Chandra sighting!

From: Wayne Hughes (
Date: Mon Jun 27 2005 - 00:19:16 PDT

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    The Chandra X-Ray Telescope has been a kind of El Dorado for me since I
    got my 12.5" scope in December.  I've  been trying to observe Chandra
    since then.  Chandra has a very eccentric orbit with a period of 3809
    min and an apogee 1/3 the distance to the moon!  While the period is 2.6
    days, it is really only accessible to us in the south US once every 2-3
    periods.  Between this matter of a week between possible sightings, the
    presence of the moon every two possibilities, and the 50% or so of days
    with cloud cover this time of year, not to mention that until now
    Chandra hasn't really topped 10 degrees above the horizon before moving
    more than 20,000 km out, I just haven't been able to see it.  But this
    morning was different.
    This morning was pleasantly cold, about 25F, and very clear, despite the
    possibility of partial clouding.  I had used Skymap Pro and the latest
    elements to locate Chandra's earliest convenient appearance at mu
    Hydrae, about 24 degrees above the horizon, at 5:10 am EST.  At that
    point it would be 18,800 km away, past its perigee at 10,400 km and I
    wasn't sure I'd be able to see it.  In fact, scanning south of the nice
    red mu Hydrae, I found it moving north at 5:05 am EST.  It passed mu
    Hydrae at 5:07:30, 2.5 minutes earlier than predicted by SkyMap Pro.  It
    was probably at a magnitude of 8-9 or so, quite bright in the 32 mm
    eyepiece.  It took about 70 seconds to traverse the 1 degree FOV.  
    No flashing or flaring was evident; it was a slight yellowish color.
    Spent the next 90 minutes watching Chandra move up through Hydra, past
    nu Hydrae, through Crater, and into Virgo.  By the time it passed the
    line between Zavijava and Zaniah at 5:49 it was pretty much on schedule
    and about 23,800 km out.  It was taking 126 seconds to traverse 1 degree
    FOV, and was only a bit dimmer really, maybe mag 9.  By the time it
    passed magnitude 5.8 K0 TYC 887-570-1 just to the east of Vindemiatrix
    it was 6:32, 30,000 km out and still visible at mag 10 but nearly washed
    out by the dawn.
    Now that's something that will make your day, or mine, at least!
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