Faint Background Stars
The AstroGrav download includes approximately 118,000 stars from the Hipparcos catalogue for use with solar system simulations. This is adequate for many purposes, but some users will require many more background stars, particularly when wanting to see the detailed star background near a faint asteroid or comet. To satisfy this requirement, millions more faint background stars are available as separate downloads. They're supplied as separate downloads because the data is many times the size of the rest of AstroGrav, and so only those who are interested need to download them.
There are four different faint background star downloads available. Drawing performance is slower for the larger downloads with more faint background stars, so it's a good idea to choose the smallest download that satisfies your requirements. If you want as many faint background stars as possible and aren't too concerned about drawing speed, choose the largest download, which contains stars down to 15th magnitude.
Download
Click on the link below to download approximately 3 million background stars down to 12th magnitude.
Download Background Stars to 12th Magnitude
Stars 12.zip : 43.9 MB (43,903,976 bytes)
Click on the link below to download approximately 7 million background stars down to 13th magnitude.
Download Background Stars to 13th Magnitude
Stars 13.zip : 103.7 MB (103,660,453 bytes)
Click on the link below to download approximately 16 million background stars down to 14th magnitude.
Download Background Stars to 14th Magnitude
Stars 14.zip : 235.4 MB (235,435,301 bytes)
Click on the link below to download approximately 36 million background stars down to 15th magnitude.
Download Background Stars to 15th Magnitude
Stars 15.zip : 512.0 MB (511,975,188 bytes)
Installation
When you have downloaded one of the above files, unzip it, and move it to the folder containing the AstroGrav application. On Windows, this is usually the C:\Program Files\AstroGrav folder, and on a Mac, this is usually the Applications/AstroGrav folder. If you already have AstroGrav running, you need to restart it in order to see the faint background stars.
If you install more than one of the above files, AstroGrav will automatically choose the largest one, with the most faint background stars.