M51 Supernova brightening. Supernova 2011dh, which was discovered in the Whirlpool Galaxy, M51, on May 31st, has been brightening ever since — though the brightening is now leveling off. As of June 16th the supernova was about V magnitude 12.6 and visible in a lot more amateur telescopes.On the evening of the 16th S&T's Dennis di Cicco imaged the galaxy and supernova again with his 16-inch scope and was able to glimpse it visually with a 6-inch despite the moonlight. He writes, "With the Moon leaving the early-evening sky [as of about June 19th] and M51 seen best as soon as it gets dark, now is the time for people to have a look. With higher magnification and a moderately good sky, anyone with an 8-inch or larger scope should be able to spot the supernova. I can’t remember the last time we had one that was this easily visible."
Friday, June 17
Saturday, June 18
Sunday, June 19
Monday, June 20
Tuesday, June 21
If you have a good view of the west-northwest horizon (from mid-northern latitudes), mark precisely where the Sun sets. In a few days you should be able to detect that it's again starting to set a little south of this point. Build your own Stonehenge?
Wednesday, June 22
Thursday, June 23
Friday, June 24
Saturday, June 25
Want to become a better amateur astronomer? Learn your way around the constellations. They're the key to locating everything fainter and deeper to hunt with binoculars or a telescope.
For an easy-to-use constellation guide covering the whole evening sky, use the big monthly map in the center of each issue of Sky & Telescope, the essential magazine of astronomy. Or download our free Getting Started in Astronomy booklet (which only has bimonthly maps).
Once you get a telescope, to put it to good use you must have a detailed, large-scale sky atlas (set of charts). The standards are the Pocket Sky Atlas, which shows stars to magnitude 7.6; the larger Sky Atlas 2000.0 (stars to magnitude 8.5); and the even larger and deeper Uranometria 2000.0 (stars to magnitude 9.75). And read how to use sky charts effectively.
You'll also want a good deep-sky guidebook, such as Sky Atlas 2000.0 Companion by Strong and Sinnott, or the more detailed and descriptive Night Sky Observer's Guide by Kepple and Sanner, or the classic if dated Burnham's Celestial Handbook.
Can a computerized telescope take their place? I don't think so — not for beginners, anyway, and especially not on mounts that are less than top-quality mechanically. As Terence Dickinson and Alan Dyer say in their Backyard Astronomer's Guide, "A full appreciation of the universe cannot come without developing the skills to find things in the sky and understanding how the sky works. This knowledge comes only by spending time under the stars with star maps in hand."
This Week's Planet Roundup
Mercury is buried deep in the glow of sunset.
Venus (magnitude –3.8) shines barely above the east-northeast horizon as dawn grows bright. Look for it 20 minutes before sunrise.
Mars (dim at magnitude +1.4) is low in the dawn very far to the lower left of Jupiter, though not as far as Venus. Try with binoculars.
Jupiter (magnitude –2.2, in southern Aries) shines in the east before and during dawn.
Saturn (magnitude +0.8, in Virgo) is in good view in the southwest after dusk. Shining 15° left of it is Spica. And just 0.3° to Saturn's upper right is fainter Porrima (Gamma Virginis), turning Saturn into a naked-eye "double star."
In a telescope Saturn's rings are 7.4° from edge on. The rings are casting a relatively wide, prominent black shadow southward onto the globe, and the globe's shadow on the rings is visible just off the globe's celestial east (following) side. The North Equatorial Belt is a dusky band. North of it, Saturn's seven-months-old white outbreak is still apparent in good images, as shown here; read more about this huge storm as studied from the Cassini Saturn orbiter and the Very Large Telescope in Chile.
See how many of Saturn's satellites you can identify in your scope using our Saturn's Moons tracker.
And don't skip over Porrima — it's a fine, close telescopic binary with equal components and a current separation of 1.7 arcseconds. Use high power and hope for good seeing. See the article in the April Sky & Telescope, page 56.
Uranus (magnitude 5.9, in western Pisces) is low in the east-southeast before the first light of dawn.
Neptune (magnitude 7.9, in Aquarius) is in the southeast before dawn.
Pluto (magnitude 14.0, in Sagittarius) is highest in the south around 1 or 2 a.m. A big finder chart for it is in the July Sky & Telescope, page 64.
All descriptions that relate to your horizon — including the words up, down, right, and left — are written for the world's mid-northern latitudes. Descriptions that also depend on longitude (mainly Moon positions) are for North America. Eastern Daylight Time (EDT) equals Universal Time (also known as UT, UTC, or GMT) minus 4 hours.
To be sure to get the current Sky at a Glance, bookmark this URL:
If pictures fail to load, refresh the page. If they still fail to load, change the 1 at the end of the URL to any other character and try again.