SaratogaSkies Jim Solomon's Astropics

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IC 1318 (Gamma Cygni Nebula)

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Prime Focus
Additional Optics: Celestron/Baader Multi Purpose Coma Corrector (MPCC)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 8 x 8min @ ISO 400
Total Exposure: 1hrs, 4min
Date: 9/6/2004, ~11:50pm PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: Manual
Guiding: GuideDog via Philips ToUcam Pro II (840k) through Orion ST80 w/ Celestron 2x "Kit" Barlow

Processing:

  • IRIS: Dark subtraction, flat field, registration, Kappa-Sigma stacking
  • Photoshop: Levels, image size, JPG conversion

Image Description:

This is IC 1318, a patch of nebulosity around the bright star Gamma Cygni (aka Sadr) in the constellation of Cygnus. In case you're wondering, Gamma Cygni is the bright star in the center of the photo. The full-size image shows excellent off-axis coma correction, indicating that the MPCC performs pretty well when the optics are well collimated.

A new-and-improved set of Flat Field frames helped in the processing of this image. The Flat Field giving the most pleasing result was generated as follows:

  • Set of 16 individual frames, median-combined
  • Captured between 5min and 8min after sundown
  • 1/8 second exposures @ ISO 100
  • DEC equal to my latitude
  • Hour Angle equal to two hours East of the Meridian
  • Tracking on during the exposure, but off between exposures (this allows the median-combine to remove any stars captured in the individual frames)

This is the full frame, scaled for display on the web. North is up.

 
M13 (Great Cluster in Hercules)
SaratogaSkies Jim Solomon's Astropics

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M13 (Great Cluster in Hercules)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Negative Projection (Barlowed)
Additional Optics: TeleVue 2x Barlow
Filter: None
Effective Focal Length: 2844mm
Effective Focal Ratio: f/14.2
Exposure: 12 x 1min @ ISO 3200
Total Exposure: 0hrs, 12min
Date: 6/23/2004 12:52am PDT (start)
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: None

Processing:

  • IRIS: Dark subtraction, flat field, registration, stacking, Richardson-Lucy Deconvoultion (5 iterations), AF5 Noise Reduction
  • Photoshop: Image scale (1/4x), JPG conversion

Image Description:

This magnification pushes the limits of my mount, especially without [auto]-guiding. Only 12 of the 32 frames were useable. The rest showed severe smearing/trailing and had to be tossed. This is a scaled version of the full-size frame. North is up.

 
NGC 6888 (Crescent Nebula)
SaratogaSkies Jim Solomon's Astropics

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December: Test shots with new scopes/mounts

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NGC 6888 (Crescent Nebula)   [obsolete]

Image Details:

Camera: Canon Digital Rebel (300D)
Mount: Celestron AS-GT
Scope: Celestron C8-N (8" f/5 Newtonian)
Configuration: Prime Focus
Additional Optics: n/a (Prime)
Filter: None
Effective Focal Length: 1000mm
Effective Focal Ratio: f/5
Exposure: 9 x 10min @ ISO 100
Total Exposure: 1hrs, 30min
Date: 8/14/2004, ~3am PDT
Location: Saratoga, CA, USA
Acquisition: DSLRfocus
Focus: DSLRFocus
Dithering: None
Guiding: GuideDog via Philips ToUcam Pro II (840k) through Orion ST80 w/ Celestron 2x "Kit" Barlow

Processing:

  • IRIS: Dark subtraction, flat field, registration, Kappa-Sigma stacking
  • Photoshop: Levels, image size, cropping, JPG conversion

Image Description:

This is NGC 6888, the Crescent Nebula, in the constellation of Cygnus and is my first autoguided photo; first, that is, with my own guiding equipment. I still haven't mastered the guiding software, so there was a bit of smearing on some of these frames, but all were decent and useable. The conditions were quite awful though, with rather horrid transparency and seeing, and clouds moving in and out. An object this faint requires pretty pristine conditions. This is a 50% crop of the full frame, scaled for display on the web. North is up.