UPDATED: TLExtract 3.5

I recently, as part of learning myself to code .NET Windows programs in Visual Basic, have started to create small, user-friendly (I hope) programs to aid satellite observers. TLExtract is a new program I have just released.

TLExtract is a program to select TLE's (satellite orbital elements) from a larger file with TLE's (for example classfd.tle or the full JSpOC TLE file), based on a custom-set condition. The resulting selection can be saved to a new TLE file.

For example, you can use it to select all objects with perigee below 2000 km from the original file. Or to select or exclude all objects containing "DEB" or "COSMOS" in the name. Or all objects with an orbital inclination larger than 45 degrees. Or all objects with a period near 1.0 rev/day (GEO). Etcetera.

Element-sets in the input file need to be 3-line elements, i.e. they need to have the line 0 with the object name.

The program runs under .NET in Windows. It accepts only one selection criterion per run, but when you want a selection to satisfy multiple criteria, you simply run another session on the output of the first session.

The program can be downloaded at my website, where you can also find other programs useful to satellite orbservers, such as IOD Entry and TLEfromProxy, as well as some general astronomical programs - for example a program to calculate Solar Longitudes, and a program to calculate the Local Sidereal Time.

UPDATE: version 3.0 features another improvement in speed, and solved a problem with hidden line carriers in the output, that messed up some software when the output file was read into them. I thank Jim King for his suggestions that led to these improvements.

UPDATE 2:  by popular request, version 3.5 includes an option to select on catalogue number.