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My recent CCD astronomy images of the solar planets captured with a low cost webcam.
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Open any astronomy magazine these days and you are sure to find an article discussing the use of webcams for CCD astrophotography, particularly our Solar planets. It seemed reasonable that I should give it a try to add to my conventional CCD astrophotography images, but try to keep it simple to start with.
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Moon image of 3 Nov. 2003. 75 mm refractor with 25 mm Ramsden eyepiece and 2x Barlow lens.
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My webcam, an Aiptek Pocket DV 3100, used mainly for general purpose, was employed. The maximum single image resolution with this webcam is 2048 x 1536 pixels (3.1 megapixels), but I used 1600 x 1200 pixels (2 megapixels) for the astrophotographs. It can, of course, be used as a video camcorder with sound, which is generally my usage at golf, with a resolution of 320 x 240 pixels. The video avi files can be captured via AstroVideo or K3 CCD Tools, and can be aligned and stacked using Registax.
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A bright Venus and the Moon above the skyline at twilight on 23 Feb.2004. Camera used directly.
Inset image at top right shows Venus on 15 Feb. 2004 using 75 mm refractor with 12.5 mm Kellner eyepiece and 2x Barlow lens.Venus phase is 0.7 with dia. of 16 arcmin.
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The focusser at the front of the webcam can be removed to allow access to the objective camera lens (8.7 mm / f3.0), but is fragile. The lens can then be unscrewed for direct access to the CCD chip. I chose the simple way and used the webcam with it's lens placed close to the eyepiece of the telescope. A coupling connector can be fashioned from tube oddments, but the camera needs good support because the fragile plastic focusser will not readily support the camera weight.
Two AA alkaline batteries suffice to power the camera, but the USB connection will provide power when controlled by computer software mentioned above. The storage medium is a Compact Flash Card. A 32MB card, for example, can store some 40 images at 1600 x 1200 pixels, or 6 minutes of AVI movie. The 1.5 inch colour TFT LCD screen readily allows good image focussing. The main problem without a truly aligned rigid connector to the telescope is flaring of the target.
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Transit of Venus - 8 June 2004
A 75 mm refractor with 25 mm Ramsden eyepiece was used to project the images onto a transparent paper screen. The images were taken between 0900 and 1100 hrs. in the North West of UK. Cloudy skies eventually cleared towards 1100 hrs. Image "c" was taken using a reflective solid screen; hence the image distortion in taking the photo at an angle.
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a (0900 hrs) b c d (1100 hrs)
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Return to the Tour
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PJM's Astronomy Gallery
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