Quickcam 4000 Telescope Adapter

High resolution imaging becomes increasingly difficult as the atmosphere becomes less stable. Imagine trying to read the fine print on a newspaper at the bottom of a pool with a rippling surface. But there is a way to partly beat the effects of the atmosphere, and that is to take many very short exposures, and select through them for the few that happened when the air was briefly still. Expensive astronomical cameras offer no help here, because they are designed for long exposure imaging. Instead, some of the best high resolution planetary images these days are coming from video cameras, which are very good at taking many fast pictures. A particularly simple and inexpensive approach to this is using a webcam, which is a video camera and frame grabber combined. Now 1/30 second, or 1/100 second isn't very long to collect light, so the source needs to be bright. This is a technique for imaging planets, not deep-sky objects.

With care, a telescopic image like this:

Seeing

Ends up being processed into this:

Mars

The original data is collected as a movie. There are several software tools available for splitting the movie into individual frames and working with them. I'm using K3CCD Tools, which is available here.

Many webcams may be used. Those that use CCD sensors generally work better than those using CMOS. I'm using a Logitech Quickcam 4000, which has a good quality CCD and a chipset that allows a lot of control over exposure time and frame rate. The QC 4000 is easily modified so that it can be attached to a telescope:

Step 1Remove the base and privacy shutter. Open the camera by removing the single screw located on one side. Remove the lens by unscrewing it from the plastic structure on the PC board. Click to see a larger image.
Step 2There is an annoyingly bright LED inside. I disabled it by lifting its current limiting resistor from the board, but you may find it easier just to paint it over with something opaque. Click to see a larger image.
Step 3The opening in the shell is just the right size for C-mount threads. Shown here is a C-mount spacer, used to convert from C-mount to CS-mount. Click to see a larger image.
Step 4 A standard C-mount to 1.25" adapter also works very well here. These are very inexpensive adapters which are widely available. Click to see a larger image.
Step 5 Once the adapter is located, replace the other half of the shell. Click to see a larger image.
Step 6 If you use a C-mount spacer rather than a 1.25" adapter, shim the outside edge with a film canister to get the necessary 1.25" diameter. Click to see a larger image.
Step 7 Generally, you want high magnification for planetary imaging. I insert the camera into a barlow lens and then into my telescope eyepiece holder. This camera is ready to image. Click to see a larger image.

© Copyright 2003, Chris L Peterson. All rights reserved.