Amateur Astronomer

Limitations of a 4.5″ Scope

May 6, 2008 on 5:14 am | In What I saw tonight |

I like my Meade 4502 4.5″ reflector, but this weekend I discovered some of the limitations of the scope. With an aperture of F/8 and a 12.5mm eyepiece, the light collecting ability of the telescope is extremely limited, something that hadn’t bothered me when looking at the stars in town, but became a huge issue this weekend when I had an opportunity for some star viewing far (very far) from any city or road lights.

Let me take a step back for a moment; every year on the first weekend of May,me, my father, my brother and about 30 other guys go on what’s called the Indian Valley Reservoir Fishing Trip. Very little fishing goes on during the trip, but a lot of other things happen, primarily drinking. We all go to the same camp site fifteen or more miles from the nearest town and more than ten miles from the nearest paved road. There’s a lot of local light pollution as the bonfire’s built up and from lights in people’s camps, but a little judicious spacing and a tent between me and the light source takes care of a lot of the problem.

I took my Meade on the trip with great expectations, but I was sorely disappointed. The first night, a lot of the problem wasn’t the telescope, it was a light cloud cover that mostly disappeared at sunset, but not completely. The Milky Way was visible and I could see a lot more than I can at home, but it still wasn’t the stunning visual I’d hoped for. Saturday night was a bit better, but still disappointing. I wish there’d been a better sky, but there’s nothing I could have done about that.

The frustrating part was scanning the skies with my binoculars, finding the stars I wanted to look at, then not being able to find them with the telescope. I would mark stars in my mind, point the telescope in the right direction, then not be able to see the stars I had marked as my guides. At first I thought my sighting scope was out of alignment, until I realized that the real problem was the stars weren’t bright enough for me to see with the telescope. My binoculars have a better aperture than my telescope and stars that were a cinch to see in the binoculars weren’t even bright enough to see at all in the telescope!

Part of the problem might have been solved if I’d brought the 25mm eyepiece, but I didn’t. The real solution will be to wait a little while until I can afford a better telescope and pay attention to what’s really important in a telescope, the aperture. It’s great to be able to magnify an object 100x, but if it’s too faint to see, you’ll walk away frustrated.

The good news is, I got to show about half a dozen rednecks Saturn. Of all the objects in the sky, that’s the one that was easiest to show them that they could recognize easily. Of course, rednecks, beer and telescopes don’t always mix, but we managed to get away without any injuries this time.