Monday, December 24, 2007
The Moon and Mars
When we woke up this morning the fog had cleared and we could see the Moon and Mars together in the western sky. I shot these two images with the coolpix 4500 mounted on a tripod. Enjoy!
Sunday, December 23, 2007
Sketching Mars
On the night of December 11 I observed Mars from 20.30 UT until 22.00 UT. I use the 300mm Orion Optics UK on a dobsonian mount. The eyepieces used were the 12mm Nagler and the 7mm Pentax. The seeing was not to good, so I was limited to medium magnifications. Still every now and again there were some fine details visible on the surface of mars. The sketch below should is just a rough impression from what I saw that night. You can see I identified a dark area looking like a large bird. The body of the bird (central part) is Syrtis Major. The wings are Mare Tyrrehnum and Mare Serpentis. I also detected the North Pole and a dark area right above the North Pole, probably Utopia.
It was made with the using the 7mm Pentax XW, giving a magnification of 229x. Of course Mars didn’t look as big as the circle on the paper, but I like to sketch objects on a larger scale. Some of the techniques used for sketching Mars come from the book “Astronomical Sketching” from the Patrick Moore Practical Astronomy Series, a book which I can highly recommend.
Tuesday, December 18, 2007
M 103 in Cassiopeia
On December the 16th I observed M103 in Cassiopeia with the 300mm f 5.3 dobson. This wonderful little cluster stands out well from the surrounding star field, and looks like a small Christmas tree. I counted 27+ stars in an area of 7’ diameter. There are many triangles and other asterisms visible in M103. This makes the sketching a lot easier. The sketch below was made using the 7mm Pentax. The faintest stars were added with the help of the 7mm Pentax. I could not detect any glow of unresolved stars, but I sometimes saw very faint stars popping in and out of view with using averted vision and a black cloak over my head. 
Sunday, November 25, 2007
Comet Holmes
During the last few weeks I observed Comet Holmes on a few occasions, and I have seen it change gradually. The first time I got a chance to see Holmes was on October 30th. The core looked very bright and compact, surrounded by a more or less faint halo. There was a very sharp and distinct division between the border and halo. Right on the borderline between the halo and the core was a bright star visible. I observed Holmes with the 85mm Zeiss and a zoom-eyepiece at 60x. The field of view was a little more than 1 degree. The sketch below should give you an idea of the view. North is up and east is to the left. 
Over the weeks I saw the halo growing in size. The core became less bright and the sharp boundary between core and halo started to vanish. Until now, the most beautiful sight of the comet was on the night of November the 17th. I observed the comet with the 12x60 Skymaster (Celestron) binocular mounted on the SkyWindow. The generous field of view of this binocular is 5.7 degrees. Comet Holmes had moved right up to the Alpha Persei Cluster and both the comet and the cluster were visible in the same field of view. The sketch below again should give you an idea. On this sketch North is to the left and and East is at the top (these strange directions are caused by viewing with the SkyWindow).
The halo looked very large and the core was still there, but it seemed more or less oval. As I mentioned earlier, the division between core and halo was not very distinct. In Alpha Persei I could detect three stars that showed some color. Alpha Persei was yellowish, and at two o’clock I detected a couple of contrasting stars. One seemed orange-red and the other seemed to be very light blue. The cluster and the comet formed a stunning pair, and I observed it for about an hour to an hour and a half. The sketch took me about 45 minutes.
Tuesday, October 02, 2007
Sundog on the Alm
At the moment I'm staying on the Emberger Alm in Austria to do some deepsky observing and a bit of lunar observing as well. We arrived on Sunday and we had three clear nights on a row. I am getting a little tired with all these short nights. A detailed report will follow later on this year. During daytime there is also plenty to observe, like this Sundog on monday afternoon. Enjoy the images!
Click to enlarge
Click to enlarge
Sunday, September 02, 2007
The Mini Coathanger
On the evening of Thursday August 23d, I had an hour of clear skies, so I quickly got out with my Sky-Window and the 15x80 Vixen binoculars and the 85mm Zeiss refractor equipped with the 20-60x-zoom eyepiece. I wanted to have a look at an asterism called the Mini Coathanger (STAR 22 from Phil Harrington’s Small Telescope Asterism Roster) in Ursa Minor. The Mini Coathanger, which looks very much like his big brother the Coathanger in Vulpecula, can be found at RA 16:29.0 and DEC +80.13. I always start the search at 16 Zeta Umi. About 2 degrees northeast of this bright magnitude 4 star, a diamond-shaped group of stars can be seen. At the Northern tip of this diamond shaped group STAR 22 can be found. The Mini Coathanger is made up off 11 almost equally bright stars, most of them of the 10th or 11th magnitude. The asterism is 15’ wide. In the Millennium Star Atlas, the whole asterism can be found on page 1046. That night, I started my observing session at 21.00 hours UT. The seeing from my backyard was only 5 on a scale of 10. Most bright naked-eye stars were blinking like crazy. The transparency and sky darkness weren’t too good either. I couldn’t see all seven stars of Ursa Minor, so the limiting magnitude was well below 5. However, with the 15x80 I quickly located the diamond shaped asterism, but the Mini Coathanger stayed invisible. After observing for a few minutes, I started to see a little bar of four or five stars, that form a part of the Mini Coathanger. The stars were very faint, and I could not see the complete asterism, not even with averted vision. Then I switched to the 85mm Zeiss. At 20x the bar of stars already looked a bit brighter, and seemed easier to identify. Zooming up to 60 times, using averted vision, I could see the whole asterism, the bar and hook. I could not detect any colour in the stars. After observing for 20 minutes from under a black hood, I could see the whole asterism with direct vision. I made the sketch below to using the 85mm refractor and the eyepiece at maximum zoom. The field of view at 60x is about 1.25 degrees, but I only sketched the central part of the field of view. Before I finished my observing session I switched back once again to the 15x80 binoculars. This time, using the black hood and averted vision, I still could not identify the whole asterism with the 15x80.
