Comet Machholz
Comet Machholz near Cassiopeia and the Double Cluster
February 5, 2005

 

 Comet Machholz (upper right with blue ion trail); Cassiopeia (bottom half); the Double Cluster (upper left); and various emission nebulae.

 

745 x 1024 version (871 kB)
2410 x 3312 version (6 MB)
  • Date/Time: February 5, 2005, beginning at 22:16 EST
  • Camera: Pentax 6x7
  • Lens: Pentax 105mm f/2.4
  • Exposure: 20 minutes @ f/2.4
  • Technique: Piggyback on (and hand-guided with) a Celestron 14 CGE
  • Film: Kodak Ektachrome 200
  • Developing: Paterson/Photocolor E-6, pushed 1 stop (8 minutes first developer @ 100 deg F)
  • Scanner: Microtek ScanMaker i900
  • Processing: Matlab & Photoshop
  • Notes:
  • Flatfielding was done with median/blur in Photoshop combined with subtraction in Matlab
  • Field shown is cropped from a horizontal 6x7 shot. The cropped area is roughly equivalent to a 645 frame.
  • The stars making up the "W" of Cassiopeia have been emphasized using the Photoshop diffusion technique detailed by Glenn Ray

A different composition, cropped from the full-resolution version of the image above.
Close-up of comet cropped from full-resolution version of the picture above
The "raw" scan. This example gives a good idea how much processing there is between the original scan (left) and the final images (above)!