This page explains how I modified a Logitech Quickcam Express webcam for astrophotography. It should be general enough to apply to just about any inexpensive webcam.

You know the kind, the little webcams mounted in a ball and sits on your computer. Sorry, I no longer have the original housing, but hopefully you get the idea.

To make a device like this, you need an inexpensive webcam, like the Logitech Quickcam. You'll also need a T adapter like that often used to mate a 35mm SLR camera to an astronomical telescope.

Astrocam Assembly Diagram

At left is a diagram of the webcam modifications.

Inside the webcam housing is usually a single circuit card, hosting the CCD array in the center of the card.

If you have machining equipment, you can make a really nifty astro-camera. Not being a machinist, I had to find a simpler way.

I was able to find an old soft-plastic pill bottle that was the right diameter to snuggly fit over the T thread. I cut off the bottom inch or so of the plastic bottle (discarding the top), cut a 1/2" hole in it to allow light to reach the CCD array, and screwed the pill bottle end onto my T thread adaptor.

I also fabricated a simple cover over the back of the circuit card, and hurray, I had a CCD camera for astrophotography.

Astrocam Parts

This image will help clarify my diagram and description.

On the left you see the modified webcam astro-camera. The white part (blackened inside) is the plastic pill bottle end. You can see the hole cut in the bottom to expose the CCD array (the square).

The pill bottle is just the right diameter to tightly fit over the T-threads of the camera to focuser adaptor, shown on the right of the picture.

You can see that with electrical tape and some thin cardboard (like poster board), I fabricated a simple cover over the rear of the astro-camera.

Assembled Astro-camera

At left you can see the assembled astro-camera. The snout slides exactly into a 1.25" focuser.

The USB cable is plugged into a computer during use, and I run the vendor supplied webcam software to make the exposures.

Astro-camera on Telescope

This is a image of the webcam astro-camera mounted to my Meade ETX90. As you can see, it simply slides into the focuser instead of an eyepiece.

If I need more magnification, I insert a barlow lens first, then the webcam.

Individual pictures can be taken with the webcam, and is the technique I used for most of the images displayed on my photography pages (I was still learning).

Since the camera takes about 10 images per second, a few seconds gives me plenty of images to work with.

Then I use an image selection and averaging program to combine the frames of a film clip into a single image. This technique helps reduce atmospheric turbulence and pixel gain errors of the camera.

Note, this technique can't really overcome a bad seeing night, but can certainly help reduce the residual turbulence on a good night.

Webcam Astro-camera Result

At left is my best Mars image, taken during the 2003 opposition with my Meade ETX90 and the modified webcam astro-camera.

I believe it to be a rather remarkable photo with such a modest instrument. It is a stack of 48 frames taken from an avi file. For this image I used the Image Stacker program.

My little device has a small CCD, so the field of view it encompasses is also small. Getting moon images is easy. If I see the moon in the finder, some portion of the moon is also in the camera. I use my handy added slow motion control on the Meade ETX90 to move to the part of the moon I want.

Planets are tougher. I may have the planet in the finder, but I often can't find it in the camera. I've gotten around this with the Meade ETX90 by removing the rear plug and putting in another eyepiece. Using the flip mirror, I can look through the auxiliary eyepiece to center the planet, then flip back to the camera.