Add a camera to your scope for cheap astrophotography
For a closer look at the finished product, launch the photo gallery here.
Make Your Camera Space-Ready
Easy | | | | |
Professional-grade astronomy cameras take great shots of the cosmos, but their prices can be, well, astronomical. Instead, attach that long-forgotten low-megapixel digital cam to your telescope-it contains the same basic type of sensor found in the high-end models: a charge-coupled device, or CCD. Of course, regular cameras aren´t built for astrophotography; the batteries and circuitry build up heat, which creates stray pixels on the sensor that look like stars in photographs. But if you´re willing to open your camera and make a few modifications, any digital with at least two megapixels can capture memorable Martian moments without the fake twinkles or the sky-high cost.
H2WHOA! Before opening any camera, remove its battery. Avoid touching the flash circuit, which stores a charge for an unpredictable length of time. Wear rubber gloves and rubber-soled shoes, and use insulated tools.
1. OPEN the camera by removing the screws holding the case together. Look for hidden screws under stickers and trim.
2. FIND and release all the cables and plugs, and then gently pull the case halves apart.
3. DISCONNECT and remove the lens assembly, but leave the ribbon cable attached to the motors.
4. ATTACH the heat sink and Peltier junction-a device that electronically draws heat away from whatever it´s next to-directly to the back of the camera´s circuit board with wire ties or, if it doesn´t fit, externally below the circuit board.
5. RELOCATE the batteries to the outside of the camera to further reduce heat. Just run longer wires to the old leads.
6. REMOVE the infrared filter, a piece of glass in front of the CCD. Your shots will take on a slight pinkish tint but should be brighter.
7. REASSEMBLE the camera and slip its lens barrel over your telescope´s eyepiece holder or focusing tube.
Click to the next page for a complete list of parts and more detailed iinstructions.
2-4MP Digital Camera with a CCD Sensor (FREE)
RadioShack 1 3/8-inch Insulated Alligator Clips (270-1545; $3.49)
RadioShack AA Battery Holder (270-409; $1.89)
RadioShack SPST Switch (275-0406; $2.49)
4 AA Rechargeable NiMH 2100mAh Batteries 9V Battery
- Build an external battery pack. On models that use regular alkaline batteries like ourOlympus DiMage Z2, this task is relatively easy. This removes a major source of heat from the camera.
- Remove the lens. You want to use the telescope instead, so you must remove the factory-installed camera lens. While not that daunting of a task, you must retain the lens and leave it connected to the camera, which can be inconvenient. While building this camera, I managed to break the lens while trying to remove it. Luckily, I was able to salvage the motors and switches-those two unsightly ribbon cables dangling out of the camera body. I had to retain the lens because the Z2’s startup sequence “expects” to receive some feedback from the lens (e.g., did the lens extend, is the shutter OK, is the aperture OK, etc.). Without this feedback, the camera becomes a doorstop. So remove the lens, but keep it attached to the camera.
- Cool the CCD with a Peltier cooling system. Actually, you’d want this cooler right behind (and attached) to the CCD. The space on this camera made that option impossible. So, I rigged the cooler to the bottom of the camera.
- Optional: Remove the IR filter. Most CCDs have an IR filter attached to them. While this filter makes our “regular” photographs look good, a reduction in IR sensitivity can be a handicap for deep space CCD photography. Removing it is easy-it’s a little sliver of glass about 3/8 x 1/4-inch in size layered on top of the camera´s sensor. It’s easy to lift off of the CCD, as well as drop and lose in your carpet.