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Workbench Creations

Workbench Creations is the place for conversation and discussion about do-it-yourself (DIY) projects. This DIY blog will feature projects completed by its owner as well as projects completed by other do-it-yourselfers. Workbench Creations is the place where DIYers can discuss ideas, learn about what others have done, and share their expertise.

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DIY Long Exposure CCD Camera for Astronomy (Part 2)

Posted June 12, 2008 12:57 PM by frankd20

I you haven't read part 1 of this check it out here

In addition to making the camera work for long exposure, the other important part is to cool the CCD. When you take a long exposure picture with a CCD, you get bright pixels that show up even when no light is present. These spots appear as white spots on the picture, and get more numerous the longer the exposure. You can probably guess how these would be a problem when you are photographing stars. To combat this we need to cool down the CCD. There are a few ways of doing this, but I chose to use a thermoelectric cooling unit. The CCD in the Vesta is housed by a metal box, so to cool it I cooled the metal box. The reason I decided to cool the box rather than the CCD directly is condensation. If you cool the CCD directly then humidity will condense on it, and I would need to keep it sealed so that this didn't happen. Instead, I cooled the metal box around to keep it cool and the humidity condenses on the metal box instead. This idea of cooling the metal box came from this website I had found, where they did just this.

Now that I had long exposure and cooling taken care of, you would think I would be happy – of course I wasn't. Why is simple, this long exposure camera was designed to work with a parallel port. My new laptop didn't have a parallel port, USB parallel port adaptors don't work, and PCMCIA adapters are expensive. I wanted the whole thing to plug into one USB port. The good thing is someone developed an additional circuit to make the thing work with a serial port, and USB serial port adapters do work.

I set out to put a USB hub and a USB serial port and the associated circuitry into a box. I ended up taking the USB hub and serial adapter apart to just use the circuit board, but once this was done I could compress this quite a lot. I made the box so that it plugs into the computer with one USB cable, and then a cable with DIN connectors plugs into the box and camera. When I had my ideal camera, I just wanted a slightly longer cable. I found a cable at a local store and plugged it in, and that's where I went wrong. I didn't realize the cable didn't have straight-through connections, and it blew out my camera. I was able to buy an identical camera off eBay, but I have yet to modify it. I took a few photos of an aurora from the roof of my house before I broke the camera, but unfortunately that is all I got to use it for. With the new advancements in digital photography, I hope to one day get or make a higher resolution astrophotography camera – but I have yet to do so.

Got a project you've done that you want to share in workbench creations? Add a comment to this entry or contact me frankd20.


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Previous in Blog: DIY Long Exposure CCD Camera for Astronomy (Part 1)   Next in Blog: DIY Backyard Pond
You might be interested in: Camera Control Units, CCD Image Sensors, CCD Cameras