Moon – September 15, 2016
After performing the first “H-alpha light” with the “new” 150mm F/8 Refractor, I’ve decided that collimating the instrument must be the next logical step.
And that I did, together with my brother in law, after the Sun went down. The best way to properly collimate an astronomical instrument is by viewing a star at very high magnification. For that I was “forced” to use a magnification of 350x, by using two Barlow lenses and a 26mm eyepiece. After verifying the collimation we’ve decided to observe the Moon for a few tens of minutes. Despite the purple halo inherent to achromatic refractors, the view of craters at 100 to 200x was fantastic, and that with the Moon rather low above the horizon. Of course, I had to get some images, but also to test a few combinations for further imaging sessions.
I’ve started by acquiring a full-disc shot using the 0.5x Reducer and ASI 174MM camera, and a Green filter (which apparently works best with this refractor).
The end result is a 500-frame (out of 3000) stack processed at normal resolution (no re-sampling).
And a few more shots, this time with a 3x barlow lens. The seeing was poor due mostly to the low altitude of the Moon above the horizon, but a few good moments allowed for some rather fine details to be captured.
First, Plato and SInus Iridum in poor seeing (3-4/10):
And part of the terminator (a three image mosaic), with Vallis Schroteri and Rima Marius well visible:
At the end of the session, Copernicus in “acceptable” seeing (5/10):
And a short “strange” processing, to better reveal the subtle ray system: