The Horsehead
Images taken: Dec 1, 2006, by Tibor Torma in strong moonlight through cirrus clouds.
Telescope: Meade 12 in at f/6.55 (f=2m). Camera: SBIG ST-10 CCD
Exposures: 2 min red, 3 min green, 3 min blue.
Images taken: March 1-4, 2005, by Tejaswi Tedepalli and Tibor Torma.
Telescope: Meade 12 in with f/4.66 focal reducer (f=56in), guided with an AO-7 adaptive optics accessory, with Ha filter.
Camera: SBIG ST-7 CCD
Exposures: 60 min with Ha filter, 20 min green, 20 min blue, guided on a 7 mg star.
Images taken: Dec. 1, 2004, by Christian Snider and Tibor Torma.
Telescope: Meade 12 in with f/4.66 focal reducer (f=56in), guided with an AO-7 adaptive optics accessory.
Camera: SBIG ST-7 CCD
Seeing: 6 as.
Exposures: 17.5 min with IR+red filter, 1 min green, 3 x 1 min blue, guided on a 11.8 mg star.
Background: 19.2 mg/as^2 in red+IR, S/N=2 reduced to S/N=10 with software.
Altitude: 30 deg.
Measured surface brightness of the bright nebula: 22.2 mg/as^2.
Images taken: Dec. 1, 2003 in somewhat hazy weather.
Students: Brigitte Parsons and Jeremy Jones
Telescope: Meade 12 in with f/4 focal reducer (f=48in) in the parking lot.
Size of the images: 15'x20'
Camera: SBIG ST-7 CCD
Seeing: 7 as.
Exposures: 20x15 sec (red filter) track and accumulate at low resolution (3x3 binning).
Background: 18.6 mg/as^2.
Altitude: 52 deg.
Measured surface brightness of the bright nebula: 20.2 mg/as^2.
The Horsehead is a dark interstellar dust cloud that blocks the light of the red glowing gas behind it. It is quite difficult to image because of it very low surface brightness (S/B=1:4.5).
Image processing: CCDoops + Photoshop Elements (image smoothed).