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Note: After installing a new comet or asteroid file, execute the "Compute All Comets" and/or "Compute All Asteroids" functions before accessing the new data.

Comet Data

Updated comet elements for MegaStar can be downloaded from
Simply download the file into the MegaStar working directory (naming it "comet.txt").

Asteroid Data

MegaStar uses asteroid elements from Dr. Ted Bowell of Lowell Observatory. You can download the raw data file from

The compressed version of this file is "astorb.dat.gz". You will need to decompress it using gzip.exe (included with MegaStar, and also available from

If you are using V5 of MegaStar, the asteroid file is used in its raw (uncompressed) text form. The file should be named "asteroid.lwl" and placed in the MegaStar working directory.

If you are using V4 of MegaStar, you will need to convert the uncompressed file to MegaStar's binary format using the "mconvert.exe" utility. (see below).

MegaStar File Conversion Utility (mconvert.exe)

NOTE: This utility is not needed for MegaStar V5 or higher.

Use this utility to convert the raw Lowell asteroid data for use with V3.x or V4.x of MegaStar. It will also convert the IAU comet file (which is already in MegaStar V4.x format) for use with V3.x of MegaStar. When you run this utility, click on Help for instructions.

This program is compressed. After downloading, open "" using a program like PKZIP to extract the executable (msconvert.exe). Next, using Windows Explorer or the Windows Run run the extracted executable (msconvert.exe).

Download the MegaStar File Conversion Utility now