8" Discovery DHQ First Light!

by Tom Campbell

STARLOG

April 7, 2001

NOTE: This was the first light for my new 8" Discovery DHQ Dobsonian telescope. As such, I merely wanted to take it out for a spin and didn't follow any set observing plan. In fact, I didn't even bring out any star charts, relying on my memory to find some of the showpiece objects. Due to the informal nature of this observing session, I didn't use my normal microcassette recorder. Therefore, this observing report is more of a narrative than an object-by-object description.

My new Discovery 8" dob arrived on March 31. But of course, the weather was rainy. Finally, after nearly a week of cloudy weather, I was finally able to get outside and test it out.

My family and I had a cookout tonight, to celebrate the nice weather. Our neighbors got the same idea, and also cooked outside. As soon as supper was over, I brought out the new telescope, to give it time to "cool down" (or maybe warm up).

Shortly after sunset, I was able to spot Jupiter in the twilight sky. I quickly inserted my 25mm eyepiece (49X) and aimed the dob. Right in the center of the field was Jupiter. (Telrads are a joy to use!) Two distinct brown bands were visible, as were four moons, two on each side. Everybody in my family, as well as the neighbors, were anxious to have a look-see. The usual Oohs and Aahs were in abundance. I popped in all of my eyepieces, but due to the moderate seeing, really wasn't able to get much better than about 188X. At this magnification, some color variations were visible along the NEB and SEB, and a couple of additional bands were visible.

A few minutes later, I was just barely able to detect Saturn in the slowly-deepening twilight. Starting at about 80X, the Cassini Division was clearly visible, and when the sky darkened a bit more, two moons were detectable. Again, lots of oohing and aahing from the family and neighbors.

The only other objects visible in the twilight sky at this time were Sirius and the full Moon. The moon was just peeking over the horizon, and there'd be plenty of time for it later, so at the urging of the neighbor's young son, I turned the scope toward Sirius. With the four diffraction spikes, Sirius (a CMa) looked just like the Christmas Star on those TV programs.

While waiting for the sky to darken a bit more, I moved the telescope back and forth between these objects, trying different magnifications, and answering questions about how much something like this telescope would cost, etc.

As the sky grew a little darker, I turned the telescope toward M41 in Canis Major. This open cluster nearly filled the field of view at 49X, and dozens of stars were visible. I'll have to try this one again on a dark night. I also quickly turned towards the Orion Nebula, before it became lost in the tree line. Even at low power (49X), four stars of the Trapezium glistened like little pinpoints, surrounded by a medium-dark greenish haze that was the nebula.

My family went inside about this time, but the neighbor's boy and his mother stayed outside to look at a few more objects. I pretty much stuck to 49X, and simply swung around at various points in the sky. I pointed out the Pleiades (M45), the M35 open cluster in Gemini, Alcor and Mizar (both main components), and a couple of other clusters and double stars. Then, I had them point at different objects in the sky that they wanted to look at, and pointed the telescope towards them and let them have a look.

During the course of the evening, the neighbor lady said that she'd never had the opportunity to look through a telescope, until I moved next door to her, and was very grateful for all of the things she was able to learn from me and to observe. That's what this hobby is all about.

I also took this opportunity to observe the Moon, while it was above the treeline in the East, but still low enough that it wasn't blindingly bright. Even so, I had to use a moon filter to block out a lot of the brightness and see details on the almost fully-lit surface. When the neighbor lady asked me what all those light-colored circles were, I thought she was kidding. But to be safe, I truthfully answered her that they were craters. She looked again and replied that she didn't realize you could see lunar craters from a telescope.

After they went inside for the evening, I began to formally test out my telescope. I had made a homemade sight tube from a film cannister, and had the mirrors about as close to alignment as this method allowed. Except for the brighter ones, most stars were pinpoints, so the alignment must be at least halfway close.

But star testing was a different matter. The in-focus and out-focus images were a bit off from normal. I'll have to go back and review the star-test patterns to see exactly what my problems are, and then correct them, if possible. Also, I may wait and try the star test again on a night when the seeing is a little better, to make sure that I'm not just seeing the results of less-than-perfect observing conditions.

I next turned my attention toward a couple of double stars that I had never been able to split with my 60mm refractor. First up was Castor. At 188X, I was finally able to definitely say they were cleanly split. Polaris was somewhat easier. I tried at 49X, and was unable to see the companion. But when I jumped to 81X, it was definitely there. However, it was right on a diffraction spike. Kicking the power back down to 49X, I could now see the companion as a bright spot along the same diffraction spike.

By this time, the Moon was high enough that it was washing everything out, so I called it an evening. Overall, I'm very pleased with my telescope, and I think its a keeper. I'm anxious to try it out on a dark night and see how it fares with galaxies and globulars.

Reports | About Reports | TAC | About TAC | Join TAC