Michael Purcell's Astrophotography

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M28

(Click on the picture above to go to the main image.)

This is one of the few cases in which there were so many background stars that the ST-7's auto-guiding could not keep track of the guide star. Instead, I had to use Track-and-Accumulate with partial images of 20 seconds each.

I took this picture in New Mexico.

Constellation	Sagittarius
Right Asc (hh:mm:ss)	18:24:30
Declination(deg:sec)	-24:52
Magnitude	7
Size (ArcMin)	11
Tirion SkyAtlas 2000	#22
Uranometria 2000	#340

CCD Camera Parameters

ST-7 Compressed Image
File_version = 3
Data_version = 1
Exposure = 5 minutes
Focal_length = 63.000
Aperture = 65.9000
Response_factor = 2000.000
Note = Image taken 04/15/96 at 04:38:52
Background = 235
Range = 1337
Height = 509
Width = 755
Date = 04/15/96
Time = 04:38:52
Exposure_state = 100
Temperature = -19.98 C
Number_exposures = 15
Each_exposure = 20 seconds
History = REKF
Observer = Michael Purcell
X_pixel_size = 0.0090
Y_pixel_size = 0.0090
Pedestal = -148
E_gain = 2.30
User_1 = CCDOPS for DOS Version 3.50B4
Filter = Clear
Readout_mode = 0
Track_time = 0
Sat_level = 65535

This page last updated on August 24, 1996 Contact Michael Purcell