Requesting Spectra of
Non-Solar System Objects
Requesting Spectra of
Non-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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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:
|
| 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:
|
| 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:
|
| 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:
|
| 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:
|
| 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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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 4 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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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 90 40 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 1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456 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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