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Pinhole "lens"
Hi
I sometimes want to do simple tests with my DSI 2 camera such as checking camera operation and its control/display software. By using a pinhole "lens" I can do such checks in my home office rather than wasting good night sky. I made the device by finding a piece of tubing that would fit snugly over the 1 1/4in camera extension. I used a piece of 1 1/4in ID white plastic drainage pipe about 2in in length. I then glued a piece of kitchen Al foil over one end. I made a small hole in the centre of the Al foil, to complete the pin hole "lens", using a sharp dressmaker's pin. This pin had a shaft diameter of about 0.6mm but to obtain a sharper image I only pierced the Al foil with the very tip of the pin rotating it bit to make a smooth round hole of say 0.2mm . When placed on the camera this gives
an image which is a bit blurry as I suppose to produce a sharper image the hole would need to be comparable to my camera pixel size of about 9 microns (difficult to achieve). I use this device by simply placing over the 1 1/4in camera extension and pointing it on my desk towards the nearby window. This type of "lens" does not require focusing. A somewhat blurry image of the window can be seen with about .25sec or less camera exposure but this is sufficient to conduct simple camera/software checks.
Cheers Peter
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