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Observatory Support
HST Secondary Mirror Moves

This table gives the dates, times, and movement in microns of the HST Secondary Mirror adjustments necessary to counter the long-term shrinkage of the telescope and maintain overall focus.

All Secondary Mirror movements are in pure despace (axial motion producing a focus change). A positive value represents a movement of the Secondary away from the Primary. 1 micron of Secondary Mirror despace induces 6.1 nanometers of rms wavefront error in focus at the SIs.

Day of Year Time (UT) Secondary Move
29 Jun 1994 17:36 UT +5.0
15 Jan 1995 23:40 UT +5.0
28 Aug 1995 15:16 UT +6.5
14 Mar 1996 18:47 UT +6.0
30 Oct 1996 17:40 UT +5.0
18 Mar 1997 22:55 UT -2.4
12 Jan 1998
(NIC3 campaign 1)
01:15 UT +21.0
01 Feb 1998 16:40 UT -18.6
04 Jun 1998
(NIC3 campaign 2)
01:01 UT +16.6
28 Jun 1998 17:26 UT -15.2
15 Sep 1999 15:40 UT +3.0
09 Jan 2000 17:42 UT +4.2
15 Jun 2000 19:38 UT +3.6
02 Dec 2002 20:50 UT +3.6
22 Dec 2004 23:12 UT +4.16
31 Jul 2006 14:35 UT +5.34
20 Jul 2009 09:35 UT +2.97
24 Jan 2013 17:58 UT +3.60
11 Nov 2013 17:41 UT +2.97