Hi guys. I am about to get into doing some video with a 10" skywatcher tracking dob and a swann hd-420 security cmos camera (please dont go into the ccd vs cmos argument) using prime focus and wanted to kno how to bring my images closer or to zoom in i guess. I have taken off the lense and exposed the sensor. Is it just a matter of stacking and enlarging or is there adapters to use like a barlow? Thanks
There are couple of ways to enlarge the image (zoom-in, or increase the focal length of the Newtonian optical system):
1) leave the objective of the camera where it was and use eyepiece (just as you would use your own eye instead of camera to look through the scope
2) With camera lens removed, use eyepiece projection (focus the image by moving the eyepiece out until the image is focussed)
3) With camera lens removed, use barlow lens instead of eyepiece
All this will be OK for planetary or Moon imaging.
There are adapters available (to start, sometimes just a bit of PVC pipe and sticky tape helps a lot.. depending on the individual taste, of course.)
ok so i got myself a webcam for $100 and did a "bit" of modification to it . i now am able to take video at decent resolution and stack it with registax (when i learn how to use it). I attached a image i took tonight. i still have to play with the settings but its a start.
Nice one.
A barlow will give you the extra magnification that you desire.
Andrews Communication have a 2.5x Apo Barlow that I think well of. It's optics are lovely and it's very reasonably priced too at $49. http://andrewscom.com.au/site-section-10.htm
It's listed in the Guan Sheng Accessories page, scroll down near the bottom of the page.
Thanks for the info. i do actually have a tele vue 2x barlow i just didnt use it that time, bit to excited. Here is a shot of saturn i took last night. it is un-edited. i have a few videos aswell i have posted on youtube.
ok i have taken a video with a 2x barlow and stacked the images. this is the outcome. i honestly don't think i could do much better than this. Thanks heaps for the help and info guys
You got some great detail considering how wee Saturn is in the field of view. Time to add that barlow to the imaging train.
You might need an extension tube to get focus. maybe
. i now am able to take video at decent resolution and stack it with registax (when i learn how to use it). I attached a image i took tonight. i still have to play with the settings but its a start.
Nice one. 
