January through March is a grim time for deep sky work, even in Canada's most southern latitude (I am at 42 N) If it is clear between last quarter moon and first quarter, it is often too cold and/or too windy to be out in an open farm field setting up a telescope, observing, and then breaking down again. So January, as usual, was a write off, despite this being our 7th warmest winter on record. However, in February came three clear nights I was able to use. There were actually six clear nights this time, but two of them were far too windy, and another was simply too cold. I have been able to push my lower temperature limit down somewhat for extended observing, but many nights are still far too cold. It's mostly the fingers; gloves have to be worn, not mittens, and even with hand warmers inside, things can still get brutal. One of the best things about winter observing (and late autumn), is
that one can put in three hours at the eyepiece and still be home by
bedtime.
So I was able to continue a years' long project in Perseus, and another in Canis Major. I had observed Perseus in some detail years ago with my Edmund 8" scope. But it is always worth having another look at objects with the 12"! And of course back in the day I did not have the detail of a Uranometria atlas. Some previously seen objects that I revisited in Perseus included gn 1579, a large reflection nebula last seen in 2004. Even larger is gn 1491, an emission nebula greatly improved with my Orion Skyglow nebula filter. Two open clusters, oc 1548 and 1528, also wowed me. 1528 is large and the stars are quite scattered, but the sheer number of bright stars makes a pleasant surprise. At 120x there are at least 100 stars. A lovely cluster and a minor showpiece.
On a second night I re-observed oc 1342. At 86x a curving line of bright stars is seen, in a rough "S" shape. Involved with it is a close and bright double star at the preceding end. 107x and 120x bring out fainter members. Again, though scattered, the cluster is pretty rich. I counted about 60 stars. I also observed a gorgeous triple star, Epsilon (Stf 471). The main pair is mag. 3 and 8, separated by 9". To me it appeared white and emerald at 43x and 86x A real beauty! There is also a mag. 14 star at 78". It was seen at 166x, but I had to put the main star just out of the field of view.
Though actually in Taurus, pn 1514 is easily accessed from Perseus. Located at 43x, the planetary nebula was bluish-gray in colour. Up to 120x without a filter I could see bright spots north of the main star, and also south following it. At 166x with a Skyglow filter, views are bright and quite impressive. The O III filter also worked well here, darkening the background even more. 221x shows several areas of varying brightness. This is an impressive object worth seeking.
On a third February night I finished up work in Perseus until next year. Oc 1545 shows many faint stars at 86x, with a bright double over top (S 445), being an orange and blue pair. At 107x about 30 stars show up, including a central curving line. Another bright star, a triple, sits at the north end. Worth a look. Also noteworthy was oc 1513. At 120x and 166x the group is moderately rich. About 20 brighter stars are noted, and about the same number of faint ones. There are several pairs, and the brightest clump is in the southern section. A mag. 9.5 star is in the north end.
During those three February nights I observed Perseus early on, turning to Canis Major later in the evening. Canis Major is mostly new territory for me, with only M 41 being previously studied in depth. This constellation is loaded with open clusters, though many of them are small, faint, and non NGC objects. But there are a few galaxies, too. An example is eg I. 456, which sits just below -30 degrees declination. It is a bright galaxy that is just separated from a 9.5 mag. star south following it. At 120x it is oval; 166x shows a distinct bright center. At 221x it isn't half bad, being fairly large and bright. Another pretty fine galaxy is eg 2325. 333x gives the best view of this somewhat bright, large object, and shows a very faint star involved. Most of these galaxies are considerably further south than I usually travel for such objects (my limit is usually -25 degrees for galaxies, and around -39 degrees for clusters and doubles).
Oc 2354 in Canis Major is a very large group at 86x, with my best view of it at 107x. There are curving lines of brighter stars, along with many fainter ones. A quick count got me to around 60 stars.
Another beauty is oc 2362, a lovely sight at 86x. 120x resolves all members, looking like little bees swarming around a bright hive. The central star 30, or Tau, is also a very pretty sight. Best view was at 166x, where about 60 stars can be counted. The main pair of the triple is yellow and blue, at mag. 4.5 and 10, separated by 8" of arc. The other member is mag. 11 at 15".
I must mention a beautiful double star, h 3495. Magnitudes 5 and 7 with a separation of 27", the colours are a striking orange and blue, very similar to B Cygni!! And just to give a (decent) sample of the many non NGC clusters that this constellation contains, let me talk about Ru 10. This is one of the larger "small" clusters, of which there are literally dozens in this area (and also in Monoceros and Puppis). At 7' in size, the brightest stars are mag. 12. North/south lines of stars precede a mag. 9.7 star. 3 somewhat bright stars sit in the central area, with many fainter ones surrounding them. Best view was at 221x. Some of these clusters (Ru, Be, Cz, and others) only begin at mag. 15, and even mag. 16, so aren't even worth bothering about with anything less than a 12" scope.
My coldest observation (except when I lived in Sudbury, many moons ago) was the night of February 17th. Upon arrival to set up it was already down to 18 F!! By the time I left it was 16 F, and 80% humidity. That was one chilly night!! But what a sky it was!!
