Two of the last three nights at my location, here in northern Alabama, were cloud free and clear as only dry north winds produce in this area. My zenith measured SQM-L reading was 19.1 to 19.2. Temperatures were in the upper 20’s with a dew point in the lower 20’s. The stars were not twinkling. By the way, I live in a very well lighted subdivision in a red-orange zone.
With these conditions I ventured out into my back yard at about 6:30 pm central to try to find a little shelter from the streetlights and my neighbors outdoor lights. My goal was to see what objects I could see using my MOD3-C filtered at 1X with an Envis f/1.2 lens. All filters used were 2” and attach to the front of the Envis with step-up rings. The first filter I tried was a 7nm Baader H-alpha narrow band filter. I started viewing toward the north west and to my surprise I saw the outline of the North American nebula with the Pelican nebula next to it. Under these conditions I frankly did not expect to see anything this near the horizon under my conditions. As it turns out I was able to clearly see the North American nebula set over my neighbors house 200’ away an hour and a half later.
As I scanned toward the zenith I also saw the Elephant Trunk, Pac man, Heart and Soul nebulae. The last 2 showed some internal detail. Again at 1X I did not expect this. I continued my sweep and saw the Flaming Star nebula and the California nebula. The California showed structure and spanned at least 5 degrees of sky, perhaps more.
I continued scanning eastward and saw the Cone and the Rosette nebula. A little detail was visible in the Rosette. While I had seen the cluster NGC 2244 in the center of the Rosette with a telescope I had never seen the nebula from this location. Next up was Orion with Barnard’s Loop clearly visible forming a half circle. Near Alnitak the Flame and IC434 were visible but my tired old eyes could not see the Horse Head. Magnification is needed for me. The Orion nebula was of course spectacular and many more nebula were visible but I did not try to identify them all at this time. Switching to a Astronomk 12nm H-alpha narrow band filter the nebula were all still visible but substantially less bright.
Also tried were three long pass filters, 640nm Lumicon, 685nm Baader and a 742nm Astronomik. I initially tried the sky unfiltered and the only nebula visible, the Orion nebula, was also visible in the 640. I used Andromeda to try to get a relative comparison of filter performance. Unfiltered Andromeda appeared as a 1/2 degree ellipse. The 642 produced an ellipse about 1 degree in extent. Through the 742 it appeared to subtend about 1.5 degrees through the 685 it appeared to be about 2 degrees in extent. I could not see any divisions or detail with any of the three filters. Perhaps a little more magnification will help. The 685 and 742 seemed to yield the most stars that is the background looked like a starry carpet with these filters.
Since I have not given the as built specifications in the past for my MOD3-C they are listed below. Values for my MOD3-C are from the inspection report which came with it.
Tube: L3, filmless, white phosphor
Dark & Bright Spots: none