Re: Iridium Flare Photography

Chris Dorreman (bram.dorreman@skynet.be)
Sun, 30 Aug 98 21:40:10 +0100 (UT)

Lee Blanton:
> I'm interested in knowing what type of film to use for Iridium photogra=
phy
> or satellite photography in general.  Thanks.

Since Iridium flares can be very bright, you don't need a sensitive
film. All my flare photos are taken on 100 or 400 ASA fujichrome film
with an exposure time of 1 to some minutes (for example, look at the
one on the VSOHP Iridium page)

For other sats, sometimes a faster film is needed. To give an idea:
with 400 ASA I can photograph satellites down to mag. +3 or +4. But
that's also dependent on the camera lens, the speed of the satellite,
the darkness of the sky, ...

I've a lot experience with fujichrome, wich is a good color slide
film for astrophotography in general. But on long exposures, the
sky sometimes has a green hue.

JackWx:
> I'm using a Pentax LX 35mm camera and have a 28mm f/2.8 wideangle lens =
now. I
> guess my biggest question would be is this a wide enough lens to use =
to
> compensate for the 2 or 3 second flare and any azimuth/elevation errors=
 that
> would occur at the time of the flash? I know even with the latest eleme=
nt sets
> and the IRIDFLAR program there is going to be a margin of error.

Iridflar is very accurate, so even with a 135mm lens you get a
predicted flare perfect in your field of view. But I think a
normal lens (50mm or so) gives the best result; the satellite is
in the field for about a minute. Mostly, a 28mm lens is somewhat
too wide I think. Except if you want constellations or the
foreground (for comparison) on the image.

Paolo Bussola:
> If you want to see my photographs go to:
> http://www.geocities.com/CapeCanaveral/Hangar/5990/iridium.html
> and click on "Fotografie di Iriudim Flares". All images were taken with=
 a 50mm
> lens and 800 ISO film.

Excellent page and nice photographs, but the sky on some of them
is too light.

Greetings,
Chris


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