Trying to shoot the ISS (Internation Space Station)

[Jaedon]

So I found this handy little sattelite tracker website that allows you to track the most visible objects in the sky about you according to your postal code.

( link : http://spaceweather.com/flybys/flybys.php?zip=m4b%203k6 )

Now according to the site the magnitude of what is expected it listed. The moon lists as a -13 (the furthest star we can see is a magnitude 6 and the brighter the object the smaller the number) and I am trying to figure out how that should translate to shooting. I shoot the moon at settings you would use in full sunlight. I am hoping that the -13 of the moon and -4 of the ISS this week translates to F-stops and that I should be able to shoot with a fairly quick shutter speed.

The travel duration over my location is only 3-4 minutes and the middle 2 minutes of that are the best opportunity.

I will keep you posted but if anyone has any suggestions or recommendations on techniques for this I would really appreciate hearing them all.

[Medley]

It CAN be done, but will have to be done by someone not so far removed from college algebra as I am, lol.

On the stellar magnitude scale, a difference of 5 magnitudes corresponds to an increase in brightness of 100X. So an increase of 1 magnitude corresponds to an increase of roughly 2.51189X (the fifth root of 100).

Armed with that knowledge, and the numbers you've provided, the difference in magnitudes between a full moon and the ISS is 9 magnitudes, which would correspond to 2.511189 to the ninth power, or 3981.

So the ISS will be about 3981 times fainter than the full moon. Now if you can translate that into f-stops, more power to you!

Here are a few links for reference:
http://csep10.phys.utk.edu/astr162/l...agnitudes.html
http://en.wikipedia.org/wiki/Apparent_magnitude

One caveat: Because the relationship between magnitude and apparent brightness is a logarithmic one, a minor change in magnitude will have an exponential change in brightness. There are many variables in this (atmospheric conditions, etc...), so I'm not sure you can get much closer then a s.w.a.g.

In reading up on this (nope, not an expert.....) I did notice that the first link has a table that lists Venus (at it's brightest) as -4.4

A difference of .4 magnitudes corresponds to Venus being 1.5 times brighter than the ISS (but only when Venus is brightest). Still, if it were me, I'd try setting the camera to capture Venus, then opening up the aperture by one stop.

Good luck!

- Joe U.

[freygr]

If the exposure time is long you will have to track the camera

To track the camera you need to use a tripod and use a optical tracking device. The tripod panning plain must match the orbits plain.

Depending on the focal length of the lens, longer = larger image the more critical the tracking is.

[Skydmark1]

Let us know how it turns out!!!