Thank you everyone for your great comments and suggestions! All very rewarding, encourages us to post more!
Quote:
Originally Posted by jjjnettie
When you look at this galaxy, you are looking at it from underneath aren't you?
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Hmm.. I've always thought it was viewed from 'above', but it could just as easily be seen as from 'underneath'. I really don't know. Confusing, since the viewing angle changes depending upon telescope design. Perhaps someone on this forum can help clear this up... underneath or above?
Quote:
Originally Posted by seeker372011
nice shot Rob.I still havent managed first light with the 127 and looks like it wont be this weekend...violet halos around bright stars though are quite apparent..maybe use Noel Carboni's PS actions to get rid of them?
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Yep, gotta get rid of those halos. The 127 has a nice flat field, but the colour correction is not perfect. Still excellent value though. I've had a look at Noel Carboni's PS actions, seems like good value and I'll probably make the investment.
Quote:
Originally Posted by ghsmith45
Nice colour, detail and contrast, but fixing the trailed stars in Photoshop would make it much better..
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Yep, trailed stars bug me. See my comments on trailed stars below..
Quote:
Originally Posted by gregbradley
Nice one Rob.
I don't quite understand something though with this image. You have the larger stars round and the other smaller stars elongated from tracking errors. How come? Were there a few subexposures with tracking errors?
Here's a technique that can save some subexposures with tracking errors:
1. make a duplicate layer.
2. Set it to "darken".
3. Filters/others/offset
4. Set it to different amounts for vertical and horzontal to help correct the elongated stars.
5. Layers/flatten image.
You can also lassoo the area of the galaxy so only the stars get offset.
You'll save some images that way.
Also you can use the smudge tool to push elongated stars from different angles to make them rounder.
A couple of tricks for you mate.
Greg.
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Thank you for the offset trick! I've given offset a quick try with OK results, but I'll give it a bit more work before I post my results. As you suggest, I need to lassoo the galaxy (and the brightest stars) to optimise the result.
I've used the rubber stamp tool to clean up trails of hot pixels, this works nicely as well.
Trailed Stars:
I have an issue with guiding/flexure on this new set-up. Imaging with the 127mm f7.5 (953mm focal length) and guiding with a webcam through an 80mm f5.0. (400mm focal length) piggyback.
The system smears 1 to 1.5 pixels every 5 minutes. Measured by observing lines of hot pixels in stacked images.
The guider does not report errors, so this suggests flexure between the guidescope and the imaging scope.
Next time out, I want to use an ED80 (600mm focal length) as my guider, and fix the piggyback arrangement to improve rigidity.
Any suggestions as to piggyback mechanical arrangements will, of course, be most welcome!
Cheers,
Rob
