanger asterism, and it passes through the Coathanger on Friday, September 2nd.
I also checked up on asteroid 4 Vesta, which is currently being orbited by the Dawn spacecraft. It currently forms a nice "double star" with 4th-magnitude Psi Capricorni.
And if you live just a little south of me in the eastern U.S., don't forget the occultation of Delta Scorpii in the early evening of Saturday, September 3rd.
First there's the supernova in M101. If you own a telescope, live at mid-northern latitudes, and haven't seen this yet, get out now and do it! It's little exaggeration to call this a chance of a lifetime. At magnitude 11, this is the brightest supernova since SN 1993J in M81. And it's still brightening, so it may well exceed that supernova.
Comet Garradd passed M71 in Sagitta on the evening of August 26th.
Nick Howes
I also checked up on asteroid 4 Vesta, which is currently being orbited by the Dawn spacecraft. It currently forms a nice "double star" with 4th-magnitude Psi Capricorni.
And if you live just a little south of me in the eastern U.S., don't forget the occultation of Delta Scorpii in the early evening of Saturday, September 3rd.
Posted by Tony Flanders, September 1, 2011
STARGAZING by Tony Flanders
Is Asteroid 2011 MD Space Junk?
Saturday, June 25th: Additional observations have made it possible to calculate 2011 MD's orbit quite accurately. Bill Gray, a well-known expert on orbital dynamics, has run the orbit backward in time, and is now quite sure that this asteroid could not have been close enough to Earth any time during the space age to have started off as a rocket booster. So it seems to be a genuine chunk of rock after all.
Original story Friday, June 24th: When I was working up the details for yesterday's story on asteroid 2011 MD, I gasped when I looked at the orbit diagram. Not only does this body's orbit intersect Earth's, but it's also in the same plane (within a few degrees), and moving at almost the same velocity. Somehow, it seemed unlikely to be an accident!
Alan MacRobert, who sits across the hall from me, immediately suggested that it is indeed no accident — that this "asteroid" is actually the upper stage of a rocket. These upper stages are abandoned to become space junk after they've released their payloads. Most of them remain in Earth orbit, but it's perfectly possible for them to escape and start looping around the Sun all on their own. Since they start out with almost the same velocity as Earth, they tend to stay in similar orbits.
What significance does this have? Not much! For all practical purposes, 2011 MD is an asteroid now, whether its origin is natural or artificial. But somehow, it seems less glamorous to get up in the middle of the night to try to glimpse a rocket upper stage than a chunk of rock. After all, anybody can see a half-dozen rocket upper stages on any clear night just by looking in the right place at the right time. You don't even need optical aid! Just check out the predictions for your location from Heavens Above.
Original story Friday, June 24th: When I was working up the details for yesterday's story on asteroid 2011 MD, I gasped when I looked at the orbit diagram. Not only does this body's orbit intersect Earth's, but it's also in the same plane (within a few degrees), and moving at almost the same velocity. Somehow, it seemed unlikely to be an accident!
Alan MacRobert, who sits across the hall from me, immediately suggested that it is indeed no accident — that this "asteroid" is actually the upper stage of a rocket. These upper stages are abandoned to become space junk after they've released their payloads. Most of them remain in Earth orbit, but it's perfectly possible for them to escape and start looping around the Sun all on their own. Since they start out with almost the same velocity as Earth, they tend to stay in similar orbits.
What significance does this have? Not much! For all practical purposes, 2011 MD is an asteroid now, whether its origin is natural or artificial. But somehow, it seems less glamorous to get up in the middle of the night to try to glimpse a rocket upper stage than a chunk of rock. After all, anybody can see a half-dozen rocket upper stages on any clear night just by looking in the right place at the right time. You don't even need optical aid! Just check out the predictions for your location from Heavens Above.
Posted by Tony Flanders, June 24, 2011
STARGAZING by Tony Flanders
Measuring Skyglow with Digital Cameras
When reading the article in the April 2011 Sky & Telescope by Brian Kloppenburg and Tom Pearson about photometry with digital cameras, I was reminded of an article I wrote 5 years ago entitled "Measuring Skyglow with Digital Cameras." (Click here to download the article in PDF form.)
The article is (to my admitedly biased taste) full of good ideas that aren't fully fleshed out. I was hoping that someone would take those ideas and run with them — bring them into a form that's usable by the average amateur. It hasn't happened, so I'm issuing the challenge again.
In retrospect, I spent far too much time talking about point-and-shoot cameras and too little on digital SLRs, which are more suitable for this application. At the time, many point-and-shoot cameras still had the manual controls and sensitivity needed for scientific work, while DSLRs were the province of professional photographers and a few serious amateurs. These days, point-and-shoot cameras have become more automatic and les sensitive, and DSLRs have become cheap enough for many people to buy.
Why use DSLRs to measure skyglow when the Sky Quality Meter is so convenient and relatively cheap? Because the SQM measures only the zenith and can't cope with the horizon, where light pollution is at its worst — and most directional. The SQM would probably yield a number around magnitude 19.5 per square arcsecond for the sky at my astronomy club's observing field, hiding the fact that it's overwhelmingly bright to the southeast, in the direction of Boston, and almost tolerable to the northwest, as shown in my digital camera mosaic.
What more needs to be done? A lot! My mosaics are produced with lots of manual labor that could theoretically be made automatic — calibrating the measurement, determining the precise fields of the component frames by matching star fields, and stitching the mosaic together. Software exists to solve each one of these problems separately, but not all together. It's all a matter of computer-programming time — which I don't have. Any takers?
The article is (to my admitedly biased taste) full of good ideas that aren't fully fleshed out. I was hoping that someone would take those ideas and run with them — bring them into a form that's usable by the average amateur. It hasn't happened, so I'm issuing the challenge again.
#checkImageURL( )
The sky at the ATMOB observing field in Westford, MA. Greens represent magnitude 19.00-19.99 per square arcsecond; oranges 18.00-18.99. White circles are at altitudes 15, 30, and 60 degrees. North is up and east is to the right. The 19.0 isophote extends down to 15 degrees in the northwest, but that altitude is three times brighter in the southeast.
