vdB 152 and LDN1217 - the Wolf's Cave in Cepheus
vdB 152 and LDN1217 - the Wolf's Cave in Cepheus
vdB 152 and LDN1217 - the Wolf's Cave in Cepheus
This fascinating field in Cepheus features the the dark nebula LDN 1217 (aka Barnard 175). LDN 1217 is a Bok globule - a region where dust condenses to form protostars. The dark nebula is dimly illuminated by ultraviolet light, yielding a reddish glow characteristic of Extended Red Emission nebulae (EREs).

On the left side of the image is the blue reflection nebula, vdB 152 (aka Cedarblad 201). The reflection nebula is illuminated by the bright star embedded within it. Curiously, though, the star's motion through space indicates that it is not formed from the condensing nebula - rather it is passing through the nebula.

In this image, North is to the right. This image is cropped to 52% of the original image.

Exposure Details
Lens Nikon 600mm f/4 ED IF
Focal Length 600mm
Focal Ratio f/4
Mount Schaefer GEM - 7 1/2 inch Byers gear
Guiding William Optics 50mm guide scope, Lodestar autoguider, PHD Guiding
Camera Hutech modified Canon 6D
Exposure 67 subexposures of 600 sec @ ISO 200 - 11+ hours
Calibration 30 darks, 30 flats, 30 dark flats, 30 bias
Date August 25 and 26, 2014
Temperature 53F on 8/25, 56F on 8/26
SQM Reading 21.35 (Bortle 4) on 8/25, 21.40 (Bortle 4) on 8/26
Seeing 3/5 on 8/25, 4/5 on 8/26
Location Pine Mountain Club, California
Software Used Images Plus 5.75 for camera control. Images Plus 6.0 Beta for calibration, stacking, digital development, feature mask, star shrinking and halo reduction, smoothing and noise reduction. Photoshop CS5 used for levels and curves, high pass filter, star shrinking, screen mask invert, lab color, vibrance, saturation adjustments, lens correction, cropping and selective color. HLVG for additional color correction, Gradient Xterminator for gradient removal. Carboni Tools for additional noise reduction and smoothing, Focus Magic for focus restoration. Registar for stack alignment.
Notes This is my first light image for my "dropped in a lake" Nikkor 600mm f/4 lens. While I need to do a little work to better align the optics in the lens, it still is performing quite well. I'm particularly happy with how relatively tight the stars are in this image, and I'm quite pleased with the nebulosity I was able to bring out in this image.