Airmass calculator
Once too often someone was wondering what might be the airmass for the object he was observing. This information is often included in the header of an image file at the telescope, but what about when you are planning and selecting which object to observe and when. Well, now you can download my simple (but exact) airmass calculator for that purpose. The calculator uses the Earth radius and height of atmosphere to extract an as exact as possible airmass for any given zenith distance. If you don't like the standard Earth radius = 6378.14 km and atmospheric thickness = 60.0 km you can modify the Airmass.ini file (Linux version) or give new value for atmosphere in the program (Linux and Windows version). In the program you can give either zenith distance or altitude of your object and the corresponding airmass is calculated accordingly. The program gives results in four/five decimal places, but I have noticed that the way different computers and systems handle real numbers and trigonometric functions produces slight errors on the last digit. Download Windows98/NT/2000 executable (v. 1.0) from here:
Download Linux executable (v. 1.0) from here:
To run the program just type Airmass (and press enter). If the current folder is not in the path you probably need to give command ./Airmass to run the proram. You can give either zenith distance or altitude of your object and the corresponding airmass is calculated accordingly. Airmass.ini is pure ASCII so you can use any editor to change values therein. If you find a bug in the program, don't be afraid to send me an email about it so I can fix the program. |
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Created by
Rami T. F. Rekola |