Date: Tue, 14 Mar 2000 09:42:48 -0800
From: Russell E Owen
Subject: Re: 3.5m Night Log 20000313
>After changing the collimation, we did a guider instrument block and a
>pointing model.  We had several difficulties with the pointing model
>related to the changes in wrap selection with TCC 2.2.4 and the fact
>that the seeing was too good.  The software wasn't happy about
>centroiding on stars less than 2 pixels FWHM, which is probably
>sensible.  Rather than change the binning and risk discovering in the
>middle of the pointing model that some strange parameters needed to be
>set at the same time, we defocused the guider.
You are welcome to change the binning factor at any time. It should
have no ill effects. To change it:
SET BLOCK INST
GIM_BINFAC newx newy
^Z
Until you type ^Z your changes are not implemented.
Warnings:
- you must specify both x and y bin factors, even if they are identical
- you will lose this value next time you perform a SET INST
- do *NOT* perform a SET INSTRUMENT while you are in the middle of a
SET BLOCK INST. The result will be a nasty collision. SET BLOCK is a
low level command that is powerful but has the potential to really
mess up the TCC.
Note that different guiders may want different binning factors, which
is why the system is somewhat clumsily. I think the real fix is to
have a centroiding algorithm that is less picky.
-----
What problem did you have with the new wrap system? The only default
I changed was making "mid" the default wrap for TRACK/ROTANG. This
was done to match the existing default for ROTATE, and that was set
to MID by request of APO years ago to avoid having the rotator
hitting limits during exposures.
-- Russell