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Hubble Space Telescope
NICMOS Focus Update as of August 6, 1998

The NICMOS focus data obtained on August 6, 1998, show that NIC3 focus continues to drift away from its nominal setting. At FOM tilt = 0, it would have a value which below its level at the end of SMOV in late May last year.

Camera 2 focus remains basically unchanged, close to the nominal PAM setting of 0.69 mm. During the focus monitoring visit on August 6, camera 1 observed in parallel with camera 2, and its field of view happened to have no star suitable for phase retrieval analysis.

The updated summary of the NICMOS focus history is given in the Table and in the focus history plot . Note that, in the plot, focus during NIC3 campaigns is corrected for the Secondary Mirror move while the Table contains the actual uncorrected values.