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The OSIRIS User's Manual [Contents] |
Observing Setup |
OSIRIS observers login to the main observing console (ctioa1 at the 4-m and ctioa2 at the 1.5-m) as user "osiris". The CTIO support scientist will provide you with the current password.
L = Login directly to OpenWindows to continue an observing run.
I = Initialize the account at the start of a new observing run.
X = Exit (logoff) the OSIRIS account
If this is the first night of your run, enter I to perform
the initialization process.
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When Prospero is started, you should be presented with two windows: an xterm labeled "Prospero Command", and a second window labeled "Prospero Status" located immediately above the command window. The status window will be blank until you have connected Prospero to the data-taking PCs and started an OSIRIS observing session. While you may make either an icon, closing either window will quit the Prospero program, requiring you restart as described above.
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caliban is started automatically upon login to the workstation after completing the first-night initialization process described above. If caliban is not running (or has crashed), it needs to be restarted from the workstation menu (left mouse button) by selecting the option labeled:
The caliban setup at CTIO is also responsible for archiving all data taken with OSIRIS via the Save-the-Bits Archive. Archive Status Reports are available on-line via the Web?
Automatic observation logging is available via caliban using the AUTOLOG option. See the description of autologging in Appendix D (Observing Tools) of the manual.
IRAF is custom configured at run initialization especially to work with OSIRIS data. It assumes all data are in FITS format with the .fits file extension. You can start IRAF in an xGTerm from the workstation Programs menu.
Regular xterms are recommended for non-IRAF use. A version of XVista is available (type xvista at the Unix prompt in an xterm) for those who prefer it to IRAF. Other programs are also available, check with your support scientist for details.
All of the OSIRIS documentation is available online via the Web. Master copies of all online documents at Ohio State have been installed on the CTIO mountain web server so that you do not need to go all the way to Ohio to read them. Netscape is available from the workstation Programs menu, with the manuals in the default OSIRIS observer's bookmarks file restored at run initialization. Note that any bookmarks you save will be lost when the next observer re-initializes the account.
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RUNINIT performs the following functions:
Save yourself potential trouble by checking the status of the data disks at the start of each night (in addition to keeping close tabs on things throughout the night). Select as your starting data disk (see RUNINIT above) the disk with the most free space among those you have access to.
For reference, each raw data frame written by OSIRIS requires 2Mb if a single frame (no co-adds) or 4Mb if co-added. The typical data disk holds about 1.5Gb, which means a typical capacity of about 350 co-added OSIRIS images per disk (depending on who else is using space on the disks).
The internal optics can be focussed by inserting one of the spectroscopic slits into the beam and then running the camera focus through a range of values. Steps of 50-100 in the camera focus are appropriate. Approximate values (Dec 1999) are "camfocus 400" for the f/2.8 camera, "camfocus 650" for the f/7 camera, and "camfocus 0" for the pupil viewing Silicon lens. These values can change approximately +/- 100 from run to run, but should be reliable once a best focus is determined on any particular run. Use the command focuscam from the Prospero command window to automatically take a set of camera focus data.
The telescope can then be focussed in the normal manner. We generally find a rough focus by starting "movie" mode on the array (which reads out the array continuously) and then running the telescope focus in and out until the image looks good, then taking a series of images at different focus settings. There is no analog to the CCD command that reads out a single frame with multiple images of a star at various telescope foci.
The focus command is provided to remotely focus the telescope (4m only) from the Prospero command window. This Prospero script is available on startup and will take a series of images with a constant focus step, returning the telescope to the beginning focus. The synax is
focus npics step current_focus
where npics is the number of focus images to take, step is the change in focus between two images, and current_focus is the beginning focus. This latter number should be around 420000. A useful series is: focus 10 1000 420000. A plot of the image FHWM can be obtained by running the IRAF script focus in the IRAF window.
Note that all the filters and prefilters are in collimated light near the instrument pupil and are reasonably parfocal. This means that there there is little or no change of optimal focus with wavelength.
A short exposure against the night sky will produce a good image of the pupil. Here is an example of what a properly aligned pupil mask should look like on the 1.5m and 4m. The pupil mask is matched to the 4m and does not cover the entire central obstruction on the 1.5m. Move "xpupil" and "ypupil" around until the dark areas obscure as much of the bright as possible. Default values are xpupil=0, ypupil=45 for the 4m and xpupil=-50, ypupil=49 on the 1.5m.
Note that this procedure need only be done at most once per run, but it is a good idea to check that the pupil mask is correctly aligned before you start observing for the night.
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