Subject: Re: [sdss3-25mlog 1181] Re: 2.5m obslog 20130401 (MJD 56384) From: Kaike Pan Date: Thu, 4 Apr 2013 15:53:51 -0600 --Apple-Mail-3-258175080 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Not sure if there is another constraints on the system. =46rom acquiring = fields and guiding aspects, it would be nice to do so. On Apr 4, 2013, at 3:49 PM, Mark Klaene wrote: > can we/should we change the acceptable error margin for the rotator = so that a "too large to correct" won't happen unless it really is too = large that it will cause problems? >=20 > mk >=20 >=20 > On Apr 4, 2013, at 3:30 PM, Dan Long wrote: >=20 >> Hi Dmitry, >>=20 >> It takes 38 arcseconds of rotator error or 1900 encoder ticks to = generate 1 arcsecond of error on the sky at the edge of the plate. A 15 = arcsecond error in rotator position would result in less than half an = arcsecond of error on the sky at the edge of the plate, and even less = towards the center . It would probably not have hindered acquisition. = While it is a little troubling to have fiducial errors too large to = correct, in the case of the rotator 600 ticks is only 12 arcseconds, and = it would take something on the order of several arcminutes of error ( = ~10,000 ticks of encoder error) to cause trouble acquiring. >>=20 >> Cheers, >>=20 >> Dan >>=20 >> On Apr 2, 2013, at 3:44 PM, dmbiz@apo.nmsu.edu wrote: >>=20 >>> Hi Kaike, >>> thank you for the comments! >>>=20 >>>> If the rotator fiducial error when slew to a field is the ONLY >>>> problem we have, I think that >>>> we should be okay to continue. Most likely, fiducial errors on the >>>> rotator will not stop us from >>>> finding guiding stars. After we get stars, no fiducial corrections = will be >>>> applied, so we are okay >>>> for that field except for observers have to tolerance multiple = verbal >>>> warnings of "fiducials". >>>=20 >>> The rotators fiducial error suggested some 15" offset. Once it = happens >>> with rotator, it is hard to predict where guide stars go, so I = recommended >>> to >>> fix the fiducials first. >>>=20 >>>> There is a bug on the "stop" of "goto Field". Clicking (applying) = the >>>> "stop" >>>> button puts sop into a confusion status although"sop ping" and "sop >>>> status" show >>>> SOP is okay. One can get SOP back to its normal status by issue two >>>> commands >>>> from STUI: >>>>=20 >>>> sop restart (this may not unnecessary, so you can try without it = first) >>>> sop reinit >>>=20 >>> Can we put it to the observing notes that we cannot use the "stop" = button >>> in STUI? >>>=20 >>> Dmitry >>>=20 >>>=20 >>> _____________________________________________________ >>> Message 1176 of sdss3-25mlog - Logs of nightly APO activities. >>> = https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1176.h= tml >>> sdss3-25mlog@sdss3.org >>> https://sdss3.org/mailman/listinfo/sdss3-25mlog >>=20 >> _____________________________________________________ >> Message 1180 of sdss3-25mlog - Logs of nightly APO activities. >> = https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1180.h= tml >> sdss3-25mlog@sdss3.org >> https://sdss3.org/mailman/listinfo/sdss3-25mlog >=20 > Mark Klaene > Site Operations Manager=20 > Apache Point Observatory voice: 575 437 6822 > PO Box 59 fax: 575 434 5555 > 2001 Apache Point Rd cell: 575 430 0210 > Sunspot NM 88349-0059 web: www.apo.nmsu.edu=20 >=20 >=20 >=20 >=20 > _____________________________________________________ > Message 1181 of sdss3-25mlog - Logs of nightly APO activities. > = https://trac.sdss3.org/tracmailman/browser/private/sdss3-25mlog/all/1181.h= tml > sdss3-25mlog@sdss3.org > https://sdss3.org/mailman/listinfo/sdss3-25mlog --Apple-Mail-3-258175080 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=us-ascii Not = sure if there is another constraints on the system. =46rom acquiring = fields and guiding aspects, it would be nice to do = so.On Apr 4, 2013, at 3:49 PM, Mark Klaene = wrote:can we/should we change = the acceptable error margin for the rotator so that a "too large = to correct" won't happen unless it really is too large that it will = cause = problems?mkOn = Apr 4, 2013, at 3:30 PM, Dan Long wrote:Hi = Dmitry, It takes 38 arcseconds of rotator = error or 1900 encoder ticks to generate 1 arcsecond of error on the sky = at the edge of the plate. A 15 arcsecond error in rotator position = would result in less than half an arcsecond of error on the sky at the = edge of the plate, and even less towards the center . It would = probably not have hindered acquisition. While it is a little = troubling to have fiducial errors too large to correct, in the case of = the rotator 600 ticks is only 12 arcseconds, and it would take something = on the order of several arcminutes of error ( ~10,000 ticks of encoder = error) to cause trouble acquiring. Cheers, = DanOn Apr 2, 2013, at 3:44 PM, dmbiz@apo.nmsu.edu = wrote:Hi = Kaike,thank you for the = comments! If the rotator fiducial error when slew = to a field is the ONLYproblem we have, I think = thatwe should be okay to continue. Most likely, fiducial = errors on therotator will not stop us = fromfinding guiding stars. After we get stars, no fiducial = corrections will beapplied, so we are = okayfor that field except for observers have to tolerance = multiple verbalwarnings of = "fiducials".The rotators = fiducial error suggested some 15" offset. Once it = happenswith rotator, it is = hard to predict where guide stars go, so I = recommendedtofix the = fiducials first. There is a bug on the "stop" of "goto Field". Clicking = (applying) the"stop"button puts sop into a confusion = status although"sop ping" and = "sopstatus" showSOP is okay. One can get SOP = back to its normal status by issue = twocommandsfrom = STUI:sop restart (this may not = unnecessary, so you can try without it = first)sop reinitCan we put it = to the observing notes that we cannot use the "stop" = buttonin = STUI?Dmitry_____________________________________________________Message 1176 of sdss3-25mlog - Logs = of nightly APO activities.https://trac.sdss3.org/tracmailman/browser/private/sdss3-25ml= og/all/1176.htmlsdss3-25mlog@sdss3.orghttps://sdss3.org= /mailman/listinfo/sdss3-25mlog___________________= __________________________________Message 1180 of sdss3-25mlog - = Logs of nightly APO activities.https://trac.sdss3.org/tracmailman/browser/private/sdss3-25ml= og/all/1180.htmlsdss3-25mlog@sdss3.orghttps= ://sdss3.org/mailman/listinfo/sdss3-25mlog Mark KlaeneSite Operations Manager Apache Point Observatory = voice: 575 437 6822PO Box 59 = = fax: 575 = 434 55552001 Apache Point Rd = = cell: 575 430 0210Sunspot NM 88349-0059 = web: www.apo.nmsu.edu = ____________________________________________________= _Message 1181 of sdss3-25mlog - Logs of nightly APO = activities.https://trac.sdss3.org/tracmailman/browser/private/sdss3-25ml= og/all/1181.htmlsdss3-25mlog@sdss3.orghttps://sdss3.org/mailma= n/listinfo/sdss3-25mlog= --Apple-Mail-3-258175080--