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REQUESTING SPECTRA OF NO-SOLAR SYSTEM OBJECTS
 
The following is the fixed format of a request for spectra of a stationary object, or for spectra of the sky background:
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS dddddddddddd   hh  mm  ss.ss  Sdd  mm  ss.s   tttt.tt       nn  vvvv  b  sss   fff    tttt    yyyy-mm-dd  yyyy-mm-dd rrr mmm   mm.m
 
The meaning of each field is explained in the table below:
 
Field Columns Meaning
NSS 1-3 This fixed 3-character code specifies that the target is outside the solar system.
dddddddddddd 5-16
This is a target name (e.g. NGC 1372) This is only used for placement in the FITS header and for other bookkeeping operations. The telescope does not look up coordinates in catalogs. You may place this name anywhere in fields 5 through 16. Note: Target names which consist of the character # followed by an integer number (e.g., #01033, # 25, etc.) cannot be accepted because they might potentially cause problems to our software.
hh mm ss.ss 18-28 This is the target right ascension in J2000.0 coordinates.
sdd mm ss.s 30-40 This is the target declination in J2000.0 coordinates.
tttt.tt 42-48 Exposure time. This must be between 0.50 seconds and 9999.99 seconds.
nn 50-51

This is the requested number of exposures. If more than one exposure is requested, the request is interpreted as a single-night time series, where each exposure will have the same length, binning factor, etc.

Notes:

  1. If you request up to 4 exposures, we will either schedule all of them or not schedule your exposures.

  2. If you request more than 4 exposures, we will schedule as many exposures as we can up to the number you requested, but can't guarantee that it will be possible to schedule all of the exposures you requested. This is because the number of exposures which it is possible to take on a single-night time series varies with target position, time interval between exposures, exposure time, etc.

  3. If you want many exposures of a given target but are not sure if it is actually possible to take that many exposures of the target at the specified exposure time and interval between exposures, you might request the number of exposures that you wish, or the maximum number you would be willing to pay for, and we will take as many exposures as we can, up to the number you requested.
vvvv 53-56
If you requested only one exposure, you may leave this field blank. If you requested more than one exposure, this field allows you to specify the time interval (in seconds) between exposures in the corresponding time series. If this value is 0 (zero), the time series will consist of exposures taken in direct succession (so that the interval between successive exposures will be approximately equal to the sum of exposure time plus camera download time plus a variable additional time required to initiate the process of taking a spectrum). For positive integer values, this field specifies the number of seconds between exposures. The scheduler does its best to ensure that exposures are equally spaced. The scheduler is usually set to 15% tolerance, which means that the actual interval between exposures will be within +/-15% of the user-specified value. The variations in the interval between exposures arise because the scheduler may insert observations of other targets between two successive exposures belonging to your time series (remember, at Tenagra each user pays for his/her total exposure time, not for a contiguous block of telescope time; any idle telescope time between exposures belonging to your time series may be used to perform other observations, possibly requested by other users). These +/-15% variations in spacing between exposures should not affect the statistical significance of the time series results.

Notes:
  1. Note that if you specify a spacing which is smaller than the sum of exposure time plus camera download time for the specified resolution and frame size, it will be physically impossible to carry out your time series with the specified interval between images. If your desired time interval between exposures is small, you may wish to set the value of this field to zero so that the exposures will be taken in succession.

  2. Time series may sometimes be interrupted by automatic "focus breaks" which occur at approximately 1-hr intervals for checking/adjusting telescope focus. These focus breaks normally take only 1-2 minutes.

  3. When you request more than 4 exposures, the time interval between some of the exposures belonging to your time series may be longer than the interval you specified in this field. This sometimes occurs when other observation requests are scheduled in the intervals between the images belonging to your time series.
b 58

Binning factor. The Tenagra cameras are based on SITe 1024 X 1024 chips (pixel size = 24 micrometers). If the value of this field is 1, you will take unbinned (high resolution) pictures at a scale of 5 angstroms/pixel; if the value of this field is 2, you will take 2x2 binned (lower resolution) pictures at a scale of 10 angstroms/pixel.
sss 60-62
Frame size. For spectra, the only allowed value is FUL (full frame). The size of a full unbinned frame (1024 x 1024 pixels) is about 2 MB; a full, 2x2 binned frame (512 x 512 pixels) is about 512 kbytes. For faster downloads, these file sizes can be decreased by about 50% using file compression. Please click here for more information about the available image compression options, and then contact us to choose the compression option which best suits your needs.
fff 64-66

Allowed values for this field are:

  1. SP1: This specifies that the target's spectrum will be taken through the spectrograph's optical fiber #1. The resulting spectrum will be located near column 448 in an unbinned full frame exposure.

