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Sit at the observer station and select a free account number from the white board behind you, say 8. A free account is an account without anyone's initials against it. Sign on with your observer identification (your initials)
*SIGNON ABC,8,8 (or si abc,8,8)
You will be given a few welcoming messages, finishing with a * as the invitation to type. Type in
This leads to a question/answer dialogue, the answers to which are mostly obvious. You are given the choice of storing your data on disk or tape - it is usual to store on disk in the first instance as it is possible to dump your data files to tape during subsequent runs (using FITSOUT). The Perkin Elmer 3210 instrument computer uses an Egle disk (called sys:) for all software and data storage - there is space for 500 FOS images, if the disk is relatively empty. This should be sufficient for several nights observing. The software informs you on startup how many images there is space for as it is unlikely that the disk will be completely empty of data files. If this is less than 50, contact a member of the software group, who will endeavour to tidy the disk and give you more space. If you have filled the disk with your own files, then use PURGE to delete files you have already written to tape. It is worth giving a word of warning here; it has happened that the Egle disk crashed losing the observer's data, hence it is a good idea to dump your data to tape every couple of hours or so. After five minutes or so, you will get the prompt
which is your invitation to type in commands in the ADAM environment. The three most important commands - after the correct A&G box and slit configuration has been set, are the WINK, GLANCE and RUN commands.
ADAM> RUN n "object comments"
Clears the CCD, opens the shutter for n seconds, closes the shutter, reads the exposure into a file SYS:FOSABC.m, where ABC is your observer id and m is the current run number, e.g. 001. The image is automatically displayed on the lexidata, erasing any previously displayed data, and the run number is updated to m+1.
ADAM> GLANCE n
Clears the CCD, opens the shutter for n seconds, closes the shutter, reads the exposure into a file SYS:FOSABC.000. The image is automatically displayed on the lexidata, erasing any previously displayed image, It will be overwritten by any subsequent GLANCE. If you decide you want to keep the GLANCE exposure, then you can do so by issuing the ADAM command
ADAM> KEEP "object name"
which copies the GLANCE file into the next file number.
A standard GLANCE includes the collection of FITS packets, So for a GLANCE of less than about 30 seconds, there is an overhead, while these are being collected. If the GLANCE is just a test exposure, without any likelihood of being saved, use WINK.
ADAM> WINK n
Operates in an identical fashion to a GLANCE command, except no FITS headers are collected for the output file. It will be overwritten by any subsequent WINK. If you decide you want to keep the WINK exposure, then you can do so by issuing the ADAM command
ADAM> KEEP "object name"
which copies the WINK into the next run number. The collection of FITS headers is done at the stage of the KEEP.
One major difference between the GLANCE, WINK and RUN commands is that GLANCE and WINK always runs as foreground tasks, tying up the terminal, but a RUN of more than 10 seconds runs as a background task, freeing the ADAM terminal so you can manipulate a previous image, write data to tape etc. However, if you do decide to use the terminal during a RUN, it is advisable to make sure you finish before the RUN does. A warning is given 30 seconds before chip readout comences.
Two other frequently used commands governing runs are ABORT and TIME, the former stopping an exposure without creating an output file, the latter amending the exposure time. A manual of all CCD commands is kept in the INT control room.