ccd computer hookups

okay , I am looking for a scsi to connect my ccd telescope to my indoor computer. Therefore, I need some long length 50-75 feet of scsi. Who else has done what to avoid buying an additional laptop ? Any input or actuall experiences would be helpful.
thanks Brian

Some info I dug up on the internet gives you an idea of length limitations and communication requirements. Unfortunately you may find the cost of that length of scsi cabling to be very expensive, roughly $5/foot or more meaning at your distance it's $350 to 400. Thats based on a couple of searches with Belkin and other providers, however you may be able to find bulk cable and connectors cheaper than I did.

http://www.pcguide.com/ref/hdd/if/scsi/summary.htm

Here is one link to actual application for CCD setups.

http://www.astronomysite.com/mapug/31/msg32155.htm

Brian,
The distance you need to run greatly exceeds the scsi specs for cable length. Scsi-1 is 6m., scsi-2 is 3m., scsi-2 ultra is 12m., scsi ultra is 3m., scsi uw is 3m. You can always stretch the maximum length a little but you are at 2X the length of scsi-2 ultra which is at 12m. The problem is the cable capacitance, which determines signal propogation delay,increases proportionally with the cable length. Add the fact that scsi is a parallel bi-directional bus with a relatively high transmission rate and you have a situation that gets to be very tricky to get to work reliably once the specs. are exceeded. Without knowing the exact camera that you are using and the exact scsi protocol that that camera uses I can't help you further. There is a possible solution and that is to use differential amplifiers at both ends but this also has limitations depending on the data transmission rate and cable length.
Ron