Introduction

The Iowa Robotic Telescope Facility operates two telescopes: the Iowa Robotic Observatory (IRO) and the Rigel telescope. Both are fully automated telescope systems located in southeastern Arizona near the town of Sonoita.. The facility is used primarily by undergraduate students in introductory astronomy laboratories. Last year more than 1,000 students submitted observing requests to the IRO, resulting in more than 10,000 images.

Prospective observers must first plan the technical details of a proposed observation (choice of object(s), exposure time, filter, number of repeat observations, etc). If the observer is an internet observer an observing code must be secured to allow observing files to be submitted. The Modern and General Astronomy lab observing file submission will be handled by the TAs. The observer then creates an observing file using the Observing Request Form. A telescope operator checks this directory every clear evening and submits as many of the requested observations as possible to the telescope scheduling program. The scheduling program sorts the observing requests on a image by image basis, trying to optimize the observation time to match the transit time of each object as closely as possible. Completed images and a copy of the computer generated observing log are written to the user's designated image save directory which can then be downloaded or ftp'ed.

Web-based Observing Schedule Input.

Schedules are normally submitted using a table-based schedule submission form. It allows the user to request scheduling up to five sources with multiple filters, exposure times, repeats with delays, and compression.

Most users should be able to use the web page for all observing requests. It is only necessary to read the detailed manual below for creating scheduling scripts which cannot fit into the Web-based form schedule (e.g. schedules with more than five objects).

Schedule Preparation

Select Sources with Appropriate Positions. Determine the celestial and horizon coordinates of the target objects and epoch using catalogs or a sky display program. The minimum elevation is 5 degress for both telescopes and there are no hour angle limits. The telescopes operate from astronomical dusk to dawn under clear sky conditions. The automated schedule optimization algorithm will schedule all observing requests as close to transit as possible for each source by default. If the observation must be must at specified LST times (e.g. stellar eclipse timing observations), the observer should specify LST start time(s) in the schedule file (see below).

Select Appropriate Exposure Times. Determine the appropriate exposure times needed for each object and filter.

     See the shorter Guide section for a table of recommended exposure times.

Note: Exposure times greater than ~60 sec are automatically aligned and stacked in multiples of 60 sec to prevent tracking errors. If you need very long exposures, specify exposure times in multiples of 60 sec.

Calibration

CCD Calibration frames

The software corrects all images for thermal noise and flat fielding by default, so there is normally no reason to obtain dark frames or flats. For observers who wish to do their own CCD calibration, a raw archive frame is always written and is available on request.

Standard BVRI Stars

Anyone who needs to measure the BVRI colors of stars should schedule one or more standard UBVRI stars from section H32-34 of the Astronomical Almanac. Choose stars as close to the target star as possible. Note that these stars are typically very bright, so the exposure times will be quite short.

Observing File Format

The observing file is an ordinary text file which can be generated by any text editor. The observing file naming convention is as follows:

abbnnn.sch

where:

• a is the institution or class letter code. Currently defined codes are: N = Internet Observers, G = UI General Astronomy class, M = UI Modern Astronomy class, F = UI Faculty and graduate students, U = UI undergraduates, W = West High School.
• bb is a two alphanumeric code unique to each observer (or observing team). This code is assigned by the teaching assistant (UI classes) or by the remote observing coordinator at each institution.
• nnn is the day of year number the observing request was submitted in numerical format. File names are recycled every calendar year so the year is not imbedded in the name.
• sch is the extension indicating it is a schedule file.

An example of a complete file name for an observation request from R. Mutel (UI faculty) made on February 15 would be frm046.sch.

Note: Only one schedule file can be submitted per observer per night. Successive submissions overwrite the preceeding files.

Keywords and Keyvalues.

The schedule file is in a keyword=keyvalue(s) format with one or more spaces between keywords. There are several mandatory keywords and many more optional keywords. A series of keywords with key values ending with a / mark constitutes a scan with repeat count given by the repeat keyword. Comments can be written by typing an exclamation mark (!) anywhere in a line.

The slash mark (/) means 'take the image' using all key values currently assigned. For observing files without repeat counts, every image request will have a slash mark in the file. Conversely, an observing file without slashes requests no images.

The currently supported keyword list is given in the Table below.

