http://www.astronomyblogs.com/member/northandeast An ETX-90 observations blog Copyright 2008 AstronomyBlogs.com Thu, 20 Nov 2008 20:45:18 -0600 720 Thu, 20 Nov 2008 20:45:18 -0600 http://blogs.law.harvard.edu/tech/rss en support@astronomyblogs.com support@astronomyblogs.com http://www.astronomyblogs.com/images/ab_rss_icon.gif http://www.astronomyblogs.com/ 88 31 Weblogs for Astronomers http://www.astronomyblogs.com/member/northandeast?xjMsgID=73273 A good dark (relatively speaking, that is, for the capital city of China) still and moonless night. I decided to try for M77, a spiral galaxy 50 or 60 million light years distant and perilously close by line of sight to a tree and a tall apartment building. It's billed as a relatively easy find in the constellation Cetus, but surprisingly I have no record of having attempted this before. If its position in the sky was a potential handicap, the ETX-90 itself almost proved a bigger one -- its slewing action inexplicably slowing and speeding up and landing several degrees away from the intended target. This made it very difficult to know whan the telescope was actually pointing to the right area of sky and start comparing the view with the chart. It took well over an hour of painstaking star hopping to get there, but the FOV with the galaxy slightly off center is quite unmistakeable with a line of three 9th magnitude stars SAO110719, SAO130081 and SAO130073 guiding the eye towards it. In such a small telescope and such a light polluted sky there was no chance of making out the spiral features, and it was best visible with averted vision. It appeared to have two brighter areas lined approximatly 90 degrees to the line of those three stars. But the shape of the feature was difficult to discern and it was quite impossible -- without knowing what it was -- to recognise it as a galaxy (it might just as well have been a globular cluster, except perhaps a bit bigger). Anyway, another one chalked up on my Messier list (34 definitely recorded) and probably the most distant object I've ever seen (and ever likely to see with the ETX-90? -- it's said to be the furthest Messier, but are there more distant non-Messier objects that can be seen with a small telescope?). The sketch above exaggerates the clarity of the object and the definition of its shape. It would be interesting to try again in a truly dark sky. Thu, 20 Nov 2008 20:45:18 -0600 http://www.astronomyblogs.com/member/northandeast?xjMsgID=73273 http://www.astronomyblogs.com/member/northandeast?xjMsgID=72195 Mostly cloudy skies again last night in this southern location. But Achernar, the alpha star of Eridanus and the eighth or ninth brightest of the night sky, flickered dimly through a veil of cloud in the south. Down and to its left was Alpha Hydri, visible only through binoculars. This was my first sighting of both these stars, and of the constellation Hydrus (not to be confused with Hydra). The more northerly stars of Eridanus are visible from BJ, but not the alpha. Sun, 09 Nov 2008 16:32:06 -0600 http://www.astronomyblogs.com/member/northandeast?xjMsgID=72195 http://www.astronomyblogs.com/member/northandeast?xjMsgID=72132 In a location about 20 degrees N, a chance to observe some hitherto unseen constellations in the south. Clouds prevented a good view, but the two brightest stars of Grus and the dimmer alpha of Phoenix stood out on the southern horizon == not remarkable but unseeable in urban BJ. Sun, 09 Nov 2008 04:36:46 -0600 http://www.astronomyblogs.com/member/northandeast?xjMsgID=72132 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71916 A feature I had never observed at leisure before -- Rupes Recta -- stood out prominently near the terminator of tonight's 8.6-day-old moon. The last time I attempted to sketch it, in March 2007, produced little worth the effort. This time I was able to record much more detail and had a better view with the moon slightly younger and the shadow of the wall longer. It is a very striking feature. The shadow on the terminator side of Crater Birt (to the right of the wall) was also much longer this time. Some of the craters nearby were nicely defined too -- Arzachel on the top left of the sketch, Thebit to the left of the wall, and small Purbach H -- about 30km in diameter -- down and