Subject: New DIS slit imager

From: Noel Camron Hastings

Submitted: Tue, 28 Nov 2000 20:47:10 -0700

Message number: 470 (previous: 469, next: 471 up: Index)

	The new DIS slit imager is place and being used now. There are a few
changes at this point, and there will be more. For now, please note the
	The new center for the DIS slit camera is at [199,297]. This is the bore
site of DIS and near the center of the grating and chip. This is where
your objects should appear after a slew.
	The new chip orientation is North/Up and East/Left. Our display here at
APO is identical to IRAF, so no more wondering if someone is looking at a
flipped image.
	The new slit imager has a larger field of view, about 2.7 minutes
square. There is no need for darks as far as we have seen, this will
speed things up quite a bit, especially for you 20th mag people!

You will find your slit images in a new directory from now on:


	All slit image file names will have the same prefix from now on and will
increment with each exposure. The prefix will always be the UT date. When
one is finished, we will just message you saying that #39 is done or
whatever the current increment is. The image names will be of the format:

	yyyymmdd.####.fits (eg. 20001129.0234.fits)

	Since this is a new imager, we are not completely sure of the
sensitivity, so please tell us the magnitude of the object before you
slew so that we can start to make mental notes about exp times and
	Eventually, this imager will be put into the hands of the observers and
you will make all offsets and monitor your objects while exposing. This
will do two things. One, give the observer the absolute knowledge of what
is going on with the object while they are taking images. Two, decrease
time from object acquisition to shutter open on the spectrograph.
	You can begin making yourself familiar with the operating system of this
camera by going to the manual link below. It is very basic, should be a
very small learning curve.

	The imager is a UNIX program, and will not analyze the images. It is
mainly for object identification. Of course, IRAF can analyze the images
if you want better ideas of focus and such. You will need to run it from
an Xterm.
	If you have any questions about the imager before a run, PLEASE let the
observing specialists know. In about a month, once we are happy that the
bugs are all run through it, we will begin transitioning from having the
observing specialists running it to having the observers running it! If
you have runs late in December or January or later, make sure you look at
the slit camera documentation above, and perhaps just log in a little
early to play with it.
  Noel Camron Hastings ~ Apache Point Observatory

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