Nick Howes
Why use DSLRs to measure skyglow when the Sky Quality Meter is so convenient and relatively cheap? Because the SQM measures only the zenith and can't cope with the horizon, where light pollution is at its worst — and most directional. The SQM would probably yield a number around magnitude 19.5 per square arcsecond for the sky at my astronomy club's observing field, hiding the fact that it's overwhelmingly bright to the southeast, in the direction of Boston, and almost tolerable to the northwest, as shown in my digital camera mosaic.
What more needs to be done? A lot! My mosaics are produced with lots of manual labor that could theoretically be made automatic — calibrating the measurement, determining the precise fields of the component frames by matching star fields, and stitching the mosaic together. Software exists to solve each one of these problems separately, but not all together. It's all a matter of computer-programming time — which I don't have. Any takers?
Posted by Tony Flanders, February 14, 2011
STARGAZING by Tony Flanders
SkyScanner 100 vs. 4.5-inch StarBlast
It was at NEAF 2010 that I first conceived the idea that culminated in the review of Three Low-Cost Telescopes in the March 2011 issue of Sky & Telescope.
I was attracted to the Orion SkyScanner 100mm TableTop Reflector as soon as I saw it. I've always been a huge fan of the Orion StarBlast 4.5 Astro, and here, apparently, was a telescope almost exactly half the weight and cost of the StarBlast, yet sporting 88% the aperture, for 77% as much light-gathering power. Could this really be 77% of a StarBlast for half the cost?
The short answer is no — the SkyScanner falls short of the StarBlast in several obvious and not-so-obvious ways. In fact, my expectations were so high that my intial reaction was disappointment.
Then, when I started using the scope again several months later, I started to appreciate the SkyScanner on its own merits. No, it's not 77% of a StarBlast for half the price, but it might well be half of a StarBlast for half the price, and that's still a huge accomplishment.
How is the SkyScanner inferior to the StarBlast, aside from its slightly smaller aperture? First, its mirror isn't diffraction-limited. And the mirror is affixed solidly to the back of the tube instead of being in a standard cell with collimation screws. And there's hardly any clearance between the tube and the light path. That's what makes it possible for the scope to be so small and light, but it also makes its cool-down time much longer.
More subtly, the SkyScanner lacks one of the unusual features of the StarBlast — the ability to rotate the tube in its rings. That makes the StarBlast extraordinarily easy to use on a tabletop; you can always rotate the eyepiece into the ideally comfortable position. Mind you, it's hardly fair to criticize the $100 SkyScanner for lacking a feature that's also lacking in most commercial Dobs — even ones costing thousands!
On the flip side, the SkyScanner can be attached to any standard photo tripod with a detachable head — a very convenient arrangement. The StarBlast isn't threaded for photo tripods, and even if it were, it would be too heavy for all but the most robust (and expensive) professional-caliber tripods. So in practice, the StarBlast requires either a sturdy table or some kind of custom-built support.
But now let's forget about the StarBlast, and compare the SkyScanner instead to a standard commercial 60-mm refractor selling for exactly the same price. The refractor probably does a better job on the planets, but that's the end of its advantages. The SkyScanner gathers fully 2.7 times as much light as a 60-mm refractor, making every star and deep-sky object appear a full magnitude brighter. It's much easier to carry and store. And its mount is a joy to use.
What's the moral? If you want the most aperture possible for $100, or if you want an ultraportable scope that can be attached to a standard photo tripod, by all means buy the SkyScanner. It's a fine scope despite its limitations, and it won't disappoint you. But if you have $200 and don't mind a somewhat heavier and bulkier telescope, you'd definitely do better with the StarBlast, which is a timeless classic.
The Orion SkyScanner 100mm (left) is half the cost and weight of the Orion StarBlast 4.5 Astro, yet its mirror is nearly as big.
Tony Flanders
The short answer is no — the SkyScanner falls short of the StarBlast in several obvious and not-so-obvious ways. In fact, my expectations were so high that my intial reaction was disappointment.
Then, when I started using the scope again several months later, I started to appreciate the SkyScanner on its own merits. No, it's not 77% of a StarBlast for half the price, but it might well be half of a StarBlast for half the price, and that's still a huge accomplishment.
The StarBlast (left) offers ample clearance between the mirror and the tube, unlike the SkyScanner.
Tony Flanders
More subtly, the SkyScanner lacks one of the unusual features of the StarBlast — the ability to rotate the tube in its rings. That makes the StarBlast extraordinarily easy to use on a tabletop; you can always rotate the eyepiece into the ideally comfortable position. Mind you, it's hardly fair to criticize the $100 SkyScanner for lacking a feature that's also lacking in most commercial Dobs — even ones costing thousands!
The Orion SkyScanner is shown here attached to a set of Bogen Manfrotto 3011 photo-tripod legs — a very solid and convenient arrangement.
Tony Flanders
But now let's forget about the StarBlast, and compare the SkyScanner instead to a standard commercial 60-mm refractor selling for exactly the same price. The refractor probably does a better job on the planets, but that's the end of its advantages. The SkyScanner gathers fully 2.7 times as much light as a 60-mm refractor, making every star and deep-sky object appear a full magnitude brighter. It's much easier to carry and store. And its mount is a joy to use.
What's the moral? If you want the most aperture possible for $100, or if you want an ultraportable scope that can be attached to a standard photo tripod, by all means buy the SkyScanner. It's a fine scope despite its limitations, and it won't disappoint you. But if you have $200 and don't mind a somewhat heavier and bulkier telescope, you'd definitely do better with the StarBlast, which is a timeless classic.
Posted by Tony Flanders, January 10, 2011
STARGAZING by Tony Flanders
The Joy of Small Instruments
Looking over my observing notes for the past few months, it's apparent that a disproportionate fraction of my sessions have been done with binoculars and small telescopes. There are several reasons.
