Tuesday, February 16, 2010

Winter Objects


After more than a two month hiatus from sketching deep sky objects due to cloudy or very cold weather, I took the opportunity to sketch these objects last Saturday night while observing at a local airstrip. NGC-1199 is a galaxy in Eridanus, one of many I wanted to sketch that night but sky conditions were not very good and this was the only one I was able to see. As such it was small, round and it's bright inner core was visible. Eridanus has numerous galaxies that are visible in modest telescopes that can be seen from the United States and along the border with Fornax is a rich galaxy cluster as well. Also located in Eridanus is the very bright double shell planetary nebula NGC-1535, also known as Cleopatra's Eye. The larger but faint outer shell surrounds the very bright and younger inner shell, which has a hole through which the central star gleams. It's a great object for small telescopes and it takes high powers and light polluted locations very well. It's definitely the best deep sky object in Eridanus.

NGC-972 is one of a number of moderately bright to faint galaxies visible in the constellation Aries. It's fairly bright and appears as a faint oval object with a brighter core at 150X. The Canis Major galaxy NGC-2207 also was observed as a faint very elongated oval with a slightly brighter core. This galaxy is anything but easy from the hazy and light polluted sites I make do with, but it was evident despite the curious difficulty I had seeing galaxies in Eridanus that were easy objects the last time I looked for them. The sky was very patchy transparency wise.

The open clusters NGC-1220 and 1245 in Perseus were also observed. NGC-1245 was a fairly large swarm of faint to very faint stars and made a pretty grouping of stars embedded in the rich Milky Way star fields that dominate Perseus. NGC-1220 on the other hand was a lot more difficult to find, and at first glance it looks like a distant unresolved globular cluster. Even at 188X, only a few stars appeared surrounded by a hazy glow of other stars too faint to see individually, but their collective glow was visible in the telescope.

Besides these objects, I observed the Orion nebula and the planetary nebulae  NGC-2438, 2440 and 2452 in Puppis, along with the emission nebula NGC-2467. In Gemini I located the faint but very rich open cluster NGC-2266, and in Orion the nebulae NGC-1788 and 1999 were also observed. In Monoceros I observed the planetary nebula NGC-2346 and the reflection nebula NGC-2261, also known as Hubble's Variable Nebula. Finally, I looked at the brightest galaxy in Aries, NGC-772 and the galaxies NGC-1023 and NGC-1161 in Perseus.

Wednesday, February 10, 2010

Focuser and finderscopes

After a short wait, the focuser, Telrad and the bracket for the 50mm finder scope arrived and I got to work installing them on the upper cage. However, I found the focuser board that I made originally to be all wrong for the focuser, and worse yet I botched the job of mounting it. So I took a piece of Brazilian cherry and made a new one, moving the hole for the focuser 3/4-inch farther back to allow some space for adjusting the position of the secondary mirror and it's holder. The board was made wider to accommodate the focuser better and I made a spacer from left over 1/4-inch aluminum used to make the tail gate so operating the focuser would be easier and there would be a thrust plate for the leveling screws to push against if their use is required to square the focuser with the optical axis. The Telrad fit right into place on it's base, but the bracket for the 50mm finder needs a riser for the finder scope to clear the rings of the upper cage. Ideally, I will be able to leave the finder scopes on the upper cage even when it's in the storage box I will be making to keep it free from dust, dirt and getting damaged. At present the focuser is just held temporarily in place until I can get a nut driver for the nuts and  notch the baffle to allow me to finish inserting the screws for it. Once the finders and focuser are mounted permanently in place, the only operation left to complete for the upper cage is to adjust the pole seats, which will not take place until the primary mirror is delivered and I can determine the length and angle of the truss poles. I am in the process of coming up with the money for the primary mirror, when I do, I will contact the optician I've chosen to make the primary mirror.