Date: Fri, 14 Jul 2000 15:44:59 -1000
From: Bill Vacca <vacca@minerva.ifa.hawaii.edu>
To: denault@jeans.ifa.hawaii.edu
Cc: rayner@jeans.ifa.hawaii.edu, vacca@minerva.ifa.hawaii.edu
Subject: Re: spex problems..


Hi Tony,

I have a suggestion for the guider set up, that I think will accommodate
the ways most observers will use SpeX.

The XUI could have a Guider Modes tab, with three "sub-tabs" (if possible).
The three sub-tabs would be the three different guider modes: offset, nod,
and step. Each tab would bring up a panel. 

The Offset panel would have a Box Center entry, a Box Width entry, a Default 
GuideBox Button, and a Send to TCS button. The observer could either give
the position and size of a box or accept the default box, which would be
centered (in both x and y) on the slit. This mode would be used by people
who observe extended objects and want to go to sky between exposures. They
could guide on the object or on something else in the field, using the
box they set up.

The Nod panel would have a Box A Center entry, a Box A Width entry, 
a Box A Center entry, a Box A Width entry, a Default GuideBoxes Button,
and a Send to TCS Button. Again, the user could either accept the default
guide boxes (the positions of which depend on the slit being used), or
they could define their own A and B beam guide boxes. This mode would
have to be able to read the position angle of the slit and figure out
the correct nod offsets for the telescope when the beam is switched. All
of this would be done once the Send to TCS button is pressed.

The Step panel would have a Number of Positions entry, a First Box Center 
entry, a Box Width entry, a Step Size entry, and a Send to TCS Button. The 
user would specify how many guide boxes she wants along the slit, the position 
of the first box, and the step size between boxes (in either arcseconds or 
pixels). This mode would also have to read the position angle of the slit 
and calculate the offsets between the various boxes. The observations would
be carried out entirely in the A beam, and the telescope would be stepped
between each exposure. When it gets to the end, the telescope is reset to
the first position.

I think this would encompass most of the ways people will observe with SpeX.
This layout would allow the observer to have a lot of freedom in setting up
the guide boxes, while not making it complicated for the 99% of the people
who will use the standard default guide boxes.

What do you think?

        - Bill