Keyword	Type	Units	Default	Example	Status	Comment
Title	String	none	none	title 'Photometry of LPV Variables'	Required	Surround with quotes, no quote marks within the title
Observer	String	none	none	obs 'A. Einstein'	Required	Surround with quotes, no quote marks within the name
Source	String	none	none	sou 'Z_Her'	Required	Must be the same as in online catalogs or user specified ra, dec, epoch
Duration	Integer	Second	none	dur 30,20,10	Required	One or more values separated by commas. If the number of durations and filters match, they are paired. If there are more filter entries than durations, the last duration value is used for unpaired filters, and conversely.
Filter	Letter	Coded	none	fil B,V,R	Required	One or more values. See duration keyword.
Comment	String	none	none	'Highly variable star'	Optional	Written to FITS header, first character must be an exclamation point (!)
Binning	Integer	pixels	integer	bin 2,2	Optional	Two values separated by commas. Defaults to 1,1
Compress	Integer	scale	0	50	Optional	File compression. Note: requires program fdecompress if compressed
RA	String	hh:mm:ss	none	ra 01:12:45	Optional	Right Ascension of uncatalogued source: must specifiy epoch.
Dec	String	dd:mm:ss	none	dec -12:23:56	Optional	Declination of uncatalogued source: must specify epoch
Epoch	Integer	Years	none	epoch 2000	Optional	Mandatory if ra, dec specified: Epoch of RA, Dec from catalog or specified non-catalogued source
Block	String	none	none	block 0:45:0	Optional	Introduces a group of commands. The commands may results in in or more scans. The group may be repeated. The value associated with this keyword is the time interval between repeating each block in h:m:s format. The group is terminated with the Blockrepeat keyword.
Blockrepeat	integer	none	none	blockrepeat 3	Optional	Closes a group of commands started within the Block keyword. The value is te total numbre of times to repeat the block.
LSTstart	String	hh:mm:ss	none	lststart 13:45:00	Optional	Requests that an observaton start at a particular local sidereal time.
LSTDelta	String	hh:mm:ss	none	lstdelta 00:30:00	Optional	Requests the scheduler to insert the file within a certain window of time specified in LSTstart
HAstart	String	hh:mm:ss	none	hastart -4:30:00	Optional	Requests that an observaton start at a particular local hour angle. The LSTdelta is the allowed tolerance.
UTdate	String	mm/dd/yyyy	none	utdate 09/06/1999	Optional	The scheduler will read this file and insert it in the schedule only if the UT date in in the file matches that given in the file.
CCDCalib	String	none	ccdcalib 'standard'	ccdcalib 'none'	Optional	This option is used if the desired sensitivity requires darks to be taken as close to the time of the image as possible for better dark subtraction. Valid values are 'none', 'bias', 'thermal', 'bias only', 'thermal only'.
FocusPos	Integer	microns	from config file	11750	Optional	Used only for focus position testing

Some additional comments on observing file keywords:

1. Keywords that are not changed between scans default to their last values.
2. Keywords and key values are not case sensitive, so that Title, title, TITLE are all acceptable.
3. Keywords which require strings, such as title and observer, should be in single quotes.
4. Keywords are parsed, so that the user need only type as many letters as are needed to distinguish different keywords. For example,
5. Durationand Durare both acceptable, but D is not because it is confused with Date.
6. Keywords which contain spaces e.g. 4 Vesta, must be surrounded by quotes.
7. The equal sign can also be a space, i.e. Filter = C,V is equivalent to Filter C,V.
8. Source names must be exactly as in the specified catalog (except for case).
9. The duration and filter keywords work as follows. If the numberof filter and duration keyvalues are equal (e.g. filter=b,v,r dur 10,5,3), they are paired (e.g. three exposures are taken using B at 10 sec, V at 5 sec, R and 3 sec). If the filter and duration keyvalue numbers do not match, the last value in the shorter list is used for all remaining values in the longer list. For example,. filter=b,v,r,i and dur = 10,5, results in four images: one in B filter for 10 sec, one each in V,R,I for 5 sec each).
10. The allowed values of the filter keyword are Clear (C), Blue (B), Visual (V), Red (R), Infrared (I), H-alpha (Z), H-off (X), H-beta (Y), and OIII (O). The X,Y, and Z filters are 1nm FWHM; filter O is 10nm so allow sufficient exposure time (see table. in brief guide)
11. Compression option: requests H-transform compression of a calibrated file. Use 1 for lossless compression (typically 3x compression), and 50 for ~6-8x compression with vitually no loss in image fidelity.
12. Block Repeat: The block/blockrepeat keywords surround a block of lines which will be repeated. See example below.
13. Binning option: Binning refers to on-chip averaging of adjacent groups of pixels in square areas. The default value for the ATF is 2x2 binning (3x3 arcsec pixels); for the IRO it is 1x1 (1.23x1.23 arcsec pixels). They provides a good match to the typical seeeing conditions at the ATF and IRO. For the ATF, the 2x2 binning results in much smaller images than 1x1 binning (512KB versus 2MB for 1x1 binning).
14. RA, Dec, Epoch: The observer may specify the equatorial coordinates of sources which are not in one of the supplied catalogs (see below). Note that the epoch of the RA and Dec must be specified.
15. LSTstart, LSTdelta: The default scheduler automatically schedules requests so that objects are observed as close to transit as possible. Observers who wish to override this default may request specific LST start times and a tolerance (LSTdelta, defaults to 30 min). The LSTdelta keyword means that the scheduler will try to insert the requested observation within a window of LSTstart +/- LSTdelta, but will not schedule the observation at all if this cannot be done.

