Webcam telescope finderscope.
Category: Astronomy Equipment
Posted by: Tom How
I am a great fan of webcams and I have always used them in my astronomy and astrophotogaphy. One of the most effective places to put a webcam on a telescope is the end of your finderscope. Many people like to operate their telescopes from indoors or remote locations and I do not know how they manage without a webcam finderscope.
Telescope finderscopes are small telescopes attached to larger telescopes. The finderscope has a much larger field of view than the main telescope, and as such can be used to help the astronomer aim the main telescope at a target of interest.
Telescope finderscopes are often mounted at around head height on the top of the telescope OTA so that the astronomer can easily look down the finder without bending his neck in 6 different places, however, they are still be uncomfortable to use.
Once you start trying to remotely operate your telescope on a GOTO telescope mount you will often find that the telescope GOTO system does not always land your astronomical target on the sensor of the CCD camera. In these situations I find it useful to sync the telescope GOTO with a nearby bright star, and then do a GOTO my astro target. But how do you get the bright star on the CCD camera sensor? Well, you look up the finderscope! This doesn't sound very good for remote operation, so what I do is have a webcam attached to the finderscope where I could normally put my eye.

Unlike most astronomical applications of webcams, you do not remove the standard lens, you leave it on. You just fix the webcam in place on the end of the finderscope with the webcam lens about where your eye normally goes. The output of the webcam now looks just like the view you get up the finderscope - cross hairs and everything!
I can normally see stars down to about Mag 6 using this method - more than enough to help me get a bright star on the CCD camera and sync the telescope GOTO system. You have to turn up the exposure etc, but it does not require any modifications to the camera.
I attach my webcam to the end of the finderscope using a piece of plastic tubing I found which slips tightly over the finderscope - I have simply glued this to the webcam.
Without the webcam finderscope I could not be able to remotely operate my telescope observatory.
A futher advantage is that you are free to position the finderscope where you like. I have mine bolted to the top of the tube rings down by the mirror end of the scope. Here it is more out of the way. In this position the finderscope helps to counter balance the weight of the CCD camera attached to the focuser of the main telescope. It is uncomfortable to eyeball the telescope finderscope in this position - I always use the webcam.
Telescope finderscopes are small telescopes attached to larger telescopes. The finderscope has a much larger field of view than the main telescope, and as such can be used to help the astronomer aim the main telescope at a target of interest.
Telescope finderscopes are often mounted at around head height on the top of the telescope OTA so that the astronomer can easily look down the finder without bending his neck in 6 different places, however, they are still be uncomfortable to use.
Once you start trying to remotely operate your telescope on a GOTO telescope mount you will often find that the telescope GOTO system does not always land your astronomical target on the sensor of the CCD camera. In these situations I find it useful to sync the telescope GOTO with a nearby bright star, and then do a GOTO my astro target. But how do you get the bright star on the CCD camera sensor? Well, you look up the finderscope! This doesn't sound very good for remote operation, so what I do is have a webcam attached to the finderscope where I could normally put my eye.

Unlike most astronomical applications of webcams, you do not remove the standard lens, you leave it on. You just fix the webcam in place on the end of the finderscope with the webcam lens about where your eye normally goes. The output of the webcam now looks just like the view you get up the finderscope - cross hairs and everything!
I can normally see stars down to about Mag 6 using this method - more than enough to help me get a bright star on the CCD camera and sync the telescope GOTO system. You have to turn up the exposure etc, but it does not require any modifications to the camera.
I attach my webcam to the end of the finderscope using a piece of plastic tubing I found which slips tightly over the finderscope - I have simply glued this to the webcam.
Without the webcam finderscope I could not be able to remotely operate my telescope observatory.
A futher advantage is that you are free to position the finderscope where you like. I have mine bolted to the top of the tube rings down by the mirror end of the scope. Here it is more out of the way. In this position the finderscope helps to counter balance the weight of the CCD camera attached to the focuser of the main telescope. It is uncomfortable to eyeball the telescope finderscope in this position - I always use the webcam.