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 REQUESTING MOSAIC SEARCHES FOR NEW SOLAR SYSTEM OBJECTS
 

It is quite easy to use the 32-inch telescope for minor planet or comet discovery work. It is possible to select an arbitrary number of positions for searching and perform an automatic mosaic of fields-of-view around each position. The following is the fixed format of a request for a search mosaic:
 
1 2 3 4 5 6 7 8 9  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
SRC  hh  mm ss.ss   sdd  mm  ss.s  tttt.tt        nn  vvvv  b  sss  fff    nn  mm  tttt    yyyy-mm-dd  yyyy-mm-dd  rrr mmm
 
The meaning of each field is explained in the table below:
 
Field Columns Meaning
 
SRC 1-3 This fixed 3-character code specifies that this is a search request.
 
hh mm ss.ss 5-15 This is the right ascension of the mosaic's center, in J2000.0 coordinates.
 
sdd mm ss.s 17-27 This is the declination of the mosaic's center, in J2000.0 coordinates.
 
tttt.tt 29-35 Exposure time. This must be between 0.50 seconds and 300.00 seconds.
 
nn 37-38 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, use the same filter, etc. One usually takes at least 3 images of each search field in order to be able to detect moving objects by blinking the resulting images. Searches near the Milky Way often require 4 or 5 images, since there is a high probability of an asteroid or comet being involved with a star on any individual frame.

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 40-43
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).
  • For positive integer values, this field specifies the number of seconds between exposures. The TAO 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 TAO 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 your ability to detect moving objects in the resulting search images.

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. 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.
  2. 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 45 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 0.87"/pixel; if the value of this field is 2, you will take 2x2 binned (lower resolution) pictures at a scale of 1.74"/pixel.
 
sss 47-49
Frame size. You can use the full 14.8 X 14.8 arcminute field or choose the central 7.4 X 7.4 arcminute field on the CCD chip. Allowed values are 'FUL' (full field of view, 14.8 arc minutes) and 'CTR' (central 7.4 arc minute field of view). The size of a full field unbinned image (1024 x 1024 pixels) is about 2 MB; a full field, 2x2 binned image (512 x 512 pixels) is about 512 kbytes. If you use only the central 7.4 arcminute field, the file sizes decrease by a factor of 4, that is, an unbinned image (512 x 512 pixels) would be 512 kbytes and a 2x2 binned image (256 x 256 pixels) would be 128 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 51-53
This is the filter selection for the exposure. See this graph for in formation about Tenagra II filters. Allowed values are U, B, V, R, I, UNF (unfiltered), IRB (IR blocking). When the filter is a single character it can be anywhere in the field.
 
nn mm 55-59 nn is the number of fields-of-view in each mosaic row; rows are parallel to the East-West direction. Allowed values are 1, 3, 5, 7,... mm is the number of rows in the mosaic. Allowed values are 1, 3, 5, 7,...

Notes:

  1. The number of exposures specified in columns 37-38 applies to each individual field of the mosaic. Therefore, if you request 3 exposures in a mosaic consisting of one row of 5 fields, you will take 3 exposures of each field, for a total of 15 exposures.

  2. The exposure time, interval between exposures, binning factor, frame size, and filter will be the same for all fields in a search mosaic.
 
tttt 61-64 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		 66-86 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 questions have 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.
  4. The observation requests for each field in a mosaic are treated independently by the scheduler. If your window of opportunity spans more than one night, different fields may be observed on different nights.
 
rrr (optional) 88-90
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, your searches will be attempted in the time interval 2003-09-15 to 2003-09-17 (until they are 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 searches of the same mosaic, 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 perform the search.
 
mmm (optional) 92-94 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 search request for a given field within a mosaic will not be carried out when the distance between the search field 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 searches extending over a long time period; the scheduler will automatically interrupt the searches during time periods when the moon is too close to your search areas.

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.
Examples
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1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
SRC  22  15  00.00  +10  00  00.0    180.00     3    900  1  FUL  UNF    3    5  32IN  2003-09-29   2003-10-01
 
The above is a request to perform a mosaic search centered at R.A. = 22h 15m 00.00s, Dec. = +10d 00m 00.0s on the 32-inch telescope. The mosaic consists of 5 east-west rows, and each row consists of 3 adjacent fields-of-view. Each mosaic field will be imaged 3 times, with an exposure time of 180 seconds and an interval of approximately 900 seconds between successive images of the same field. The exposures will not be binned (0.87"/pixel), will use the full 14.8 x 14.8 arcminute field of the CCD detector (1024 X 1024 pixels), and will be taken using the clear filter. The observations of the various search fields will be attempted between 2003 Sept. 29 and 2003 Oct. 1 UT. If for some reason a given field is not observed on 2003 Sept. 29 UT, it will be attempted until 2003 Oct. 1 UT; we will stop retrying a field once it is observed. Since the repeat field (columns 88-90) was left blank, the request will not be repeated. Since the moon exclusion radius (columns 92-94) 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  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
SRC  05  30  00.00  +30  00  00.0      60.00     3    0      2  FUL  R        3    3  32IN  2003-09-25   2003-09-25
 
The above is a request to perform a mosaic search centered at R.A. = 05h 30m 00.00s, Dec. = +30d 00m 00.0s on the 32-inch telescope. The mosaic consists of 3 east-west rows, and each row consists of 3 adjacent fields-of-view. Each mosaic field will be imaged with 3 successive 60-second exposures. The exposures will use 2x2 binning (1.74"/pixel), will use the full 14.8 x 14.8 arcminute field of the CCD detector (512 x 512 pixels), and will be taken with the R filter. Since the dates are equal, and the repeat field (columns 88-90) was left blank, the searches will be attempted only on 2003 Sept. 25 UT. Since the moon exclusion radius (columns 92-94) 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  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
SRC  05  30  00.00  +30  00  00.0      60.00     3    0      2  FUL  R        3    3  32IN  2003-09-25   2003-09-25       2
 
The above request is identical to the previous one, except that the repeat field (columns 88-90) was set to 2. This means that the search mosaic will be attempted on 2003 Sept. 25 and 26 UT. Since the moon exclusion radius (columns 92-94) 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  
1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234567890 1234
SRC  05  30  00.00  +30  00  00.0      60.00     3    0      2  FUL  R        3    3  32IN  2003-09-25   2003-09-25       2    45
 
The above request is identical to the previous one, except that the exclusion radius around the full moon (columns 92-94) was set to 45 deg, and will be scaled down for other moon phases.
 
If you have questions about the the observation request format or about the above processes please e-mail them to mbs@tenagraobservatories.
 
If you wish to set up an account on the Tenagra II telescope click here.
 
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