Hi all, I have been thinking a long time about what to put in this post, because 1) I have a million questions and 2) I have a tendency to overcomplicate things!
I started out last year. As soon as I got an astrocamera with the idea of doing some EAA, I've been bit pretty hard by the AP bug. In fact my wife complained the other day that "we never look at the stars anymore!" since I'm staring at - and cursing at - my laptop instead. Anyway, I'm thinking about converting to a small guided EQ setup in hopes of getting sharper DSO images.
Current setup (details in sig): 72ED refractor (2.1 kg), SW AZGti mount on a photo tripod, IMX385-based camera. Gives me FOV 0.96° x 0.54°, 1.79"/pixel (rather a bit under- than oversampled)
Main challenges I'm facing: I only have a clear view of the sky in a Southern direction (pretty much 90° to 270°, i.e. E-S-W) and my telescope is a rather strange "hybrid" that must be mounted using a Vixen-compatible "foot" (no rings).
Fundamental question first: is it even possible to polar align under these conditions?
"Not being able to see Polaris" is one thing, but not being able to see any part of the northern sky is a different ballgame! As an experiment I tried to place the mount on a fluid video head (not geared) and align "freestyle" using the Synscan polar alignment routine as well as the drift method. I utterly failed twice, but is it because I didn't have a proper wedge or because it just can't be done from a south-facing location? If the latter, I'd rather stop right here.
Here's what I'm thinking of buying:
EQ "wedge": Benro GD3WH (based on the good opinions I read in this thread)
Dovetail (for side-by-side setup): TS Guidemount
Power/control: i-tec USB 3.0 Charging HUB 7-port 36W (I'm running 3 cables from the scope: USB + EQMOD to laptop, 12v to AC)
Guide scope: SvBony SV165 (120/30mm f/4) or SvBony SV106 (190/50mm f3.8)
Guide Camera: SV105 or ZWO ASI120MM Mini or ZWO ASI290MM Mini
And here are the predictable concerns and questions (beyond the fundamental one above):
Weight: total (depending on guidescope) will be ~3.0 to 3.4 kg. AZGti weighs 1.3kg. Counterweights, I have 1kg and 2kg. GD3WH is rated for 6kg, should I be worried? (I'll be at at the limit with CW). My RT75C tripod can supposedly carry 20kg - I have my doubts about that value but still I think I should be OK.
Guide scope: which one? Am I asking for trouble by trying to attach the 190/50 on that Guidemount clamp? (flexing!) Also, what's more important, light collection or larger FOV? (i.e. more "dimmer" stars or fewer "brighter" ones)
Camera: which one? (or another one altogether? The ASI174 is really expensive...) Thoughts about my choices:
SV105 (on 120/30: 5.15° x 1.83°, 5.15"/px; on 190/50: 1.73° x 1.16°, 3.25"/px)
Why? Price of course, plus wider FOV and better resolution than ASI120MM!
However, it's OSC and apparently only max. 500ms (can't this be hacked?). Would that be "good enough" for my setup?
ASI120MM (on 120/30: 2.29° x 1.72°, 6.44"/px; on 190/50: 1.45° x 1.08°, 4.07"/px)
Currently my favorite. I am contemplating the Mini rather than the -S; my 385 is already a very fast planetary camera so why USB3. Thoughts?
ASI290MM (on 120/30: 2.68° x 1.52°, 4.98"/px; on 190/50: 1.69° x 0.96°, 3.14"/px)
Seems a bit overkill to me. However, could I potentially use it to collect additional Luminance data (maybe Ha) on planets or even DSO (if I swap and guide with
ASI385)? Otherwise, what would the extra 100.- really get me in my specific situation?
Also, I am hoping that within a year or so I'll have access to more open spaces and darker (maybe Bortle 5) skies. I dream of upgrading at that point to something larger and better, and put say 10k into a 8" to 10" SCT or RC with a good mount and a cooled camera. I'm only mentioning this here because my plan would then be to recycle my 385 camera for guiding (OAG, or perhaps with the 72ED as guide scope). Is this viable? Since the stuff I'm buying now would pretty much only be used for this smaller setup, I prefer to save more for later rather than get too fancy here...
What would you do in my stead? (Or would my money be better spent on a larger camera and a field flattener? I already have a good bridge camera (Lumix FZ1000) so I'm not keen on getting a DSLR at the moment...)
And few bonus questions
Naive question of the day: why don't they make "hybrid" mono AND color cameras? i.e. by placing the Bayer mask on some kind of flip mechanism to switch from one to the other. I'm not an engineer so maybe this is a stupid idea...
I'm attaching an image of M81 that I obtained in Alt-AZ without guiding from a Bortle 5 sky (obviously not from home). However, I feel a bit guilty: I think I processed it so hard (cf raw stack) that it's simply "cheating" at this point! (stacked FITS and details available here) Thoughts?
Is this about in line what I can expect with my setup, or should I just practice more rather than spend more money at this point?