This is the multislit spectroscopy setup with the slitmask and
narrowband filter in the red.
1. We need the spectrograph to be in good focus (FWHM smaller than 2.5
pixels for arc lines with the 1.5 arcsec slit).
2. We will use the R1200 grating.
3. Desired central wavelengths are 4900 (B) and 6550 (R). +/- 50A is
fine. Blue is not critical; if everything goes as planned, we will
not use it.
4. We need one hydrogen lamp (in place of one of the He lamps) mounted
on the truss for wavelength calibration.
5. We will use the NMSU 657/2.5 filter. [Specify if this is different from the filter used for the last observing run.]
6. NECESSARY PIECES OF EQUIPMENT:
- DIS filterwheel A.
- An aluminum (silver-colored) filter holder for filter wheel A that
allows the slitmask and Halpha filter to be mounted perpendicular to
the light beam. The perpendicular mount is critical to not change the
filter passband. (Wheel A may be the only one that allows this type
of mount.)
- An additional filter holder to mount another narrowband filter in
the same filter wheel (but without a slitmask). This will likely be
one of the black anodized filter holders that mounts the filter tilted
to the light beam, since we only found one aluminum-colored filter
holder that allowed the filter to be mounted perpendicular.
- The aluminum (silver-colored) slitmask with 11 1.5 arcsec wide slits.
- NMSU 656/2.5 1m Halpha filter.
- NMSU 657/2.5 1m Halpha filter.
- One metal shimmy (orange), about 0.6mm thick. It is essentially a
rectangular frame that fits around the filter hole in the wheel. This
is required for mounting the filter and slitmask such that the slits
on the mask are in focus. Mounting details are below.
- The regular 1.5 arcsec DIS long slit mounted in its own hole.
Note: The slitmasks were last used [May 2010]. They are still at APO.
The filters should be in the NMSU filter box in the 1m observing room
if they are not in the filter wheel.
Setup for filter wheel A:
- one slot for the standard 1.5 arcsec DIS long slit.
- one slot with the slitmask, filter holder, and 657/2.5nm NMSU
filter. WE MUST USE THE SILVER-COLORED FILTER HOLDER FOR THIS ONE
which allows perpendicular mounting for the filter.
- one slot with the 656/2.5 filter (no slitmask). This is required
to get the telescope focus properly set up for DIS to work with the
mask.
Mounting the slitmask:
1. Place one orange shimmy in the filter hole.
2. Place the slitmask with the narrow openings of the slits pointing
up. The wider openings face downward toward the detector.
3. Put the silver-colored filter holder on top of that.
4. Please make sure the slitmask is tight and will not slide. If it
is loose, please place a shimmy on top of the slitmask, underneath the
filter holder.
5. Mount the filter in the top of the filter holder as usual.
Note: In July 09, we used black cardboard to reduce light leaks
around the filter edge. The cardboard was mounted on the two edges
that are perpendicular to the direction of the slits. Hopefully it is
still there. Please make sure the cardboard is arranged so the slit
lengths are uniform across the slitmask.