First, the weather has been in an odd pattern, unpredictable and prone to rapid changes. That means grabbing anything I can lay my hands on as quickly as possible when a hole opens unexpectedly in the clouds. My life has also been busier than usual, pushing me toward short sessions where the setup time for a big scope isn't justified. And my last major project was the review of three small and inexpensive telescopes. I collaborated on that with Josh Roth, who's even more of a small-scope fanatic than I am.
In fact, the highlight of last year's observing for me came during that review. I had already observed Saturn with one of the test scopes some months earlier, in the evening, but I wanted one more peek. So early one workday I set up the scopes on the sidewalk, right in front of our office, with the sky already blue, and took a good look at Saturn.
I was totally blown away! The view through the Orion SpaceProbe 3 was particularly impressive — small, but as crisp as anybody could possibly want. Most of the credit, of course, goes to Saturn itself, whose rings are now opened wider than they've been since 2008. But's there something special about the view through a small scopes with good optics — and this little $100 wonder definitely qualifies.
My first session of 2011 was also with small instruments: my 8×32 monocular and 10×30 and 12×60 binoculars. I'll write about that soon if I get the time — it was quite revealing.
First, the weather has been in an odd pattern, unpredictable and prone to rapid changes. That means grabbing anything I can lay my hands on as quickly as possible when a hole opens unexpectedly in the clouds. My life has also been busier than usual, pushing me toward short sessions where the setup time for a big scope isn't justified. And my last major project was the review of three small and inexpensive telescopes. I collaborated on that with Josh Roth, who's even more of a small-scope fanatic than I am.
Saturn's rings are roughly as wide open now as they were when the Hubble Space Telescope captured this shot in October 1997. No earth-based telescope will give you a view this detailed. On the other hand, no photograph can compare with the experience of viewing Saturn directly.
NASA / STSCI / AURA / Hubble Heritage Team
I was totally blown away! The view through the Orion SpaceProbe 3 was particularly impressive — small, but as crisp as anybody could possibly want. Most of the credit, of course, goes to Saturn itself, whose rings are now opened wider than they've been since 2008. But's there something special about the view through a small scopes with good optics — and this little $100 wonder definitely qualifies.
My first session of 2011 was also with small instruments: my 8×32 monocular and 10×30 and 12×60 binoculars. I'll write about that soon if I get the time — it was quite revealing.
Posted by Tony Flanders, January 7, 2011
STARGAZING by Tony Flanders
Guest Blog: In Defence of GPS
I was particularly struck by one of the comments on my blog Tunnel Vision Navigation, by Dieter Kreuer from Germany. Sadly, our web software removes paragraph breaks from comments, making long ones hard to read. So I'm reproducing it here, with permission and a few minor edits.
I agree with absolutely everything that Dieter has said — except that anybody who thinks that all streets in the U.S. are geometrically laid out and well signed has never been in Boston! I particularly admire the way he took my metaphor of automobile navigation and turned it around. Yes, driving a car while reading a map is incredibly dangerous — no doubt about it.
On balance, I have no doubt that GPS devices in cars and Go To drives on telescopes are good things. At the same time, it's clear to me that they have serious downsides. And the good and bad seem to be inextricably linked.
Anyway, here is Dieter's comment:
It's certainly true that reading a GPS device can distract the driver and cause serious accidents. However, so can reading a printed map while driving! I would even say that a GPS device mounted with a suction holder to the windscreen and giving additional vocal directions distracts less than a map held to steering wheel or lying on the co-driver's seat (unless you have an actual co-driver giving the directions!).
In Europe, where streets are not geometrically laid out and well tagged with names as in the US, even looking around to find the correct turn may be a distraction, which is lowered a lot by using a GPS. But yes, there are stories of people misinterpreting GPS directions and ending up on railroad tracks, and even down ferry ramps into rivers. And very often trucks get stuck in front of bridges or tunnels on streets much too small for them. So checking a map before the trip is certainly a good idea.
To get back on topic, the same is true for watching the skies. Tony's point is certainly that some people use their Go To scopes without the slightest idea how to get around in the skies, which is a valid argument. Every amateur astronomer should learn the constellations, star names of bright stars and locations of the most important sky splendors. I too have done so for more than 30 years, but I'm really thankful that Go To now enables me to spend most of the time with watching my desired target rather than finding my way to it.
I agree with absolutely everything that Dieter has said — except that anybody who thinks that all streets in the U.S. are geometrically laid out and well signed has never been in Boston! I particularly admire the way he took my metaphor of automobile navigation and turned it around. Yes, driving a car while reading a map is incredibly dangerous — no doubt about it.
On balance, I have no doubt that GPS devices in cars and Go To drives on telescopes are good things. At the same time, it's clear to me that they have serious downsides. And the good and bad seem to be inextricably linked.
Anyway, here is Dieter's comment:
Dieter Kreuer
In Europe, where streets are not geometrically laid out and well tagged with names as in the US, even looking around to find the correct turn may be a distraction, which is lowered a lot by using a GPS. But yes, there are stories of people misinterpreting GPS directions and ending up on railroad tracks, and even down ferry ramps into rivers. And very often trucks get stuck in front of bridges or tunnels on streets much too small for them. So checking a map before the trip is certainly a good idea.
To get back on topic, the same is true for watching the skies. Tony's point is certainly that some people use their Go To scopes without the slightest idea how to get around in the skies, which is a valid argument. Every amateur astronomer should learn the constellations, star names of bright stars and locations of the most important sky splendors. I too have done so for more than 30 years, but I'm really thankful that Go To now enables me to spend most of the time with watching my desired target rather than finding my way to it.
Posted by Tony Flanders, October 26, 2010
STARGAZING by Tony Flanders
Has Your Observing Site Gotten Brighter?
I was rather taken aback a few weeks ago when Kelly Beatty started his blog about Kitt Peak by asking, "How many of you can claim that your favorite stargazing spot is as dark now as it was five years ago, let alone 10 or 20?" — as though he was clearly expecting the answer to be "no."
