Saturday, September 23, 2017

Large Format Astrophotography

Well, I went and did it.  I took the plunge. Conditions were average.  My Unihedron Sky Quality Meter (SQM) read 21.4 mags/sq-arc-sec.  This is a bit below average.  Some pesky clouds bothered at times.  High humidity and hazy skies with poor transparency contributed to some lowering of quality to the final image. This was my first large format effort and I did not expect it to be perfect or ideal.  It did however come out just fine all things considered.

The setup Calumet (Cambo) 4x5 mounted atop my classic 8" Meade

The circa 1984 Calumet / Cambo 4x5 monorail rode atop my old Meade 2080.  My friend Danny Spence from Texas gifted me the wonderful Schneider 150mm f/5.6 Super Symmar HM lens.  It's fine quality allowed for great wide-open performance.  Images were sharp and with little vignetting.

The 40 minute exposure on Fuji Acros 100

The 40 minute exposure was adequate at f/5.6, but when developing I thought it best to push 1 stop to bring about some finer details in the Great Rift.  Kodak Xtol was used diluted 1+1 and a 13 minute development for an effective speed of ISO 200 was completed in my kitchen.

The film was scanned on my Epson V600 with two passes as this is not a 4x5 scanner.  The two images were assembled in Microsoft ICE.  I have proudly left the film edge revealing the emulsion tag, basically signalling that this was shot on film!

This area of the Great Rift centered on the constellation Aquila, was done by convenience.  It allowed a low enough angle to not stress the system and it was well placed away from trees on my site.  You can make out many dark nebulae and star clouds throughout.

I'm very pleased with this first attempt.  In time I will do more.  There are very few that have attempted large format work in the first of guided astrophotography.  I'm glad to have to have made at least one successful effort.

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