Bigger size: 1200x785
December 26th, 30th, 2008 and January 3rd, 2008
L: 12x10' @ 1x1
R: 15x7' @ 2x2
G: 15x7' @ 2x2
B: 10x12' @ 2x2
Total: 7.5 hours
Focal: 530mm, f/5
Imaging scope: Takahashi FSQ 106 EDX
Guiding camera: StarShoot AutoGuider
Guiding scope: Orion ShortTube 80mm
Mount: Takahashi EM-400
SITE & CONDITIONS
Dinosaur Point (12/26/08), Henry Coe (12/30/08) and Coyote Lake(1/3/09)
Processing: PixInsight & Photoshop
COMMENTSMost images of the M81 and M82 galaxy pair
will show the two galaxies (of course), the surrounding stars and a few smaller galaxies here and there.
But a deeper exposure and a much more careful processing will reveal that these galaxies, far from being visualized against a nearly dark, empty background, they are surrounded by huge clouds of dust.
The truth is that the galaxies are not surrounded by this dust - the dust is much closer to us than the galaxies - it just happens to look that way. Kind of like looking at the moon on a partially cloudy night.
This dust, unlike classic reflection nebulas - that are usually illuminated by neighboring stars - is actually illuminated by the glow of our own Milky Way galaxy. And yes, it is very very faint. Steve Mandel named this nebulosity Integrated Flux Nebula, or IFN.
One of the first things I wanted to do once I've got my CCD was to try this field and see if I was able to pull out all that IFN. So I spent three nights capturing data, at three different sites and under three different - but similar - skies. BTW, using several sites is not a requirement to capture IFN, it just so happened that on each of these nights I went to different dark sites.
I ended up only collecting the luminance acquired in one night at Henry Coe (I had to throw away the previous luminance collected at Dino Point), then the RGB at Coyote Lake. The sky conditions at Henry Coe started a bit below average, but around 1:30am the fog rolled in the valley, completely covering the lights of San Jose and Morgan Hill, leaving the site in spooky darkness. Still, I believe this is probably so far the only clear capture of IFN through an image of only 2 hours of luminance, and all under skies not far from city lights (Morgan Hill is only about 6 miles west of the location at Henry Coe State Park where I captured the luminance)
It is my second "serious" image with the FSQ and the STL11k, proving so far that they are a team. Processing this image was extremely challenging but despite I'm not completely satisfied the way the stars ended up, I'm very pleased with the image and in particular the amount of IFN that I was able to pull out.