Spot Titan’s Shadow on Saturn!

If you've looked at Saturn through a telescope recently, clearly the planet is not its usual gorgeous self. Those famous rings are angled nearly edge-on to our line of sight, appearing like a spear through Saturn's midsection.

Titan’s shadow was an obvious black dot on the planet when Christopher Go of Cebu, Philippines, caught it at 12:22 UT on March 12th. The rings at the time were tilted just 2.7° from our line of sight.
Sean Walker
Like the rings, the orbits of Saturn's major satellites are also seen nearly edge-on this year. As a result, the satellites now pass in front of and behind Saturn, casting their tiny shadows onto the planet's face and ducking in and out of its shadow, just like the moons of Jupiter do.

Saturn is about twice Jupiter's distance from us, however, and only Titan is a match for Jupiter's Galilean moons in terms of size. Nevertheless, notes Belgian astronomer Jean Meeus, the classic guidebook Saturn by A. F. O. Alexander describes Titan's shadow on Saturn being seen "quite easily" in a small refractor as early as 1862.

Meeus calculated the Titan timetable below so that you can try for yourself. The dates and times are in Universal Time. Oc refers to an occultation of Titan behind Saturn's limb. Ec means eclipse in Saturn's shadow. Tr is a transit of Titan across Saturn's face. Sh refers to Titan casting its shadow onto the planet.

An occultation or eclipse begins when Titan disappears (D) or reappears (R). A transit or shadow passage begins at ingress (I) and ends at egress (E). Each event is gradual, taking several minutes.

Titan and Its Shadow on Saturn
Date UT Event Date UT Event
Apr. 5 9:21 Ec. D. May 23 6:30 Ec. D.
Apr. 5 13:37 Ec. R. May 23 12:06 Ec. R.
Apr. 13 7:22 Sh. I. May 31 4:32 Sh. I.
Apr. 13 11:51 Sh. E. May 31 10:00 Sh. E.
Apr. 21 8:20 Ec. D. June 8 5:39 Ec. D.
Apr. 21 13:10 Ec. R. June 8 11:31 Ec. R.
Apr. 29 6:22 Sh. I. June 16 3:40 Sh. I.
Apr. 29 11:16 Sh. E. June 16 9:18 Sh. E.
May 7 7:23 Ec. D. June 24 4:50 Ec. D.
May 7 12:40 Ec. R. June 24 10:53 Ec. R.
May 15 5:26 Sh. I.
May 15 10:39 Sh. E.

If you manage to snap a shot of Titan crossing Saturn's disk, please share it with other visitors by posting it to our online photo gallery.

17 thoughts on “Spot Titan’s Shadow on Saturn!

  1. Nathaniel Sailor

    Ok Titan shadow will be cast on Saturn because its rings are on edge. But for me, I don’t really care. I want to see the individual rings. I got a 6 in. reflector in December and I want to see all the rings but I got to wait now. Great! I had some friends come over and that is what they saw. It kinda stinks not being able to see the rings.
    P.S. Question for all with a 6 in. Newtonian. When I put scope magnifying power to 240x, it seem like it was no bigger than what it looked like in my 60mm refractor at 70x. Is because I was rushing when my friends were around or is that what it really looks like? E-mail is adm.x421@yahoo.com.

  2. W

    Well the zoom lens makes it larger because you’re getting closer to it, but the detail may lack depending on the focal length. is it 1000mm? more? Try using the calculator provided on the website, and it may tell you how far you can see with lens sizes.

  3. snowstargazer

    This is a response to Nathaniel Sailor.

    Nathaniel, the rings are less edgewise than they were awhile back. I guess they will become more so again. But I had no trouble seeing the rings at any time, with my 6 inch reflector.

    I wonder if you are allowing your mirror to cool properly? You can’t rush viewing nature, it’s not television. Try setting up your scope at least an hour early, don’t let the sun shine on the mirror. A fan blowing on the mirror’s back will help it cool faster, just make sure you are not blowing dust into the scope.

    You also must make sure your optical train is collimated, that is aligned. Look it up. Even a pill bottle with a hole in the lid and the bottom cut off will help. Insert in the eyepiece holder and check for everything being centered. There are many ways, and it can be confusing, but even a rough job is better than none.

    You can definitely get better images from a decent reflector if the aperture is bigger than your refractor. But it takes a bit of effort and time to get it set up properly.

    Remember that it may be very clear but still can be poor “seeing”, with turbulence making images terrible. You can’t compare different nights with different instruments. Google Clear Sky Charts for seeing conditions.

