[daip] Spectral line question (have to write a schedule by Dec29th)
Michael Bietenholz
michael at polaris.phys.yorku.ca
Sat Dec 20 15:01:01 EST 2003
I need to write a schedule for partIII of AB1097 for Dec.29th and had
some questions concerning the bandpass shape I saw for the earlier parts
of AB1097.
Q: what is the normal change in gain or in uncalibrated amplitude over
~40 MHz at 1.4GHz, ie. how square is the bandpass response usually?
I was looking at 0137+331 observations, in pseudo-continuum mode, with
7 channels/IF at L-band. I noticed on a POSSM plot (attached) that
the amplitudes on 0137+331 (and on other sources) were very uneven
across each IF - they change by a factor of >2 from the low end of the
IF to the high end. Is this normal? Did I do something wrong when
scheduling? Presumably, I can run BPASS and clean this up, I was just
surprised at the size of the difference in Gain between channel 1 and
7. Did I inadvertantly fall off the edge of some passband?
The IF frequencies are 1.4649 and 1.3851 GHz, the freq-axis looks
as follows.
Type Pixels Coord value at Pixel Coord incr Rotat
FREQ 7 1.4649000E+09 4.00 6.2500000E+06 0.00
thanks, michael bietenholz
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/.AB1097 1477
//* ***
//* *** NRAO VLA Observe Program, JObserve 1.7.0, February 10 2003
//* ***
//* *** Observation day 59,553 at 19 30 00 LST, 2003.07.17 00:01:41 MST.
//* ***
//* *** Observer
//* *** M. Bietenholz Phone
//* *** Dept. Physics and Astronomy Office: (416) 736 2100 ext 60259
//* *** York University During Observations: (416) 537 1802
//* *** 4700 Keele St.
//* ***
//* ***
//* *** E-Mail address
//* *** mbieten at yorku.ca
//* ***
//* *** Observing mode(s): line
//* ***
//* *** Special Instructions
//* *** 1. Please use the other version of this observe file (4IF * 25MHz) if
//* *** that correlator mode is possible;
//* *** 2. Extend the first scan (3C48)
//* *** for 2 minutes of good data if necessary.
//* ***
//* ***
//* *** Date Prepared: July 16, 2003 5:06:36 PM GMT-04:00
//* ***
0137+331 19 40 00 01 37 41.2994 +33 09 35.132C LL B 0000 16.50
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
0228+673 19 43 15 02 28 50.0514 +67 21 03.029C LL A 0000 1.25
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
3C58 19 49 15 02 05 39.0000 +64 49 33.000C LL 0000
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
0228+673 19 50 25 02 28 50.0514 +67 21 03.029C LL A 0000 1.25
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
3C58 19 58 25 02 05 39.0000 +64 49 33.000C LL 0000
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
0228+673 19 59 35 02 28 50.0514 +67 21 03.029C LL A 0000 1.25
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
//* ***Warning*** Observation longer than 65 minutes.
//* fast switching 3C58 / 0228+673 combo
3C58 07 15 35 02 05 39.0000 +64 49 33.000C LL 0000
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
//OF NOD SKY 02 28 50.0514 +67 21 03.029 720 50
3C58 07 24 35 02 05 39.0000 +64 49 33.000C LL 0000
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
0228+673 07 26 35 02 28 50.0514 +67 21 03.029C LL A 0000 1.25
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
0137+331 07 30 00 01 37 41.2994 +33 09 35.132C LL B 0000 16.50
//DS 2AB 5 3 3 3 3
//LO -3.2 -3.2 3640 3560 0000
//FISF 100.000000 200.000000
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