[Peyton-observing] Wednesday

[jegunn]

Chris wrote to me last night that the telescope is malfunctioning 
(mildly). The EAST button does not seem to work with any movement
speed, though the telescope slews east when setting on objects without
any problem and guides east fine when commanded through the CCD controller
port. All other functions seem to be fine. Whether this is just a problem
with the contact in the control paddle or is more complicated I do not
know at the moment.

I think for the public session one can use a simple workaround. There is
a lock and a fine-motion knob on the polar axle, and the telescope can be
moved arbitrarily and freely by hand if the lock is unlocked. The
fine knob runs a pinion gear which engages a large gear locked to the
fork, and allows pretty fine motion of the telescope by hand. Moving
the telescope in this way does not influence where the control system
thinks the telescope IS. So the ritual is as follows.

For setup:

Find a star. use the N and S buttons to go N and S; unlock the
polar axle and move the telescope to the star by hand. The lock
can be lightly set, which will still allow you to move the telescope
with the knob. Center the star with the N and S buttons and the knob,
and lock the lock tightly.

Tell the telescope which star you have and tell it you are there.

Further GOTOs should work fine, but since the coordinates and
setup are not perfect, you will need to tweak the centering. Do this
with the buttons for N and S. For E and W, if you want to go W, use
the button; to go E, VERY CAREFULLY undo the clamp while you are holding
on to the fine knob, use the knob to center, and lock again.

I am away Monday and Tuesday, returning Wednesday, but I may not
be in in time to help. So Ai-Lei, if you would like, I could meet
with you tomorrow to go through this. I will later in the week
try to contact Meade and figure out what we can do to fix it--
It may involve buying another controller, or shipping this one
to them for a while. I am convinced (perhaps incorrectly) that
it is a controller problem; the telescope itself seems to be
fine.

I will TRY to get finished a little guide box which plugs into
the CCD port (it is just a 5-wire interface to tell the telescope to
guide N,S,E, or W), so you will have some electrical control to
move E, though it only works at guide speed and so is VERY slo-o-ow.
I tested the functionality this afternoon by just shorting wires
together in a cable, and it works (even east), but I do not have the
necessary parts to put together a pusbutton box at the moment.


--jim