Re: California Nebula with the G-11 PMC-Eight #astrophotography

Steve Siedentop

I unfortunately don’t have an answer for you.  I actually don’t use flats, believe it or not.  There isn’t enough vignetting in my images for me to justify the extra time and work to generate flats.


On Wed, Feb 12, 2020 at 8:55 AM Jennifer Shelly via Groups.Io <> wrote:


Thank you. It appears your setup the measurement begins at the threads of the ES adapter to get you to 55mm. 

Canon camera    44mm
T-ring                   11mm
Total back focus  55mm

If that is correct have you determined how flat your field is (percentage)?




Jennifer Shelly
AstroPorch, VA

: ES PMC-8 G-11, ES PMC-8 EXOS-2
Scopes: ES ED127 FCD-100, ES Levy Comet Hunter, ES N208CF, QHY Mini Guide Scope, Solomark F60 Guide Scope
Cameras: QHY128C, QHY168C, Nikon D5600
Misc: MoonLite CFL 2.5 / High Res Stepper / V2 Mini Controller, Baader SteelTrack NT / SteelDrive II, Baader UFC, Optolong 2" L-Pro / L-eNhance
Imaging Software:  APT, BYN, SharpCap Pro, ASICap
Processing Software: PixInsight, Lightroom, Premiere Elements

Mounts: ES PMC-8 G11 with Ruland Couplers and One Piece Worm Blocks, Skywatcher NEQ-6
Scopes: ES ED127CF FCD100, Orion 6” Mak, Stellarvue SV80EDT, Coronado Solarmax 40
Cameras:  CentralDS CDS-600, CentralDS Astro 60D, Orion Starshoot SSAG
Msc: Moonlite Focusers, Astrozap Dew Straps, Pegasus Ultimate PowerBox
Software: PixInsight, Cartes du Ciel, BackyardEOS, SkySafari

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