Hi all:
This 36 degree by 24 degree image of Orion and part of Monoceros is my first light for a 55mm Pentax 67 camera lens at f5.4. The lens is coupled to a FLI Microline 11002M, CFW-7 filter wheel and PDF focuser.
I was inspired to try the Pentax 67 medium format lenses by Richard Crisp who has imaged extensively with this lens family and FLI products. Thanks Richard!
The Pentax 67 family of lenses makes a lot of sense for me, because the field flattener of my primary refractor requires 85 mm between the back of the flattener and the image plane. 85mm was selected by the lens designer so that the refractor/field flattener could be used with a Pentax 67 medium format film camera body, which requires 85 mm of back focus.
85 mm is a lot more than the back focus of a 35mm format lens. With a 35mm lens it would be difficult or maybe impossible to use a ccd camera, filter wheel and PDF type focuser after the lens, there just isn’t enough back focus room. However, the Finger Lakes Instruments focuser and wheel, plus the distance from the front of the chip to the front of the camera are less than 85mm. So, to make a long story short, I have made one adapter that attaches my camera/wheel/focuser system to the refractor/field flattener and another adapter that attaches the same imaging gear to any Pentax 67 lens. Now, I can keep the camera, filter wheel and focuser more or less permanently hooked together and easily select a camera lens or the telescope. I made a simple platform that holds the camera and mini-Borg guide scope when imaging with a camera lens.
This particular image is only 20 minutes of L, in 2 minute subs and 120 minutes of Ha; 30 minute subs. The moon, plus the moon reflecting off of snow, plus Denver's light dome made for some very dramatic gradients! I am very pleased with this for first light given that I have so few subs. The full resolution version is here:
http://home.comcast.net/~jameslbrown/pwpimages/new%20final.jpg
Take a look around and you will see that the well known objects in this field (M42, The Rosette, The Horsehead/Flame) are reasonably well rendered, given the extremely wide image scale.
The Pentax 67 lenses are quite affordable on the used market; I'm looking forward to using this versatile system with a few different focal lengths.
Thanks for looking!
Jim
This 36 degree by 24 degree image of Orion and part of Monoceros is my first light for a 55mm Pentax 67 camera lens at f5.4. The lens is coupled to a FLI Microline 11002M, CFW-7 filter wheel and PDF focuser.
I was inspired to try the Pentax 67 medium format lenses by Richard Crisp who has imaged extensively with this lens family and FLI products. Thanks Richard!
The Pentax 67 family of lenses makes a lot of sense for me, because the field flattener of my primary refractor requires 85 mm between the back of the flattener and the image plane. 85mm was selected by the lens designer so that the refractor/field flattener could be used with a Pentax 67 medium format film camera body, which requires 85 mm of back focus.
85 mm is a lot more than the back focus of a 35mm format lens. With a 35mm lens it would be difficult or maybe impossible to use a ccd camera, filter wheel and PDF type focuser after the lens, there just isn’t enough back focus room. However, the Finger Lakes Instruments focuser and wheel, plus the distance from the front of the chip to the front of the camera are less than 85mm. So, to make a long story short, I have made one adapter that attaches my camera/wheel/focuser system to the refractor/field flattener and another adapter that attaches the same imaging gear to any Pentax 67 lens. Now, I can keep the camera, filter wheel and focuser more or less permanently hooked together and easily select a camera lens or the telescope. I made a simple platform that holds the camera and mini-Borg guide scope when imaging with a camera lens.
This particular image is only 20 minutes of L, in 2 minute subs and 120 minutes of Ha; 30 minute subs. The moon, plus the moon reflecting off of snow, plus Denver's light dome made for some very dramatic gradients! I am very pleased with this for first light given that I have so few subs. The full resolution version is here:
http://home.comcast.net/~jameslbrown/pwpimages/new%20final.jpg
Take a look around and you will see that the well known objects in this field (M42, The Rosette, The Horsehead/Flame) are reasonably well rendered, given the extremely wide image scale.
The Pentax 67 lenses are quite affordable on the used market; I'm looking forward to using this versatile system with a few different focal lengths.
Thanks for looking!
Jim
Attached Image:
