Last updated: 17 December 2005
Subject: Improving DSX goto accuracy Sent: Thursday, December 15, 2005 20:14:07 From: Bill Swartout (firstname.lastname@example.org) I found a little trick that seems to have improved the pointing accuracy of my DSX-90 scope and I thought I'd pass it along. In the book "How to Use a Computerized Telescope" the author, Michael Covington points out that one of the factors that can adversely affect pointing accuracy is nonperpendicularity. That is, the alignment software assumes that the azimuth and altitude axes are perpendicular to each other and that the OTA is perpendicular to the altitude axis. If that's off, pointing will be less accurate. On the DSX scopes there's no easy way to adjust the azimuth and altitude axes with respect to each other, however, because the telescope is attached to the mount with two thumbscrews and the slot the screws run in has some play in it, you can adjust the OTA to get it perpendicular to the altitude axis. Here's how I adjusted mine: 1) put a bubble level on the flat part of the telescope base (just in front of the battery cover). 2) Level the tripod until the base is perfectly level. 3) Release the altitude clutch and rotate the OTA until it is pointing straight up. 4) With the metal lens cover in place on the OTA, put the bubble level on the lens cover. 5) Loosen the thumbscrews attaching the OTA to the mount slightly so that it can be wiggled a bit back and forth. 6) wiggle the OTA back and forth until the bubble level shows that the lens cover is perfectly level. 7) Tighten the thumbscrews Following the procedure I found (in admittedly limited testing) that objects were consistently in the 26mm FOV. Before this adjustment, I was only getting object in the 26mm FOV about 50% of the time. I'd be interested to hear if others have luck with this. -Bill
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