Observing Catalogs Format

Required Fields: 16 (16th field can be left as 0.000 (zero) if you have zero proper motions entered in fields 6 and 7)   You can add additional information that you desire beyond the required data, but should place a '#' character at the beginning of the extra data to mark it as commentary. The catalog may contain header and commentary lines which do not contain observing targets; these lines should begin with a '#' character.

Field#1: reference number (integer number)

Field#2: object name (can use alphanumeric characters, plus, minus, period, and underscore, but no whitespace or other symbols: *,!,?,&...)

Field#3: RA given in hh:mm:ss.s or in decimal hours

Field#4: Dec given in ±dd:mm:ss or in decimal degrees

Field#5: equinox given in yyyy.y

Field#6: proper motion in RA given in seconds of time per year, i.e. RA_rate = PM_RA/15000/cos(Dec)

Field#7: proper motion in Dec given in arcseconds per year, i.e. Dec_rate = PM_Dec/1000

The next two fields are instrument dependent and need to be specified correctly. This is the responsibility of the observer, not the Telescope Operator. Please read below for details of the various rotator modes available with the various instruments.

Field#8: instrument rotator offset angle given in degrees (dd.d)

Field#9: instrument rotator offset mode

The next 6 required fields (10-15) specify positions of the guide probes. If you dont need to preselect guide stars, please use zero values for these fields.

Field#10: RA of guide probe#1 given in hh:mm:ss.s or decimal hours

Field#11: Dec of guide probe#1 given in ±dd:mm:ss or decimal degrees

Field#12: equinox of guide probe#1 positions given in yyyy.y

Field#13: RA of guide probe#2 given in hh:mm:ss.s or decimal hours

Field#14: Dec of guide probe#2 given in ±dd:mm:ss or decimal degrees

Field#15: equinox of guide probe#2 positions given in yyyy.y

Field#16: observation epoch of the given coords as in yyyy.y , for example 2015.5 for most of GAIA published observations. This field is relevant if the proper motion (PM) is not zero, as the current position (P_now) of such object will be calculated as:

P_now = P_epoch + PM (t_now - t_epoch)

otherwise can be left as 0 (zero).

An example file is available.

Instrument Rotator Offset Angles & Modes

Rotator limits vary from port-to-port but are nominally close to +/- 180 at the rotator.

MODES

Four primary rotator offset modes exist:

• OFF - This simply applies the desired offset angle to the current rotator position.
• EQU - This is the default mode for most instruments. It will apply the noted offset angle to the current rotator position for targets in the South and will apply the noted offset angle - 180 degrees for targets in the North. This mode is designed to allow for the maximum continuous time on target before running into a rotator limit. Using large offsets near 180 deg will nullify this effect and make running into rotator limits more likely.
• HRZ - This mode is used to maintain the noted offset angle aligned with the paralactic angle (the angle is usually chosen to place a spectroscopic slit within the instrument along the paralactic angle.). NOTE: In HRZ mode a slew sets the rotator 1/2 hour before transiting the parallactic angle, tracking the sky normally. This is required to be able to guide and run the wavefront sensor. To maintain the instrument near the parallactic angle requires a periodic slew and reacquisition. 
• GRV - This mode will hold the rotator (and thus the connected instrument) at a gravity invariant angle (i.e. it will keep the instrument horizontal to the platform provided the offset angle matches the rotator angle of the horizontal instrument when the telescope is pointing at the zenith. NOTE: IN GRV mode a slew sets the rotator 1/2 hour before transiting the gravity invariant angle and then tracks the sky. To maintain the instrument near the gravity invariant angle requires a periodic slew and reacquisition.   

INSTRUMENT DEFAULTS

• IMACS (-46.15 EQU) This will align the standard long slits (and slitview mode) along N-S. For the f/2 camera pointing at targets in the South will have N to the right and E down on the array. For the f/2 camera pointing at targets in the North will have N to the left and E up on the array. For the f/4 camera pointing at targets in the South will have N down and E to the right on the array. For the f/4 camera pointing at targets in the North will have N up and E to the left on the array. To align the slits along the paralactic angle, use (-46.15 HRZ). If you would like to orient the slit along a particular position angle, use (PA-46.15, EQU). If you are using multislit masks, the latest version of the mask generation software now contains a program named "obscat" that will generate the appropriate catalog file entry with input of the .SMF file.
• FOURSTAR (0 EQU) Targets in the North will have N down and E to the left on the array. Targets in the South will have N up and E to the right on the array. This catalog has a different format than the rest. All is needed is a simple text file containing the following columns (separated by a pipe | ): Object name, RA, DEC, EQUINOX, POSITION ANGLE, comment (optional). The coordinates can be sexagesimal or decimal and the filename extension should be ".objects". Example line: object | 10:00:00 | -56:00:00 | 2000 | 0 |
• FIRE (-30 HRZ) Most users will want to orient the slit along the parallactic angle. To achieve this, you should use the following values: Echelle mode: -30 HRZ
  Longslit mode: 60 HRZ . If you would like to orient the slit along a particular position angle, replace these fields with the following: Echelle mode: [PA-30] EQU
  Longslit mode: [PA+60] EQU
• MagE (44.5 HRZ) This will maintain the slit along the paralactic angle. For aligning the CCD with cardinal directions on sky, use (44.5 EQU). Targets in the South will have N up and E to the right on the array. Targets in the North will have N down and E to the left on the array. If you would like to orient the slit along a particular position angle, use (PA+44.5, EQU).
• LDSS3C (27.5 EQU) For the LDSS3 detector, this will align the standard long slits along E-W. Targets in the South will have N up and E to the right on the array. Targets in the North will have N down and E to the left on the array.  To align the slits along the paralactic angle, LDSS3C must subtract 90 deg for slit orientation on detector (27.5-90 = -62.5) (-62.5 HRZ) If you would like to orient the slit along a particular position angle, LDSS3C use (PA+27.5-90.0 EQU) If you are using multislit masks, the latest version of the mask generation software now contains a program named "obscat" that will generate the appropriate catalog file entry with input of the .SMF file.  Older mask files generated for LDSS3 should change offset angle by +89.8deg.
• MIKE (0 GRV) MIKE is not attached directly to the rotator, therfore the guiders are best maintained in the gravity invariant mode. For the case of MIKE Fibers, please use (-7.5 EQU) to account for the fiber mounting plate to the rotator in front of the instrument.