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General hardware description
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The Orthogonal Parallel Transfer Imaging Camera (OPTIC) consists of
two Lincoln Lab CCID28 2K x 4K chips mounted side by side in a dewar.
The gap between them is 1mm, approximately 60 pixels.  The dewar
connects to SDSU-2 electronics which contains a 12-board backplane.
At present there are seven boards present:

  Timing board			- the DSP which runs the whole thing
  Utility board			- another DSP which does auxiliary functions
  Clock board (serial)		- controls serial clocking on both chips
  Clock board (chip1 parallel)	- parallel clocking for chip1
  Clock board (chip2 parallel)	- parallel clocking for chip2
  Video board (chip1)		- biases and video processing for chip1
  Video board (chip2)		- biases and video processing for chip2

The connection between the dewar is by a pair of 18" 128-pin cables,
and the connectors on the dewar go directly to the CCDs so PLEASE NOTE:

   These pins are fairly delicate and it takes a lot of force to put
   on these connectors, so be VERY certain that 

    - no male pins are even slightly bent out of line
    - ease the connectors together before tightening
    - you, the dewar, and the controller box are grounded together

The SDSU-2 controller box is in turn connected to a power supply box
via a 6' cable, a host computer via a pair of fibers (fragile,
vulnerable connectors!), and the shutter and TFW filterwheel via a
15-pin, optoisolated Dsub cable to the TFW controller box.  There is
also a BNC connector which can be used as an alternate TTL shutter
signal, and there are two TFD's on the focal plane which are brought
out to BNC connectors.

At the UH2.2-m approximately 30-50VAC exists between the metal of the
back of the telescope and the AC ground found at the outlets on the
dome floor, so it is essential that the dewar and SDSU boxes be
insulated from the telescope and power brought up from the dome floor.

The SDSU controller talks to a Dell Dimension 4300 host computer with
a 1 GHz processor, 0.5 Gb of memory, and 80 Gb of IDE disk, of which
65 Gb is available for data storage.  It has a CDR drive which can be
used with to burn CDs.  This seems to be reasonably reliable, although
it does not check that you might overfill the CDR:

   mkisofs -R -J MY_DIR | cdrecord -v fs=6m speed=8 dev=0,0 -

Don't try do this if you are loading the CPU, especially taking data!

This will write the entire directory "MY_DIR" onto the CDR.  Note that
these will make "MY_DIR" the root of the CDR, i.e. a file MY_DIR/myfile 
will appear as /mnt/cdrom/myfile when you have mounted the burned CD.
A typical night's observing, once compressed, will fit on four CDRs,
taking about 10 minutes apiece to burn at 8x.

The computer permits ftp and telnet as well as scp, ssh, etc, but
please be careful about security.

Communications is through an SDSU-2 PCI interface board.  The host is
running a nominal RedHat 7.3 Linux, although the kernel was rebuilt in
order to enable IDE disk DMA as well as to provide a source tree that
the device driver could be compiled with.  The default kernel is called
"2.4.18-3new", and "2.4.18-3" is the basic RH7.3 kernel.  The device
driver is provided by Sidik Isani at CFHT, currently v2.11.

OPTIC includes a filter wheel/shutter assembly.  The filter wheel has
four slots for 100mm round filters of thickness up to about 1cm.  The
filter wheel position is sensed with a magnet and Hall effect sensors,
and has four detents and a fairly strong spring loaded roller to lock
down the wheel at repeatable positions.  The filter wheel has a hatch
for changing filters.  Note that the filter wheel has a moderately
fragile drive mechanism, and will *not* turn freely without power.
The shutter is a 100mm Prontor electronic unit.  There is no provision
for power reduction when the shutter is open, so it tends to generate
a bit of heat.  The filter wheel and shutter are run by a custom
controller which connects to the SDSU utility board via opto-isolated
signals through a 15-pin Dsub connector.

The Prontor shutter is not extremely fast, and the center of the field
of view gets approximately 100msec more exposure than the nominal
exposure time.  For precision photometry, therefore, it is necessary
to construct an exposure map which can be derived from the ratio of
two flatfields of different (known) exposure times illuminated by a
constant light source (a dome flat lamp which has been on for a few
minutes is fine).  I believe that the shutter exposure map is very
reproduceable, so I've put an exposure map called shutter.time in
/usr/local/inst/etc.  If you add this file to a constant nominal
exposure time (in sec) you will get the actual exposure (as a function
of position).