Contents
The preferred way to do this is simply to create a new identity
and begin using that. Please note that doing so may result in
warnings when you specify masks on your instrument configuration
form due to a mismatch between your email address and that of
the owner of the slitmasks. However, this is only a warning and
should not prevent you from using your masks.
Slits are milled using an endmill with a diameter of
0.015 inches. We mill slits in two passes: a first rought
cut, and a second cleanup cut that removes a section 10% the width
of the tool. Hence, the minimum slit width is 0.018 inches
on the mask; at the LRIS and DEIMOS telescope focal plane plate
scales of 0.727 mm/arcsec, this corresponds to a projected
slit width of 0.63 arcsec if the slit is not tilted (i.e.,
the position angle of the slit project onto the sky matches the
postion angle of the mask).
The answer depends on your slit width, according to the formula
pa_max = acos(0.63/w)*180./pi
where pa_max is the maximum PA of the slit (relative to
the mask), and w is the slit width in arcsec. For a
slit width of 1.0 arcsec, the slit may be tilted by up to
50° relative to the mask position angle. For a slit width of
0.7 arcsec, the maximum tilt is 26°.
The deadlines for submitting your slitmask designs are the same:
four weeks for normal LRIS and DEIMOS slitmasks, and eight weeks
for masks with more than 200 slits. Exceptions to the deadline
may be granted for valid scientific reasons if a request is made
by contacting the director of Science
(jomeara@nullkeck.hawaii.edu),
before the deadline.
There are 3 steps in the process, all at different times:
- The analysis and consistency check for all submitted masks
occurs twice daily at 18:00 Pacific Time and 05:00 Pacific Time.
- The checkout of the mask data in preparation for transfer
to Hawaii happens at 07:00 Pacific Time.
- The transfer of mask data to Hawaii from here happens at
06:00 Pacific Time.
Thus, anything submitted after 05:00 PT will not get consistency
checks, and anything submitted after 07:00 PT will be transferred.
- Login to the slitmask
database.
- Click the Show Me My Mask
Inventory button to get a list of your masks.
- For each mask you want to remill, click the Forget button.
Use the forget function to remove the old
masks from the database, then submit revised mask files.
Any newly submitted mask which has a “guiname” that
matches any existing mask which is intended to be used in the
future is assigned a new guiname. This is required in order to
prevent confusion about the conflicting masknames. When a mask
is renamed, the slitmask owner should receive an email about the
change.
Unfortunately, no. Once the slitmask information has been
ingested, it will be transferred to the milling site and the
slitmask should be milled. Since the database computer in Santa
Cruz has no way of knowing whether the mask data have been
transferred to the slitmask mill on the Mauna Kea summit, it is
not safe to change the slitmask name once the mask has been
ingested. If we did change the name in the database, we could end
up having the name recorded in the database disagree with the name
milled into the physical mask. There is no way to change the
metal, and the inscription on the mask is used as a cross-check by
the technicians who are loading the masks. We wish to prevent
such confusion.
What you can do is to forget the masks you
submitted, change the mask names in your DSIMULATOR
output files, and submit revised mask files.
For security reasons, LRIS mask names are now being overridden
with automatically generated names to prevent the possibility of a
malicious filename causing trouble with the database. Your
support astronomer can change the slitmask names back to their
original values on the day of your run; however, when completing
the LRIS configuration form you must use the nonsensical names
assigned by the slitmask ingestion system.
Only registered users of the slitmask database system are
permitted to submit slitmask design files. You can either have
the other user register, or you can use the fv program
as described above to edit the observer
email. Then you should be able to submit the file successfully.
The final check to make sure that all your slits and alignment boxes
will be correctly milled is to check the
blueprints in the slitmask database, once the slitmask has been
submitted (see sanity-check
your slitmasks)
Generally, no. You'll need to update the Use Date
field in the FITS header of the slitmask design files first,
because if the mask design file has an invalid Use Date (i.e., a
date which has already passed) then the slitmask database will
reject the mask and it will not be milled. It's simple to edit
the file if you install the fv
program:
- First, make a copy of your mask design file for
safekeeping!
- Run fv and open the mask design file (FITS
format). Note that on a truecolor display you may need to issue
the command as fv -cmap 2.
- The fv program will display a
list of the existing extensions with various options
(Header, Hist, Plot,
All, Select).
- In the row labeled MaskBlu, click the
All button to bring up a new window showing this
extension.
- Use the scroll bar to scroll right until you find the
field Date_Use.
- Click on the displayed date and the value will be copied
into the Edit cell field below.
- Enter the new use date in YYYY-MM-DD format
and press the Return or Enter key to
update the field.
- Select File > Save to save the change.
- Exit fv.
By default, slitmasks are retained for 6 months past their "Use
Date". This is the date you specified in DSIMULATOR when you
designed your DEIMOS mask, or the date you entered on the web
page when you submitted your LRIS mask. If in doubt, check the
LRIS/DEIMOS
Slitmask Database and view the record for your mask. If it
shows a valid barcode then we should still have the mask in our
summit collection. If you plan to re-use a mask you probably
want to extend the Use Date past the date of your upcoming run
to ensure that it is not discarded; please see the next entry.
- Login to the slitmask
database.
- Click the Show Me My Mask
Inventory button to get a list of your masks.
- For each mask you want to remill, click the Remill button.
- You should receive email notification when the mask has
been remilled. Note the barcode number assigned to the mask.
- When completing the instrument
configuration form for your run, be sure to enter the
appropriate barcode number for your mask to ensure that we
select the correct mask.
By default, the slitmask droplists on the LRIS/DEIMOS run
configuration form list all of the slitmasks which have "use
dates" that occur during your run. If you wish to use a mask
which has a use date outside of this range, simply do the
following:
- Select the first item in the slitmask droplist, labeled
EDIT.
- After you have clicked EDIT, use the
Backspace/Delete keys to remove the word EDIT.
- Type in either the barcode number or name for your slitmask.
Please note that this function only appears to work in the
Firefox browser! Alternatively, you can update the use dates on
your mask (as described below) to the
date of the run. Doing so should cause them to become visible
on your mask list within 5 minutes.
We delete a mask record from the database and discard the mask
itself when it is over 6 months past its Use Date as
recorded in the database.
An email is sent to the mask owner two weeks prior to the date
of deletion notifying him or her of the pending mask removal.
To ensure that the mask is retained beyind the standard 6-month
retention period, the mask owner must complete the following
steps to extend the use date:
- Log in to the LRIS/DEIMOS
Slitmask Database
- Click on the Show Me My Mask Inventory button.
- Locate the mask to be extended.
- Click the Edit Use Date button.
- Select the number of days/weeks/month/years to extend by
(max 1 year).
- Click the Extend Mask button.
- Return to mask inventory page and reload; verify that Use
Date has changed.