Bring 'em closer

[Anthonyexmouth]

Ok, so I want to get a bit closer to the galaxies this year but don't really want to spend a lot to do it.

Is

1. getting a cheapish barlow for my 90mm triplet a good idea? 

 

2. Use my uncooled 290mc instead of my 294mc

 

3. try and find a used 6" RC scope 

 

4. Something else. 

[ollypenrice]

I'd start by thinking about image scale. You may find it difficult to get beyond about 1.5 arcseconds per pixel when it comes to finding real detail. You can certainly get decent galaxy results at that and you need a guide RMS of about half that. 0.75"RMS should not be too difficult.

Next, you want as much light as possible at that image scale, which means aperture, but it must be within range of what your mount can carry. 

Basically, I'd focus on those numbers, image scale and aperture.

Olly

[Anthonyexmouth]

8 minutes ago, ollypenrice said:

I'd start by thinking about image scale. You may find it difficult to get beyond about 1.5 arcseconds per pixel when it comes to finding real detail. You can certainly get decent galaxy results at that and you need a guide RMS of about half that. 0.75"RMS should not be too difficult.

Next, you want as much light as possible at that image scale, which means aperture, but it must be within range of what your mount can carry. 

Basically, I'd focus on those numbers, image scale and aperture.

Olly

a 1.5x barlow would give me 1.2 ratio and I normally guide between .65 and 1 depending on seeing. 

I just tend to avoid galaxy season because i'm never that happy with my results, although this is the first year with my triplet so maybe they'll look nicer anyway. 

 

[ollypenrice]

6 minutes ago, Anthonyexmouth said:

a 1.5x barlow would give me 1.2 ratio and I normally guide between .65 and 1 depending on seeing. 

I just tend to avoid galaxy season because i'm never that happy with my results, although this is the first year with my triplet so maybe they'll look nicer anyway. 

 

Personally I wouldn't Barlow the 90mm triplet. Not enough light per pixel. Experiment always wins, though...

Olly

[Clarkey]

I think the RC6 is your best option out of those listed. This will give you 0.7" / px which you could bin2 to give a decent light grasp and pixel scale. I suspect for the 6" scope you might need a flattener too. The 8" you probably wouldn't need the flattener with the 294. Another option would be look for a 150PDS or something similar and crop out the surrounding skies. This gives you 1.27" / px which is also about right. You would need a coma corrector though.