EQMod - now includes Air Mass

[Merlin66]

Chris, once again, has done a great job of improving and enhancing the EQmod software ( for SW Eq. mounts) by adding the calculation of Air mass to the display screen.

Go to the EQMod group and download the latest version V1.27o from the files area.

https://groups.yahoo.com/neo/groups/EQMOD/files/A%20EQMOD%20Release/EQASCOM/

[russellhq]

Apologies for the daft question, but how do you use the "air mass" parameter?

[Merlin66]

It is widely used in photometry and spectroscopy as a key measure of the amount of atmosphere between us (on earth) and the "target object"

Simplistically, the higher the air mass the higher the light loss, which has then to be compensated in your measurements.

[russellhq]

Thanks, makes sense.

[malc-c]

I assume this is calculated based on the angle through the atmosphere ?  The density of the air surely must vary depending on local air pressure

[Merlin66]

The only variable used is the altitude of the target.

[Tinker1947]

It sounds a very good addition, but i will stick to 800 ISO, 30 seconds unguided, 180 seconds guided and take a chance on the light loss...thats of course if its a AP addition and not purely Spectroscope usage....

[Merlin66]

The effects of Air mass can be seen in all images....

To image and object say 10 degree above the horizon you are effectively looking through x5.58 the amount of atmosphere you'd have if you imaged above you at the Zenith.

[astrogardener]

Thanks Merlin,

Thanks Chris.

Eqmod just gets better and better!

I do photometry and this is a brilliant addition

Thanks again.