I have three telescopes, all computer assisted, but I also want to learn how to find targets by other methods.
I have used star hopping but I find it difficult in my very light polluted area. I estimate the sky is Bortel 8. On the www.darksitefinder.com map I am in a dark white zone, the second worst.
What this means is that there are entire parts of my sky that have no visible stars. Even in my best direction, NE through SE there aren’t a lot. For example, Cassiopeia floats in a gray sea with not much around it.
I had read about the use of digital angle gauges as a method of finding targets, so I purchased one from Harbor Freight about a year ago. It is normally $34. I had a 25% off coupon so I bought one to try out the idea. However it sat in my workshop unused until a clear night on 9/23.
Harbor Freight Digital Angle Finder,
I pulled out my Orion XT8i Intelliscope, an 8” Dobsonian. I decided to star hop rather than turn on the Intelliscope. I wanted to see if I could find M92, a globular star cluster in Hercules in a bad part of my sky. I have tried to star hop to this one several times but with no success. I would start at Vega and work my way over to M92. But I was having problems seeing the guide stars or recognizing star patterns in my 9X50 finder scope. Even using my lowest power 31.5X and 2.2 degrees eyepeice I was not able to find it.
Then I remembered the Harbor Freight Angle Gauge that I had purchased a year ago. It magnetically attached to the tube of the XT8i. I did no calibration and the ground I was on was not level. I just turned it on and read the screen. This is not an illuminated screen so I used my red flashlight to read it.
M92 - Stellarium said that M92 should be at 38 degrees altitude. I reset the tube to 38 degrees. Swung to the left of where I was and BINGO, there it was. I was just high and and a bit to the right. This angle gauge worked great! In the 9X50 finder I could see some stars in the area but had to use averted vision to see the slight smudge that was the cluster. I must have gone right past it.
Hercules Cluster - Next I went for the Great Cluster in Hercules. Stellarium said this was at about 25 degrees, down and a bit to the left of M92. This was just barely above the trees, and I would be looking through a lot of atmosphere and a lot of sky glow. No way I could star hop to this one. I reset the telescope to 25 degrees and drifted a bit to the left and I found it in my low power eyepiece. In my finder scope I saw very little in stars and could not see the cluster at all.
Capella – Moving to the NE part of the sky, a much better part of my sky. Capella was bright and beautiful. I used it to confirm that the gauge was again accurately matching to what Stellarium said was the altitude of Capella. Good match.
Mirphak – Stellarium said 40.4 degrees. I could see it so I centered it in the eyepiece. I read the angle gauge. A good match to what Stellarium predicted.
This was only one night but it showed me that I have another method of finding targets and it works well. If I can get the angle right and get the scope into the right area, just a little left and right sweep finds the target. The angle gauge now lives on the XT8i.
Next time out I may try a compass in combination with the angle gauge.
If you have a manual scope and are having trouble finding your targets, try one of these angle gauges. Get one that is magnetic so it attaches to the optical tube. This one is very small, on 2" square so it is not bothersome but the numbers are large so it is easy to read.
Edited by aeajr, 24 September 2017 - 12:31 PM.