to the right of Thebit (filled with inky shadow). The wall itself is about 110 km long, and a useful indicator of lunar scale. ETX-90 with 20mm plus 2x Barlow. Seeing poor to medium. Transparency good. Thu, 06 Nov 2008 07:14:53 -0600 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71916 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71678 Another beautiful array of Jupiter, the moon and Venus after sunset. I attempted another sketch of the moon, but even though now five days old it remains a challenge given its low altitude and an array of tall buildings on that horizon. This shows Mare Nectaris -- the orange/brown area in the sketch -- with Theophilus above it, Cyrillus F to its right and then Beaumont. The crater on the far right of the sketch is high-walled Piccolomini. My guess is that the two craters shown to the left of Mare Nectaris are, top to bottom, Isidorus and Capella. The semicircular protuberance on the right of Mare Nectaris is Fracastorius. Poor seeing and a haze that rendered the moon an orangey colour made it very difficult to pick out much detail with these features. The result is a messy sketch, drawn in much haste. Mon, 03 Nov 2008 06:48:20 -0600 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71678 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71509 A beautiful conjunction of the waxing crescent moon and Venus after sunset, with Jupiter further to the south. In terrible seeing, compounded by horizon haze, and with very limited time before the moon disappeared below the urban skyline, I sketched Mare Crisium and adjacent Cleomedes; the wall of the terminator side of Crisium jutting into the darkened lunar surface beyond. Sat, 01 Nov 2008 08:21:07 -0500 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71509 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71035 Jupiter brilliant in the south early evening. Sometimes in recent days it has been possible to see both Jupiter and Venus at the same time when gaps between buildings allow. Saw (by chance) Lacrosse 2, an American spy satellite, high overhead passing through the summer triangle at 6:32pm. It looked brighter at first than the magnitude given in Heavens Above, but soon faded to the advertised figure. Sun, 26 Oct 2008 19:56:03 -0500 http://www.astronomyblogs.com/member/northandeast?xjMsgID=71035 http://www.astronomyblogs.com/member/northandeast?xjMsgID=70482 In the afternoon and early evening, in relatively clear sky (later largely obscured by haze) I looked at the spotless sun and then, shortly after sunset, Venus. I've never followed its phases closely (the last attempt was in January). Here is my sketch of what I thought I saw using the ETX-90 and 20mm EP with 2x Barlow. It is reassuringly close to the image (mine is a mirror one) produced by this site: http://aa.usno.navy.mil/data/docs/diskmap.php. Spotting it in a crescent phase would be trickier, it being closer to the sun then. Sun, 19 Oct 2008 23:49:04 -0500 http://www.astronomyblogs.com/member/northandeast?xjMsgID=70482 http://www.astronomyblogs.com/member/northandeast?xjMsgID=69601 Murky post-Olympic skies, bad weather and work have prevented much viewing recently. I would have liked to see Shenzhou 7 while it was orbiting late last month but cloud prevented that. Oct 8, however, was a clear evening and I managed to get a bit of binocular viewing in. For some reason I decided to check my estimates of the relative magnitudes of the defining stars of the Great Square of Pegasus against their actual values. To my surprise I found that Algenib at the bottom left of the square and Scheat at the top right appeared of similar magnitude to my eye but were indicated by the software as being quite different: Algenib at 2.83 and Scheat at 2.44. Wondering whether Scheat might be a variable (rather than my judgment impaired) I checked online later and found indeed that it is, with an irregular variation of magnitude that would reduce its brightness to close to that of Algenib. Wed, 08 Oct 2008 19:00:54 -0500 http://www.astronomyblogs.com/member/northandeast?xjMsgID=69601 http://www.astronomyblogs.com/member/northandeast?xjMsgID=67542 Another very fine day/night. NELM >3. Thu, 11 Sep 2008 17:34:23 -0500 http://www.astronomyblogs.com/member/northandeast?xjMsgID=67542