
Input an image and get back astrometric calibration metadata - davidbarker
http://nova.astrometry.net
======
jcurbo
Since this is fairly popular and no one has responded yet, I will give it a
shot!

This service does what is called 'plate solving' \- plate coming from the
photographic term. This technology uses pattern matching to identify
photographs of the night sky based on existing sky surveys. You submit your
image and get back an annotated version that lists what objects it detected.
Here are a few examples that I have submitted in the past:

[http://nova.astrometry.net/user_images/758190#annotated](http://nova.astrometry.net/user_images/758190#annotated)
\- the Cygnus region

[http://nova.astrometry.net/user_images/737354#annotated](http://nova.astrometry.net/user_images/737354#annotated)
\- a wider shot of Cygnus and some other nearby constellations

[http://nova.astrometry.net/user_images/932613#annotated](http://nova.astrometry.net/user_images/932613#annotated)
\- just south of the Orion Nebula

As you can see it will annotate constellations, specific stars, and other deep
sky objects.

This is a very useful feature for an amateur astronomer's workflow (which is
what I use it for) especially when doing long exposure astrophotography as you
may not be able to tell exactly where your telescope is pointed when it's
zoomed in. Many people use a local version of this software bundled with a
program called Astrotorilla
([http://sourceforge.net/p/astrotortilla/home/Home/](http://sourceforge.net/p/astrotortilla/home/Home/))
tied in with their imaging software (such as BackyardEOS) to ensure they are
pointed at the right place and to correct drift. The software will take a
photo, send it to the plate solver, which returns an annotated version, and if
your computer is connected to a compatible mount, it will send the right
commands to move the telescope.

There's even a Reddit bot that uses astronomy.net and replies to sky images
with an annotated version. Here's an AMA from the author:
[https://www.reddit.com/r/astrophotography/comments/1ptdkv/hi...](https://www.reddit.com/r/astrophotography/comments/1ptdkv/hi_i_made_uastrobot_ama/)
Here is another neat post showing a map of the night sky and highlighting
where astro-bot has plate solved:
[https://www.reddit.com/r/dataisbeautiful/comments/1wdfe4/the...](https://www.reddit.com/r/dataisbeautiful/comments/1wdfe4/the_heatmap_showing_all_reddit_astrophotographies/)

~~~
rripken
There was a google talk about the CS behind astro-bot.

Scale, rotation and translation invarient searches. Pointerless kd-tree
implementation.

[http://cosmo.nyu.edu/hogg/research/2006/09/28/astrometry_goo...](http://cosmo.nyu.edu/hogg/research/2006/09/28/astrometry_google.pdf)

------
Tossrock
Looks like they left debug=True on in their config :(
[http://nova.astrometry.net/user_images/946382](http://nova.astrometry.net/user_images/946382)

