Quote:
Originally Posted by Atmos
They could be binning artefacts, your best way to see would be to take a dozen or so bias' and stack them, see if they remain.
From the 1x1 it looks like you have done tilt. The smaller the pixels are the more readily they become observable (I think).
What is a QHY22 worth these days? I have been considering making the change from my QHY9 for the much larger QE in Ha (30% vs 60%).
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thanks Colin, I think you are right on the tilt - i'll definitely check bias too. have sent a PM for more details on the cost.
Quote:
Originally Posted by Shiraz
that is starting to look really promising Russ.
You know this stuff, but FWIW, the various faults might possibly be:
1. field rotation - see if the star elongation changes with exposure length.
2. collimation - did you collimate through the CC? - minor tilt in the CC elements can throw everything off and I found that collimating through the CC was essential.
3. image plane tilt - anything other than screw thread or flange extensions will be too sloppy to keep stuff aligned. If the image train is rigid and there is still some tilt, I think that the camera has a tilt adjustment ring? the SX website has a great procedure for adjusting CCD tilt using laser projection if you need to adjust the camera - should work fine with a QHY
4. flex - if that is one of the GSO steel tube scopes, it would be a good idea to reinforce it around the focuser.
5. CC spacing - has to be exact including any filters - there is nowhere for minor aberration to hide with small pixels
not seen anything like the row fault in the 2x2 image - could it be a jpeg compression artefact maybe. Maybe ask Theo for an opinion, but I would sort out the other stuff before worrying about that issue. Otherwise, the chip looks very clean.
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thanks for commenting Ray - yes if I can get everything working together reasonably well I should be able to punch out some half reasonable images - with the 12"f4, 694 chip combo. well actually the qhy22 is lighter than the old 600d (470grams vs 570) and I think has larger pixels too (4.54 vs 4.3)! definitely a much smaller fov which should make it image capture easier ... in theory atleast! if I had that result on a dslr it would be even more of a shocker! (the weight the depth of the qhy22 does possibly shift the centre of gravity further from the focuser than the dslr - could be a factor and I may need to therefore do further focuser strengthening).
i'll aim to correct, tilt and coma corrector distancing first as I am fairly confident most other things shouldn't have changed from my setting up procedure, I would get pretty good stars most of the time.
I've ordered a 15mm and a 20mm spacer from TS. in conjunction with my 17-23mm variable spacer, tsoag9, filter draw - i'll be able to get the RCC1 up and running again and avoid that terrible extension tube I had to use.
thanks for the comments i'm hoping the spacers and RCC1 (and better PA) will do the trick. Just a question on collimating through a CC? The MPCC has connectors to use visual, I don't think the RCC1 does, how do you do it for yours? I assume there is a 1.25" eyepiece adaptor available?