MOS Fiber Configuration Data File

The automated fiber assignment code (assign) must be given a description of the MOS mechanism. It uses this information to construct its model of the MOS.

This file must be available to observers in advance of their runs. Someone who is familiar with the expected configuration for upcoming runs must be responsible for maintaining and publishing it.

Design Question

The nature of the MOS construction makes it extremely unlikely that some of the data (pivot & park locations) in this table will change. Other data (fiber/slit/pivot assignments) are quite likely to change. This invites typographic errors that modify data that should not be modified.

Do we understand the MOS hardware and the instrument technician task well enough that we should separate the pivot location and hypodermic lengths from the fiber/slit/pivot and status fields? We do not want to scatter the information into more files than necessary.

The PROPOSED file format

This follows the general guidelines and should be compared with the format currently in use.

The Magic Number

The first line of the file must be

#@ MOS Fiber Configuration File

Keyword/Value Pairs

There are no keywords in the existing fiber configuration file.

The button size(s) and hypodermic diameter(s) could be good additions to this file. Some discussion would be needed. For example, the current configuration has identical buttons and hypodermics on all fibers except the big guide bundle. If this were guaranteed to remain so then these sizes could be added as keywords. If it is possible that future MOS configurations might have heterogeneous fiber hardware then buttons and fibers belong in the main body of the table. This would make the table quite wide and would probably induce us to split this into two tables. Suggestions are welcome.

The Magic Number starting the table

The table begins after the line

#@ MOS Fiber Configuration Table

Contents of the table

The table shall consist of these entries in this order:

PIVOTID FIBERID SLITID FIBSTAT PIV_POSX PIV_POSY PRK_POSX PRK_POSY HYPOLEN ANGMAX

The data dictionary contains definitions of each of these entries.

PIVOTID is the master key into this table; it must be unique. Furthermore, the current architecture of the code requires that this table be ordered sequentially around the circle of pivots.

Back to the MOS home page.

Steve Allen <sla@ucolick.org>