Now on to March observing, which was mostly in Canis Major, except for two very low objects in Puppis. While waiting for last quarter to approach in March, I set up detailed worksheets for Puppis, in case I had a run of clear nights and managed to finish work in Canis Major (no need to worry, as it turned out). I have about 19 pages of work awaiting in Puppis now, perhaps for next year. But then I went ahead and prepared Pyxis, based on some low latitude successes recently. and then I prepared Crater as well. So I am set for the next 100 springs, at least. Later in the season I will resume work in Sextans, and, of course, in my main spring area, the indomitable and inexhaustible Coma Berenices, which is well up by the time I stop now.
I will begin first with two low objects I observed in Puppis. After all that prep work, I had to at least observe an object or two there. Besides, I wanted to see how good my lowest sky was. Things turned out quite well. My first object was gc 2298, a globular that sits low for me at -36 degrees. No problem! I located it easily at 107x, and it appears quite large and reasonably bright. But as the magnification increased, it quickly grew faint. I was unable to resolve any but the most outer and brighter stars. 221x did show a brighter core with a fainter envelope surrounding it.
The second and final Puppis object for me this season was Cr 135. Monstrously sized at 49', it contains a 2.7 mag. orange star in the south end. Uranometria clocks 13 stars, and that is about what can be seen at 43x and 86x. Of course there are much fainter stars, too, but they must be background to the cluster. The bright orange star has a blue companion, making a fine sight. Wikipedia has a decent image, if interested.
With only two clear nights in March I was unable to complete my work in Canis Major this year. At least one more (long) night will be required, before I move back to Puppis. But I still got through an incredible 37 objects this month, a tribute to good planning (very necessary, especially in winter) and excellent skies (not to mention a very trustworthy scope!). I usually use a hand held computer to find the first object of the night, but due to cold temps I didn't bother. There are enough bright stars in Canis Major that it is easy to star hop and find one's way.
Here is one those minor, extremely faint clusters I was talking about earlier. Oc Tom 2 was only 3' in size (a decent size for a galaxy, but not so much for a cluster). It is supposed to have 50 stars, with the brightest star at mag. 16. What I actually saw were 4 stars, exceedingly faint, at 221x and 333x, with some faint haze in behind. A close pair was part of the deal. Obviously at least an 18" would be needed here, but I went there anyway (because it's there).
Oc 2384 was considerably better, part of a double cluster with nearby 2383. Both clusters fit into my field of view at all powers up to 221x. 2284 has two brighter stars within it at 86x, but at 120x both of these have their own little collection of stars near them. And the preceding bright star is now a very close double star (Bu 199: 7.2-8.1 at 1.8" of arc). At 166x, the following bright star has 6 little stars around it, while the preceding one has 7. Best view was at 221x, and shows an attractive little group. Oc 2383 is a moderately rich group at 120x and 166x, and it immediately follows a mag. 9.8 star. At 221x and 333x there appears to be a distinct north group and a south one, relative to this star. The richer of the pair is south; the north group is sparse by comparison.
A couple of half decent minor clusters came next. Oc Ru 18 was located at 86x, where I saw a few brighter stars against some haze. 120x begins to resolve the haze. At 166x and especially 221x the cluster is moderately rich, with about 30 stars counted. Oc Ru 20 resolves into about 20 stars all around a brighter one. It was a decent group at 166x, though it can be located at 86x. At the opposite extreme is Collinder 140, in the far corner (southeast) of Canis Major. At 30', it is very large. Near the center is Dunn 42, a superb gold and blue double star. The magnitudes are 5.5 and 7.5, with a wide separation of 99". Another orange and very blue pair are south preceding. Unranometria shows 10 of the brightest stars. The entire area makes for fine sweeping at 43x.
Taking a cluster break for a few moments, there are two small nebula to find. 2296 is tiny but bright, somewhat following Sirius. It lies just beyond its bright influence. I located the nebula at 166x, but the best view of this small, round nebula was at 221x. No filter is needed to see it. There may be a star involved. It strongly resembles a galaxy, and was thought to be one for a long time.
The other nebula is up near the border with Monoceros, being gn 2327. This one is curiously located at the end of a curl of stars, and at low power can be mistaken for a star. It is quite bright, with my best view at 221x, where small filaments could be seen coming away from the main brightness. The star following it is also a nebula, though it appears stellar in the scope.
Along with 1528 in Perseus, perhaps the finest cluster of the winter sessions was oc 2345, with it's brightest star at mag. 9. It's not a super standout object, but it has a curious overlay of bright stars in a horseshoe shape, with fainter ones in behind. At the apex of the horseshoe, in the north, is a bright double star. 166x gives a fine view of this fairly large open cluster. At this range, the 2nd star in the horseshoe in the following end is also a close double. This pair has a particularly rich group of faint stars around it. 221x and 333x resolve more and more faint stars. This is a moderately rich group with widely scattered fields, some of these being fairly dense.
With a cloudy week ahead (new moon is tomorrow), I am finished until April. Last year I had 0 clear nights in March, so at least I scored twice this year.
*All images are taken from http://www.astrosurf.com/benoit/p23.html, which are in turn from NASA.
Mapman Mike
No comments:
Post a Comment