In fact, I use several different observing sites, and I think they're all as dark as they were 5 or 10 years ago — so I sort of assumed that this is typical for the U.S. Northeast. In fact, I kinda think that my my country home is as dark as it was 35 years ago, when I first started seriously exploring the sky with 7×35 binoculars. But I strongly suspect that's not typical.
I actually have solid evidence from the last 5 years, ever since I purchased my Sky Quality Meter. I've taken hundreds of readings with it, and none of them show a clear trend of change over time.
This isn't entirely surprising, because to some extent light pollution is proportional to population, and most of the population growth in the U.S. over the past few decades has been in the South and the West. The Northeast has grown, but at a very modest pace.
Moreover, almost all the growth in the Northeast has been in middle and outer suburbs. The major cities all reached their current configuration in the 20s, and the inner suburbs in the 50s and 60s. And rural areas have, if anything, lost population.
So what about the mid and outer suburbs? Well, that'sexactly where my astronomy club's observing field is. And there, also, I see no evidence of change over the last 5 years. (Click here if you can't see the graph at right.)
Round about now you may be wondering if all these Sky Quality Meter readings are just noise. Are there any meaningful patterns to be made out of them? Well, yes, in fact. When I plotted the measurements against time of night, the darkest readings are all around or after midnight. (Click here if you can't see them.) In case you're wondering — yes, I filtered out all the readings before the end of astronomical twilight. This effect is entirely due to decrease in artificial light. The same trend is discernible, though much weaker, at my country home. My guess is that it's partly due to commercial and home lights being turned off, but also very largely to the decrease in traffic. I strongly suspect that automobile headlights are the second biggest source of light pollution, exceeded only by streetlights.
But the most striking trend of all comes when I plot the measurements against time of year. The graph at right (click here if you can't see it) shows that darkness falls sharply after mid-October . . . just like the falling leaves on the trees, which are no doubt the primary culprit. That's not surprising at all, because New England is very heavily wooded. In the cities in particular, almost all the streetlights are directly under trees, which prevent their light from shining up into the sky. Conversely, the sky becomes much brighter when there's fresh snow under the streetlights. For more information on this effect, see my blog on the Snow-Corrected Light-Pollution Atlas.
The zenithal sky brightness in New Lebanon, NY, has not changed appreciably over the last 5 years. Measurements are in magnitude per square arcsecond, and higher values mean darker skies.
Dieter Kreuer
I actually have solid evidence from the last 5 years, ever since I purchased my Sky Quality Meter. I've taken hundreds of readings with it, and none of them show a clear trend of change over time.
This isn't entirely surprising, because to some extent light pollution is proportional to population, and most of the population growth in the U.S. over the past few decades has been in the South and the West. The Northeast has grown, but at a very modest pace.
Skies have not changed appreciably since 2005 at the Amateur Telescope Makers of Boston observing field in Westford, MA.
Dieter Kreuer
So what about the mid and outer suburbs? Well, that'sexactly where my astronomy club's observing field is. And there, also, I see no evidence of change over the last 5 years. (Click here if you can't see the graph at right.)
Dieter Kreuer
Dieter Kreuer
Posted by Tony Flanders, October 23, 2010
STARGAZING by Tony Flanders
Tunnel Vision Navigation
After a couple of digressions into hard-core observing targets (which some people might argue is my proper domain), let me continue my discussion of the tunnel vision induced by flashlights — and how it can serve as a metaphor for life.
Some months ago, I was buying milk and gas at Stewart's in New Lebanon, NY, my country hometown. A car pulled up and asked how to get to Route 8 — a question that knocked me cold, as it were, because there are a bunch of Route 8s, and none are especially close to New Lebanon. The conversation proceeded:
Me: Route 8 in what state?
Them: Connecticut
Me:Where are you coming from?
Them: Syracuse, NY
Me:: How did you wind up here?
Turns out they had consulted an internet mapping program, and it told them to get on Interstate 90, stay on it for a really long time, get off on U.S. 20, then take a right on Rt. 8. All of which is exactly correct, but ...
What they didn't realize is that I-90 is basically the modern version of old Route 20, the road from Boston to Chicago. The two roads crisscross repeatedly. They had gotten off at the first interchange, in East Greenbush, NY, instead of the correct one, in Lee, MA. And since they had only printed out the directions, and had no map whatsoever, they were then utterly and totally lost. They would indeed have gotten to the right place eventually by following Route 20 — if they stayed alert to the fact that it makes multiple right-angle turns — but they would have lost well over an hour in the process.
The moral of this story is not that you should avoid computer mapping services. On the contrary, I find Google Maps in particular quite liberating. I'm always looking for new ways to get from point A to point B, and Google Maps lets you alter its chosen route by "pulling" it to different intermediate points. That's no big deal in and of itself, but what is a big deal is that it will add up the mileage for each route in a split-second. You can do that with a convenientional road map, too, but it's a very time-consuming and error-prone process.
As Humpty Dumpty says, it's all a question of which is to be the master. If you take the easy way, following the computer's advice blindly, then you will never have any idea how origin and destination are connected, where you are at any moment along the trip, and what to do if anything unexpected happens. But if you use the computer as an aid rather than a crutch, then it becomes life-enhancing rather than crippling.
This has obvious application to astronomical observing strategies in the age of modern electronics. But I'll come to that in another blog.
It's convenient to print out the directions from an internet mapping program. But if you don't take the map too, then you're totally lost if you make a single mistake.
Google Maps
Me: Route 8 in what state?
Them: Connecticut
Me:Where are you coming from?
Them: Syracuse, NY
Me:: How did you wind up here?
Turns out they had consulted an internet mapping program, and it told them to get on Interstate 90, stay on it for a really long time, get off on U.S. 20, then take a right on Rt. 8. All of which is exactly correct, but ...
