From hermanm@rowland.msfc.nasa.gov Fri Apr 18 14:12:30 1997
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Date: Fri, 18 Apr 97 14:12:53 EDT
From: hermanm@rowland.msfc.nasa.gov (Herman L. Marshall)
Message-Id: <9704181812.AA05514@rowland.msfc.nasa.gov.>
To: dd, kaf, jdrake@head-cfa.harvard.edu, jiahong@head-cfa.harvard.edu,
        juda@cfa.harvard.edu, frits@astro.columbia.edu, bertb@sron.ruu.nl,
        theog@sron.ruu.nl, kaastra@rulrol.LEIDENUNIV.NL,
        prp@mpe-garching.mpg.de, hermanm, dsd, dph, wise, crc
Subject: XRCF Grating report
Status: R

Again, time is short but I can report that we have ACIS data but no
grating tests yet.  There was a delay before opening HRMA contamination
covers last night, so first light wasn't until just before midnight
on Thursday.  After a CMDB mixup (several releases in one day), they
started ACIS testing in earnest and have gotten some lovely off-axis,
out-of-focus images for EA tests at high energy with the DCM.

Problems have surfaced, of course.  The one I know most about is
that there are lost frames which are apparently the result of high
count rates.  The losses are likely due to an unaccountedly high
background.  The background per pixel may be low but when summed over
6,000,000 pixels, it fills a significant part of the telemetry stream.
I don't know the exact numbers, so I'll pass that info along later.
The net effect is that count rates in the desired images may be
decreased, so that integration times should be increased.

My CMDB replacement has arrived, so I'll switch over to HETG duty
scientist after working with him to release adjustments to the
current test list.  Kathy and Mike should arrive today as well.
I will take tomorrow off to travel with my family and be back on 
Sunday or Monday.

First light with ACIS/HETG in flight configuration should occur
within hours.  I'm not leaving until I see it firsthand!

Herman