Newbie

[twobleak]

Hi Everyone

I'm a complete beginner with Astrophotography (fairly competent with a DSLR though) and I've just managed to get my hands on a Skyguider Pro and have a first attempt at some imaging. I only have a Nikon 35mm 1.8 lens right now so I'm just getting to grips with the basics. I've had a crude attempt at capturing Andromeda but I'm wondering what might be going on with the image after stacking in Astro Pixel Processor? Now I realise I was fighting all kinds of problems with this - a fair amount of cloud, street lamp very close to my garden and ~80% moon illumination for starters but being a complete newbie, I'm not really sure what to make of the problems in this image? It does appear to clean up better when using the light pollution removal tools but am I doing something horribly wrong?

Some info on what I grabbed: 60 x 1 minute lights (iso 400, f4), 20 dark frames, 40 bias frames and 40 flat frames. Stacked in APP with all the defaults chosen.

Dropbox link to a higher quality jpg https://www.dropbox.com/s/09883stb6wxccj8/test-RGB-session_1-St.jpg?dl=0

Thanks

 

 

Edited December 5, 2020 by twobleak

[wimvb]

Better post the stacked but otherwise unprocessed tiff or fits file, if you want help. Diagnosing a processed jpeg is nigh impossible.

[twobleak]

Ok, fits file is here https://www.dropbox.com/s/il2t6z7ia8en3va/andromeda-RGB-session_1-St.fits?dl=0

It was 45 lights, not 60. My mistake.

[wimvb]

2 hours ago, twobleak said:

Ok, fits file is here https://www.dropbox.com/s/il2t6z7ia8en3va/andromeda-RGB-session_1-St.fits?dl=0

It was 45 lights, not 60. My mistake.

If this is the unprocessed stacked image, there is either something seriously wrong with your stacking workflow, or your data capture.  What do single subframes look like? If they look similar, you may have had dew on your telescope lens. If the subs look clean, it must be your workflow.

[twobleak]

I was very critical about checking for dew as I had a new dew strap fitted which I wasn't sure was any good. However no dew formed on the lens or in general. This is only my Nikon 35mm 1.8 lens though, not a telescope.

Here are two raw files (lights) from that session, the first and the last. Fair bit of cloud but they seem ok I thought? 

https://www.dropbox.com/s/lg8bwyc76tcvl86/LIGHT_60s_400iso_4-0_20201204-21h58m32s349ms.NEF?dl=0

https://www.dropbox.com/s/4505j9qou922n3k/LIGHT_60s_400iso_4-0_20201204-22h47m08s061ms.NEF?dl=0

I've also stacked everything again in DeepSkyStacker using the defaults/recommended settings. Here is the unprocessed TIFF:-

https://www.dropbox.com/s/nlxo2o2dal6zgkb/Autosave.tif?dl=0

 

[wimvb]

It was clouds that spoiled your image. Here's a single sub

Btw, do you have software to evaluate raw image files (NEF)? If not, I can recommend RawTherapee. It allows batch processing and examination of raw files.

And here's a somewhat cleaned up stack

Next time, if you center on the bright star between Andromeda and the lower left corner, you will also capture M33. In this shot, you just missed it.

 

[twobleak]

Thanks so much for looking. I did also import the raw files into Lightroom and some of the lights had to be rotated left to get them back into landscape orientation - I have no idea why though. I then run another stack through Astro Pixel Processor and this does look a lot better (one corner appears to suffer from clouds/light pollution the most), could the orientation of the images (and then the clouds) have a big impact on the final image? 

[wimvb]

The image information, including camera orientation, is kept in the exif image header. Astronomy programs don't usually read this information. Instead they use the stars to orient the image. There shouldn't be any impact on the final stack.

[rickwayne]

You can easily do that yourself, by the way -- just go to nova.astrometry.net and upload your image (they list supported formats). You will get back exceedingly precise information on exactly where you were pointed, how much the camera was rotated WRT the standard coordinate system, objects in the field of view, etc.

Shockingly (to me, at least) that plate-solving software can also be run on your own computer. In fact it runs on a Raspberry Pi!  Most folks using computers to drive their telescopes depend heavily on it. Sky ignoramus that I am, if plate solving tanks for some reason, I'm left literally stumbling around in the dark.

[twobleak]

20 hours ago, rickwayne said:

You can easily do that yourself, by the way -- just go to nova.astrometry.net and upload your image (they list supported formats). You will get back exceedingly precise information on exactly where you were pointed, how much the camera was rotated WRT the standard coordinate system, objects in the field of view, etc.

Shockingly (to me, at least) that plate-solving software can also be run on your own computer. In fact it runs on a Raspberry Pi!  Most folks using computers to drive their telescopes depend heavily on it. Sky ignoramus that I am, if plate solving tanks for some reason, I'm left literally stumbling around in the dark.

Thank you, I will take a look at that.