U.S. 20 (the northern route shown here) goes to the same places as Interstate 90, but takes a lot longer to do so.
Google Maps
The moral of this story is not that you should avoid computer mapping services. On the contrary, I find Google Maps in particular quite liberating. I'm always looking for new ways to get from point A to point B, and Google Maps lets you alter its chosen route by "pulling" it to different intermediate points. That's no big deal in and of itself, but what is a big deal is that it will add up the mileage for each route in a split-second. You can do that with a convenientional road map, too, but it's a very time-consuming and error-prone process.
As Humpty Dumpty says, it's all a question of which is to be the master. If you take the easy way, following the computer's advice blindly, then you will never have any idea how origin and destination are connected, where you are at any moment along the trip, and what to do if anything unexpected happens. But if you use the computer as an aid rather than a crutch, then it becomes life-enhancing rather than crippling.
This has obvious application to astronomical observing strategies in the age of modern electronics. But I'll come to that in another blog.
Posted by Tony Flanders, October 18, 2010
STARGAZING by Tony Flanders
The North America Nebula
Stargazers in California wouldn't understand.
Three good nights back to back, coinciding with a 3-day weekend, at new Moon. It's almost beyond belief!
Columbus Day is pretty much of a non-event in most of the U.S., but most school districts in the Northeast have the day off, making it a 3-day weekend. With weather that's crisp but not cold and the leaves at their most colorful, Columbus Day Weekend is often considered the very best time of all year in this part of the world.
How about getting three deep-sky viewing nights in a row? I estimate that on average, one night in five in New England has suitable weather, with mostly cloudless skies and good transparency. If they happened at random, you'd expect about three 3-night good-weather spells per year. But in fact, weather tends to stay the same for a few days at a time, so the actual number of 3-day good spells per year is probably more. On the other hand, everybody knows that new-Moon periods and weekends are cursed. It's rare enough to get two good weekend nights in a row, much less three!
The downside of last weekend was that I was afflicted by a mysterious illness, whose main symptom were intermittent high fever, headache, and fatigue — so no all-night sessions for me. But that's the beauty of having three nights to play with — I could observe for just a few hours per night and still not feel cheated, as I would if I had only one good-weather night. What a strange experience! I suppose that must be the norm for people who live in dark locations in the semi-arid West — they just take good weather for granted. Not here!
The highlight of my 3-night observing session was repeating the Deep-Sky Wonders column for October, 2004. (Click on the link in the previous sentence to download the article as a 550-Kb PDF.) The entire article is about a single object — the North America Nebula. This huge nebula is visible only under fairly dark skies, and it looks most impressive through a nebula filter. Many people take an occasional quick look at it, but few take the time to explore it in detail. That's not surprising, because it's easy to get lost in such a huge, complex object.
What you need is a road map — and that's exactly what this article gives you. I had "done" the whole thing before using my 4-inch refractor, but I wanted to repeat the experience with the vastly greater light grasp (though much smaller field of view) of my 12.5-inch Dob.
What a treat! The key to the article is the complementary presentation in four different forms. There are Sue French's descriptions, a superb pencil sketch also by her, Rob Gendler's photograph, and a detailed star chart.
Sue's sketch is the most accurate depiction of what you see through an eyepiece looking through a nebula filter, but it misses many of the subtle shadings visible in the photo. The photo, on the other hand, has such bright nebulosity that many of the stars are completely obscured — which is where the star chart proves to be handy. And Sue's descriptions tell you what to look for and how to interpret it. Taking it all together, I got many hours of pleasure from the North America Nebula with the aid of this article.
This weekend is forecast to be cloudy, but that's OK. The Moon would make deep-sky observing impossible before midnight anyway, and I already got a good month-long fix last weekend.
The author's 12.5-inch Dob warms up in the Sun on Monday morning so the mirror won't fog up when it's brought indoors.
Tony Flanders
Columbus Day is pretty much of a non-event in most of the U.S., but most school districts in the Northeast have the day off, making it a 3-day weekend. With weather that's crisp but not cold and the leaves at their most colorful, Columbus Day Weekend is often considered the very best time of all year in this part of the world.
How about getting three deep-sky viewing nights in a row? I estimate that on average, one night in five in New England has suitable weather, with mostly cloudless skies and good transparency. If they happened at random, you'd expect about three 3-night good-weather spells per year. But in fact, weather tends to stay the same for a few days at a time, so the actual number of 3-day good spells per year is probably more. On the other hand, everybody knows that new-Moon periods and weekends are cursed. It's rare enough to get two good weekend nights in a row, much less three!
The downside of last weekend was that I was afflicted by a mysterious illness, whose main symptom were intermittent high fever, headache, and fatigue — so no all-night sessions for me. But that's the beauty of having three nights to play with — I could observe for just a few hours per night and still not feel cheated, as I would if I had only one good-weather night. What a strange experience! I suppose that must be the norm for people who live in dark locations in the semi-arid West — they just take good weather for granted. Not here!
Photo: Robert Gendler; Sketch: Sue French
What you need is a road map — and that's exactly what this article gives you. I had "done" the whole thing before using my 4-inch refractor, but I wanted to repeat the experience with the vastly greater light grasp (though much smaller field of view) of my 12.5-inch Dob.
S&T diagram
Sue's sketch is the most accurate depiction of what you see through an eyepiece looking through a nebula filter, but it misses many of the subtle shadings visible in the photo. The photo, on the other hand, has such bright nebulosity that many of the stars are completely obscured — which is where the star chart proves to be handy. And Sue's descriptions tell you what to look for and how to interpret it. Taking it all together, I got many hours of pleasure from the North America Nebula with the aid of this article.
This weekend is forecast to be cloudy, but that's OK. The Moon would make deep-sky observing impossible before midnight anyway, and I already got a good month-long fix last weekend.
Posted by Tony Flanders, October 13, 2010
STARGAZING by Tony Flanders
Deep-Sky Wonders Again
Last week I promised to write about the flashlight at night as a metaphor for stargazing techniques — and I'll get to that in due time. But first I want to write about my observing session last weekend.
