Re: Chandra visibility

Philip Chien (
Sat, 24 Jul 1999 01:58:28 -0400

"Sean Sullivan <>" <> said:

>In response to your post on Chandra's brightness.  My calculations:
>Perigee is aronud 10,000 km post-thrusting, I think.  That makes perigee
>16 times farther than Hubble.  Assuming same intrinsic magnitude, that
>makes Chandra 1/16^2 (1/256) as bright.  That's almost exactly 6
>magnitudes fainter.  If Hubble is around +1 or +0 on favorable passes,
>that makes a perigee Chandra around +7 or +6.
>Of course, perigee passes aren't that common.

And that's the key issue - with such an elliptical orbit it will spend very
little time at perigee.

Still, it ought to be interesting to try for the more experienced
observers.  I don't believe I've ever seen a satellite with that high an
apogee in orbit!

>Well, I figure you got to see it in the clean room.  I'll have to settle
>for my backyard :)

Nope.  Didn't get to see either FUSE or AXAF.  Something about not only no
- but hell no.  Sheesh - just because a single molecular layer of skin oil
would contaminate the optics ...

Philip Chien, KC4YER
Earth News
world (in)famous writer, science fiction fan, ham radio operator,
all-around nice guy, etc.