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What am i doing wrong ?


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So most nebula images i take end up link the following picture

 

This is about 40 x 80 second  images stacked in Sequator then i tried to auto stretch the image in pixingight and also manual in photoshop but they end up turning out roughly the same.

 

Sensor noise ? I am really unsure what im doing so wrong. I am new to this so please any advice would be welcomed.

 

 

Stretched image of North American Nebula.png

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Nikon D750 with 300mm lens but i can take images on any of my lenses and they look like this when auto stretched.

 

Tracked on star adventurer pro in a bortle 5 - 6 with ISO 400 for 80 seconds at f10 for better star rounding as wide open the stars are not so great

 

Like i say i can take this on a 50mm prime and still end up with some red distored stuff in my images. 

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There are some issues with your image: possible vignetting, dust specs, gradient caused by light polluting/moon (if it was taken in the last couple of nights), a fair bit of noise and probably some hot/cold pixels as well. 

The vignetting and dust can be corrected by taking flat frames after an imaging session.

For the hot and cold pixels, taking darks with a DSLR is not generally recommended, so ideally you'd want to dither between frames. It's possible to do this without an autoguiding system through software such as NINA, but I don't know if it's possible with your specific set up.

To reduce the noise, you'll want a combination of more integration time and careful processing. Proper processing should also remove the gradient. Acquiring the images is only about half of what astrophotography entails!

If you post up a link to download your stacked image, there are some experienced guys on here will be able to show you what's possible with proper processing of your current image. 

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Thank you for the replies all i will try to use flat frames next time and yes the moon was out about half moon showing so i will wait some time and try some without and see what happens with some flats. I can see this can be quite unforgiving but trying to stick with it.

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20 minutes ago, UberStar said:

Thank you for the replies all i will try to use flat frames next time and yes the moon was out about half moon showing so i will wait some time and try some without and see what happens with some flats. I can see this can be quite unforgiving but trying to stick with it.

It's possible to create a synthetic flat in software, it won't correct the dark spots caused by dust, but could help with vignetting and allow you to work with your current image a bit. 

This is not an easy hobby, but it really is quite incredible it's possible at all,  considering you are trying to capture photons of light that are thousands or even millions of years old which have travelled - unobstructed - across unfathomably large distances to get here.

Edited by The Lazy Astronomer
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