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: http://www.naic.edu/~phil/usrproj/a2351/a2351.html
Дата изменения: Sun Jul 6 19:15:41 2008
Дата индексирования: Wed Jan 14 02:13:55 2009
Кодировка:
A2351 is doing 300 sec on,off position switching
with the xband receiver.
Pointing/calibration checks:
Pointing data taken 20jun08->30jun08 showed a 5
asec offset in the za errors. On 01jul08 15:00 hours I modified the
xband pointing model to remove a 4 asec offset from the constant za
term. The
Page 1: calibration. Gain, Tsys, Sefd, and avgBeamwidth for all
the data
B1622+238 shouldn't be used for pointing or gain checks at
xband. It has a width of 24 asecs which is close to the beam width.
B1607+268 at za=13 was taken on on 02jul08. For some reason
this pattern had about 1/2 the gain of the 3 other patterns for this
source before transit. The fit for the 4th board didn't converge at
all.
The pointing error for the 3 boards that did fit is close
to 0.
I looked at the tiedown tensions since it was at az=131
which is close to pointing at td4, but the tensions did not go to zero.
The coma is large at hi za. This is probably coming from the
shimming of the za rails.
B1622+238 should be ignored because it is extended.
Page3: pointing errors all data:
1,2nd plots: za errors vs za and az.
3rd,4th plots: az errors vs za,az
Page4: pointing errors 30jun08. Prior to 01jul08 the za
Errors have a mean offset of about 5 asecs.
I removed 4 asec from the model on 01jul08 15:00.
Page5: pointing errors after 4asec offset removed in za constant
term. The offset is now close to zero .
Page6: pointing errors vs az,za. The length of the tick mark
is
proportional to the pointing error. 1 tick mark is 5 asecs. The
direction of the arrow is the direction of the error.