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How come I never hear about Saturn's moons?

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#1 Lee Jay

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Posted 03 May 2013 - 03:07 PM

I mean, you always hear about what it takes (not much) to observe the Jovian moons, but rarely, if ever hear about the same with Saturn. Heck, I wasn't even aware before a few weeks ago that they (aside from Titan, obviously) are visible with modest scopes.

Finally had a clear night last night after 4 weeks of non-stop snow, wind and clouds, so I went out and saw FIVE (!) of Saturn's moons in my EdgeHD 11. That's one more than I've seen in my eyepiece before!

#2 leviathan

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Posted 03 May 2013 - 05:22 PM

Of course Jovian moons are much brighter and "popular", but you can see up to 6-7 Saturn moons in rather small telescope.

#3 MikeBOKC

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Posted 03 May 2013 - 05:25 PM

Well I suspect the disparity is due to the fact that Saturn is a lot further out, making all but Titan a bit of a challenge in average sized and smaller scopes. Plus the four Galilean satellites are all of similar size and present themselves in an array most nights that can easily be seen even in a finderscope. Finally I suspect a factor is that we know so much more about Io (volcanoes!), Europa (ice! oceans!) Gannymede and Callisto, whereas all but Titan of the major moons of Saturn are less extensively explored so far. Most people with typical scopes can see five Saturn moons most nights, and some can spot seven, but only Titan really jumps out at you like the four Jovian favorites. Saturn's satellites are just not as spectacular in the eyepiece.

#4 Rick Woods

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Posted 03 May 2013 - 08:07 PM

The Saturnian moons (particularly Titan and Enceladus) are more suited to book study than direct study; I don't think there are any reports of any features being visible (other than Coma Solas' Titan report in the early 20th century). Features on the Galilean moons can actually be resolved by amateur telescopes, occasionally.
I have a now-moribund thread going on Titan references in the Stellar Media forum, if you want more information about this most interesting of moons.

#5 David Knisely

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Posted 04 May 2013 - 12:54 AM

OK, we can definitely supply some talk on that subject :). I can often see Titan in my 9x50 finderscope when it is nearing maximum elongation from the planet. In my 100mm f/6, I can catch it easily along with Rhea, Dione, and Tethys. Iapetus was also occasionally visible, although it sometimes took some reference to data sources describing exactly where it would be found. It is often quite a distance from the planet (often confused with background stars) and varies in brightness, so sometimes is would be visible in the 100mm f/6 and sometimes I would miss it. In my 9.25 inch SCT, Titan shows its dim orangish disk fairly easily at high power. I have also caught Enceladus in that scope from time to time, although it was a lot easier to see it when the ring tilt was much closer to edge-on than it is now. Mimas was only readily visible in my 10 inch when the rings were very nearly nearly edge-on, as now, it is compromised by the glare of the more open rings. I haven't seen Mimas recently, but then again, this year's weather hasn't given me much of a chance to observe much. I could also catch distant Hyperion (mag. 14.2) in the 10 inch, but again, due to its faintness, I needed charting software to identify it from the background stars in the area. Now that I have the 14 inch, I may have to try for Phoebe, but its magnitude 16.5 may prove a little too much of a challenge for that aperture. I guess eight moons in a 10 inch isn't too bad (and maybe nine in the 14 inch if luck and transparency are in my favor). Gee, when I started my amateur astronomy hobby back in the mid 1960's, most books I had said Saturn only *had* nine moons! I even remember the announcement of the "10th Moon of Saturn" (Janus) and at the time, that was considered an exciting discovery. Now, it is "Eh, so, somebody found yet another moon around Jupiter, Saturn, Pluto, etc...". The "excitement" has faded a little since then. I guess I will just have to be satisfied in viewing the ones that I can see. Clear skies to you.

#6 azure1961p

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Posted 04 May 2013 - 08:14 PM

Jupiters moon shuttle back and fourth brightly at magnitude 6 in these apparent linear to and for movement that makes it all seem so neat and tidy. Saturns moons with the inclined presentation of the whole enterprise can appear like a haphazard smattering of faint field stars. Too, even in small apertures at least Ganymede resolves as a disc while medium and larger reveals all four in differing sizes and with attention, color tints. While both planets have faint moons that make them beyond even large aperture Saturns brightest, Titan starts the parade at magnitude 9 - quite a step down from 6 Joves bright four. Only larger medium aperture resolves Titan so its a little exclusive in that way too.

I've come to enjoy Saturns moons quite a bit. They aren't as childishly whimsical as the bright tidy Galilleans but they are rewarding in pursuit, particularly in seeking the fainter in Saturns relatively beaming glare. A tall order for moons 11v and fainter.

High transparency and magnification make ferreting out the toughies a little easier so long as steady seeing obliges. Good luck.

Pete

#7 azure1961p

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Posted 04 May 2013 - 08:14 PM

Post deleted by RLTYS

#8 Rick Woods

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Posted 05 May 2013 - 12:52 AM

Pete,
Is that a Voyager image of Titan in your avatar now? The north-south dichotomy and the north polar band show, and the phase looks like a Voyager image. Not sure if the dichotomy still looks like that (it's seasonal).

