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Old 05-10-2020, 07:44 PM
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Slawomir (Suavi)
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Saturn's moons

Hi all,

I have been trying to take advantage of Saturn and Jupiter both being pretty much at zenith after sunset from our location.

I was happy as a child on Christmas when for the past two nights I could see Dione and Tethys. Two very faint pinpoints very close to Saturn. Rhea and Titan were quite obvious. I think I also might have gotten Iapetus, but not 100% sure with this one and would need to check again on following nights.

Rig: 105mm refractor, 5mm and 3.5mm eyepieces and a manual alt-az.
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Old 06-10-2020, 08:05 AM
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Wow, just spent a week in port Douglas ( took some gear as well) and I got clouds all week at night (beautiful and clear during the day though)

Hemi
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Old 06-10-2020, 06:00 PM
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Slawomir (Suavi)
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Hi Hemi,

It's certainly a beautiful part of the world, and so is the NT
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Old 06-10-2020, 07:27 PM
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Hi all,

So tonight I tried to confirm whether I really could see Iapetus.

And yes, I have got him again. So with my 105mm I bagged again 5 Saturn's moons, in order of easiness tonight it was Titan, Rhea and Tethys, Iapetus and Dione. The last was quite a challenge due to the moon's proximity to the planet. Could see them all in a 5mm as well as 3.5mm eyepiece.

I will keep trying to spot Enceladus, but not sure if this can be done with my setup.
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Old 07-10-2020, 02:22 PM
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mental4astro (Alexander)
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Suavi,

You've brought up an important point in your last post about being able to view the fainter moons with very short focal length eyepieces.

Most of us will be familiar with the "limiting magnitude" of a given aperture thing. The trick with this though is that it requires high power in order to achieve this. Higher magnification helps improve contrast, and so helps bring out the fainter stars, and also nebulous details, including details in galaxies. This is an old observer's trick to help bring out faint galaxies and even details in brighter ones Don't be shy about increasing the magnification sometimes.

This is why you couldn't see the fainter saturnian moons with long focal length eyepieces.

Alex.
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Old 07-10-2020, 07:15 PM
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Thank you Alex,

I don't have much experience so I was quite happy to spot 5 moons around Saturn on two consecutive nights with such small telescope.

It was equally easy/challenging to see them with both 3.5mm as well as with 5mm eyepieces, and only two out of the five could be seen with a 13mm eyepiece. However, once I added a Barlow to the 5mm eyepiece, there was certainly more scattered light and I could not spot Dione anymore with added Barlow.
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Old 09-10-2020, 06:14 AM
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Hi all,

Skies were quite steady last night, so I had another look at Saturn. Again, 5 moons were spotted. On this occasion, in order of increasing difficulty: Titan, Dione + Rhea, Tethys, Iapetus. Enceladus was at mag 12.6, so I had no chances of observing it.
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Old 09-10-2020, 03:14 PM
bigjoe (JOSEPH)
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Quote:
Originally Posted by Slawomir View Post
Hi all,

Skies were quite steady last night, so I had another look at Saturn. Again, 5 moons were spotted. On this occasion, in order of increasing difficulty: Titan, Dione + Rhea, Tethys, Iapetus. Enceladus was at mag 12.6, so I had no chances of observing it.
.

Nice work Slawomir.
Alexs correct tip about Mag should be noted by observers.
You've got me inspired to try in my 115, prob in a few days as clouds and a jetstream here in Sydney.
Bigjoe
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Old 09-10-2020, 06:16 PM
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Quote:
Originally Posted by bigjoe View Post
.

Nice work Slawomir.
Alexs correct tip about Mag should be noted by observers.
You've got me inspired to try in my 115, prob in a few days as clouds and a jetstream here in Sydney.
Bigjoe
Thank you Bigjoe.

I shall try again tonight, but Enceladus will be less optimally positioned than last night, meaning closer to Saturn.

I look forward to reading your report Bigjoe.

Wishing everyone clear skies tonight
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Old 09-10-2020, 07:50 PM
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Hi all,

Reporting that all five could be confidently seen again tonight. Titan was very easy to spot (mag 9.3), then Rhea (mag 10.5), followed by a little bit harder to spot Dione (mag 11.3) and Tethys (mag 11.1) because the last two were the closest to Saturn. A more distant from Saturn Iapetus (mag 11.8) became more obvious once the skies got darker. Enceladus (mag 12.7) was beyond my reach again.

