This is an elaboration of the standard long exposure mod which now gives the pc control over individual interlaced frame downloads (self-guide), on chip amp and shutter disable.


Interlaced Frames

The charge transfer pluses into pins 8 and 13 of the d15201 control image retrieval from lines 1,2,5,6,9,10….. and 3,4,7,8,11,12…… respectively This feature has the potential to be used for self guiding the webam. Basically one frame is downloaded at a fast rate (1-5 sec) and any drift countered by the pc sending guiding commands to the telescope mount. The second frame is exposed for much longer (up to 20 min or so). This has the potential to allow very deep exposures. The pictures below give an example of the frames being read at different rates.

On Chip Amp.

The sony ccd uses a small pre-amp to increase the video signal before it leaves the ccd. The problem with this is the electro luminescence that it gives off. See below

Shutter disable.

The mods require that the signal to pin 10 of the d15210 (shutter pluse) is disabled during a long exposure. This is conveniently achieved using a simple switch. However this mod give the option of controlling it at the pc.


Who will find the mod useful?

Probably many fewer people than use the standard mod! This version is aimed at allowing very long exposure pictures. In addition to the modified camera you will also need a telescope and mount capable of taking guiding instructions. Without this the self guide feature will not be useful. Also if exposures are kept to below 30 sec or so standard dark frame subtraction can be used to remove the amp glow. However if you do have a computerised scope then this camera has a very great potential.

Copyright.

The novel information on these pages is copyright. It is forbidden to use this information for profit. Should you receive any money as a result of performing this mod or selling a modified camera send the money (less parts) to www.msf.org.

Over the last year I have received some requests from people who are looking for a way round these restrictions. I would like to take this opportunity to specifically state that it not OK to give modified cameras away free with other products nor is it OK to charge people for you time when going mods for others.

Any individuals of companies wishing to produce commercial products based on these modifications please contact me directly smunch@clara.co.uk .

Please abide by these restrictions, as this will ensure that future developments can disclosed in the same way.

Steve Chambers