#9 Qwickdraw

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Posted 05 May 2013 - 01:17 PM

I am thinking maybe because Saturn's rings are always stealing the show.

#10 azure1961p

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Posted 05 May 2013 - 02:21 PM

No Rick I imaged it through my DBK21au. I stacked several powermates ;)

Okay sorry Im in wise---- mood. Actually I don't know where it came from. I liked the image particularly because that's the colors that sparkle out of that tiny point in better seeing. Its my favorite challenging little resolvable orb next to the Galilean moons and Neptune. I love the info Huygens brought back to us and Ive always felt it was a little glossed over by the media in general.

Ill tell you - you get a stellar seeing night and something like 700x and man o man - Id pay admission to see the view!

Pete

#11 Rick Woods

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Posted 05 May 2013 - 11:42 PM

Everyone's a comedian! :rolling:

Now that I have a better idea what I'm looking at, I'm gonna spend some serious Titan time, if I ever get a night where it hasn't been really windy all day. (It's always some blasted thing!)

#12 dscarpa

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Posted 06 May 2013 - 11:47 AM

I noticed Sky and Telescope doesn't have the graph of Saturn's moons like the one they have of Jupiter's. I enjoy observing both planet's moons and have seen 5 of Saturn's in my WO ZS-110. David

#13 Kraus

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Posted 06 May 2013 - 12:48 PM


I take it you want to know which moon is which? 'Astronomy' magazine's 'Sky Dome' is your answer. I can't say the same for 'Sky and Telescope'. I can never get the interactive sky thing to work. It won't let me even change the latitude.

But Tony's 'Sky Watch' videos are right neat to watch when he can produce them. He's a busy guy I think. That's why he can't shave. He just hasn't the time.

#14 Rick Woods

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Posted 06 May 2013 - 03:41 PM

I noticed Sky and Telescope doesn't have the graph of Saturn's moons like the one they have of Jupiter's. I enjoy observing both planet's moons and have seen 5 of Saturn's in my WO ZS-110. David


I think the reason for that is that Saturn spends most of its time at an angle to us. The Jovian moon graph allows you to just take a straight edge and see where all the moons are at a given time, as Jupiter's axial tilt is barely over 3 degrees. You can only get that perspective on Saturn when the rings are edge-on to us, since Saturn's tilt is almost 27 degrees. And S&T does publish that graphic for Saturn during that period.

Now, that's just my theory. Could one of you S&T guys confirm or correct that?

#15 Cotts

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Posted 06 May 2013 - 04:47 PM

Saturn moon observation from TSP last night. Very nice view of 5 moons. Titan, Rhea, Dione, Tethys and Iapetus. 8" TEC Mak/Cass, various mags from 101x to 390x. I knew where Mimas and Enceladus were supposed to be but no amount of staring could tease them out of the glare.

In my 66mm finder scope only
titan and Rhea could be seen.

Dave

#16 azure1961p

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Posted 06 May 2013 - 07:03 PM

Dave,

Last time I saw Enceladus the rings were spiderweb thin (apparently you know) and even then it seemed virtually an averted vision thing. One thing Ive gathered from folks who've seen it at higher ring presentations is really high magnification does the best job of separating its light from the glare . I'm guessing something like 400x-480x might be the way - seeing obliging.

Just a thought.

Pete

#17 brianb11213

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Posted 07 May 2013 - 03:31 AM

Last time I saw Enceladus the rings were spiderweb thin (apparently you know) and even then it seemed virtually an averted vision thing. One thing Ive gathered from folks who've seen it at higher ring presentations is really high magnification does the best job of separating its light from the glare . I'm guessing something like 400x-480x might be the way - seeing obliging.

Well, you need transparent(*) air to minimise the glare from the planet but, as usual, aperture helps more than magnification. For faint objects, even in the glare of the planet, 20x per inch of aperture is about optimal.

Saturn's moons are easily identified using planetarium software like Starry Night or Stellarium. The fainter ones are best observed when near elongation as the glare is much less then. Enceladus is challenging with 6" even when the rings are edge on but should still be possible with 8" ... with 12" Mimas should be seen though not easily.

Hyperion is a toughie through being faint though it does get well seperated from the planet's glare. Look for it when it is near elongation and close to Titan, then move Saturn out of the field ...

The difference between Saturn's moons and Jupiter's is that Jupiter's Galilean four satellites are so obvious with minimal optical aid ... and no more become accessible however much aperture is available. Saturn's moons are far less "in your face" but with reasonable aperture you should be able to see six, seven or eight of them & the Saturnian system responds to increasing aperture far better than the Jovian one.

(*) Do not mistake transparency for lack of light pollution. The big "pollution" issue here is the planet itself! Moonlight or artificial sky glow is hardly an issue for detecting satellites of Saturn, Uranus, Neptune or Mars.






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