A good night to see Iapetus

[John]

Tonight Iapetus is looking a little brighter than I would have expected, again. It seems close to Rhea in brightness and certainly brighter than Dione although the latter pair are quite a bit closer to Saturn itself so will be affected by it's glare. Tethys and Enceladus are too close to the planet to discern tonight. Dione is quite tough to spot with the 4 inch refractor that I'm using tonight. 

 

 

Edited September 2, 2023 by John

[IB20]

Iapetus fairly easy to see last night in the 4”, certainly not far off Rhea’s brightness; so somewhere around +10.0-10.3 I’d estimate.

 

[johnturley]

12 hours ago, John said:

Tonight Iapetus is looking a little brighter than I would have expected, again. It seems close to Rhea in brightness and certainly brighter than Dione although the latter pair are quite a bit closer to Saturn itself so will be affected by it's glare. Tethys and Enceladus are too close to the planet to discern tonight. Dione is quite tough to spot with the 4 inch refractor that I'm using tonight. 

 

 

 

I found Dione difficult last night even with my 14in, as mentioned before I put it partly down to my deteriorating eyesight, although I have had a cataract operation in my (right), observing eye. Also I was viewing Saturn through some thin high cloud, and there was a not far off full moon not far away.

John 

Edited September 3, 2023 by johnturley

[IB20]

Back with the Tak 76Q. Rhea just off the underneath of the ring system so looks dimmer than Iapetus. Really hard to estimate the mag but it looks bright maybe even under +10.0. Saturn is majestic tonight, simply captivating.

 

[melsmore]

Iapetus made an attractive pairing with TYC 5807-0033-1 at 2023-09-03.23:30 UTC. APM140 x245 (4mm Nirvana). 

1 iapetus 

2 TYC 5807-0033-1

3 Titan

4 Rhea

5 HD 212113 (which I've drawn too far East ). Here's a poor sketch.

 

 

 

[IB20]

Same deal as the previous night. Rhea slightly further away from Saturn but stilled slightly dimmed by proximity. Again this made Iapetus the 2nd brightest moon of the three visible so I’d put it about somewhere around 9.8-10. Very, very occasionally there was an aberration just off the left shoulder of Saturn, which may have been Tethys. It was a very rare sight so might not have been, interestingly it was something I glimpsed in both fracs though.

[John]

I saw Tethys last night but it was close in by the rings so not easy. Dione was even closer to the ring system and I only got a couple of glimpses of that one with the 130mm refractor.

 

[josefk]

it was good sport last night trying for Saturn's Moons. Rhea, Titan and Lapetus were observed. Rhea needed Saturn holding out of the EP  FOV to first see it then i could pick it up with a little averted vision even with Saturn in the FOV. I couldn't repeat the trick with Tethys, Enceladus or Dione. A good test of reflections and glare in the EP barrel 😉

[Nik271]

I managed Rhea, Titan and Iapetus with my 127 Mak last night. I looked for Tethys but couldn't see it. Again the light mist was creating a soft glow around Saturn. The seeing was pretty good though, saw the banding on the planet and a hint of the Cassini division.

[John]

4 hours ago, josefk said:

.... A good test of reflections and glare in the EP barrel 😉

As I have been comparing a number of different short FL eyepieces over the past couple of nights, it has been the extent of the glare / scatter of light around Saturn that has been the main thing that varied in their performance. None were notably bad in this respect but I noticed that the abbe orthos and, a little surprisingly, the 6mm and 4.7mm Ethos that consistently showed the least. 

I've found glare / scatter control has been a significant factor in being able to see faint planetary moons close to their parent planets disks and also cracking challenges like spotting the "Pup" star, Sirius B. 

I'm looking forward to having a look at Neptune's moon Triton and trying to spot Uranus's brightest 4 moons when those planets are better positioned from my back yard. 

Edited September 5, 2023 by John

[melsmore]

10 minutes ago, John said:

As I have been comparing a number of different short FL eyepieces over the past couple of nights, it has been the extent of the glare / scatter of light around Saturn that has been the main thing that varied in their performance. None were notably bad in this respect but I noticed that the abbe orthos and, a little surprisingly, the 6mm and 4.7mm Ethos that consistently showed the least. 

I've found glare / scatter control has been a significant factor in being able to see faint planetary moons close to their parent planets disks and also cracking challenges like spotting the "Pup" star, Sirius B. 

I'm looking forward to having a look at Neptune's moon Triton and trying to spot Uranus's brightest 4 moons when those planets are better positioned from my back yard.

 Did you try a svbonny 3-8 and TV 3-6 zooms? I'd be interested to know how well they do.

[John]

21 minutes ago, melsmore said:

 Did you try a svbonny 3-8 and TV 3-6 zooms? I'd be interested to know how well they do.

I've been using the Svbony zoom (kindly loaned by @bomberbaz) and my Nagler 2-4 zoom, along with other options. The Svbony is very sharp but shows a little more light scatter around a bright targets at the 4mm and 3mm settings than the Nagler does. Given the cost of the Nagler is 3x the Svbony that is perhaps not entirely surprising though. The Svbony is remarkably good for what it costs to be honest with you, spans a lot of focal lengths and has a 56 degree AFoV compared to 50 for the Nagler. Both are pretty much par focal through their zoom range just needing a very small tweak now and then as you move through the focal lengths.  

