From: William A. Podgorski Date: Tue, 22 Jul 1997 07:51:01 -0400 To: Terry Gaetz, Steve O'Dell Subject: (Fwd) Focus Alignment Check Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-UIDL: 6c74b4d2af2bdf711349ae94568c03e0 Status: RO --- Forwarded mail from "Scott C. Texter" Date: Thu, 17 Apr 1997 13:17:12 -0700 To: wpodgorski@cfa From: Scott C. Texter Subject: Focus Alignment Check Cc: (list) Hi Bill, Here are the numbers you seek: The OPTICAL distance measured between the XARM and the HRC ARM (HARM) using our laser rangefinder when the HRC-I was known to be at the XRCF Finite Conjugate focus was 10182.0: Here are the corrections: 10182.0 optical distance measured between XARM and HARM -29.7 phase delay ranging through 56mm thick XARM rather than air(BK-7, calibrated earlier at TRW) -47.4 distance from +X surface of XARM to +X(P side) surface of CAP (DATUM A) +169.2 distance from +X surface of HARM to HRC MCP surface (from Randy Moore) ---------- 10274.1 XRCF Finite Conjugate distance from CAP DATUM A to image -195.0 Finite to Infinite Conjugate shift ------------ 10079.1 HRMA on-orbit distance from CAP DATUM A to image We also made a second measurement through a different, thinner, region of the XARM (clear center region but not including the glued on reticle) 10179.9 optical distance measured between XARM and HARM -26.5 correction for phase delay ranging through 50mm XARM (BK-7, calibrated earlier at TRW) -47.4 distance from +X surface of XARM to +X(P side) surface of CAP (DATUM A) +169.2 distance from +X surface of HARM to HRC MCP surface (from Randy Moore) ---------- 10275.2 XRCF Finite Conjugate distance from CAP DATUM A to image -195.0 Finite to Infinite Conjugate shift ------------ 10080.2 HRMA on-orbit distance from CAP DATUM A to image This gives a good indication of the error, which seems to be about a millimeter. ================================ Charlie, I had a discussion with Greg Young on the phone and I think he understands everything I need to do the FACT at TRW. The plan is, indeed, to look at the reference buttons (polished gauge blocks really) and then look between the RRCA struts at the HARM. Glad you like LA, Scott ======================== Scott Texter ---End of forwarded mail from "Scott C. Texter" -- =============================================================================== William A. Podgorski Harvard-Smithsonian Center for Astrophysics, Smithsonian Astrophysical Observatory