The forecast for Saturday night was good, so I made the long drive to my country home just to get in five or six hours of stargazing between the end of dusk and moonrise. I obviously wanted to look for Comet Hartley 2, which I did. (See my brief observing report.) But I also wanted to get to my deep-sky bread and butter; Sue French's Deep-Sky Wonders columns. Due to vagaries of weather and schedule, I hadn't done either the October or November 2010 column yet, and I also had an old one (September 2006) to catch up on.
Can a little 3-page column really keep a deep-sky observer busy for hours with a pretty big telescope at a fairly dark site? You bet it can — and then some!
First of all, Sue has a gift for finding fascinating, oddball objects that don't make most people's regular observing lists. I'd never seen either NGC 7281 or 7261 before, and as Sue says, they turn out to be connected by a charming (though totally accidental) chain of stars, which she calls the Dit-Dit-Dit asterism. And I'd never even contemplated observing the interesting planetary nebula Minkowski 2-51. That one took me a bit of work.
But the real payoff came when I hit IC 1396, the huge star cluster and nebula in Cepheus. I'd made several forays into this object before, but Sue's guidance gave me that critical little nudge to get to the next deeper layer of understanding of this vast, difficult, enigmatic object.
This was the first time I'd tracked down the dark Elephant Trunk Nebula, IC 1396A, which is a favorite subject for astrophotographers but challenging to pick out through the eyepiece of a telescope. And it was certainly the first time I'd though to look for Struve double stars or dark Barnard nebulae inside IC 1396.
And then, to cap it all, what Sue describes as "the little-known planetary nebula Preite-Martinez 1-333." Little-known indeed! Where does Sue find stuff like this? How many people besides her have ever viewed it through a telescope? Not many, I bet.
It was also a vindication of the hard work I'd put into labeling the photo shown above. It took some serious effort to pinpoint the location of PM 1-333, but sure enough, there it was. "Faintly visible with averted vision, but a narrowband filter makes it fairly easy," just as Sue said.
I'm not done with IC 1396, mind you — not by a long shot. Like the Great Orion Nebula, this is an object to last a lifetime. Next time, I think, I'll revisit it with a smaller telescope, something that can fit the whole nebula in one field of view, like my 4-inch refractor or the 4.5-inch StarBlast.
The huge cluster and emission nebula IC 1396 is the centerpiece of Sue French's Deep-Sky Wonders column for November 2010. Click above for a larger image.
Photo: Richard Crisp; Labels: S&T
Can a little 3-page column really keep a deep-sky observer busy for hours with a pretty big telescope at a fairly dark site? You bet it can — and then some!
First of all, Sue has a gift for finding fascinating, oddball objects that don't make most people's regular observing lists. I'd never seen either NGC 7281 or 7261 before, and as Sue says, they turn out to be connected by a charming (though totally accidental) chain of stars, which she calls the Dit-Dit-Dit asterism. And I'd never even contemplated observing the interesting planetary nebula Minkowski 2-51. That one took me a bit of work.
Photo: Richard Crisp; Labels: S&T
This was the first time I'd tracked down the dark Elephant Trunk Nebula, IC 1396A, which is a favorite subject for astrophotographers but challenging to pick out through the eyepiece of a telescope. And it was certainly the first time I'd though to look for Struve double stars or dark Barnard nebulae inside IC 1396.
Photo: Richard Crisp; Labels: S&T
It was also a vindication of the hard work I'd put into labeling the photo shown above. It took some serious effort to pinpoint the location of PM 1-333, but sure enough, there it was. "Faintly visible with averted vision, but a narrowband filter makes it fairly easy," just as Sue said.
I'm not done with IC 1396, mind you — not by a long shot. Like the Great Orion Nebula, this is an object to last a lifetime. Next time, I think, I'll revisit it with a smaller telescope, something that can fit the whole nebula in one field of view, like my 4-inch refractor or the 4.5-inch StarBlast.
Posted by Tony Flanders, October 4, 2010
STARGAZING by Tony Flanders
Blinded by the Light
When I was hiking a week ago, I had a couple of interesting revelations about using flashlights at night.
Both happened in the pre-dawn hours. The first revelation came second chronologically, on Sunday morning. It was mostly overcast, so I wasn't motivated to spend lots of time looking at the sky. So I went down to the stream early to fetch water to boil for my morning coffee. The path is quite steep and fairly long, so I was using my headlamp. And I mused — not for the first time — how a flashlight cuts you off from the world around you. When you're in the woods on a moonless night, you can't see much without a flashlight, but you can see equally well (or poorly) in every direction. The flashlight creates a bubble of light around you. Inside that bubble, everything is clear. Outside, it's totally black.
Many sites on the web review flashlights, and it's a little startling how much they assume that brighter flashlights are always better. In the backcountry that's simply not true. The last thing you want to do is to blow your dark adaptation completely.
So is the faintest possible flashlight best, then? No, that's not true either — as my experience the previous morning had shown. On Saturday morning, when it was clear, I did want to see the sky as much as possible, and didn't want to destroy my dark adaptation. So I climbed down from the boulder where I was perched using just my red flashlight.
Frankly, it was pretty scary. The highest point of the boulder is perhaps 10 feet off the ground — not a long enough drop to kill, but enough to be quite unpleasant. On the side I climbed up, there was a rock pile reaching almost to the top — but not quite within reach of my foot as I lowered myself off the boulder. I knew quite well that there was solid ground just inches below my foot, but the red flashlight wasn't bright enough to illuminate it. So I had to trust my memory, and jump blind. Needless to say, it worked. But I'm not sure that preserving my dark adaptation was worth the brief moment of terror.
What does this have to do with astronomy? I'll get to that in my next blog.
A flashlight creates a capsule of light around you — at the cost of hiding the wider world.
