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:
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/) 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.
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 - the Cygnus region
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 - 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/) 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... 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...