At 22.00 hours UT I packed up and went inside (had to work the next day), enjoyed my cup of coffee and put down a few notes. Looking back at the short observing session I can definitely say that the refractor with its 85mm aperture shows stars of the 11th magnitude much easier than the 15x80 binoculars. With the big binoculars, you use two eyes, which should compensate for the 5mm difference with the 85mm Zeiss. But in the end, I think that the higher magnification (you start at 20x with the Zeiss) makes the difference. The slightly higher magnification gives a little more contrast. If you zoom in to 60x, the 15x80 can in no way keep up with the views the refractor shows. However, I will try to hunt down all the asterisms on Harrington’s STAR list using both instruments. They are ideal for short observing sessions. Both instruments are mounted on video tripods permanently, so I only have to take them into the garden and I’m ready to go!
Friday, August 24, 2007
NGC 7510, a very distant open cluster in Cepheus
At the border of Cassiopeia and Cepheus, near M52, a whole group of open clusters can be found. One of them is the magnitude 9.2 NGC 7510. Last Saturday, August 11th 2007, I decided to revisit this small, (6’ in diameter) open cluster, and make a sketch at the eyepiece. 
Image from "Where is M13?" by Think Astronomy
To observe NGC 7510 I used the 300mm Dob with the 21mm Denkmeier, the 12mm Nagler and the 7 and 5mm Pentax XW. After locating it with my Argo-Navis, I immediately recognized the small and rich open cluster, even with the lowest magnification (76x). The familiar arrowhead shape is something you will not forget, once you’ve seen it. At first glance, NGC 7510 looks very small indeed. This is in part because of its distance. NGC 7510 lies in the Perseus Arm of our galaxy, approximately at a distance of 10.200 light-years. This makes it one of the more distant open clusters. However, would you place NGC 7510 at 440 light-years, where we find the Pleiades, it’s apparent size would be 1.55 degrees! It would 30% larger than M45.
After increasing the power to 320x (5mm Pentax) I noticed that a lot of stars I’d seen on previous occasions stayed invisible. In fact, the transparency proved to be horrible. When comparing the sketch with a printed map from SkyTools2 the next day, the faintest star I plotted using my 12-inch scope was only magnitude 13.3. From the same location, my own backyard, I reached magnitude 13.5 with the 8-inch TAL 200K, on a very good night a few years ago.
Anyway, I made a sketch at the telescope with just a HB pencil, eraser and a piece of sketching paper. I did not plot all the field stars. I only concentrated on the possible cluster members. It is always very hard to recognize the real border of a cluster, and to determine which stars do belong to the cluster and which don’t. But I’m not the only one! When checking different entries in my observing guides I noticed that the values for size, numbers of stars and even magnitude vary a lot from one another. The eyepiece used for the sketch was the 5mm Pentax XW (320x). It took me 45 minutes to observe NGC 7510 and to complete the rough sketch. The next morning, with the help of my rough sketch and the notes I recorded on my Ipod, I made a new, final sketch to file in my observing log. For this final sketch (see image below) I used black paper and very a very soft white pencil. I only plotted the stars I had on my original sketch. I used a printed map from Skytools2 to check the positions of the stars and to the check the limiting magnitude for that night.
As you can see, I counted about 19 stars in the cluster. There was no real color visible in the stars, though I suspected a little color in the brightest. It seemed a bit yellowish, but I must have been wrong because when checking my observing library, I found out that its Lucida is a luminous blue B1.5 III giant (Sky Vistas, page 78, Crossen and Rhemann). The sketch is made with north up and east is to the left.
Wednesday, August 08, 2007
Deepsky observing with an Owl.......
Last Saturday I had a great time together with Leo. Together we observed not only some well-known deepsky objects, but also a few "new" objects. I used my 300mm Dob and got a chance to test my two new eyepieces, the 21mm Denkmeier and the 5mm Pentax XW. Leo observed with the TAL 250K. The outside temperature was between the 15 and 20 degrees Celsius. The seeing was average, but the transparency was not too good. We barely could make out all the 7 stars of Ursa Minor. But after months of rain and clouds, you are happy with every observing opportunity, so we took it with both hands. The waning last quarter Moon came up around 00.00 hours and stayed out of the way (behind some trees) until 03.00 hours. Anyway, we had a good time observing the deepsky from 22.30 until 03.00 o' clock. 