Tony Flanders
Many sites on the web review flashlights, and it's a little startling how much they assume that brighter flashlights are always better. In the backcountry that's simply not true. The last thing you want to do is to blow your dark adaptation completely.
Without a flashlight, you see equally well — or poorly — in all directions. This photograph and the one above were taken in a city park, lit by skyglow and the nearly full Moon filtering through a moderate overcast.
Tony Flanders
Frankly, it was pretty scary. The highest point of the boulder is perhaps 10 feet off the ground — not a long enough drop to kill, but enough to be quite unpleasant. On the side I climbed up, there was a rock pile reaching almost to the top — but not quite within reach of my foot as I lowered myself off the boulder. I knew quite well that there was solid ground just inches below my foot, but the red flashlight wasn't bright enough to illuminate it. So I had to trust my memory, and jump blind. Needless to say, it worked. But I'm not sure that preserving my dark adaptation was worth the brief moment of terror.
What does this have to do with astronomy? I'll get to that in my next blog.
Posted by Tony Flanders, September 27, 2010
STARGAZING by Tony Flanders
Backcountry Stargazing Again
I hate to keep harping on the same theme, but I had another lovely backcountry stargazing session last weekend.
The basic problem with backcountry stargazing in the U.S. Northeast — by which I mean stargazing from spots more than a short walk from a road — is trees. As I've written in another blog, trees are the single biggest obstacle to stargazing in my part of the world. In the western U.S., it's easy to find deserts, prairies, or mountain meadows. In the Northeast, by contrast, there's just a few square miles of mountaintop above treeline, and it's illegal to camp there, to prevent it from being loved to death.
At lower elevations, it's just endless trees. So it's very hard to find a legal wilderness campsite with a decent view of the sky. One of my favorites is a spot called The Bluff a few miles north of Mt. Washington, the highest mountain in the Northeast. It's on the edge of a gorge, steep enough so that you can actually see a little through the tops of the trees. And there's a lovely boulder there from whose top you have quite a decent view. The only downside is that Mount Washington blocks much of the southern sky.
I ended up camping there last weekend. I had intended to walk farther and camp in the woods, so I didn't bother to bring any astronomy equipment. But when I got there and remembered just what a charmed spot it is, I couldn't resist staying. Saturday morning, I woke up at 4 a.m. to watch the zodiacal light from the top of the boulder. It was a very memorable view, with the tall, rightward slanting pyramid of zodiacal light reaching up to cross the left-slanting Milky Way in the foot of Gemini, right about M35. But without my DSLR, I couldn't capture that, so you'll have to settle for the view of Jupiter setting over Sphinx Col that's shown at upper right.
Saturday evening, like the dutiful astronomer that I am, I went back up on the boulder to celebrate International Observe the Moon Night. True, I'd brought no real astronomical instruments, but I never go anywhere without my 6×15 monocular. And you know what? It's amazing how much you can see on the Moon at 6×. The wall of Sinus Iridum jutting out from the terminator was particularly lovely.
The basic problem with backcountry stargazing in the U.S. Northeast — by which I mean stargazing from spots more than a short walk from a road — is trees. As I've written in another blog, trees are the single biggest obstacle to stargazing in my part of the world. In the western U.S., it's easy to find deserts, prairies, or mountain meadows. In the Northeast, by contrast, there's just a few square miles of mountaintop above treeline, and it's illegal to camp there, to prevent it from being loved to death.
At lower elevations, it's just endless trees. So it's very hard to find a legal wilderness campsite with a decent view of the sky. One of my favorites is a spot called The Bluff a few miles north of Mt. Washington, the highest mountain in the Northeast. It's on the edge of a gorge, steep enough so that you can actually see a little through the tops of the trees. And there's a lovely boulder there from whose top you have quite a decent view. The only downside is that Mount Washington blocks much of the southern sky.
Jupiter sets over Sphinx Col in New Hampshire's White Mountains.
Tony Flanders
Saturday evening, like the dutiful astronomer that I am, I went back up on the boulder to celebrate International Observe the Moon Night. True, I'd brought no real astronomical instruments, but I never go anywhere without my 6×15 monocular. And you know what? It's amazing how much you can see on the Moon at 6×. The wall of Sinus Iridum jutting out from the terminator was particularly lovely.
Posted by Tony Flanders, September 20, 2010
STARGAZING by Tony Flanders
S&T's New Single-Issue Magazine
The very favorite job I've ever had at Sky Publishing was writing the Constellation Close-Up column for Night Sky magazine. Each one described a constellation, its associated star lore, and anything else that took my fancy. For the first and probably last time in my life, I got to combine the three disciplines I majored in at college: folklore and mythology, mathematics, and English.
Much to my (and many other peoples') sorrow, Night Sky ceased publication 3 years ago. But although the magazine was never a commercial success, the articles in its 18 slender issues have proved to be immortal. In them, we explained all the essentials of astronomy in terms that any beginner can understand. Having written it once to our perfect satisfaction, why write it again in different words? Many of the articles on this website were adapted from Night Sky. We've often re-run them in SkyWatch, our annual publication. And now all the Constellation Close-Up articles have been gathered into a magazine called Popular Astronomy, which may be selling right now at your local newsstand. If not, you can purchase copies from our online store.
Why would you want to read it? Much as I love those Constellation Close-Up articles, they're not the main attraction. To my mind, by far the most useful thing about this magazine is its pairs of matching sky maps — two per month for each of the 12 months. The right-hand page shows the sky with bright stars against a dark background, just as you see it in real life. And the facing page has a labeled version of the same map printed in black on white for clarity. Click here to see what they look like at a reasonably large scale. This idea was pioneered, or at least popularized, by the superb book NightWatch, but NightWatch only has one map pair per season, not one per month, like Popular Astronomy.
We used these same map pairs in SkyWatch in 2008 and 2009, and they proved to be immensely popular. But SkyWatch has always been an ambitious magazine, packed full of information, and devoting two pages of maps to each month simply crowded out too much other information. So if you want this format now, Popular Astronomy is your only option. The only downside is that the ones in Popular Astronomy don't show the planets. The planets change from year to year, and we want this publication to be timeless.
