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Dithering without a autoguider


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Hi all,im starting astrophotography,and i was wondering if i should dither if i don’t have a autoguider.I have read a few posts about that and some guys said that i don’t need to dither if i don’t use a autoguider,some said that i should use APT dithering or NINA’s direct guider device.What should i do?

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It would help to know what equipment you are using, but you did preface with 'I'm new' so it's probably safe to assume that your polar alignment isn't spot on, which can be advantage for dithering. So long as you keep your exposures short, say 10 seconds, you shouldn't have star trails, and that makes guiding redundant for you. The disadvantage with that is that you will have a huge number of total exposures to store, and later stack, which will take up a lot of storage space and time when it comes to stacking. The advantage is that you will not pay a penalty for taking short exposures in terms of image quality, just so long as your total integration time is reasonable.

If your polar alignment was spot on then in theory you would track your target precisely. That would imply that the dead, hot pixels and thermal noise are always aligned, requiring dark frames to remove them. That is what dithering helps with, and is effective during stacking.

I do use NINA and rate it highly, but if you don't already use a computer to control your sessions then dithering is not a reason to make that change.

I should probably caveat everything i have written with 'it's a bit more complicated than that' but you will learn that yourself.

I recommend watching Dr Robin Glover's Youtube videos on CMOS sensors regarding exposure length.

TLDR: Probably don't worry about it.

HTH

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16 minutes ago, Ohgodwherediditgo said:

It would help to know what equipment you are using, but you did preface with 'I'm new' so it's probably safe to assume that your polar alignment isn't spot on, which can be advantage for dithering. So long as you keep your exposures short, say 10 seconds, you shouldn't have star trails, and that makes guiding redundant for you. The disadvantage with that is that you will have a huge number of total exposures to store, and later stack, which will take up a lot of storage space and time when it comes to stacking. The advantage is that you will not pay a penalty for taking short exposures in terms of image quality, just so long as your total integration time is reasonable.

If your polar alignment was spot on then in theory you would track your target precisely. That would imply that the dead, hot pixels and thermal noise are always aligned, requiring dark frames to remove them. That is what dithering helps with, and is effective during stacking.

I do use NINA and rate it highly, but if you don't already use a computer to control your sessions then dithering is not a reason to make that change.

I should probably caveat everything i have written with 'it's a bit more complicated than that' but you will learn that yourself.

I recommend watching Dr Robin Glover's Youtube videos on CMOS sensors regarding exposure length.

TLDR: Probably don't worry about it.

HTH

I have a HEQ5,Canon 450D and ED80 with a lenovo laptop

i had some experience with GoTo mounts,but i never used a EQ mount before

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Then i will suggest using NINA, even without guiding you can use it with Stellarium for a rough go to, then plate solve using ASTAP. You can plan your sequence ahead of darkness then just press play when it's time. The flats wizard is really handy. You can still use the 3 point polar align feature because you can plate solve. There is a guy called Cuiv the Lazy Geek that has a Youtube channel, he has covered everything you need to get it running. It's free!, and when you're ready to start guiding NINA will start that for you as part of the sequence.

I've probably oversold NINA a bit, but once you get a good handle on it it's great.

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2 hours ago, Ohgodwherediditgo said:

Then i will suggest using NINA

I would agree with OMGWDIG there, and my experience with a DSLR and APT was to always dither so that you don't have to take dark frames. 

I'm a true NINA convert too, but I'd recommend not rushing to enable every feature from the get-go - start with the simple things then add more to your routine as you get used to how things work.

I remember in my first couple of sessions simply setting exposure 'loop' and 'save' in the imaging tab, and not going anywhere near the scheduler options. 

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3 hours ago, Ohgodwherediditgo said:

Then i will suggest using NINA, even without guiding you can use it with Stellarium for a rough go to, then plate solve using ASTAP. You can plan your sequence ahead of darkness then just press play when it's time. The flats wizard is really handy. You can still use the 3 point polar align feature because you can plate solve. There is a guy called Cuiv the Lazy Geek that has a Youtube channel, he has covered everything you need to get it running. It's free!, and when you're ready to start guiding NINA will start that for you as part of the sequence.

I've probably oversold NINA a bit, but once you get a good handle on it it's great.

 

19 minutes ago, adyj1 said:

I would agree with OMGWDIG there, and my experience with a DSLR and APT was to always dither so that you don't have to take dark frames. 

I'm a true NINA convert too, but I'd recommend not rushing to enable every feature from the get-go - start with the simple things then add more to your routine as you get used to how things work.

I remember in my first couple of sessions simply setting exposure 'loop' and 'save' in the imaging tab, and not going anywhere near the scheduler options. 

Ok thx guys

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