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Best way to know how many galaxies in an image?

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#1 hyperhugs

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Posted 08 March 2021 - 04:34 PM

This weekend we had some rare clear skies in New Hampshire, so I took about 6 hours of data of Markarian's Chain. I'm very curious to know how many galaxies I captured in my final image. I put it into Astrometry.net and got a decent result, but there are fuzzy spots which I assume are galaxies that were not picked up. Is there a different service or program that might give a better result?



#2 rj144

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Posted 08 March 2021 - 04:35 PM

Did you hit the link to go to World Wide Telescope?  You can probably see everything there under the overlay.


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#3 klaussius

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Posted 08 March 2021 - 04:41 PM

Aladin lite is a great place for that kind of hunt.

 

But I can answer it for you rather easily: billions upon billions.

 

Wherever you point your scope to, there will be lots of background galaxies. The question is whether you can resolve them in your image, and AFAIK platesolvers don't tell you that, they just mark objects that should be there based on a database of objects.

 

What I usually do is look at my image in high zoom and check anything fuzzy in that site I linked above. Often it's a galaxy, but sometimes I've found other objects, like supernova remnants, AGN, etc. Quite fun. Set up an alarm to get bring you back from that rabbit hole though.


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#4 limeyx

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Posted 08 March 2021 - 07:38 PM

This weekend we had some rare clear skies in New Hampshire, so I took about 6 hours of data of Markarian's Chain. I'm very curious to know how many galaxies I captured in my final image. I put it into Astrometry.net and got a decent result, but there are fuzzy spots which I assume are galaxies that were not picked up. Is there a different service or program that might give a better result?

Pixinsight has a great "Annotate" script

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#5 hyperhugs

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Posted 09 March 2021 - 12:04 PM

Thanks everyone, this has been very helpful!




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