Horsehead Nebula B33

FOV: 40.98' high by 55.23' wide
North is left, West is top

Object Information
Barnard Catalog of 349 Dark Objects in the Sky: B33
Common name for object: Horsehead Nebula
Located in constellation: Orion
Right ascension in hours:minutes: 5:41
Declination in degrees:minutes: -2:30
Size: arc minutes

Observing Log
Date December 21, 1998
Time at end of first CCD image 00:35 PDT
Time at end of last CCD image 00:44 PDT
Discription: Absorption or dark nebula, The glare on the left side of the image is from the star Alnitak which is the right star in Orion's belt. Alnitak is a very bright 1.74 magnitude star.
CCD image time: Four 180 seconds images added together
Sky transparency: 5.5 (Magnitude of the faintest star visible with the unaided eye in Ursa Minor)
Moon sets at 18:31 PDT
Astronomical twilight ends in the evening at 18:16 PDT
Astronomical twilight starts in morning at 6:00 PDT

Observing Location

On the drive way at home
City: Camas
State: Washington
Country: U.S.A.
Longitude: 122 degrees 23.01 minutes
Latitude: 45 degrees 40.09 minutes

Observing Equipment

CCD observing telescope:
Orion ShortTube™ 80 mm aperture refractor, f/5 focal ratio, 400 mm focal length
Filter used on CCD camera:
Santa Barbara Instrument Group IR filter
CCD camera:
Richard Berry CCD Cookbook CB245 built by David Haworth
Telescope Finder:
Celestron CG-11 schmidt-cassegrain 11" (279 mm) aperture, f/6.3 focal ratio, 1764 mm focal length (using Celestron f/6.3 focal reducer), Tel Vue 35 mm Panoptic eye piece, magnification 50.4
Telescope mount:
Losmandy G-11
Polar aligment:
Used the Polar Axis Finderscope in the G-11 telescope mount
CCD Camera Computer:
Compaq LTE Lite/25 386

CB245 Camera Image Configuration

CCD chip:
Texas Instrument TC245
CCD size:
252 horizontal x 242 vertical photosites
25.5 um-wide by 19.7 um-high
Total CCD chip image size:
6.426 mm-wide by 4.7674 mm-high
Photosite resolution with Orion telescope:
13.15" wide by 10.16" high
Photosite width/hight aspect ratio:
1.294 to 1
Image rotation:
The acquired image is rotated 90 degrees to position the north edge of the image at the top of the Web page.
Image resampling:
Image resampled to correct the aspect ratio of the nonsquare photosites to display square pixels. Resampling creates a width/hight aspect ratio 1 to 1 with 187 horizontal x 252 vertical pixels.
Image croping:
Image croped to 187 x 226 pixels to remove star blooming.
Image FOV:
CCD image field of view (FOV) for the above images with the Orion telescope is 49.53' high by 40.98' wide

CB245 Camera Control Software Configuration

CB245 control software: 245Plus by Richard Berry
245Plus image mode: external binning mode
245Plus gamma LUT: on
245Plus dark current reduction: off (no LDC modifications)
245Plus drift subtract: on
245Plus display: VGA mode
245Plus both delays: 10

Imaging Processing Software

Image Calibration
Richard Berry's Multi245 version 40d for averaging 8 dark frames, registering multiple images, and stacking images to create a single calibrated image to be used for image processing. No flat fields were taken.
Image Processing
Richard Berry's CB245 version 60a for using Kunihiko Okano's Digital Development on the calibrated image. Software Bisque CCDSoft CCD Astronomy Software version 4.00.018 for brightness and contrast adjustments, rotating image, resampling to correct aspect ratio, and saving the image as a JPEG file for Web pages. JASC Inc. Paint Shop Pro version 4.12 used for editing star blooming in the image.

Use Test patterns to calibrate monitor brightness, contrast, height and width