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Re: ATM center dotting secondaries

ÿþ<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META content="text/html; charset=unicode" http-equiv=Content-Type> <META content="MSHTML 5.00.2314.1000" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=#ffffff> <DIV><FONT face="Times New Roman">I center dotted my secondary with a .11 offset as outlined in David Kriege and Richard Berry's book.&nbsp; In my first attempt to finish collimation, the secondary ended up being tilted at a noticeable angle and the center dot on the secondary way off when viewed under the crosshairs.</FONT></DIV> <DIV>&nbsp;</DIV> <DIV><FONT face="Times New Roman">I removed the cage and centered the secondary under the focuser once again.&nbsp; I used a laser collimator to complete the collimation process.&nbsp; The beam hit the dot on the secondary and was 10" off center on my 16" primary.&nbsp; A very slight rotation of the secondary mirror holder placed the beam very close the center of the primary.&nbsp; </FONT></DIV> <DIV>&nbsp;</DIV> <DIV><FONT face="Times New Roman">Axial rotation of the secondary was not mentioned in the book and the amount that I rotated the secondary is&nbsp; not noticeable by eye or under the cross hairs.&nbsp; I could not imagine offsetting the secondary with out dotting it.</FONT></DIV> <DIV>&nbsp;</DIV> <DIV><FONT face="Times New Roman">Under a nearly full moon with an uncoated primary, I could not detect the dot on the secondary.</FONT></DIV> <DIV>&nbsp;</DIV> <DIV><FONT face="Times New Roman">David Danskey</FONT></DIV> <DIV><FONT face="Times New Roman"><A href="mailto:ddanskey@web-ster.com">ddanskey@web-ster.com</A></FONT></DIV> <DIV>&nbsp;</DIV> <DIV>&nbsp;</DIV> <DIV>&nbsp;</DIV></BODY></HTML>