A webcamscope provides a simple and cheap introduction to astrophotography. As its name suggests, it’s built around the sort of webcam you might buy for Zoom meetings, rather than a DSLR camera.
The components you need to make a webcamscope are widely available and, whether you choose brand-new or second-hand parts, they won’t cost much. You may even have some of them in a spare drawer.
I paid £11 for the webcam and £16 for the 200mm M42 lens on eBay, while the eyepiece adaptor, which replaces the webcam’s lens, was £10.
Second-hand M42 lenses are commonly available and, as they use a screw thread rather than a bayonet fitting, you can make a mount for one from an old rear lens cap.
Lenses can be heavy, though, so you can adapt the wooden mount to incorporate a cradle to support the front part as well.
When building your webcamscope, it’s important to get the correct distance between the backplate of the lens and the surface of the sensor in your webcam (the registration distance).
For M42 lenses, the registration distance is 45.5mm. If you vary this by too much, you might not be able to focus.
I drilled a 32mm-diameter hole through the wooden mount to hold the webcam adaptor, with a wider recess for the M42 rear lens cap, so the webcam and camera lens were held close together.
A little masking tape wrapped around the adaptor stops it slipping out.
Once set up, you shouldn’t need to make big changes to the focus, but it helps to be able to turn the lens’s focus ring if you shift targets.
Cutting away the sides of the wooden mount will make it easier to access the ring.
A metal strip with a ¼-inch hole allows the mount to be fixed to a tripod.
Position this once you’ve established the balance point of the assembled instrument, to reduce any tripping potential.
How to take a photograph with your webcam telescope
Once you have a clip you can use stacking software to align and stack the best frames from the video, as well as to remove any noise, and produce a high-quality, still image.
Using this webcamscope is as easy as making it: point, focus and record a video clip.
Experiment with different exposure settings to see which clips are better to process. You’ll become addicted.
Tools and materials
- Marking-out tools (a ruler, compasses and a pencil)
- Coping saw (or drill and hole saws)
- Plywood or softwood, approximately 600mm x 80mm x 15mm (or 12mm)
- Small strip of stiff metal (approximately 100mm x 25mm x 3mm)
- Small screws
- Wood glue
- M42 camera lens (with a focal length of 200mm or similar)
- M42 screw cap
- Webcam (and a laptop)
- 1.25-inch webcam eyepiece adaptor
Make an astrophotography webcam scope: step-by-step
Unscrew and remove the built-in lens unit of the webcam: some cases just prize apart, while others have small screws.
You can also remove the stand/clip (but you don’t need to for this project) and you may need to enlarge the hole in the casing to fit your adaptor.
Your adaptor might screw into the old lens thread. If it’s an odd size you may be able to use the metal adaptor’s internal thread to screw it onto the smooth outside of the plastic lens fitting.
It’s important to align it above, and perpendicular to, the sensor.
Download and print the webcam scope plan (PDF) and mark out the parts for the mount on the wood and cut them out.
Adjust the cradle at the front and the overall length of the mount to fit your lens. It needs to be held so you can still focus.
Once you’re happy with how your lens fits in your mount, glue and clamp the parts together.
Use pilot holes if you’re going to add screws to stop the plywood splitting.
Once the glue is dry, smooth the surfaces down with sandpaper and give them a coat of paint.
If you find your mount is too thick to achieve focus, you can cut a recess for a modified M42 rear lens cap.
You may need to adapt the design a little, depending on the registration distance of your lens.
Cut a metal strip to make a bracket to mount the webcamscope to a tripod.
Next, assemble the parts.
Find the best position for the bracket by finding the balance point of your webcamscope.
Use a camera screw, 0.25-inch x 20tpi (thread pitch) to fit it to the tripod.
This guide originally appeared in the July 2022 issue of BBC Sky at Night Magazine.