I decided to put a spare webcam to use that would not take very long and require less than $15.
1) Install the driver on the supported OS and confirm that the webcam still works. In this case it is a Logitech QuickCam communicate STX, 1.3M pixels, running on Windows XP.
2) Note that step 1) is the most difficult part of the entire project, and you will remember why you originally tossed the piece of junk in the shed.
3) Go to your local hardware store.
4) Realise that corporate globalisation has bankrupted your local hardware store, then go to your local giant hardware store.
5) While selecting some pipe fittings from the plumbing isle, take special note of the bewildered expression on the customer service specialist when you say you require pipe fittings to house the guts of a webcam.
6) Unscrew the single screw holing the webcam casing together.
7) Remove the microphone.
8) Drill a hole in the pipe fitting that is the end cap, large enough to feed through the USB connector and balun (the bit near the USB connector end shaped like Gina Rinehart).
9) Feed the cord through and screw the webcam circuit board into the thread of the end cap. This is where I got supremely lucky and it simply fitted perfectly. It screwed in about 5 turns.
10) Wrap the step-down pipe fitting thread in plumbers tape. Its not for water proofing, but to fatten the thread so that it goes in nice and tight. This is important because it will screw into the end cap and rest against the circuit board, so it can not be done up too tight.
11) Unscrew the webcam lens.
12) Screw in the next step-down pipe fitting, this is to give you a female thread to screw in the last piece.
13) The last piece is a riser pipe, cut off a length that is as long as the thread plus the length of a 1.25" eyepiece barrel.
14) Sand down the last piece so that it snugly fits into a 1.25" draw tube. You will only need to sand off a very small amount, about as much as is equivalent to the median size of the male reproductive organ of a healthy Apis mellifera.
14) You can now put a standard 1.25" lens cap on the end, and use some black duck tape and/or a grommet to seal the other end where the USB cord comes out.
15) Note, I left the power LED on the circuit board, because when fitting a variable polarizing filter onto the end of the camera you can adjust the filters while looking down the barrel of the camera to get a feel for how much light you want to block out. At least that is my excuse for forgetting to remove it or cover it up.
16) Take some video, spin some people out, then remember to use your reading glasses next time when focusing your telescope because you are now looking at a laptop monitor!
Refinement to the original design by replacing some of the poly-pipe step-down fittings with a $15 Bintel 2" Chrome eyepiece barrel and some araldite. It works well and takes a 2" filter.
Yes both upgrades are shinier and cost you money, but my upgrade results in a smaller and more functional product than the original which does not introduce new problems, or necessitate three more upgrades that cause seemingly unrelated systems (like your woollen astronomy beanie) to stop functioning. Although I must admit replacing the plastic poly-pipe with a 2" chrome barrel does require .NET version 4.5 and Adobe PDF reader to be upgraded.
Nice work. How do you find out how long the tube needs to be to get focus? I tried doing this with one of the webcams I bought from ebay but I just couldnt find that "sweet spot" where the image was crisp and in focus
Hi Niv,
My first design was guess work, and it was too long for my 12" Saxon f5 dob to get into focus using the 1.25" poly pipe, and so I took the 2" to 1.25" adapter out of the telescope draw tube. I could then get most of the camera into the tube so that the ccd was only about 5cm further out from the end of the draw tube. So the photo showing the camera in the telescope did not actually allow it to come into focus being that far out. In general a camera will need to be closer than an eyepiece, so I remade the camera allowing the ccd to be only a few cm past the end of the draw tube. I figured that since I have both a 35mm and a 50mm extension tube then this was the most flexible solution. I have only tried my new shorter web-cam on a friends Skywatcher ED80, and without any extension tubes it came into focus with only 1 or 2 cm free travel with the draw tube almost all the way in. So make the camera body as short as you can.
Cheers Tim.
