Trip Report

[Tom Droege <tdroege@veriomail.com>]

I will try to reconstruct a trip report though it is all a blur and the 
notes that would be useful to reconstruct the events are in a log book at NOFS.

Bill Haynes accompanied me on the trip and was a tremendous help.  I could 
not have made the trip without him, and it would have taken a lot longer to 
get things working without his help.  Bill brought his lap top and his GPS 
receiver and we were able to navigate through all kinds of obstacles.  At 
one point we succeeded in getting on a new expressway that was not yet 
open.  So we knew where we were even though there were no lines on the 
map.  This was about midnight and we were fortunate to run into Daryl who 
guided us out of the maze of barrels.  Just what Daryl was doing with his 
two buddies with his pick up truck on a new piece of expressway late in the 
day will never be determined.  ;^)

I brought all kinds of spares with me and used almost everything that I 
brought.  For once I brought enough tools, and the only thing that we had 
to borrow from the shop was an offset screwdriver to adjust where the brake 
disk was positioned.

We arrived late Tuesday and were ready to start setting up the Mark IV 
Wednesday morning.  Arne set us up in the 1.0m Ritchey-Chretten telescope 
dome for the assembly.  http://www.nofs.navy.mil/  This building is set 
between 4 tall "flag poles" which protect it from lightning.  The pier for 
mounting the Mark IV is just on the edge of the protected area.  We had one 
exciting day during the assembly when we were sitting in the dome working 
and there was a big thunder storm going on.  There was some hail and lots 
of lightning.  The sounds inside the dome were something wonderful.  We 
were working at roughly the sonic focus of the dome and the hail and rain 
on the dome, and the lightning crashing all around was an all sensory 
experience.  Hmmm!  There is more incentive to revive the fiber optic link 
to the Mark IV.

By Friday we had it assembled, and I recall that we moved it out on the 
pier on Saturday.  There were some problems.  I recall that I replaced 3 of 
the four pc boards and shuffled the cameras.  It is not clear what any of 
the problems actually were.  The Stamp/Scanner board clock would not 
stop.  I think this was the main problem.

The people at NOFS think I have been too cheap in the side plates of the 
Mark IV.  They are 1/8" material.  It is after all the Navy, and they are 
used to building battleships out of 12" armour plate.  So possibly they 
will remake the side plates.  I am yet to see any evidence that they wiggle 
enough to affect the exposures.  But I can be shown.   Arne kept pointing 
to the second pier sitting next to the one with the Mark IV and offering it 
for ARNE2.  This will depend on my getting someone to Lumigen coat a CCD so 
it is sensitive in the blue.  We shall see if this can be done.

 From Saturday on, we were trying to take data through various holes in the 
monsoon clouds.  The rain was expected, and more clear sky would have just 
exhausted us.  The rain gave us time to think.  After this, the main 
problem was that the RA drive would just quit running.

Thinking back, this is an old problem for me.  I have often seen the first 
frame in a sequence to have the stars as streaks.  I had thought this to be 
a "shutter open" problem.  I now think it is a RA drive stopped problem.  I 
have mostly made runs where I track for one set of frames then rewind the 
RA and start over.  Arne wanted to track the sky taking repeated exposures 
of the same piece of sky.  So we noticed it more quickly.  It was also that 
there were three of us and I was sitting at the terminal while Arne and 
Bill were at the Mark IV.

I recall that Saturday we took a side trip to the Grand Canyon and Sunday 
Bill got to take a bike ride up a mountain.

This problem would now appear to be software.  Yep, us hardware guys want 
to blame software even when we have written it.  It is not yet clear what 
the problem is.  It mostly runs with my computer, and mostly fails with 
Arne's computer with is faster.  In the end, I left the computer I had 
brought so that Arne could work to try to isolate the problem to the software.

We were able to get a few good exposures.  Really enough to show what the 
Mark IV could do and what might be possible.

Monday afternoon I gave a talk to a group of astronomers.  You can find the 
abstract on the nofs home page above.  I survived.  Tuesday morning we had 
one last pass at fixing the problem, declared it to be software and left.

Tuesday we drove up through monument valley to Grand Junction.  Leaving 
Grand Junction at 9 Am or so Wednesday we just drove home to Chicago, 
arriving at 6 AM or so Thursday.  I have spent the last couple of days 
recovering.

All in all a successful trip.  I have seen enough that I think that the 
Mark IV can do what it is intended to do.  There are a few bugs to be found 
that may really be software.  I will now write up some more description of 
the hardware so that Arne can poke around and possibly find the 
problem.  Chris, I hope that you can find time to help Arne to bring up 
your software.  I think it is time.  I would appreciate being copied on any 
private correspondence on this subject, though it seems OK to me to just 
put it up on the list.

Tom Droege