Enceladus challenge!

[badhex]

On 07/10/2023 at 09:11, Nik271 said:

Currently I don't think I have much of a chance of success at Enceladus, the rings ar still too bright and Saturn too low in the haze. The second half of 2025 looks like the best time:

 

 

Sorry Nik, didn't see this at the time. The screengrab you posted looks promising, what was the date for that? I might as well get in the diary! 🙂

[badhex]

7 hours ago, Jim L said:

My wife, Monica, observed Enceladus last night using a Celestron 6SE SCT and looking through a SvBony 7-21 mm zoom eyepiece. We were observing from the Gulf of a Mexico coastline just north of the Mexican border. Seeing and transparency were listed as average in Astrospheric. This was the alignment at the time:

Congrats! Excellent work, especially given the close proximity of Tethys and Enceladus to each other! How dark are the skies where you are?

[Nik271]

5 hours ago, badhex said:

Sorry Nik, didn't see this at the time. The screengrab you posted looks promising, what was the date for that? I might as well get in the diary! 🙂

I believe it was for some evening of mid December 2025. We have some time to get ready for it!

[Jim L]

7 hours ago, badhex said:

Congrats! Excellent work, especially given the close proximity of Tethys and Enceladus to each other! How dark are the skies where you are?

Hi Joe,

The skies overhead aren’t particularly dark being that we’re staying at the SpaceX Starbase, which is a beehive of activity both day and night. I’d say it’s not as light polluted here as it would be from within a small to medium sized city, but it’s certainly not a dark site by astronomy standards from my son’s back yard. The band of the Milky Way isn’t at all visible.

What I think the site has going for it, and which probably helped Monica spot Enceladus, is that Saturn was in the southeast over the warm, moist, and relatively steady air over the gulf. High altitude frozen water vapor that scatters light at so many other locations seemed completely absent, and glare from Saturns disk and rings was far less intrusive than is the norm from my own home northeast of San Francisco.

While Monica saw Enceladus using averted vision I could not, so good eyes also play a role when objects are at the margin of what’s possible to see. Then there’s the issue of having sufficient aperture, and the 6” SCT was probably close to its practical limit as well for a visual magnitude 12.4 object.

Monica and I were actually chasing Saturn’s Cassini Division when she saw Enceladus. Since I didn’t see either I guess I’ve now got two targets to look for over the next few weeks.

[badhex]

17 hours ago, Jim L said:

Hi Joe,

The skies overhead aren’t particularly dark being that we’re staying at the SpaceX Starbase, which is a beehive of activity both day and night. I’d say it’s not as light polluted here as it would be from within a small to medium sized city, but it’s certainly not a dark site by astronomy standards from my son’s back yard. The band of the Milky Way isn’t at all visible.

What I think the site has going for it, and which probably helped Monica spot Enceladus, is that Saturn was in the southeast over the warm, moist, and relatively steady air over the gulf. High altitude frozen water vapor that scatters light at so many other locations seemed completely absent, and glare from Saturns disk and rings was far less intrusive than is the norm from my own home northeast of San Francisco.

While Monica saw Enceladus using averted vision I could not, so good eyes also play a role when objects are at the margin of what’s possible to see. Then there’s the issue of having sufficient aperture, and the 6” SCT was probably close to its practical limit as well for a visual magnitude 12.4 object.

Monica and I were actually chasing Saturn’s Cassini Division when she saw Enceladus. Since I didn’t see either I guess I’ve now got two targets to look for over the next few weeks.

Interesting! Yeah, I strongly suspect that even under ideal conditions the 73mm won't be enough, but hopeful for the 102mm. Depending which calculation you use, a 102mm frac could have a limiting mag of up to about 12.7. I spotted Dione last year with that scope, which is only just over one magnitude brighter than Enceladus. By the way, Stellarium is reporting mag. 11.8 and Skysafari 12.1 for Enceladus at the moment. Not really sure where we can get real-time mag values but I'm sure they must be knocking about somewhere.

[badhex]

Had another crack at Enceladus the other night from a Bortle 4 location with the 102mm. Titan and Iapetus were easy, also managed Tethys, Rhea and Dione - but sadly Enceladus was probably just too close to Saturn to make out, and conditions were good but not perfect at that point. Annoyingly, conditions actually improved even more later, and Enceladus was much further out away from the planet so I may have been in with a chance, but it was all hidden by a house. 

Stellarium screen grab from the approx time of observation below.

[josefk]

How easy or not was Tethys at that proximity @badhex in the 100mm? I had similar proximity of the moons to Saturn one evening last week and could pick out Rhea (with 85mm) but not Tethys (and not Enceladus). There was some glare in the atmosphere but not loads.

[badhex]

1 hour ago, josefk said:

How easy or not was Tethys at that proximity @badhex in the 100mm? I had similar proximity of the moons to Saturn one evening last week and could pick out Rhea (with 85mm) but not Tethys (and not Enceladus). There was some glare in the atmosphere but not loads.

It was not immediately obvious, nor were any of that trio, however after a couple of mins at the eyepiece they became apparent, and once I'd got them they remained in view for most of the time. I did also have a touch of glare in the atmosphere but not much. I think local LP plays a huge part here too, even though the skies are pretty dark. Views improved significantly when I pulled my parka hood over my head.