23 replies to this topic

[CHnuschti]

Saturn's Titan: shadow passes and transits observations 2024/2025/2026

 

It's quite interesting. To see the event at all of course, this is my first encounter with "shadows on Saturn".

 

In central Europe (I would guess also in UK?), there were already 2 events. First one 4. Nov. 2024 was grazing. Next one 20. Nov. 2024 I was able to look a it with my 110/660: good clarity, awful seeing. I was not able to locate it undoubted, too close to the edge. I'm confident to see it once it moves more inwards.

 

Next opportunities are 6. and 22. Dec. 2024, more inwards on the sphere.

 

One orbit of Titan last quite precisely 16 days, and the interesting part is that it looks to be quite precise 24hrs intervals. From the first mentioned 4. Nov. 2024 up to 24. Febr. 2025 it is visible (in the "dark" here in central Europe) at every orbit pass every 16 days . Then it's gone (=in daylight), next will be the more difficult to see transits beginning just 6. Oct.  2025

 

So I suppose the different earth regions (longitudes) all have their window of a recurrent set of shadow passes. I guess?

 

regards

 

List of apparitions (it's for Austria, but I suppose valid +/- for all central Europe):
https://www.waa.at/h...titan-transits/

 

A thread with sketches with successful sightings (so far):
https://forum.astron...-saturn.371276/

Edited by CHnuschti, 30 November 2024 - 07:11 PM.

[ButterFly]

The shadow transit on the 6th is very low in the sky for me, in broad daylight.  The daylight is NOT really the problem, so much as the lowness.  It's still worth looking for.  The shadow transit of the 22nd is higher, and should be better, but still at only twenty degrees.  Those on the East coast of the US will have a much better shot, with Saturn at nearly forty degrees up.  Of course, another issue for daylight observation is finding the thing, but if one can leave their setups aligned from the night before, that will make it a lot easier to find.

[CHnuschti]

Was able to look at it today 6. Dec. with my 110/660. Clarity was decent on the second half of the shadow pass. Unfortunately, ugly seeing, could barely have been worse. The look on the moon 1hr earlier was a mess and gave the forecast so to say what to expect.

 

Secondwise it shined through when looking at it mostly in 190x. Also in 110x it was perceivable in few moments. @265x best (in the bad) so to say, was worked out there the most distinct, but again only intermittend. It was never really good/clear, and I spent almost 1hr on it.

 

But I could make out the clear detachment from the limb.

 

Looks very seeing dependant and more aperture very likely is of help, is my first impression.

 

regards

Edited by CHnuschti, 06 December 2024 - 06:44 PM.

[Cpk133]

All clouds here. 

[Magnus Ahrling]

Thanks for your report CHnuschtiAnd congratulations to your observation I was prepared to have a try to observe Titans shadow but unfortunately the sky was cloudy. Hope for better luck 22/12!

 

Magnus

Edited by Magnus Ahrling, 07 December 2024 - 03:37 PM.

[Bill Barlow]

What time is the Titan shadow transit on 12/22?  Thanks.

[ButterFly]

What time is the Titan shadow transit on 12/22?  Thanks.

Keep a bookmark to Carona's Saturn Moons page.  Set the date at the top, and explore.  "Timing Events" has a giant table per moon.  That's easier if you know what's coming up, otherwise you will be sorting through the "Condensed Timing" page.

[Magnus Ahrling]

Bill Barlow: Titan shadow transit 12/22, 17:36-21:55 UT. According to BBC Sky at Night.

 

Magnus

[Serack]

The shadow transit on the 6th is very low in the sky for me, in broad daylight.  The daylight is NOT really the problem, so much as the lowness.  It's still worth looking for.  The shadow transit of the 22nd is higher, and should be better, but still at only twenty degrees.  Those on the East coast of the US will have a much better shot, with Saturn at nearly forty degrees up.  Of course, another issue for daylight observation is finding the thing, but if one can leave their setups aligned from the night before, that will make it a lot easier to find.

