Date: Wed, 19 Sep 2012 13:57:42 -0000 (UTC) Subject: Re: [sdss3-25mlog 828] Re: 2.5m obslog 20120915 (MJD 56186) From: "Garrett Ebelke" Hi Dan, The angles that we measured were not absolute angles, they were with respect to the rest of the fibers. The first time we did this test, Steph told us to setup the guider and before observing, then offset the RA or Dec by 2". When we do this, all of the fibers should point in roughly the same direction. However, the fibers that we noted were offset. Most notably and the easiest to measure were the fibers on cart 18, that were 45 degrees ccw and 45 degrees cw of the group (those two fibers formed a right angle), next time I am on and am able to observe those carts again, we will use the command you included to get exact values. We usually only record that all fibers are pointing relatively the same direction to one another. In the future would you like all observers to use the command ( platedb getGprobes cartridge=16) to get exact values? -Garrett >>---------------------------- Original Message >> ---------------------------- >>Subject: [sdss3-25mlog 820] Re: 2.5m obslog 20120915 (MJD 56186) >>From: dmbiz@apo.nmsu.edu >>Date: Mon, September 17, 2012 4:10 am >>To: long@apo.nmsu.edu >>Cc: obs-report-25m@apo.nmsu.edu >>-------------------------------------------------------------------------- >> >>Hi Dan, >>from the eye ball testing that we did it is hard to say the angles >>exactly, we can only tell 30 degrees from 45 degrees and from 90. Also >> all >>this angles we wrote are "with respect to the crowd", so they are >> relative >>and don't have to match the values from the table. >> >>Dmitry > >> >> On Sep 16, 2012, at 6:25 AM, dmbiz@apo.nmsu.edu wrote: >> >>> >>> APACHE POINT OBSERVATORY SDSS 2.5M >>> >>> OBSERVING LOG >>> Saturday September 15, 2012 >>> >>> (MJD 56186) >>> >>> ---- Observing Team ---- >>> >>> Garrett Ebelke >>> Dmitry Bizyaev >>> Karen Kinemuchi >>> >>> ---- Observing Plan ---- >>> >>> 15 Sep 2012 56186.0 0.03 02:32 11:25 19:10 04:05 BOSS 8.9 hours >>> >>> >>> ---- Observing Summary ---- >>> >>> Clear night with decent seeing. >>> >>> BOSS plates exposed: >>> 10 6318 - DONE >>> 11 6121 - not done >>> 12 5044 - not done >>> 13 4410 - not done >>> 16 6201 - DONE >>> 18 6150 - not done >>> 14 4664 - DONE >>> >>> >>> APOGEE plates exposed: >>> 8 5531 - AB only >>> >>> We checked the guide fiber rotation angles for cartridges 10, 11, 12, >>> 13, 17, >>> 14, and 8. >>> They are okay. >>> >>> Cart 16 had guide fibers 12 and 13 are off by ~30 degrees (CCW). Guide >>> fiber 9 >>> is off by ~20 degrees (CW). >>> Cart 18 - fiber 15 off by 45 degrees (CCW) and fiber 16 is off by 45 >>> (CW). >>> >>> The values have been updated on the Wiki. >>> >> >> Hi Dmitry and Garrett, >> >> What are the error bounds on these measurements? The original angles >> were >> measured to within a degree or so. A quick check of the fiber angle >> images show the angle attributed to each of the fibers in question to be >> reasonable. I can't log in to check the actual angles installed, but >> they >> should be >> >> C16 gF09 102 >> C16 gF12 153 >> C16 gF13 123 >> >> C18 gF15 103 >> C18 gF16 59 >> >> You can get the angles with the following command issued from the STUI >> command line >> >> platedb getGprobes cartridge=16 (or whatever cartridge you want the >> angles for) >> >> I can't recall the format, but one of the entries in the output is the >> fiber angle. >> >> If the angles are correct in the file and really that different as >> checked >> on sky it is worrying. Either something has moved, or the index pin was >> not in its hole on the plate. >> >> Cheers, >> >> Dan >> >> _____________________________________________________ >> Message 828 of sdss3-25mlog - Logs of nightly APO activities. >> https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/828.html >> sdss3-25mlog@sdss3.org >> https://sdss3.org/mailman/listinfo/sdss3-25mlog >> >