Edited September 5, 2023 by John

[johnturley]

58 minutes ago, John said:

 

I'm looking forward to having a look at Neptune's moon Triton and trying to spot Uranus's brightest 4 moons when those planets are better positioned from my back yard. 

I've never been able to see Triton, or any of the moons of Uranus visually, even through my 14in Reflector going back to the 1980's, when my eyesight was better than it is now, and when I found the fainter moons of Saturn much easier spot than I do now.  It will depend to a certain extent on how light polluted your location is.

John 

Edited September 5, 2023 by johnturley

[johnturley]

5 hours ago, josefk said:

it was good sport last night trying for Saturn's Moons. Rhea, Titan and Lapetus were observed. Rhea needed Saturn holding out of the EP  FOV to first see it then i could pick it up with a little averted vision even with Saturn in the FOV. I couldn't repeat the trick with Tethys, Enceladus or Dione. A good test of reflections and glare in the EP barrel 😉

What size scope was that with, the other night I found Rhea fairly easy with my 150mm Refractor, but could could only spot Dione through my 14in Newtonian. As mentioned earlier, in the 1970's I found Rhea, Tethys, and Dione, and occasionally Enceladus, fairly easy through my then 10in Newtonian, but then Saturn was higher up, my eyesight better, and skies less light polluted. 

[John]

15 minutes ago, johnturley said:

I've never been able to see Triton, or any of the moons of Uranus visually, even through my 14in Reflector going back to the 1980's, when my eyesight was better than it is now, and when I found the fainter moons of Saturn much easier spot than I do now.  It will depend to a certain extent on how light polluted your location is.

John 

I saw Triton fairly regularly with my 12 inch dob and I have seen it a couple of times with my 130mm refractor. I caught the two brightest Uranian moons a couple of times with the 12 inch but, so far, I've not seen them with anything smaller. Lots of magnification helps.

I didn't have any joy with Phobos and Deimos during the last martian opposition even with my 12 inch.

 

[josefk]

5 hours ago, John said:

As I have been comparing a number of different short FL eyepieces over the past couple of nights, it has been the extent of the glare / scatter of light around Saturn that has been the main thing that varied in their performance. None were notably bad in this respect but I noticed that the abbe orthos and, a little surprisingly, the 6mm and 4.7mm Ethos that consistently showed the least. 

I've found glare / scatter control has been a significant factor in being able to see faint planetary moons close to their parent planets disks and also cracking challenges like spotting the "Pup" star, Sirius B. 

I'm looking forward to having a look at Neptune's moon Triton and trying to spot Uranus's brightest 4 moons when those planets are better positioned from my back yard. 

As a rule I don't like to turn my observing into an "eye test" type sport but it is funny and surprisingly satisfying actually to try and wring the best out of everything for these little challenges and to work out what is the best tool for the job. 

I'm encouraged by your seeing Triton with 130mm of aperture. I have a list of solar system objects that would be feasible for my kit and i am slowly ticking them off. Triton is still "to do".

[josefk]

4 hours ago, johnturley said:

What size scope was that with, the other night I found Rhea fairly easy with my 150mm Refractor, but could could only spot Dione through my 14in Newtonian. As mentioned earlier, in the 1970's I found Rhea, Tethys, and Dione, and occasionally Enceladus, fairly easy through my then 10in Newtonian, but then Saturn was higher up, my eyesight better, and skies less light polluted. 

Hi John - those three on Monday evening were with 85mm of aperture. i have seen other moons with bigger scopes on different nights but this week i'm not sure bigger scopes would have helped me because the other moons have been extremely close in to the body of Saturn (at least on Sunday and Monday). Hyperion was/is further out but that is too faint my apertures.

[John]

1 hour ago, josefk said:

As a rule I don't like to turn my observing into an "eye test" type sport but it is funny and surprisingly satisfying actually to try and wring the best out of everything for these little challenges and to work out what is the best tool for the job. 

I'm encouraged by your seeing Triton with 130mm of aperture. I have a list of solar system objects that would be feasible for my kit and i am slowly ticking them off. Triton is still "to do".

I take your point about not making it into a "sport" John 🙂

I like to stretch my eye, scope and observing conditions out of curiosity and often the slight thrill of seeing something far off and "exotic" with relatively modest equipment. It feels like you have "beaten the system" in some odd way when you get something like this even if it is the faintest point of light or vaguest puff of nebulosity 😁 

[josefk]

@John 100% and i get a particular kick out of doing it with small scopes for some reason. Definitely attempting to "beat the system".

i think it is a genuine observing pursuit anyway (never mind my "eye test" / "sport" comment) because the observing task in these challenges is in fact really intense and considered - loads of time to contemplate what you are really doing when you hold an absolutely massive planet out of the FOV to put a little bit of dark space between it and another massive solar system object even if that massive object is only a faint point for our eye. I mean ...wow.

[IB20]

Blew the doors off it and got the 8” dob out last night. Titan extremely obvious and far off Iapetus competing with two field stars. Just off the right side of the ring system, two other points of light easily visible in a little adjacent formation - Rhea and Tethys. Occasionally one more point of light appeared on the opposite edge with averted vision; finally Dione but requiring aperture. 

Once Saturn got high enough, the views stabilised and were exquisite in the 9mm BGO and 7mm XW. All the usual features were easier and comfortable to see, I wouldn’t say I saw any more than the smaller scopes however, with the exception of Dione. Perhaps higher altitude and better seeing is required.

So aperture rules eh? Yet somehow I much prefer the views through the 3” pea-shooter…