I've never tried to do planetary viewing during daylight.  Any tips?  it looks as though the 12/22 and 1/7 shadow transits will be during the day for me.  

[ButterFly]

I've never tried to do planetary viewing during daylight.  Any tips?  it looks as though the 12/22 and 1/7 shadow transits will be during the day for me.  

 

Sun safety is paramount during the day.  This is far away enough that it shouldn't be a problem, but that's no excuse to be unsafe either.  Be mindful.

Finding it is the biggest challenge.  A compass (along with the magnetic declination in your area) will help you find the proper AZ to look at.  Start a little lower than the predicted alt, then scan along working your way upward.  If you fail the first time, start a little Eastward, and repeat, heading Westward.  Practice with Venus, as it is naked eye visible to help you out.

 

Of course, you could cheat and leave a goto setup powered on from the night before.  That will get you close enough, if not spot on.

 

A single polarizer is very helpful to darken the sky during the daytime.  The effect is greatest ninety degrees away from the Sun.  On the 22nd, Saturn's elongation will be around 72 degrees, so the sky background will respond very well to polarizers.  Place a single filter on your eyepiece, then rotate the eyepiece in your focuser to where the sky background is the darkest.  Lock the eyepiece in the focuser.  When looking for dark features, such as a shadow transit, it very much helps to have that dark feature as dark as you can get it.  This will give you a boost in actual contrast.  It's also very helpful for daytime moon, which is a lot easier to find!  You get an actual boost in contrast by darkening the sky in front of the object.  Sure, the object dims by about 40%, but the sky dims by a lot more, especially around ninety degrees away from the Sun.

 

If you don't happen to have a polarizing filter, you can try polarized sunglasses.  You can tell whether or not the sunglasses are polarized on a cloudy day by wearing them, looking at clouds about ninety degrees away from the Sun, then tilting your head.  If the sky darkens or lightens as you tilt your head, the sunglasses are polarized.  This can get annoying at the eyepiece if the angle is tuned oddly, so that you will have to tilt your head at a strange angle relative to the eyepiece.  A chair on the side of the scope helps make it more comfortable.  If using a prism diagonal, you may get a line through the middle, depending on the type of prism.  Some prisms polarize the left and right sides differently, so you should use a mirror diagonal at that point, if you must polarize after the prism.

 

Definitely practice on Venus to help find the things.  Look at the Moon (especially when it's quarter phase) during the day to see what a single polarizer can do during the day.  The polarizer also makes it much easier to focus on clouds, so that's also fun as well with a wide field scope and fluffy or thinner higher clouds.

[ButterFly]

Here is NOAA's site to find your magnetic declination: https://www.ngdc.noa...s/magcalc.shtml

 

The result gives you where the compass points relative to true north.  For example, in New York City, the magnetic declination is now 12° 33' W  ± 0° 22'  changing by  0° 2' E per year.  That means the compass points about 12.5 degrees West of True North.  There is a little map to help you out as well, with true North pointing upward, and with a compass rose overlay.

[MJB87]

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[Bill Barlow]

Bill Barlow: Titan shadow transit 12/22, 17:36-21:55 UT. According to BBC Sky at Night.

 

Magnus

Thanks for the information, Magnus.  From those times, it won't be visible here in the central US as that will be from 11:36 AM too 3:55 PM.

 

Bill

[ButterFly]

Thanks for the information, Magnus.  From those times, it won't be visible here in the central US as that will be from 11:36 AM too 3:55 PM.

 

Bill

Saturn is up and you're looking for a dark spot on its face.  Clouds may get in the way, but you should try if they're not.

[Jan Hattenbach]

Hi!

 

*Finally* after three failed attempts, the weather was kind to me tonight. I managed to see Titan's shadow in my 10" f/4.8 Newtonian. Seeing was great (0.6"), so it wasn't even hard: the black dot stood out clearly even at medium magnification. The sketch was made at 300x, at 19:10 UT.