This time I also tried a borrowed Lunt zoom 7.2-21.5 mm eyepiece and was surprised that it was quite sharp and comfortable to use, so I could eventually and with some effort and patience see all 5 at maximum magnification with this zoom eyepiece. But switching to 5mm Delite as well as 3.5mm Delos made seeing the 5 moons easier, probably because background with those two was significantly darker.

I also tried 2x TV Barlow with 5mm Delite and 3.5mm Delos, and this made seeing Iapetus somehow easier, but, at the same time the moons that were very close to Saturn were nearly impossible to see when barlowed.

All in all, it has been fun spotting the moons around Saturn with my 105mm fast refractor and I think I learnt a thing or two during the past week or so of observing Saturn more systematically.
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Old 10-10-2020, 09:20 PM
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Good work Suavi on picking out five moons of Saturn. Observing the Solar System moons is an area I really enjoy and spend lots of time doing. I’ve seen 29 moons in the 32”, including 9 moons of Saturn.

Enceladus can be a challenge. It is 70,000 times fainter than Saturn, and would likely need an 8” class scope or more to see through the glare of Saturn.

Mimas is inboard of Enceladus and fainter, so that moon is a real challenge, even in a 16”. There’s Hyperion which is fainter, but well separated from Saturn and not too difficult in a 16”. Phoebe was the last moon of Saturn I observed, and at magnitude 17, I’ve only ever sent it in the 32”.
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Old 11-10-2020, 07:59 AM
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29 moons - that's awesome Allan. A bet only a very few human souls have seen this many moons through a telescope.

I may have a go at Mars' companions with my 105 mm during the coming weeks, because it seems that all other remaining moons in the solar system would require a more serious aperture. Unfortunately, work gets in the way of staying up late and exploring the night sky.
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Old 11-10-2020, 09:27 AM
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Thanks Suavi. Yes I’m fairly sure no one has seen 29 moons. There are several moons of Jupiter that I observed, and are likely the first time they have been visually seen. Amalthea is one I know only around 20 people have seen since Barnard discovered it in 1892. It took me three years to finally see Amalthea. It is beyond difficult, and the most satisfying observation I have made. Then there’s the very faint group of Sinope, Carme, Lysithea and Ananke that have no known visual observations I can find anywhere.

I have been checking in on Deimos and Phobos for the last couple of months in the 32”. The smallest scope I’ve tried seeing those in was a 12” dob. They weren’t too difficult to see at opposition time. Deimos is the far easier moon to see, and I’m going to see if it’s possible in the TOA130 next week from my dark site. I know they are achievable in 8 inch unobstructed scopes after someone I know in the US recently did it.
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Old 11-10-2020, 10:23 AM
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I managed to observe Phobos during the 2015 Opposition with my 5.5” refractor. I could not find Deimos at the time with it being very close to the limit for my scope. I was using an occulting bar to block out the bright glare of Mars when trying to find the very faint Deimos, but to no avail.

Your reports are inspiring me to have another go. The challenge of course, is to have good seeing conditions during those small time windows where the moons are well separated from Mars.
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Old 11-10-2020, 02:54 PM
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That is sensational observing Steve. Certainly that would have to be the smallest aperture anyone has ever used to seen Phobos. You definitely should have been able to see Deimos as it is far, far easier to see than Phobos.
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Old 11-10-2020, 07:19 PM
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That is fascinating Allan, and what a fantastic unique achievement with 29 moons.

Steve - please let us know how you go with chasing the moons.

After having a camera pretty much permanently attached to the back of my telescopes for about a decade, carefully looking through an eyepiece it's a completely new territory to me.

Tonight I set up before the sunset and was already watching both gas giants as the sun was setting. At 6.45 pm I ticked off the 5 moons of Saturn again, this time the order of increasing difficulty was: Titan, Rhea, Dione, Iapetus (much easier to see tonight, relatively speaking), and lastly, although it took a bit more trying until the skies darkened and also a few Saturn's passes through the fov, that I could finally confidently see Tethys.

As I waited for the skies darken to hopefully find Tethys, I tried to spot Ganymede's transit but could only see the moon at the end of transit as it started emerging at the side of the planet. Perhaps need a bit more eye (s)training to see one of the four in front of Jupiter.
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Old 17-10-2020, 06:59 AM
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Hi all,

Just a quick update.

Although I could see 5 moons of Saturn during each session, but still no luck with Enceladus. I even got a 2.5mm eyepiece for this task but no Enceladus in sight. I will keep trying but I believe my eyes need a larger aperture to witness Enceladus.
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