Some of the problems associated with digiscoping with scopes of longer focal length are a high magnification ratio and vignetting, particularly with cameras such as the Panasonic FZ30 and similar devices, never mind the price of long focal length 2" eyepieces. To this end I made a simple digiscoping adapter which fits into a standard 2" eyepiece/diagonal holder and uses a camera lens instead of an eyepiece. This follows on from my previous post which used a temporary lash up to prove the principle. (http://www.birdforum.net/showthread.php?t=51652) If you're handy you can make one of these and all you need are:
1. A piece of 2" thick walled (3/16") alloy tube about 1 3/8" long
2. A piece of 3/16" alloy sheet (though 3/32" would do)
3. Some 2-56 screws
4. A 50 drill
5. A 2-56 tap
6. A couple of files and a saw
7. An extension tube which fits your camera lenses
It would have been better to turn a one piece adapter but not everyone has a lathe. Pictures 1 and show the component parts. Picture 3 shows the assembled adapter. Picture 4 shows the adapter in place on the scope with a 90mm lens attached and Picture 5 shows the whole caboodle - a Meade 4" SCT with a Panasonic FZ30. Since the scope has a focal length of 1000mm, the magnification ratio is 1000/90 or 11.1x. A 135mm lens gives a ratio of 7.4x.
There is some vignetting below a setting of 300mm on the FZ30, mostly caused by the scope which is intended for 1.25" eyepieces. An 8" scope would have been better in this respect. There is also some vignetting due to the automatic diaphragm in the FZ30 which cannot be disabled. A neutral density filter of around 10x or 12x would help.
Another advantage of this method is that a 2" diagonal can be used, so the camera can be perched on top of the lens thus reducing the moment and allowing an adapter to be used between the camera and the lens.
Bryan
1. A piece of 2" thick walled (3/16") alloy tube about 1 3/8" long
2. A piece of 3/16" alloy sheet (though 3/32" would do)
3. Some 2-56 screws
4. A 50 drill
5. A 2-56 tap
6. A couple of files and a saw
7. An extension tube which fits your camera lenses
It would have been better to turn a one piece adapter but not everyone has a lathe. Pictures 1 and show the component parts. Picture 3 shows the assembled adapter. Picture 4 shows the adapter in place on the scope with a 90mm lens attached and Picture 5 shows the whole caboodle - a Meade 4" SCT with a Panasonic FZ30. Since the scope has a focal length of 1000mm, the magnification ratio is 1000/90 or 11.1x. A 135mm lens gives a ratio of 7.4x.
There is some vignetting below a setting of 300mm on the FZ30, mostly caused by the scope which is intended for 1.25" eyepieces. An 8" scope would have been better in this respect. There is also some vignetting due to the automatic diaphragm in the FZ30 which cannot be disabled. A neutral density filter of around 10x or 12x would help.
Another advantage of this method is that a 2" diagonal can be used, so the camera can be perched on top of the lens thus reducing the moment and allowing an adapter to be used between the camera and the lens.
Bryan