 

This was the first time I saw a shadow transit on Saturn. After 30+ years of amateur astronomy, there are still new things to see... 

 

 

cs,

Jan

Attached Thumbnails

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[CHnuschti]

Was able to look at it today. From start up to 2hrs later. With my 110/660, with 190x and 265x alternating.

 

Seeing was average first. Shadow could be detected right after entry, maybe best then as it laid still in some height. Up to 45min after entry it could be seen secondwise, flashing through. After a cloud passage, I could look at it again some 1.5hrs after entry. Seeing had notably improved (checked on the moon), clarity was also decent. Nevertheless, it was barely detectable anymore, just in few seconds, although it was nearly in the center now. Too low in the meanwhile at some 20°, the flickering ruined it.

 

All in all it was more a perceiving than a real "seeing".

 

Needs good seeing at least, and to really "see" it static, I guess you need top seeing.
No easy task, needs its accompanying luck of suiting conditions.

 

regards

Edited by CHnuschti, 07 January 2025 - 05:58 PM.

[Special Ed]

Congratulations to both of you!

[John Huntley]

I managed to see Titan's shadow transit from here in the UK on the evening of the 6th January using my ED120 refractor. The seeing was steady early in the transit but gradually got worse as Saturn got lower in the sky. I could not observe the event beyond the shadow reaching Saturn's central meridian because the planet had got too low in the sky.

 

I found 225x and 257x magnification the optimum to use. Titan's shadow popped into view during the moments of better seeing, less often as the transit proceeded. The shadow did not seem to me to be as dark and well defined as a Jovian moon shadow transit - it was really quite challenging to see.

 

This was my first observation of a moon shadow on Saturn in 40+ years of observing so I was very pleased to be able to see it. Getting clear skies at the right time at this time of year is challenging itself here in the UK !

[quilty]

No doubt Titan's transit is a harder nut than Ganymede's on Jupe.
much smaller, much more resolution necessary to properly spot and much more exceptional to happen.
Was looking forward to but poor weather and Sat that low there was no chance.
Next step then would be to not just spot the Titan's shatow but to spot the ball in front of Sat.

[quilty]

Edited by quilty, 11 January 2025 - 05:00 AM.

[quilty]

withdrawn

Edited by quilty, 11 January 2025 - 04:59 AM.

[CHnuschti]

Could look at it tonight 23. Jan. With my 110/660 @ alternatively 110x 190x 265x.
Only later when clouds allowed and the shadow already was in the middle of the body, at some 15° height. Clarity was quite good sometimes, seeing not that bad.

 

Nevertheless I only could perceive it for few seconds, can barely be accounted to have "seen" it. I guess the best view would be if you can get it higher up at entry phase.

 

Venus looked GRRREAT! , is at little less of 50%, very nicely to see.

 

regards

[AndrMar]

Just watched Titan's shadow on the Saturn.

Devices: Sky Watcher dob10, same brand barlow 2x and eyepiece Meade UWA 5000 8.8mm.

Magnification: 273.

Location: southern part of Ukraine.

Seeing was not good. Windy weather. Saturn's altitude above the horizon was between 16 and 14 degrees.

At 15:38 UTC, I observed the shadow in the form of a compact black circle. Saturn’s rings had a perfect angle today, dividing the eyepiece’s field of view exactly in half—top and bottom. The shadow was in the upper right part.

Wind gusts shook the telescope and disturbed the atmosphere. During moments of strong turbulence, the shadow became invisible.

By 15:43 UTC, the shadow remained visible even in the strongest wind gusts.

I did not see Titan. It was invisible against Saturn’s disk. I also didn’t notice it emerging because, at 16:01 UTC, the image completely blurred and became unusable—even without a barlow lens.

I ended the session with a quick look at all the bright planets.

[SP21]

And who can share the moments of future transits of Titan's shadow for Europe for the second half of 2025 and 2026?