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! Regards, Wayne http://morgan.botany.uga.edu/wayne/astronomy.htm ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html
This archive was generated by hypermail 2b29 : Fri Feb 04 2000 - 04:44:28 PST