Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~palfa/observing.notes/obslog.20050409.txt Дата изменения: Sat Apr 9 21:26:11 2005 Дата индексирования: Sun Apr 10 23:50:56 2016 Кодировка:

Dear PALFA consortium members,

Today Jim joined me and Ramesh on our observing run. We've been
somewhat unlucky today, since we had our first ever WAPP glitches and
we were heavily blasted by RFI right through the day. Some of our
scans were hit by 22 pulses in 130 secs (12 sec radar beam and a
sidelobe/counter-beam?).

In spite of the RFI, we have a faint possible re-detection of
yesterday's single pulse candidate (maybe; S/N~5 but the DM is right)
and a good new single pulse candidate (one burst in two adjacent
beams, at DM=92). Plots for both are posted online (~palfa/candidates/).

Other than that, today's quicklook was quite ineffective due to the
RFI - frequently, all top 10 candidates were filtered out and the
single pulse plot was a mess. We did not even detect J1928+1746,
thhough we did see B1933+16 in all beams. And unlike previous days,
where we'd have 0-2 scans "stuck" as incomplete on ASP, today we
have 38 beams stuck. Can anyone recommend a fix?

Ramesh and I finish today; Jim is around till Tuesday and will overlap
with Scott Ransom; and I've updated palfa_observe.txt (online at
~palfa/doc/) and recommend it to future observers.

Cheers,
Shami


A note on T_sys: Phil Perillat asked if we were doing any monitoring
of the system temperature. The G/EALFA folks care about amplitude
calibration, but since we don't, the receiver performance is often not
being monitored for long stretches. Phil suggested that if we were to
take 10-15 seconds of data on each run with cals turned on, he'd be
willing to monitor them to make sure that ALFA T_sys was as expected
over time. This may be something useful for us too, e.g. to make sure
one beam has not suddenly degraded in sensitivity? If we do take cal
scans, it should be coordinated with Phil.


----------- obslog.09apr05.txt ---------
P2030 Observing Notes, 9 Apr 2005, Ramesh Bhat, Shami Chatterjee, Jim Cordes

* Lots of RFI on monitor (radar pulses)
* ALFA feed rotation had to be reset MANUALLY (to 18.999933).
* Frequency setup didn't work correctly: needed to verify on IF monitor.
(Added warnings about both to palfa_observe.txt)

Start with scans on J1928+1746.
WAPP gets into odd state on first 268 sec scan.
Re-do scan - things are fine on second 268 sec scan.

Observe B1933+16 (test) in each beam (67 secs each): beam 0 okay
* Really bad RFI
We're getting overflows on WAPP3... problem.
Stop observations: "WAPP3 never aborted"?
Restart all WAPPs.
Redo setups - okay, it seems fine now. Be wary with snap/quicklook
Finish all B1933+16 test obs: beams okay.

Start catalog observations: 6:06 AST

Follow-up on yesterday's single pulse candidate:
G56.01+01.54.N_53468_0089:4
Around 10 bursts; DM bin = 16 (i.e. DM=56), S/N~10;
Today:
Faint detection (S/N=5) but scans affected by RFI.

Good single pulse candidate:
G57.81+00.23.N_53469_0119:3 and G57.81+00.23.N_53469_0119:4
One burst; DM bin=26 (ie, DM=91.9), S/N~16.
(See plots online at ~palfa/candidates/)
But note, beams 0,2,5,6,7 have lots of RFI.

Rest of quicklook is pretty bad: too much RFI, most cands filtered.
(End)