TheSkySearchers

Early last year I finished the original Herschel 400 (H1) List of deep sky objects. I viewed the vast majority of them with my 4-inch refractor--and probably could have seen them ALL with it. I recently started working through the Herschel 400-2 (H2) List, having already viewed a good chunk of the objects over the years, but not following the list.

Anyway, it looks like my 8-inch scope is gonna see a lot more use for this list due to the prevalence of fairly faint galaxies. I can see galaxies down to about 12.5 with the 4-inch, if they have a high surface brightness (and stars past 13.5) under excellent conditions, but the H2 has a lot of objects that are dimmer. The challenge (really, a time-consuming pain-in-the-ass) will be using the 8-inch SCT during the cold winter months. Long cool-down times, stiff focuser, foggy eyepieces, and serious frosting/condensation on the scope when I bring it in from a sub-zero observing session are the challenges.

This got me thinking about efficiency. I think I will search for a yogurt heater on eBay and adapt it for keeping eyepieces warm (but not TOO warm). I will also research some sort of heavy-duty, waterproof bag that I can wrap the scope in before bringing it into the warm house. This should reduce the condensation problem.

Any thoughts?

I have completed both H1 and H2 with scopes from 4" to 8". While there are still many brighter targets on H2 you would definitely need larger aperture to complete it. How large depends on the sky quality. I have feeling that under very good skies 6" might be enough.

I don't have much experience with very cold weather, but can see how SCT design will be more sensitive. Maybe it is a time for a new scope? Have you considered a large Newt/DOB? In particular if you want to continue with Herschel beyond H2.

If you like refractors 150mm F5 short tube achro is a pleasure to use and great on DSOs. It has faster cool down times, resist dewing better (with oversized dew shield) than SCT, and will also complement nicely your 8".

I really like the compact nature of the SCT, and it has hauled in a lot of dim DSOs. I know I can knock off the H2 with the 8-inch from my Bortle 3 backyard. Can't imagine dealing with a bigger Newt---the condensation/frosting would be even worse due to the surface area of the scope in cold weather. I DO like fracs, though, and could see getting a fast 6-inch at some point...

Arctic wrote: ↑Mon Aug 05, 2019 9:54 pm I really like the compact nature of the SCT, and it has hauled in a lot of dim DSOs. I know I can knock off the H2 with the 8-inch from my Bortle 3 backyard. Can't imagine dealing with a bigger Newt---the condensation/frosting would be even worse due to the surface area of the scope in cold weather. I DO like fracs, though, and could see getting a fast 6-inch at some point...

Yes, 8" SCT is the scope everyone should have. Amazing combination of great performance on all types of targets and compact size and light weight.