Date: Sat, 02 Oct 1999 08:16:58 -0600 From: "s. a. snedden" Subject: 2.5m obslog 19991001 (MJD 51453) --------------8B5CB366A0AF2E5571E9075C Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Friday October 1, 1999 Apache Point Observatory SDSS 2.5m Observing Log (MJD 51453) Observing Team: Steph Snedden (APO) Scot Kleinmann (APO) Ellyne Kinney (APO) Russell Owen (UW) Scott Burles (UC) Tonight our goal was to obtain a pointing model, since the secondary had just been collimated and Scot and Steph needed training on this. We also intended to test the MCP latest version, however, other problems prevented this. I would like to suggest that we stick with the version used during the last dark run until at least near the end of this dark run. The good news is we did get a 48 star pointing model with a 2.38" sample standard deviation. Focus on the engineering camera was -3400 at the beginning of the pointing model and -3350 at the end of the model. The counterweights for the alignment telescope and "manhole cover" plus spectrographs with empty dewars were set to 50. The counterweights for the engineering camera with 2 empty dewars on the spectrographs were set to 280. ___________ Problems: (Reports to be filed) We had some initial delays shuffling the cartridge plus corrector and engineering camera around. It turned out the engineering camera was somehow put in the bay rotated 180 degrees, so when we tried to install it it was on the cart backwards. We rotated it back around and eventually got it installed. At about 22:30 the telescope ran away in altitude while slewing using the Menu. It could very well have been a balance problem, but if so, I am concerned because balance was not that far off. If this was due to imbalance, it is much more sensitive than I like. At about 23:00 we had trouble relaxing the primary. We had moved to 87 degrees in altitude using the MCP menu. Russell told us to move using the track command in the TCC instead. We were then able to relax the mirror normally. At 23:15, we had trouble with the flat field screens not opening. We eventually called French and tracked the problem to the manual toggle switch at the front of the telescope inside the windscreen. It had been shut off. Per French's instructions, we disconnected the Burndy connector to disable the toggle, turned the toggle to "on" and reconnected the Burndy. Once the interlocks and altitude were checked, we tried again, and the petals opened. *NOTE* we could not find the manual crank for the flat field screen. It would have been very useful. Could we find a place to keep it where it is easy to locate? At approximately 00:30 during a large (0.6 degrees) offset command, azimuth motion stopped. An axis init command was issued and the track command sent again, and we were back in business. At about 1:00 we acquired our first star for the pointing model with the engineering camera. It appeared as a streak across the CCD, with an oblong image (of low counts) near the center of the streak. Russell soon diagnosed this as due to an oscillation of the primary mirror. This was dealt with by: issuing STOP T_COLLIMATE moving the mirror to the reverse axial limits issuing a RESTART COLLIMATE issuing a SET FOC/INC The star images then looked normal and we proceeded with a 12 star pointing model, followed with the 48 point model mentioned in the first paragraph. Twice during the pointing model, a track command failed, with an error message that it failed to converge. issuing the "track" command a second time worked. At the end of the night, after stowing the telescope and closing the building, we noticed that the mirror was oscillating again. We opened back up and tried relaxing the mirror again. We also tried the same procedure (reverse limits) that had worked earlier. Moving the mirror back off the limits started it oscillating again. Per French's advice we stowed the telescope in the enclosure with the mirror left on the reverse axial limits. At 18 degrees altitude in this condition, the pressure gauge for the PMSS was reading 50 PSI. We finished at 07:00 Weather: Mostly clear and cool (high 50's) with W winds at 10-15 mph. RH was about 30%. Dust counts were at 70 particles/ft^3 or lower. Steph & Scot --------------8B5CB366A0AF2E5571E9075C Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit Friday October 1, 1999 Apache Point Observatory SDSS 2.5m Observing Log (MJD 51453) Observing Team: Steph Snedden (APO) Scot Kleinmann (APO) Ellyne Kinney (APO) Russell Owen (UW) Scott Burles (UC) Tonight our goal was to obtain a pointing model, since the secondary had just been collimated and Scot and Steph needed training on this. We also intended to test the MCP latest version, however, other problems prevented this. I would like to suggest that we stick with the version used during the last dark run until at least near the end of this dark run. The good news is we did get a 48 star pointing model with a 2.38" sample standard deviation. Focus on the engineering camera was -3400 at the beginning of the pointing model and -3350 at the end of the model. The counterweights for the alignment telescope and "manhole cover" plus spectrographs with empty dewars were set to 50. The counterweights for the engineering camera with 2 empty dewars on the spectrographs were set to 280. ___________ Problems: (Reports to be filed) We had some initial delays shuffling the cartridge plus corrector and engineering camera around. It turned out the engineering camera was somehow put in the bay rotated 180 degrees, so when we tried to install it it was on the cart backwards. We rotated it back around and eventually got it installed. At about 22:30 the telescope ran away in altitude while slewing using the Menu. It could very well have been a balance problem, but if so, I am concerned because balance was not that far off. If this was due to imbalance, it is much more sensitive than I like. At about 23:00 we had trouble relaxing the primary. We had moved to 87 degrees in altitude using the MCP menu. Russell told us to move using the track command in the TCC instead. We were then able to relax the mirror normally. At 23:15, we had trouble with the flat field screens not opening. We eventually called French and tracked the problem to the manual toggle switch at the front of the telescope inside the windscreen. It had been shut off. Per French's instructions, we disconnected the Burndy connector to disable the toggle, turned the toggle to "on" and reconnected the Burndy. Once the interlocks and altitude were checked, we tried again, and the petals opened. *NOTE* we could not find the manual crank for the flat field screen. It would have been very useful. Could we find a place to keep it where it is easy to locate? At approximately 00:30 during a large (0.6 degrees) offset command, azimuth motion stopped. An axis init command was issued and the track command sent again, and we were back in business. At about 1:00 we acquired our first star for the pointing model with the engineering camera. It appeared as a streak across the CCD, with an oblong image (of low counts) near the center of the streak. Russell soon diagnosed this as due to an oscillation of the primary mirror. This was dealt with by: issuing STOP T_COLLIMATE moving the mirror to the reverse axial limits issuing a RESTART COLLIMATE issuing a SET FOC/INC The star images then looked normal and we proceeded with a 12 star pointing model, followed with the 48 point model mentioned in the first paragraph. Twice during the pointing model, a track command failed, with an error message that it failed to converge. issuing the "track" command a second time worked. At the end of the night, after stowing the telescope and closing the building, we noticed that the mirror was oscillating again. We opened back up and tried relaxing the mirror again. We also tried the same procedure (reverse limits) that had worked earlier. Moving the mirror back off the limits started it oscillating again. Per French's advice we stowed the telescope in the enclosure with the mirror left on the reverse axial limits. At 18 degrees altitude in this condition, the pressure gauge for the PMSS was reading 50 PSI. We finished at 07:00 Weather: Mostly clear and cool (high 50's) with W winds at 10-15 mph. RH was about 30%. Dust counts were at 70 particles/ft^3 or lower. Steph & Scot --------------8B5CB366A0AF2E5571E9075C--