  2. SP2: This specifies that the target's spectrum will be taken through the spectrograph's optical fiber #2. The resulting spectrum will be located near column 422 in an unbinned full frame exposure.

  3. SPB: This specifies that a spectrum of the sky background will be taken near the target coordinates. The sky background spectra from fibers #1 and #2 will be located near columns 448 and 422, respectively, in an unbinned full frame exposure.
tttt 68-71
This allows you to choose the Tenagra telescope you wish to use. Currently the only allowed value is 32IN.
yyyy-mm-dd
yyyy-mm-dd		 73-93
These two fields specify a window of opportunity for your observation request. The first date specifies the earliest night in which you wish the observation to be made; in case we are unable to carry out your observation request on the night specified on the first date field, we will retry it on subsequent nights until the date specified in the second date field. If the request is carried out, we will stop retrying; if by the final date it still couldn't be carried out, you will either not be charged for the observations, or will receive a refund in case the observations in question has already been paid for.

Notes:
  1. Dates are referred to universal time.

  2. Nighttime in Arizona always starts at most a few hours after 0:00 UT, so each night at Tenagra can be uniquely identified by its UT date.

  3. When the two date fields are the same, your observation request will be submitted to the scheduler for that night only.
rrr (optional) 95-97
This optional field specifies the number of times to repeat your observing request. For example, if you specify the "window of opportunity" (see above) for your observing request as 2003-09-15 to 2003-09-17, and set the value of this field to 3, the observation will be attempted in the time interval 2003-09-15 to 2003-09-17 (until it is carried out or until this window of opportunity passes), and then the same process will happen in the time intervals 2003-09-18 to 2003-09-20 and 2003-09-21 to 2003-09-23. To request daily observations of a target, use the starting date as a single-night window of opportunity (e.g., 2003-09-15 to 2003-09-15) and use this field to specify the number of nights on which you wish to observe the target.
mmm (optional) 99-101
This optional field specifies a variable exclusion radius (in degrees) around the moon, which serves to prevent observations too close to the moon. The radius specified in this field is the exclusion radius around the full moon. For other moon phases, the exclusion radius is scaled by a cosine factor so that it drops to one half its full moon value when the moon is in quadrature, and to zero at new moon. Your observation request will not be carried out when the distance between your target and the moon is smaller than the scaled exclusion radius for the moon phase at the date of the observations. This feature is particularly useful when you request long-term observations of a given target; the scheduler will automatically interrupt the observations during time periods when the moon is too close to your target.

Notes:
  1. If you leave this field blank, a default moon exclusion radius of 5 deg will be adopted.

  2. The exclusion radius only takes effect when the moon is at an altitude greater than -5 deg as seen from Tenagra. This allows certain observations to made at distances from the moon which are smaller than the exclusion radius, if they can be carried out while the moon is below altitude -5 deg.
mm.m 103-106
If you requested an object's spectrum (that is, if columns 64-66 contain either SP1 or SP2 (see above), this field must specify the target's magnitude. If you requested a spectrum of the sky background (that is, if columns 64-66 contain SPB (see above), this field must be left blank.

