OSIRIS Hieroglyph The OSIRIS User's Manual
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Observing Setup

This section discusses the following topics:

Unix Workstation Startup

OSIRIS is operated using the Prospero Interactive Data Acquisition Program. Details for how to use Prospero for observing are described in detail in the Prospero Observer's Guide (available in the control room or on-line from the anonymous ftp sites, see Appendix C). This section describes the setup procedures you need to follow on the first night of your observing run.

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.

Startup the First Night

At the very beginning of your run at CTIO, you need to configure the OSIRIS observing account for running the Prospero data-taking package and otherwise undo any changes the previous observer may have made. This is accomplished with the following procedure: Once logged all the way in for a run, there should be no need, other than a full system crash, to have to ever logoff the observer's workstation. If you do have to log back in, remember to use the L option presented by the login screen and NOT redo the initialization procedure.

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Starting Prospero

Prospero should startup automatically when you log back in after completing the first-night initialization process described above. If for any reason you need to restart Prospero during an observing run, use the workstation menu (left mouse button) and select the option labeled:
Restart Prospero
from the menu.

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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Other Programs

Before Prospero can be connected to the data-taking PCs, you need to make sure that two other auxiliary programs are running: ariel and caliban.

ariel:

The ariel program mediates communications between Prospero and the PC computers running the ICIMACS system. At present, the ariel program is only started from the keyboard of the WC using the ariel command. Under normal circumstances, ariel is executed automatically when the PC system is started up.

caliban:

The caliban program is a unix daemon responsible for transferring OSIRIS images in FITS format from the data-taking PCs to the Sparcstation data disks. Before starting caliban, the data-taking PC system must be turned on and ready to go.

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:

Restart Caliban
from the menu. caliban will start up as an icon labeled "Caliban" and automatically connect to the WC and mount the two data transfer disks. Normally caliban is left as an icon to save on workstation screen space, and should only need to be opened if you need to interact directly with caliban to investigate problems. Typing the "?" in the caliban window will give a list of interactive commands. Be aware that careless use of the caliban command window could shutdown the data transfer system and lead to loss of data (if you don't have a good reason to mess with it, don't!).

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.

Additional Tools & Documentation:

In addition to starting Prospero and caliban, an IRAF XImTool window will be started at login. If a second monitor is available (there should be two monitors on each of the observing workstations at the 1.5-m and 4-m telescopes), a full-size XImTool will be started on the second screen. If only one monitor is working, a somewhat smaller XImTool will be started on the main console to keep it from getting in the way of the data-acquisition screens. The windows have the OpenWindows "virtual desktop" enabled so you can customize the desktop to keep things from getting on top of each other.

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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Nightly Setup Checklist

Nightly Initialization

At the beginning of each night, after starting the data-taking system from the Prospero console using the STARTUP command, you need to do the nightly run initialization. This is performed via the RUNINIT.

RUNINIT performs the following functions:

In addition to setting these defaults, RUNINIT also updates the initialization/restart files used by all data-taking computer subsystems. This ensures that if you need to restart the system for any reason during the night you will quickly recover the appropriate defaults for filenames, data directories, etc. This can save you a great deal of time and trouble on crash recovery.

Check the Data Disks for Space

All computers and programs behave badly if you fill a disk. In general there are a few gigabytes of disk space available to you during the run, but if you fill up a disk in the middle of a critical observation, the data-taking system will start choking, and you will have to stop and fix things, almost always at the most inopportune time possible.

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).

Focussing

Both the internal optics and the telescope should be in focus for the most optimal images.

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.

Pupil Mask Alignment

In imaging mode, the silicon lens camera images the telescope pupil onto the detector array. There is also a cold pupil mask in the dewar that can be moved (using the "xpupil" and "ypupil" commands) to align the mask with the pupil to reject the thermal emission from the telescope secondary support and mirror cell. The procedure for aligning the mask is to insert the Silicon lens and the K filter into the beam (see the list of filter wheel populations for OSIRIS), select CAMERA 2 (Pupil Viewing Camera), and set the camera focus to 0 ("camfocus 0").

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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Updated: 1999 December 22