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I'm new to all this and trying to implement galaxy counting. For the initial stage I need raw image data, that is images with galaxies and stars along with a count of how many galaxies there are in the image.

I came across this which seems to have a way to label galaxies

http://skyserver.sdss.org/dr13/en/tools/chart/navi.aspx?ra=179.68929&dec=-0.45438&opt=

but I cannot figure it out at all, I used this page

http://skyserver.sdss.org/dr13/en/tools/chart/chartinfo.aspx

to try to get it to label only galaxies are seen but I got nothing (put G in opt section, did not make a difference).

Does anyone know how to operate the above or where I could get images with lots of galaxies (any number would do) in them along with a count of how many galaxies there are in the image?

I found https://data.galaxyzoo.org/ but traversing it seems impossible

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You might find the NED database and Astrometry.net useful. NED is NASA's extragalactic database. You can search by a position in the sky with a radius and it will give you a list of known objects in that field.

Astrometry.net lets you upload images and will resolve what you're looking at, also giving you a list of known objects in your image.

I like to use CDS for a quick look up on objects. This will let you browse images from different surveys easily and links you to other sources on that object as well as publications about your object.

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  • $\begingroup$ Do you have any idea how I could use image processing to classify different kinds of galaxies? I know that for elliptical galaxies, I can directly estimate the parameters of the best fit ellipse (to the contour) and get the eccentricity, thresholding on its value can give me a rough E0 - E5 scale. What about the other kinds? Also Do you know how to differentiate between stars and galaxies, given only image data? Not any other sensor/header data, but only image data? $\endgroup$
    – astroman
    Commented Apr 19, 2017 at 6:51
  • $\begingroup$ Please tell me how to use the NED, I cannot get it to give me the images! $\endgroup$
    – astroman
    Commented Apr 19, 2017 at 12:46
  • $\begingroup$ I get this when trying to do a search ned.ipac.caltech.edu/cgi-bin/… $\endgroup$
    – astroman
    Commented Apr 19, 2017 at 12:49
  • $\begingroup$ Can you tell me how I could use the queries? Say I want an image of a region with only the count of ALL galaxies in that region, then save that image without any labels $\endgroup$
    – astroman
    Commented Apr 19, 2017 at 12:50
  • $\begingroup$ If you want to build some software then you might want to have a look at Astropy, I believe it has programmatic interfaces for querying databases like NED. $\endgroup$
    – zeitoon
    Commented Apr 19, 2017 at 17:32

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