Note: At this time, the faintest targets for which a spectrum can be taken have magnitudes between 11 and 12. Reaching this magnitude requires long exposures (30-60 min).
Examples
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS  SAO  83958      15   42  44.57  +26  17  44.3    120.00     1        0  1  FUL   SP1 32IN   2006-09-15   2006-09-17                     3.8
 
The above is a request to take a single 120-second spectrum of the star SAO 83958 (R.A. = 15h 42m 44.57s, Dec. = +26d 17m 44.3s, magnitude 3.8), using the spectrograph's optical fiber #1. The exposure will not be binned (5 angstroms/pixel), and will use the full field of view of the CCD detector (1024 x 1024 pixels). The request will be attempted between 2006 Sept. 15 and 2006 Sept. 17 UT. If for some reason the request is not carried out on 2006 Sept. 15 UT, it will be attempted until 2006 Sept. 17 UT; we will stop retrying if the request is carried out. Since the repeat field (columns 95-97) was left blank, the request will not be repeated. Since the moon exclusion radius was left blank, the default value of 5 deg around the full moon (scaled down for other moon phases) will be adopted.
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS  GSC 2574:647  15   42  45.34  +33  58  04.0    900.00     5   1800  1  FUL   SP2 32IN   2006-09-15   2006-09-15                    9.8
 
The above is a request to take a single-night time series consisting of five 900-second spectra of the star GSC 2574:647 (R.A. = 15h 42m 45.34s, Dec. = +33d 58m 04.0s, magnitude 9.8), using the spectrograph's optical fiber #2. Successive exposures in the series will be separated by approximately 1800 seconds. The exposures will not be binned (5 angstroms/pixel), and will use the full field of view of the CCD detector (1024 x 1024 pixels). Since the initial and final dates are equal, and the repeat field (columns 95-97) was left blank, the time series will be attempted only on 2006 Sept. 15 UT. Since the moon exclusion radius was left blank, the default value of 5 deg around the full moon (scaled down for other moon phases) will be adopted.
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS  SAO  104736      19   20  27.56  +16  50  28.7    400.00     5        0  1  FUL   SP1 32IN   2006-09-15   2006-09-15                    8.6
 
The above is a request to take a single-night time series consisting of five 400-second spectra of the star SAO 104736 (R.A. = 19h 20m 27.56s, Dec. = +16d 50m 28.7s, magnitude 8.6), in direct succession, using the spectrograph's optical fiber #1. The exposures will not be binned (5 angstroms/pixel), and will use the full field of view of the CCD detector (1024 x 1024 pixels). Since the initial and final dates are equal, and the repeat field (columns 95-97) was set to 4, the time series will be attempted on the four nights 2006 Sept. 15, 16, 17, and 18 UT. Since the moon exclusion radius was left blank, the default value of 5 deg around the full moon (scaled down for other moon phases) will be adopted.
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS  HIP  46853      09   32  51.43  +51  40  38.3    30.00     3        3600  1  FUL   SP1 32IN   2006-09-15   2006-09-15                   3.2
 
The above is a request for monitoring the spectrum of star HIP 46853 (R.A. = 09h 32m 51.43s, Dec. = +51d 40m 38.3s, magnitude 3.2) over a 90-day period starting on 2006 Sept. 15 UT, using the spectrograph's optical fiber #1. On every night in this period, a time series consisting of three 30-second spectra is requested. Successive exposures in the series will be separated by approximately 3600 seconds. The exposures will not be binned (5 angstroms/pixel), and will use the full field of view of the CCD detector (1024 x 1024 pixels). The exclusion radius around the full moon was set to 40 deg, and will be scaled down for other moon phases.
 
1 2 3 4 5 6 7 8 9 10  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 123456
NSS  Background-1    06  39  52.01  -01   18  09.4   3600.00     1        0  1  FUL  SPB  32IN   2006-09-15   2006-09-15             35
 

The above is a request to take a single 3600-second spectrum of the sky background near a user-defined position Background-1 (R.A. = 06h 39m 52.01s, Dec. = -01d 18m 09.4s). The exposure will not be binned (5 angstroms/pixel), and will use the full field of view of the CCD detector (1024 x 1024 pixels). Since the initial and final dates are equal, and the repeat field (columns 95-97) was left blank, the sky background spectrum will be attempted only on 2006 Sept. 15 UT. The exclusion radius around the full moon was set to 35 deg, and will be scaled down for other moon phases.

A file is produced for every spectrum that gives an idea of the efficiency of the spectrum.  Click here for more information.  Other files needed for spectrum calibration are also described in this section
 
If you have questions about the the observation request format or about the above processes please e-mail them to mbs@tenagraobservatories.
 
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