The Eskimo Nebula
Another deep-sky object. This time is the Eskimo Nebula (NGC 2392) in Gemini, a planetary nebula that also goes by the name of “the Clown face”. The resemblance is evident in most images.
The image below was acquired on the night of March 21, 2014 at around 20:00 U.T., with the C11 SCT at F/10 and the ASI120MM camera without any filters. The image is a stack of 1000 frames, each a 3 second exposure to diminish as much as possible the seeing effects (which was terrible) and the tracking errors of my NEQ6 mount (which was not properly aligned for long exposure photography).
Despite the bad seeing, I did process the image in such a way that some fine details were revealed. Of course, the verification of the details had to come from a comparison with an image taken by a “better” (actually “the best”) telescope: the Hubble Space Telescope (HST):
The original Hubble image can be found here.
The above sequence shows that even a small amateur telescope (8.5 times smaller than Hubble, and terrestrial) can show details in objects like these rather small planetary nebulae.
I should repeat this exercise on this object in better seeing conditions and in more transparent skies. Maybe an RGB image would also help a bit…
(March 28, 2014)
UPDATE (April 1, 2014)
I’ve acquired some color data, so now I’m able to post a color version of the above image. Actually it’s an LRGB image, with the Green being extracted from images using the Baader UV/IR cut filter, so it’s not the true green, but after some processing I was able to make a rather good replacement for this color channel. The Luminance channel is now composed from both the older no-filter data (basically the image above) and the new UV/IR cut data. The result is perhaps better looking, and shows the colors of the main details of the nebula.
And a resized version, comparing the new color data with the new black-and-white one: