Reading some online reviews of CMOS and CCD detectors for amateur telescopes, I often came across words to the effect of “basically a glorified web-cam”. It got me to thinking: my old iSight camera (the cylindrical ones we used to buy before they were built in to all Apple products) might fit into an eyepiece holder.
iSight adapter.
Alas, it was just a little too wide to fit in. But thanks to they guys at our machine shop, I soon had an adapter. Made from some scrap aluminum using a lathe.
The next step was to remove the lens from the iSight. The reason is that the camera will take the place of the eyepiece, and so the image from the telescope will be made directly on the CCD and you don’t want a lens in the way. Luckily, there are YouTube instructions for doing this, so I wasn’t flying blind.
iSight mounted on the Coronado Solarmax II 60mm telescope.
The next image shows the iSight mounted on our Coronado Solarmax II 60mm solar telescope. This telescope is equipped with a “tunable” H-alpha filter, so it can pick up great details on the surface of the sun. Luckily, the telescope’s focal length was just long enough to make an image at the CCD without having to remove it from the iSight enclosure.
The next trick was finding an old enough laptop. The iSight has a firewire 400 cable, and those are pretty hard to come by. My old MacBook Pro did the trick. Plugged in the iSight, opened QuickTime Pro, and started recording a movie. Focusing was tricky as the screen is hard to see in broad daylight (firewire cables are pretty short).
Single frame from the sun movie.
After recording the movie, I extracted the individual frames. Each one looked like the image at right. You can certainly see two sunspots and maybe a hint of granulation. But I was a little disappointed in the dynamic range and contrast. So I did what any astronomer would do: co-add the frames.
This last image is a simple co-add without any fancy image registration or anything. Converted to grayscale to enhance the features. Not too shabby. Can hardly wait until next week when I can try this out on the moon.
Co-add of 30 frames from the iSight.