Sunday, June 19, 2016

reshot NGC 6940 (Halifax)

Another redo. The May 21 image of the open cluster NGC 6940 showed some trailing. This one worked out much better. Also, I used a different stretch function, Log(x), which seems to be much nicer on star groups...

RASC Finest open cluster NGC 6940 luminance

Luminance only, 60 seconds subexposures, 10 stacked shots. FITS Liberator, Paint.NET. North is up; left is east.


There's an interesting triple star south of centre: L48 (Thomas Lewis). The B star is shown to the south in SkyTools 3 Pro; the image shows it to the east.

Oops! I think I judged the first run images based on the bright star at the bottom right—and interpreted the elongated shape as trailed images. In fact, that peanut is a bright pair of stars! That the double HD 196021, aka Σ2698. SkyTools shows the 8.7 and 9.7 magnitude stars just outside the boundary of the open cluster.


It's interesting to me that this latest image is not exactly the same framing as the earlier. Why? Why would BGO point to a slightly different spot?

No comments: