New setup for EEVA... working AT LAST?

[AKB]

It's been so... long... since I've done anything here.  But with a nice few evenings recently, I thought I'd get going again and try a new configuration for EEVA (old hardware, I've just not used it this way before):

• Celectron 9.25" SCT XLT
• Celestron x0.63 reducer/flattener
• ASI-294MC OSC
• IDAP-P2 filter in Baader filter slider

This should give me about 0.74° FOV and 0.6" per pixel – way over sampled, but good to bin x2.

However, I've wasted days trying to get this working without ghastly abberations.  I thought it was ...

• collimation, so that's been done again and again
• dirt on the corrector plate
• wrong back focus from the reducer (may still be)
• camera tilt
• something dreadfully wrong with the primary mirror alignment...

....but in desperation (late) last night, I pulled out the filter, and lo and behold things seems to get a lot better.

So I took I a few shots of a rich starfield in Cygnus, to run in CCD Inspector (yet to be done) and a few of

• M13  –  15 x 1 minute (happy to get a bonus galaxy, but didn't try to process for this)
• Albireo – 10 x 10 seconds

If there's anyone out the who feels qualified to comment on whether I should expect better result from this configuration, I'd be very grateful. I'm just not sure what to expect in terms of star quality.  These are binned x2 images, after a bit of stetching (darks but no flats).

Thanks

Tony

 

 

 

[Martin Meredith]

Hi Tony

They're certainly very nice EAA shots! Great resolution. Looking more closely I can see what you mean about odd effects (more visible on the Albireo shot). There is a certain triangularity that is characteristic of pinched optics, but it is not very equilateral and not apparent everywhere. I think you might get more joy asking the hard-core AP crowd.

Have you rules out stacking artefacts? What does a single sub look like?

I'd be interested to know how you get on with CCDInspector. I've always wanted to use it analyse what I suspect is tilt in my setup but I believe it doesn't (or didn't, last time I looked) run on Macs.

cheers

Martin

[AKB]

Hi Martin

 

Thanks for the comments.  I'll hit the AP crowd later, but getting things right for EAA is what I'm after.  Single frames have the same issue.

Speaking of which, any updates to Jocular?

I'm actually out in the observatory right now...looking at M3... anything spring to mind for this FOV?

 

Thanks

Tony

[AKB]

Well, I decided to tweak the setup a bit more and try it out on something a bit more interesting, so here's NGC 185 (C18), 10 x 2min, cropped.

Perhaps not what you'd call EAA, though (too long an exposure?)

 

 

[Mike JW]

Hi Tony, I use to use a C9 and the C x0.63 reducer, now I use a C11 and the reducer. Back focus for the reducer is 105mm but 100mm works fine.  I do clean the corrector plate (very carefully) and that reduces the dust bunnies.

Your results are way better than I ever got but then I was using the Ultrastar and not a small pixel camera. Mike

[Martin Meredith]

12 hours ago, AKB said:

Hi Martin

 

Thanks for the comments.  I'll hit the AP crowd later, but getting things right for EAA is what I'm after.  Single frames have the same issue.

Speaking of which, any updates to Jocular?

I'm actually out in the observatory right now...looking at M3... anything spring to mind for this FOV?

 

Thanks

Tony

HI Tony

Aiming to release Jocular for testing in a week or two and more widely in October.... (looking at your sig line) with native support for the mono Ultrastar (mono Lodestar is already there). 

For that FOV I think some of the larger Abell galaxy clusters would look superb. I'm thinking Abell 426 in Perseus which covers just under a degree, and 2147 and 2199 in Hercules.

From a distance, NGC 185 looks like the view of Centaurus A through a small refractor. Very interesting to see it in colour with that clear dust lane. I don't find 20 mins excessive for EAA for an interesting object like this, but I myself would be using shorter subs in a live context (not least because I'm using alt-az!)

cheers

Martin