<p>For a few years now, I've been shooting photos of the night sky with just a tripod and my Nikon DSLR.  After extensive post-processing to mitigate light pollution, I usually submit the final results to nova.astrometry.net for constellation diagrams and labels.  For basic orientation this works very well, but not for judging how well my camera is picking up the faintest stars.  The difficulty is that in trying to compare my photo with an app like Sky Safari or Stellarium, I can usually look at either the app or my photo, but not both at the same time.  In switching from one view to the other, I &quot;lose my place&quot;, as it were.  Moreover, unlike most terrestrial map tools, apps like Stellarium generally don't allow you to arbitrarily rotate the display, so a constellation might be lying sideways in my photo but standing upright in Stellarium.  (I know, I could rotate my photo display, but that's not always convenient, either.)</p>
<p>Obviously, a grid of celestial coordinates would be a huge help here.  Is there an app or website that can do this?  How about if one can identify some known stars in the photo?</p>

CC BY-SA 4.0
2022-06-14T09:07:08.567Z
I guess this algorithm ought to exist already. If I'm not mistaken the star trackers in the spacecraft are supposed to do a similar job to what you're after. They take pictures of the space (stars) and the on-board computer (algorithm/software) subsequently work out the orientation of the spacecraft using the catalogues available. Hope someone will be able to point you to the right source.
mysterium
CC BY-SA 4.0
2022-06-14T12:46:34.697Z
It looks like Pixinsight does what you want: https://www.youtube.com/watch?v=n6IXE7JwQl8 . Another possibility is ASTAP.
Greg Miller
CC BY-SA 4.0
2022-06-14T14:16:59.720Z
I use [ASTAP](http://www.hnsky.org/astap.htm) for this
Aaron F
CC BY-SA 4.0
2022-06-17T07:20:18.200Z
Thanks for the suggestions, I'll look into those products.

I might need to clear some space on my hard drive, though.  I've been needing to do that anyway.
user382459
<photography><astrometry>
Is there a website or app that can add declination and RA grid to an existing photo?
user382459
# Is there a website or app that can add declination and RA grid to an existing photo?

(Asked by: username_0 on 2022-06-14)

For a few years now, I've been shooting photos of the night sky with just a tripod and my Nikon DSLR. After extensive post-processing to mitigate light pollution, I usually submit the final results to nova.astrometry.net for constellation diagrams and labels. For basic orientation this works very well, but not for judging how well my camera is picking up the faintest stars. The difficulty is that in trying to compare my photo with an app like Sky Safari or Stellarium, I can usually look at either the app or my photo, but not both at the same time. In switching from one view to the other, I "lose my place", as it were. Moreover, unlike most terrestrial map tools, apps like Stellarium generally don't allow you to arbitrarily rotate the display, so a constellation might be lying sideways in my photo but standing upright in Stellarium. (I know, I could rotate my photo display, but that's not always convenient, either.)

Obviously, a grid of celestial coordinates would be a huge help here. Is there an app or website that can do this? How about if one can identify some known stars in the photo?

**Tags:** photography, astrometry
> **Comments:**
> **username_1**: I guess this algorithm ought to exist already. If I'm not mistaken the star trackers in the spacecraft are supposed to do a similar job to what you're after. They take pictures of the space (stars) and the on-board computer (algorithm/software) subsequently work out the orientation of the spacecraft using the catalogues available. Hope someone will be able to point you to the right source.  
> **username_2**: It looks like Pixinsight does what you want: https://www.youtube.com/watch?v=n6IXE7JwQl8 . Another possibility is ASTAP.  
> **username_3**: I use [ASTAP](http://www.hnsky.org/astap.htm) for this  
> **username_0**: Thanks for the suggestions, I'll look into those products.  I might need to clear some space on my hard drive, though.  I've been needing to do that anyway.  

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## 0 answers