Thanks to S&T contributing editor Gary Seronik and ex-S&T artist Ellen Rooney for their mighty labors in assembling and laying out this magazine in record time.
Tony Flanders
The most useful feature of Popular Astronomy is the pairs of matching sky maps. Click above for a larger image.
Tony Flanders
We used these same map pairs in SkyWatch in 2008 and 2009, and they proved to be immensely popular. But SkyWatch has always been an ambitious magazine, packed full of information, and devoting two pages of maps to each month simply crowded out too much other information. So if you want this format now, Popular Astronomy is your only option. The only downside is that the ones in Popular Astronomy don't show the planets. The planets change from year to year, and we want this publication to be timeless.
Thanks to S&T contributing editor Gary Seronik and ex-S&T artist Ellen Rooney for their mighty labors in assembling and laying out this magazine in record time.
Posted by Tony Flanders, September 1, 2010
STARGAZING by Tony Flanders
Stargazing versus Hiking
As I've written before, I love to combine hiking and astronomy. Unfortunately, there are several practical obstacles to doing this.
A few weeks ago, my wife and I took a 5-day backpacking trip in California's Sierra Nevada mountains — our first long hike since adopting our daughter. (This doesn't count a modest trek in the Himalaya which was thoroughly enjoyable, but in many ways more of a circus than a serious hike.) Odd to think of 5 days as long; I can remember when a 2-week hike seemed short!
On this recent trip, I certainly wanted to take advantage of the Sierra's famously dark skies and excellent transparency to do some stargazing, but my primary goal was to make the most of the mountains — to see as much as possible and climb as high and steep as possible.
Sadly, at age 56, after leading a primarily sedentary lifestyle, there's a limit to my ability to exercise hard all day and then stay up all night. Moreover, there's a limit to how much astronomy equipment I want to carry in addition to tent, sleeping bags, cooking gear, food (in bulky bear canisters), and warm clothing. In retrospect, I wish I had brought my image-stabilized 10×30 binoculars, but in fact I saved a pound (and considerable bulk) by taking my 8×32 monocular instead. The monocular worked OK for picking out climbing routes on the crags, but binoculars would have been much better for astronomy.
Another thing that people unfamiliar with mountains tend not to realize is that it's often hard to find a spot with a good view of the sky. In the Sierra Nevada, trees grow well above 10,000 feet, and trees are the worst enemy of astronomy. The second worst enemy are the mountains themselves — the more rugged the terrain, the more of the sky is blocked by nearby mountains. Bare mountaintops have unobstructed views but are extremely inhospitable places to spend the night.
So for our last two nights in the Sierras, I picked out a campsite specifically for its astronomy potential. A high meadow at around 11,000 feet, it had enough trees to provide shelter without blocking too much sky. And it faced south to a notch on the opposing ridge, allowing a nearly unobstructed view of the southern sky — the part that matters most for astronomy.
What stargazing could I do despite my limited equipment and even more limited energy? Quite a lot, it turns out. On the first night, I solved the time problem by taking a nap after supper, then rising toward the end of twilight, cooking cups of cocoa for me and my wife, and then pointing out the sky's highlights to her. After she returned to her sleeping bad, I stayed up for an hour or two observing dark lanes in the Milky Way — a job that requires very dark skies but very little optical aid.
The last night we were camping I woke up at 3 a.m. to watch for early Perseids. There weren't many (this was the morning of August 7th, 5½ days before the peak), but the ones I saw were mostly quite bright. Between meteors, I puzzled out the constellations around Sculptor and Fornax, a part of the sky that's hard to see from my home in Massachusetts, and also one that resists easy memorization.
I could not, alas, explore the splendid galaxy fields of these two constellations, due to the limitations of my equipment. But my 8×32 monocular did provide a reassuring view of the big, bright galaxy NGC 253. When all is said and done, it doesn't take a big telescope and lots of time to enjoy the night sky. Even a half hour of naked-eye stargazing is enough to slake my craving for astronomy — for a while.
Morning alpenglow shines on the Palisades, California's most rugged high mountain group.
Tony Flanders
On this recent trip, I certainly wanted to take advantage of the Sierra's famously dark skies and excellent transparency to do some stargazing, but my primary goal was to make the most of the mountains — to see as much as possible and climb as high and steep as possible.
Of the author's three smallest optical instruments, the 8×32 monocular (center) works best for astronomy.
Tony Flanders
Tony Flanders
So for our last two nights in the Sierras, I picked out a campsite specifically for its astronomy potential. A high meadow at around 11,000 feet, it had enough trees to provide shelter without blocking too much sky. And it faced south to a notch on the opposing ridge, allowing a nearly unobstructed view of the southern sky — the part that matters most for astronomy.
What stargazing could I do despite my limited equipment and even more limited energy? Quite a lot, it turns out. On the first night, I solved the time problem by taking a nap after supper, then rising toward the end of twilight, cooking cups of cocoa for me and my wife, and then pointing out the sky's highlights to her. After she returned to her sleeping bad, I stayed up for an hour or two observing dark lanes in the Milky Way — a job that requires very dark skies but very little optical aid.
The last night we were camping I woke up at 3 a.m. to watch for early Perseids. There weren't many (this was the morning of August 7th, 5½ days before the peak), but the ones I saw were mostly quite bright. Between meteors, I puzzled out the constellations around Sculptor and Fornax, a part of the sky that's hard to see from my home in Massachusetts, and also one that resists easy memorization.
I could not, alas, explore the splendid galaxy fields of these two constellations, due to the limitations of my equipment. But my 8×32 monocular did provide a reassuring view of the big, bright galaxy NGC 253. When all is said and done, it doesn't take a big telescope and lots of time to enjoy the night sky. Even a half hour of naked-eye stargazing is enough to slake my craving for astronomy — for a while.
Posted by Tony Flanders, August 22, 2010
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