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M31 1 frame


Petrol
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Finally upgraded my EQ5 to go to but only managed one pic before the clouds rolled in. I appreciate it’s very poor :D and it seems the alignment isn’t correct due to the trails but we all have to start somewhere :)

The question is, if I were to take loads of exposures over maybe an hour and stack them, would I end up with something with a little bit more detail? Also, it looks like there’s a bit of light pollution going on there, would a filter help that?

Skywatcher 200P

Nikon D70s, unmodified at prime focus

800 iso

174 secs

Auto WB

M31.jpg

Thanks for looking and any comments / advice are more than welcome

Pete

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That's a good first shot, Pete. It looks like your polar alignment is a little off but when you sample down (resize the image down) it will reduce the effect of the star trails.

A light pollution filter would certainly help. There are a few choices for this, largely depending on how much money you want to spend. The Skywatcher LPF is pretty good at cutting out most of the orange but the Astronimik CLS-CCD is even better, cutting out mercury vapour and many other contributing factors to sky glow too. The Hutech IDAS filter is a little better than the Astronomik CLS-CCD as it doesn't cut as harshly. The Baader LPF is similar to the Skywatcher LPF in terms of frequency cut.

More light subs helps reduce the noise which in turn allows you to pull more detail out of the images before noise becomes a problem. Take darks, flats and bias too and stack them all in Deep Sky Stacker (or similar). Then process in Photoshop (or similar).

Hope this helps?

Mike

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I would have a go at getting as good a polar alignment as you can and then findind the longest you can expose the camera for before trailing becomes evident. Then take as many subs as you can. Take at least 10 frames of the same length with the scope capped off for the dark frames.

If you suffer from mostly sodium light pollution which your image indicates, I would use a Neodymium Filter which leaves less of a colour cast on the image and is easy to process out. It's also a lot cheaper than the others mentioned.

Regards

Kevin

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That’s a massive help! The modded picture looks miles better and has inspired me- thanks Mike.

I didn’t know about dark & flat frames. I have downloaded Deep Sky Stacker and it explains what’s required in the manual.

Next time I will get better alignment, take some trial subs to get my maximum exposure without trails. Then it’s lots of subs and finally darks & flats. Wow – there’s a lot to learn but I love something to “get my teeth into” Oh and it’s RAW from now on.

On the light pollution issue, I have bought a skywatcher 2” Thought I would go cheap and cheerful for starters and see how it goes.

Guys, thanks for helping a newbie out :)

Pete

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