From lfoley@aoc.nrao.edu Mon Jan 30 13:41:12 2006 Date: Mon, 30 Jan 2006 13:41:08 -0700 (MST) From: Lisa Foley To: vlbiobs@aoc.nrao.edu Subject: Re: bs161 ---------- Forwarded message ---------- Date: Tue, 13 Dec 2005 17:17:06 -0700 (MST) From: George Moellenbrock To: Lisa Foley Subject: Re: bs161 Hi Lisa- Firstly, thanks for all of your efforts on this observation. I really appreciate it. Sorry I screwed it up---clearly it made for more work for you! > I've had a look at the bs161b file and indeed it is the same as 'a'. So > not only does it need to be revised to fix the oversampling problem, i > must also ask that the mode changes be reduced to once per hour. We try to > be flexible and cooperative about observing guidelines, but this was a bit > much. Not only did it take a while to generate the jobs scan-by-scan for > the first attempt, the regeneration and revisions to fix the oversampling > error took twice as long. > So you mean that we have to use the same bandwidth for all scans, and not change this more than once an hour. OK, this will require some careful thinking. The mode changing so often was a result of the attempt to achieve high spectral resolution on the target source *and* have sufficient SNR on the calibrator. This is difficult (impossible?) to achieve w/out changing the bandwidth. Reducing the mode changes to less than once an hour isn't a viable option because the calibration scans simply must occur more often than this. I guess we'll probably have to compromise on spectral resolution. (So we should DEFINITELY correlate the observation we already did.) I'm going to have to think about this some more and see if there is a way out. Hopefully tomorrow, but I'm currently swamped with other things. Stay tuned. Thanks again, George