As of September 2009, the standard for moving filters in NIRSPEC is to use the "filt" or "filter" commands from the command line. Previous observing scripts used the "fil1pos" or "fil2pos" keywords. These keywords still exist and should work when NIRSPEC is on RNAS (non-AO); however, the "filt"/"filter" combination is recommended.
The shell script "filter" uses the index positions as defined in the table below to move the two filter wheels. For instance, to use the KL filter, one types "filter 5 11" to move filter 1 to position 5 (KL) and filter 2 to position 11 (OPEN). To use the NIRSPEC-7 with the thin blocker (standard), one types "filter 1 6".
The shell script "filt" is a higher level script that interprets filter names then calls the "filter" script. To use the KL filter, one types "filt kl". The script knows to send filter 2 to the OPEN position when NIRSPEC is non-AO and knows to send filter 2 to the AO STOP when NIRSPEC is behind AO. To use NIRSPEC-7 with the thin blocker, one types "filt n7" or "filt n7 thin".
|Position||Motor Steps||Filter 1||Filter 2|