Omega cent plus a repro of eta

[vash (Ashley)]

My new field flattener came in and took a little while with rain and all to get a clear night to test it out. I'm not happy with it but I need to do some testing in case it is another issue entirely.

Didn't give it much effort though still a good result and has given me another taste of what this scope can do.

modded 450d - FLT110.
15x2minutes
no darks or flats

first is the full frame low res and the other a crop of the glob itself.

I also just reprocessed my eta data from the last image I posted, I tried too contrast the colour to get more detail out, I like it a little more that the older one but thats my opinion.

hires cent - http://i286.photobucket.com/albums/l...g?t=1245460039
repro eta - http://i286.photobucket.com/albums/l...g?t=1245460397

[multiweb (Marc)]

Hi Ashley, it looks like you have a slight astigmatism problem. I'd take care of this before targeting any field coma. Once it's clearer where the problem lies you can move on and sort the rest out. I assume it's a refractor. If it has any way of tilting or rotating the lenses you might want to try that first. Slight rotation goes a long way. Give it a go, see if it gets better or worse.

[vash (Ashley)]

if it was astigmatism wouldn't it be visible in the eta shot? although that was with the MPCC and not the W/O one. I did a star test and as far as I can tell the scope is good, nice clear round rings in the airey disk cause at first I thought it might be collimation but i didn't notice it was on all corners.

[multiweb (Marc)]

Originally Posted by vash

if it was astigmatism wouldn't it be visible in the eta shot? although that was with the MPCC and not the W/O one. I did a star test and as far as I can tell the scope is good, nice clear round rings in the airey disk cause at first I thought it might be collimation but i didn't notice it was on all corners.

It is visible also in the ETA shot although not as noticeable as the stars are a bit more bloated. Maybe due to longer exposures.

[Hagar (Doug)]

Hi Ashley Nice image just the curvature. It might need a bit of experimentation to get the distance behind the flattener just right to remove this.

Nice stars in the central area.

[peter_4059 (Peter)]

Are you using the MPCC with a refractor? I thought it was designed for newtonians.

http://www.baader-planetarium.com/pdf/mpcc_e.pdf

[vash (Ashley)]

yeah, I used the MPCC when I first got the scope as I didn't have the proper one and it was the only way to attach the camera to the scope, for this purpose it worked but it over corrected the image and gave what I thought was reversed coma.

Once it clears up I can do a prime focus shot with out any correcters in place if it is still there then I got onto the next phase of problem solving if not than the Feild flattener might be at fault, I'll test it on my ed80 as well and see what it does with it compares with prime focus one.