    I know how difficult it can be trying to show impatient people the pleasures of viewing the heavens. You need to use your new telescope by yourself or with other experienced people until you get used to it. It will work, and work fine. And you have to look at what is there, it’s not like a photo album. It’s ever changing.

    Best wishes.

  4. Nathaniel Sailor

    I’m not trying to be mean but I’ll say this. A. I’m in high school, I don’t have the time to let the telescope cool. Plus I don’t have cash for a fan. Nor can I make one right now. But also I was showing two of my friends so right there that’s a problem B. I know the rings were on edge. I read my E-mail once a week. At least. C. I have collimater. I worked on my mirror heavy before I took my friends out to give them the best view I can give. D. I got it for my birthday in December. It was like early March when I showed my friends. So I have little to no time learning how to work my scope. As I said, I’m not trying to be mean but I want ya to understand that I don’t have a lot of what ya’ll have. Right now I’m my best to deal with. Want to talk to me, E-maill address is in the First response.

  5. Pete

    That reflector ought to swamp the refractor on every front. Send the friends home and give yourself some quiet focused time with this instrument.

    Pete

  6. Pete

    That reflector ought to swamp the refractor on every front. Send the friends home and give yourself some quiet focused time with this instrument.

    Pete

  7. Nathaniel Sailor

    Well Pete I wanted to show my friends some objects in the sky. Telling me to send my friends home I see as vary rude. Should spend some time looking at Saturn before they came? Won’t hurt. But I find your comment rude. Also to add, they weren’t noisy. They behaved themselves. And the observing part was my dealing with my state of mind, I wasn’t paying attention.

  8. astronig

    The wonderful hobby of astronomy is one that takes patience . Time , money , travel to dark sky sites (unless you’re lucky enough to live in one) & a little research doesn’t hurt either .
    Most of all patience & relaxation is what is needed & is the virtue of this hobby . If one cannot bring himself to appreciate these values , then it quite very well be time to find another hobby .

  9. Nathaniel Sailor

    Astroning, you just cross the line with the find another hobby part. A. I am patiance, but when ya get to go tho bed at 10:00 it’s a little hard not to rush. B. I watching auto racing. There is like no patiance in racing because when you slack off on the track and not fight to one -thousanth of a second, you lose.

  10. Zoomit

    Here’s a topical question. Where can I find more Titan shadow dates after the ones in this article?

  11. Elias

    Nathaniel, I understand that you don’t have much time to do your observing especially since the sun sets around 9 o’clock in summer months. But you really don’t want to rush astronomy. I can see that you want to set-up your scope and see something quick but thats not really as fun as taking the time to really “Observe” and recognize detail in the object, which in this case is saturn a planet that has a lot of amazing features. I can understand many off the problems you have by taking a “quick look” and showing your friends before you go to bed or watch a race, but try setting up half an hour or so before darkness, let your scope reach thermal equilibrium, and maybe even prepare for some outreach (i.e. showing your friends) As to your scope problem, depending on your scopes optics the reflector should beat the refractor in all ways. You might want to try out a comparison one night, set-up both scopes and use the same eyepiece and compare. Lastly, Wait another 7 years and the rings will be back with all there glory. (But then you might say, dang I wish the rings were edge on)
    All the Best,
    Elias Jordan

  12. Nathaniel Sailor

    Elias, thanks for giving some hints. It’s is a good idea to put the big 6in. outside to cool but than theft becomes an issue( trust me, a lot people really don’t like me!) But since Orion Telescopes and Binoculars have a lay away program, I could be a cooling fan or heating unit. But right now I’m looking for a job. But thanks for the help.

  13. Nathaniel Sailor

    Elias, thanks for giving some hints. It’s is a good idea to put the big 6in. outside to cool but than theft becomes an issue( trust me, a lot people really don’t like me!) But since Orion Telescopes and Binoculars have a lay away program, I could be a cooling fan or heating unit. But right now I’m looking for a job. But thanks for the help.

  14. Dale

    I tried to observe Titan’s shadow on Saturn Monday night, per the above schedule. By the time the event was supposed to start (11:40 pm Eastern Daylight Time on June 15), Saturn was low in the sky from my vantage point in Michigan, USA. I wish I had been in the western U.S. so that it would have been higher in the sky. The image was blurry and “colorful”, indicating differential refraction of different wavelengths of light. After watching for an hour, I gave up seeing the shadow. In retrospect, I wish that I had tried using a filter to reduce chromatic blurring of the image. In fact, I wish that I had tried an oxygen III filter. There might be enough light in this wavelength range (reflecting black body radiation from the Sun) to be visible. So, I’d like to give this another try. Please extend the above chart so that I can plan for the next “shadow” event. Thanks!

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