Search
Text Size:
Smaller Text Normal Text Larger Text

Facebook

Follow us on Twitter

ALFOSC rotation centre monitoring

The rotation centre is calculated from two consecutive frames with rotator turned 180 degrees between the frames.

ALFOSC rotation centre monitoring
Date / night x-rc

average

y-rc

average

x-standard

deviation

x-standard

deviation

Number

of stars

x

range

y

range

x

avg

y

avg

Rotator

position

Image Instrument

change

Comments
23-12-2015 1041.2 1028.3 0.21 0.13 14 111-2002 170-1914 1111 1146 -158, 22 ALyl230344-5 23-12-2015 R-filter(#76) ; 2 rotator angles
02-06-2015 1073.1 994.6 0.31 0.30 12 275-2000 52-1936 1196 939 -155, 24 ALyf020201-2 02-06-2015 R-filter(#76) ; 2 rotator angles
13-06-2014 1076.0 989.4 0.29 0.32 26 84-2081 29-1958 1075 980 -159, 20 ALxf130082-83 12-06-2014 R-filter(#76) ; 2 rotator angles
22-09-2013 1073.2 1069.8 994.9 992.3 0.27 & 0.27 0.40 & 0.22 22 & 25 110-1988 17-1960 1016 786 -134, 46 ALwi220059-61 22-09-2013 R-filter(#76) ; 2 rotator angles; three frames
07-09-2013 1067.4 980.6 0.36 0.20 12 104-1987 75-1786 1016 786 -131, 55 ALwi070224-5 06-09-2013 R-filter(#76) ; 2 rotator angles
02-06-2013 1067.0 1002.5 0.66 0.19 10 145-1972 29-1849 948 893 -128, 52 ALwf020232-3 28-05-2013 i-filter(#12) ; 2 rotator angles
03-02-2013 1066.5 1001.0 2 ALwb030171-4 03-02-2013 V-filter ; 4 rotator angles
09-01-2012 1069.1 1006.6 0.38 0.17 29 177-2053 24-1924 1199 922 22,-157 ALva090306-7 09-01-12 i-filter
26-12-2011 1072.4 998.2 0.23 0.17 33 76-2049 183-1978 1069 1000 -2,-182 ALul260059-60 16-12-11 R-filter
15-11-2011 1072.1 1007.1 0.29 0.20 36 82-1960 17-1952 1108 1072 114,-65 ALuk150226-7 10-11-11 R-filter

The centre of the imaging area of the CCD is x=1074, y=1024.

Some older data:

July 2006 (pg110089-90)
18 stars, average from two measurements, accuracy about two pixels.
The drift between the first and third images was x=+3.2 and y=-2.7 pixels
and standard deviation of one measurement 0.3 pixels or better.

x = 1088,
y = 996

-----------------
ALFOSC rotation center measured from data taken on the night of 20
January 2004 from 42 stars spread over the field:

x = 1082.31 , Standard dev.: 0.28
y = 995.86 , Standard dev.: 0.24

-----------------
November 2004
x = 1085,
y = 997


Back to top Last modified: 28-Dec-2015