Tirgo Worm Handling

We will describe the basic user operations for Tirgo Nicmos3 data handling as well as data format and telescope archiving items. We will cover the following items:

Data Structure

All data taken with Tirgo Nicmos3 instruments (Arnica and Longsp) are stored directly as standard FITS files at 16 bits integer format.

Every file has an unique name formed from the last 4 digits of the integer part of current Julian date and from 4 digit of a sequencial number. The acquisition program never rewrites over an old file. If program is forced to send data to an existing file, it increments automatically the sequencial number until it get a not already used filename. Sequencial number is protected from casual user, and should be changed only for special purposes. To each file is associated an one line description, accessible to DOS dir or in the file "lista.txt" on other systems. The comment contains source name, integration time, and, if telescope is connected, also the coordinates with a limited precision. An example in table 1.

 Volume in drive D is ULTERIORE      Serial number is 3713:19EE
 Directory of  d:\arnica\data\*.*

95130049.fts   135360   6-10-94  16:50 NGC4590 K -4.0s 12.39.30 -26.45.1
95130050.fts   135360   6-10-94  16:50 NGC4590#00 K -4.0s 12.39.30 -26.45.1
95130051.fts   135360   6-10-94  16:51 NGC4590#05 K -4.0s 12.39.30 -26.45.1
95130052.fts   135360   6-10-94  16:51 NGC4590#07 K -4.0s 12.39.30 -26.45.1
95130053.fts   135360   6-10-94  16:51 NGC4590#08 K -4.0s 12.39.30 -26.45.1
   1,218,708 bytes in 5 file(s)         1,257,472 bytes allocated
 120,770,560 bytes free

Data are stored in a working directory. Due to limitation of Dos, the more files are present there, the slower is the processing of a new file. After having collected a between 50 to 100 data files, observer should use a 4Dos procedure (savedata) to move data files to a different location.

We have chosed to include in the fits header all relevant informations available to the system, as source name, telescope position and so on. That choise is intended as an help in the reduction phase and as the backbone of the forthcoming Tirgo data archive. We give here an example.

  SIMPLE  =                    T
  BITPIX  =                   16
  NAXIS   =                    2
  NAXIS1  =                  256
  NAXIS2  =                  256
  ORIGIN  = 'T I R G O'            / TIRGO Observatory
  BSCALE  =        1.0000000E+00   / real_value = tape_value * BSCALE + BZERO
  BZERO   =        0.0000000E+00   / real_value = tape_value * BSCALE + BZERO
  BUNIT   = 'COUNTS'               / Each count corresponds to  19  electrons
  OBJECT  = 'NGC4590'              / Identifier of source
  DATE-OBS= ' 10/06/94'            / UT date of data acquisition
  TIME-OBS= ' 15:49:55'            / UT Time of data acquisition
  J-DAY   =        9.5131597E+03   / Julia n date of acquisition minus 2440000
  DATE    = ' 10/06/94'            / UT date this file was written
  NUMBER  =                   49   / Incremental acquisition number
  INSTRUME= 'ARNICA    '           / Device who measured data
  OBSERVER= '    Carlo_Baffa'      / Observer name
  FILTER  = ' K 1200 '             / Filter name and wheel position
  TIME-INT=        1.0000000E+00   / Integration time on detector  1.0 * 4
  COADDS  =                    4   / Number of frames added togheter
  RA      = '12.39.30,0'           / Right ascension of source
  DEC     = '-26.45.10'            / Declination     of source
  EPOCH   =        1.9500000E+03   / Epoch of coordinates
  AIRMASS =        2.3000000E+00   / Airmass when acquisition started
  DATAMIN =        9.1000000E+01   / minimum value in array
  DATAMAX =        9.9990000E+03   / maximum value in array
  DOUBLESA= 'ON '                  / Double sampling enabled

Data handling during measurements

Data are stored in a working directory. Due to limitation of Dos, the more files are present there, the slower is the processing of a new file. After having collected a between 50 to 100 data files, observer should use a 4Dos procedure ( savedata) to move data files to a more suitable location. The command savedata has no arguments. If the acquisition program is running inside DVX, can be called from a normal dos window, precede (only one time) by the command cnir.

Data will be moved in a directory belonging to a tree of directories which permits to separate easily data of different dates, as in the followin table. Each savedata creates a new subdirectory in the present day directory. The present version limit the number of subdirectory of each day to 14.

                                  |   +---1
                                  |   +---2

Permanent Data archiving

At the end of each night, data must be moved to the a permanent Write-Once Worm disk. Observer must place the current Worm cartridge in the pc and run the procedure trandata which will automatically copy data. We strongly suggest that the observer

trandata must be run ouside DVX environments. Trandata will display informations on free space on Worm and on the quantity of data to be transferred. If Worm free space is low, data should go to next cartridge side or next cartridge. At the end of copy which can take few hours, the procedure asks if all has be done properly and, if it is the case, it deletes data from the hard disk. Too many data sitting on hard disk will slow down data acquisition till to stop, so it is observer's cure not to exeed efficiency limit.

If the copy fails for some reasons, trandata ca be restarted (if current julian date is unchanged, see below), and will continue the copy from the point where stopped. However, if the cartridge has been damaged, the test program will warn user and sygnal which program must be used to correct fault. Normally is the repair command, and the command to be executed are:

Note that trandata can transfer only the data of current julian day, so this operation should be done before noon, and, for its duration we suggest to run it at the end of the observation. In case older data should be transferred, please contact Carlo Baffa ( baffa@tirgo ).

We mantain an archive of all data taken with our instruments. Data are stored in a series of write only cartridge (Worm) each containing some less than 400 Mega bytes of data on each side. Each cartridge contains data of few weeks of observations, and has a progressive label which identify the sequence as in DATA_9A and DATA_9B (the two sides of a cartridge). It is a wise idea to annotate on the ufficial logbook the name of the cartridge in use.

Data can be trasferred to the tirgo sun (tirgo or toutatis). Small amount of data can be tranferred by ftp, remeber that data must be transferred in bin mode!

A procedure called worm2tar is meant to tranfer all data belonging to an observer together with appropriate standard stars to a dat cartridge. The procedure scan all Worm subdirectories and transfer all data whose object names appeare in a given observation catalog. Also all Arnica standars appearing in the same subdirectories are transferred. The appropriate catalog must be in the \arnica\catalog directory, and the system should be configured properly in order to access dat device on sun. This operation is NOT intended as a generic user operation and shoud be done by a staff member. The following table lists wor2tar summary usage.

usage:  worm2tar obs_cat_name [-h host] [-u user] [-s source] [-f destination]
         host:     toutatis    (Sun TIRGO)
         user:     softir
       source:     F:          (worm drive)
  destination:     /dev/rst1   (DAT drive)

Worm cartridge formatting

Normally should be assistant's responsibility to format a new cartridge, but can be done by the observer. Can also be done remotely by me (contact baffa@tirgo ). From a dos window or from the full screen status the command sequence is: The whole process will take less than five minutes.
Last updated 14 Dec 95

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