A list of currently supported catalogs is in the following table. Check the catalog for the correct name of each source before using in a schedule file. Note that planets are recognized by name (e.g . Jupiter, Neptune).

Catalog Name	Objects	Example	Description
ybsc	6430	BS45	Yale bright star catalog, declinations > -30
GCVS	2487	'S_Uma'	General Catalog of Variable Stars, 2nd edition
Messier	109	M67	Messier catalog
NGC	2405	NGC5471	New General Catalog of Non-Stellar Objects
Asteroids	4848	'67'	Asteroid orbital elements, epoch 1994.7
Comets	~10	Borrelly	Comet orbital elements (only a few at present)
sao	~250,000	SAO45367	Smithsonian Astrophysical Obs. star catalog

The asteroid catalog is updated regularly from the Lowell Observatory ftp site. The source name format 'ny' (e.g. '4') for named asteroids (Vesta in this case), or 'number year' (e.g. '2866 1961') for asteroids without names.

Oberving File Examples

Three examples of schedule files are given below.

• Example 1: A very simple schedule file requesting a single image of M81 with a clear filter.

  Title 'M81' Observation' Observer 'F. Sinatra'

  Fil C Dur 60 source 'M81' /

   

• Example 2: A Schedule File for observing Saturn and the asteroid 67 Asia using B and V filters with different exposure times. Calibration stars from the Yale bright star catalog are also observed with different exposure times. The entire set of observations is repeated three times separated by 30 min each.

  Title 'Photometry of Saturn and 67 Asia'

  Observer 'E. Hubble'

  Block 00:30:00

  Filter B,V Duration 30,15

  source saturn /

  ! This is a comment line - star is from the Yale BS catalog

  source 'And 65' dur 10,5 /

  source '67' dur 40,20 / ! Asia is about V=9

  Blockrepeat 3

   

• Example 3: A schedule file for observing galaxy NGC224 six times separated by one hour each observation, followed by observations of three galaxies observed four times in the sequence NGC 891, 931,45, 891, 931,45, etc. Note that neither block start or blockrepeat has a slash (/) after it and that block start is two words while blockrepeat is one (key)word followed by a repeat count.

  Title 'Strange Galaxies' Observer 'Fred Astair'

  filter V

  block 01:00:00

  source ngc224 dur 10 /

  blockrepeat 6

  ! Note: The next block of 3 galaxies repeated 4 times, all with C filter

  block

  filter c ngc891 dur 15 /

  source ngc931 dur 10 /

  source ngc45 dur 20 /

  blockrepeat 4

   

• Example 4: A schedule file for observing two asteroids every 20 minutes for 8 hours to obtain a light curve. The HAstart has be chosen to correspond to 4 hours before transit.

  Title 'Asteroid Light Curves' Observer 'Fred Astair'

  filter R duration 20

  block 0:20:0 hastart -4:00:00

  source '4' / !Vesta

  source '264' dur 60 / !Libussa

  blockrepeat 24

Note that observing requests with incorrect formats will not be observed.

Submitting Observing Files

The observing files should be completed using the Observing File Request Form Each clear evening, the telescope operator will check both email and the incoming directories for observing requests. She/he will generally give higher priority to the earlier requests, but this may be modified by length of observation (shorter observations get higher priority) and timeliness (e.g. favorable eclipse of a binary star which must be done on a given night). Schedules which are in correct format and do not violate the maxumum time/source guidelines are accepted into the incoming directory.

Checking Status of Observations

Summary log files

There are two summary log files generated every night that observations are made. They are named mmmdd.lis and mmmdd.sum where mmmdd is the month and day (e.g. mar05). The .lis file contain one line per image and is generated by the scheduler just before observations begin and contains all the images to be observed that evening. This is the planned schedule> If weather or mechanical problems arise during the night, not all scans will be observed. The .sum file is a short text file which the telescope operator generates the next morning indicating the overall status of the previous nights observations.

Observers' log files

A copy of the observing log is generated by the telescope control program using the file name abbnnn.lis where abbnnn is the same as the schedule file. The log files are available online. If the schedule is observed over several days, the log file is appended.

Retrieving Image and Logs

Images and log files from the IRO are distributed after the CDROM is received in Iowa City, typically 2-3 days after the observation. Internet users can retrieve their logs and images over the Web on the image retrieval page by specifying their code.

Image files which are more than 7 days old may be deleted. Any images which were not downloaded before this time can be restored from the backup medium on request.

Contacting the Operator

The operator can be called during late afternoon or early evening at (319)-335-1605. Electronic mail can be sent to user irtoper. For remote sites connected to internet, an interactive Unix 'talk' session can be established during observations. Telephone the telescope operator for details.