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The Heart. Back to basics.

davew

By davew
in Imaging - Deep Sky

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davew

davew

Posted
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Processing this image has reminded me to take care of calibrating and stacking like I used to ! It’s too easy to chuck things into your favourite program and sit back.

Due to the fact that clear nights don’t come that often, I decided to image when there was thin cloud and damp air about. I really should have done something more productive like watch TV ! Even the guider was bleeping every few minutes. Ha is good at punching through most rubbish but it isn’t a miracle worker.

The usual routine is collect all dithered subs, flats and bias and run auto calibrate and SD mask in Maxim with no darks. 10 subs will usually do but this time the result was painfully lacking in signal, no contrast, slightly larger than normal stars, residual hot pixels and heaps of noise.

So…… back to basics. I already knew about Russell Croman’s ( He wrote Gradient XTerminator ) RC Console so set about using it sub by sub.

http://www.rc-astro.com/resources/rc_console.html

With this plug-in it’s possible to manually calibrate and look at the results as you go. I let Maxim do most of the flats and bias settings but used the hot pixel filters, normalisation, Sigma reject processes and even tried the anisotropic blur for the background. I even tried Maxim’s DDP but failed miserably as usual. What would take two minutes to set up now took me well over forty minutes !

Into PS for levels and many curves. More slight background noise reduction via inverted layer mask. No sharpening but two iterations of Peter Shah’s star reduction routine. And a few more things I’ve forgotten about I’m sure but all aimed at bringing out the fainter stuff. Shame I messed up the top left corner but I’m not doing it yet again !

The image is not going to win any competitions but it’s shown me not to get too complacent with my calibration and to think once in a while. The original was (more) awful I assure you. A fair salvage operation in the end after three separate stacks and four processes.

I hope this tale of woe persuades others to try and try again when things don’t go right.

Moravian G2 8300. Astrodon Ha filter. 10 x 15 minutes dithered. 250mm camera lens at f4 ( wide open ). Cropped to square.

Dave.

post-493-0-48784400-1363885924_thumb.jpg

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Fay

Fay

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well done Dave. lots of lovely detail in there.

it has been a bad year, for a lot of us, up to now, for imaging. you did well to get something so good in the continuing adverse conditions

Fay

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davew

davew

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Blimey Dave, you have really captured some detail in this image! I like it :smiley:

Thanks Sara. It's partly down to you that I re assessed my calibration. I noted on one of your posts that you had your calibration files open when you used them in Maxim. I took it from there so Cheers :)

Dave.

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