Help Processing Horsehead Nebula

[russellhq]

I've been practising on the following data I captured over the last couple nights while the clouds are here (definitely need more data but the skies aren't playing ball). This is the best I've achieved so far:

Equipment details are in signature, data details are 19 lights 300s@ISO1600, 100 Bias, 100 Flats.

The stacked TIF from DSS is in my dropbox:

https://www.dropbox....L-100F-100B.TIF

(you need to click through and on the next page there is a "Download" button you need to click to get the TIF.

Any help or suggestions on how I could get the best from the data would be greatly appreciated!

[russellhq]

Bump

[Leebert]

That's a great image

I'm very much a newbie at this but thought I'd give it a go... I used curves, levels and a few other bits that I've learnt from the great easy to follow video tutorials from here : http://www.eprisephoto.com/videos

A couple of things I have learnt with processing is that less is more and there's no substitute for more data - not easy with the last few moths weather!!

Could you share how you got Alnitak nice and small please?

[russellhq]

I used a curve like this:

I use the dropper tool and scan over the area near the star then set a point on the curve to represent the edge of the star. So when I stretch the nebulosity, I don't stretch the bright areas near the star.

I hope that makes sense.

[Leebert]

Thanks for the tip. It makes perfect sense. I did try and get a bit more out the image with no luck really. Just slightly different variations. Thanks for sharing your data - I appreciate being able to have a practise run at processing in these cloudy times. Apologies I couldn't improve on your image.

[rfdesigner]

Hi

I used IRIS to apply selective blurring, apply the equivelence of curves, adjust the saturation and gamma.

I also noticed your raw data looks like your scope was out of focus. (11 arc sec FWHM), did you use a FWHM focussing tool or a Bahtinov mask?

Derek

[russellhq]

I tried using the FWHM tool in APT but I might not be using it correctly. I use live view at full zoom and when I adjust focus (electric motor), the star moves slightly out the box (it's almost the same size as the box), so makes things tricky. So I usually end up focusing by eye at full zoom until I get the sharpest looking star.

I really should get/make a mask!

Thanks for having a go with the image, I definitely need more data! Just need the clouds to go away (and the moon).

[stem1989]

vote for a mask here, It makes life much easier! I find it easier to use than the FWHM tool.

[russellhq]

Made a mask today and boy is that a lot easier to focus with!! I also managed to grab another 30mins of data between the clouds:

[rfdesigner]

Those stars look a bit tighter.. looks like you've roughly halved your star size, which means you'll be sitting around 5 or 6 arc seconds FWHM. Which is starting to be respectable (and means you're now 4 times more sensitive to dim stars).

Nice improvement

Derek

[russellhq]

Thanks, though I'm not entirely convinced it was my focus that was out.

Here is an example single sub from my first image:

And here's a sub from last night:

I also have subs like this where my stars have little bits poking out from them.

I think this is my mount causing this. My guiding can be going fine, the skies can be clear then all of a sudden the PHD graph will spike (iv'e attached the PHD log for info).

PHD_log_01Feb13.txt

[rfdesigner]

if you're using a guide scope, are you certain that you don't have differential flexure or even fractional slippage?

Derek

[russellhq]

if you're using a guide scope, are you certain that you don't have differential flexure or even fractional slippage?

Derek

I can't be sure, but I started another topic (see link below) to discuss the mount as I think it might have something to do with it. You can see from the PHD Logs there is something going on with the declination axis, causing the star to jump quite reqularly.:

http://stargazerslou...-with-my-mount/