Running the Mark IV

[Tom Droege <droege@wwa.com>]

I have been quiet because I have been running the Mark IV.  I have had 3-4
nights in a row where the sky is acceptable for calibration and ajustment.
I am worn out from working all day to make changes and calibrations and
taking data all night.

Each night I take 1.6 GB of data, then throw it away the next morning when
I identify a problem.  First the electronics was saturating.  So I reduced
the gain by a factor of 6.  Then this hurt the signal to noise.  So I
cranked the gain back up by a factor of 3.  The V camera has been flakey.
last night I found out why.  The shutter was hitting the side panel.  So I
moved it.  Main reason for throwing out last nights data.  

Slowly I am finding the right focus and adjusting the RA drive and the
mount orientation to north.

I am working on collecting enough data so that I can put out a series of CD
ROMS to put you all to work.

One project is to take the format that I write the files out in and convert
it to .FTS.  I think Ted Woodhouse has volunteered to do this.

Another is to take a series of files that have been exposed at different
focus positions and pick out the best focus.  I now have a program whih
will start at a given focus position and step in arbitrary steps.  The
program should take the starting position and the step size, examine the
exposures and pick out the best position for the focus.

I will shortly have a bunch of images.  I will be looking for someone to
look at them and map what is wrong.

I know a few things already.  There is coma in the corners.  But no worse
that the camera lens that I previously used.  The field is *much* flatter
than the camera lens.  But someone should look at this and try to
characterize it.

I will also be producing a string of overlapping images in simultaneous V
and I.  Just the right material for someone to tune up their star
processing program.  

I am set up and ready to write CD-ROMs and send them out to those ready to
work on these tasks.  At the rate I am going, I think I will be ready to
send out stuff in a week or so when the moon comes back.

Meanwhile, back at the ranch, Dan will be in next week and we will start
assembling the Mark IV for Arne.  Actually we will probably put together
two or three at a time.  It all depends on finding enough room.  A ton of
parts will arrive on Monday.  

I am still holding off buying the CCDs for the production run.  It is a lot
of money and I want to make sure that we can do science with the design.

Tom Droege