Headers

OBSERVING follows the FIGARO file name convention. All files containing images end in .DST. The actual file name for a CCD image or a 1d spectrum is of the form A123F.DST, where ``A'' is a one-letter code describing the type of exposure (see Section X for details), 123 is the frame number of the exposure, and F is the filter code. The exposures are numbered consecutively between 001 and 999.

WARNING

Do not ever have quotation marks within your object name. If you do, the command line interpreter will fail to correctly process the command line, and all long exposures will fail to work.

FRAME

The command FRAME will enable you to set the frame number counter to any desired value. It is normally used to reset the number to one at the beginning of your run.

Header Information

The header of the file is contained in the structure A123F.OBS, and can be listed on the terminal by typing EXAM A123F.OBS. The header contains the information you type in, as well as that obtained from the telescope control computer, and from various other sources. The header contains a slightly different subset of parameters for direct as compared to spectroscopic images.

Note that the call to the telescope control computer is at the end of the exposure, so the universal time, etc., refer specifically to that moment.

Note also that the erase level given in the header is the mean of the values in the erase line. Thus if there is a saturated (i.e. a hot) column, the erase level in the header will be larger than the actual mean erase level of normal pixels in the CCD. The FIGARO routines all use the erase line, which is within the image itself, and do not use the value in the header.

In the table below are listed the various quantities which are included in the header, the source of the information, and an indication as to whether the item is included in headers for direct (D) or spectroscopic (S) images. Items in the header are identified by a character code.

Header Items

Object Name OBJECT typed in both

Frame no. FRAME Microvax both

Night no. NIGHT typed in both

Date DATE Microvax both

Telescope TEL typed in both

Camera Port no. PORT Microvax both

Dewar no. DEWAR Microvax both

Chip Serial no. CHIP Microvax both

Exposure Time ETIME Microvax both

Actual Accum. Exp. Time TIME Microvax both

RA and Dec RA, DEC 11/73 both

Epoch of Coordinates EPOCH 11/73 both

Universal Time UT 11/73 both

Hour Angle HA 11/73 both

Airmass SECZ 11/73 both

Ring Rotation Angle ROTATION 11/73* both

RA Tracking Rate RA_RATE 11/73* both (only if non-sidereal)

Dec Tracking Rate DEC_RATE 11/73* both (only if non-sidereal)

Chip Temp. TEMP Microvax both

Average Erase Level ERASE Microvax both

No. Saturated Pixels SATURATED Microvax S

Filter FILTER Microvax both

Image Scale SCALE type in D

Scan millisec/line MSEC_LINE Microvax D (scan only)

Grating g/mm GRATING type in S

Grating Angle ANGLE type in S

Slit Size SLIT 11/73* S

(Note -- items marked * are not transmitted to Microvax from 11/73 in telescope control program version 3.0. Also note that at the 200-inch telescope only, right ascension is given in hours, minutes, seconds and hundredths of seconds. At the 60-inch telescope, right ascension is given in hours, minutes, seconds and tenths of seconds.)