| 321 | | ''No on-sky observations are permitted before 10 deg twilight.'' |
| 322 | | [wiki:MayallZbandLegacy/NotesforObservers/TenDegTwilight] |
| 323 | | |
| 324 | | 1. At start of night, check telescope pointing (see item [8].4 above; you should already be there!) and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane; i.e. in the chip gaps). |
| 325 | | |
| 326 | | When taking the image of the bright star, make sure to create an OBJECT script with NGUI (not a TEST, because MOSSTAT will ignore it), zd filter, 1 - 5 sec exposure. Watch for MOSSTAT to process the image and report the RA, Dec offsets. If mosstat fails, it could be because (a) the telescope is mis-pointed, (b) the telescope is out of focus (set the focus approx using the formula above and try again). Once you are able to determine offsets, give these offsets to the OA with **opposite** sign. That is, if mosstat reads "RA,Dec offsets = -15.34, 18.32", then you need to provide the OA with the offsets of +15,-18 to zero the telescope coordinates. |
| 327 | | |
| 328 | | You can take another OBJECT frame if you want to check to make sure the offset went in the right direction. |
| 329 | | |
| 330 | | 2. Move back to the first MzLS tile position from item [8].4. |
| 331 | | |
| 332 | | 3. Focus the telescope |
| 333 | | - create a focus script using the NGUI: exposure time 5 or 10 seconds, zd filter, -100 micron focus steps, click Midpoint to *on*, 9 exposures. |
| 334 | | - run the focus script from the /home/observer/exec directory (./FOCUS.sh) |
| 335 | | - copilot will automatically analyze and report the best focus in the mayall-idl window. |
| 336 | | - or alternately, analyze the focus image using the IRAF script mscstarfocus |
| 337 | | - edit the /data/observer/mscfoc.cl script to correct the name of the image that needs to be analyzed |
| 338 | | - run 'cl < /data/observer/mscfoc.cl' in iraf window in data directory. |
| 339 | | - mark about 10 stars around the image; to get a quick idea if you have covered the right focus range mark "g" on the top star in a sequence which will pop up a graph that you will need to type "q" to get out of; mark the top star in each remaining sequence using "m"; "q" to quit; "d" to delete bad points; "q" to quit, then will get best focus value. |
| 340 | | - log the Truss temperature |
| 341 | | - set the telescope focus in the Configuration Monitor: Enter the value in Pedestal focus, **hit return**, and then hit Apply. If you forget the return, it will do nothing. |
| 342 | | - focus the guiders; this way you can use the guider images to monitor focus drifts |
| 343 | | |
| 344 | | **[wiki:MayallZbandLegacy/NotesforObservers/FocusInfo Example of a focus sequence] |
| | 321 | ''No on-sky observations are permitted before 10 deg twilight.'' [wiki:MayallZbandLegacy/NotesforObservers/TenDegTwilight] |
| | 322 | |
| | 323 | 1. At start of night, check telescope pointing (see item 8.4 above; you should already be there!) and zero the telescope coordinates using a bright star placed on the telescope boresight (defined as the center of the mosaic3 focal plane; ''i.e.'' in the chip gaps).[[BR]][[BR]] |
| | 324 | When taking the image of the bright star, make sure to create an OBJECT script with NGUI (not a TEST, because MOSSTAT will ignore it), zd filter, 1 - 5 sec exposure. Watch for MOSSTAT to process the image and report the RA, Dec offsets. If mosstat fails, it could be because (a) the telescope is mis-pointed, (b) the telescope is out of focus (set the focus approx using the formula above and try again). Once you are able to determine offsets, give these offsets to the OA with '''opposite''' sign. That is, if mosstat reads "RA,Dec offsets = -15.34, 18.32", then you need to provide the OA with the offsets of +15,-18 to zero the telescope coordinates.[[BR]][[BR]] |
| | 325 | You can take another OBJECT frame if you want to check to make sure the offset went in the right direction. |
| | 326 | 1. Move back to the first MzLS tile position from item 8.4. |
| | 327 | 1. Focus the telescope |
| | 328 | - Create a focus script using the NGUI: exposure time 5 or 10 seconds, zd filter, -75 micron focus steps, click Midpoint to *on*, 9 exposures. |
| | 329 | - run the focus script from the /home/observer/exec directory (./FOCUS.sh) |
| | 330 | - copilot will automatically analyze and report the best focus in the mayall-idl window. |
| | 331 | - or alternately, analyze the focus image using the IRAF script mscstarfocus |
| | 332 | - edit the /data/observer/mscfoc.cl script to correct the name of the image that needs to be analyzed |
| | 333 | - run 'cl < /data/observer/mscfoc.cl' in iraf window in data directory. |
| | 334 | - mark about 10 stars around the image; to get a quick idea if you have covered the right focus range mark "g" on the top star in a sequence which will pop up a graph that you will need to type "q" to get out of; mark the top star in each remaining sequence using "m"; "q" to quit; "d" to delete bad points; "q" to quit, then will get best focus value. |
| | 335 | - log the Truss temperature |
| | 336 | - set the telescope focus in the Configuration Monitor: Enter the value in Pedestal focus, '''hit return''', and then hit Apply. If you forget the return, it will do nothing. |
| | 337 | - focus the guiders; this way you can use the guider images to monitor focus drifts |
| | 338 | - [wiki:MayallZbandLegacy/NotesforObservers/FocusInfo Example of a focus sequence] |
