Requesting observations of
Solar System Objects With a Published Ephemeris

Targets in this category must have an ephemeris available at the MPC web site (at either the Minor Planet & Comet Ephemeris Service or at the NEO Confirmation Page). The scheduler automatically downloads the ephemeris data from the internet (if it is not already available at our local orbit and ephemeris database) and the target's R.A. and Dec. are computed for the observation time chosen by the scheduler. Note that if you use this method the observation will not be carried out if the ephemeris for some reason cannot be obtained. The following is the fixed format for the entries in a request file for objects with published ephemerides:

         1         2         3         4         5         6         7         8
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP dddddddddddd tttt.tt nn vvvv b sss fff nn mm ppp tttt yyyy-mm-dd yyyy-mm-dd rrr mmm

The meaning of each field is explained in the table below:

Field	Columns	Meaning
SSP	1-3	This fixed 3-character code specifies that the target is a solar-system object with a published ephemeris.
dddddddddddd	5-16	Target designation. The designation must match the official designation assigned by the MPC. The following are common examples: (13421) Numbered asteroids (number must be enclosed in parentheses) 2003 RU11 Unnumbered asteroids (note single space between the year and the alphanumeric code that follows it) 48G002 Object listed on the NEO Confirmation Page C/2003 R1 Unnumbered comets 139P Numbered periodic comets Notes: The target designation may be typed anywhere in the field, between columns 5 and 16. Do not use asteroid names, e.g., "Ceres" or "Varuna". Do not use packed designations for unnumbered asteroids or comets, e.g., K03R11U or CK03R010.
tttt.tt	18-24	Exposure time. This must be between 0.50 seconds and 300.00 seconds.
nn	26-27	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 a given minor solar system body in order to be able to detect it by blinking the resulting images. Targets near the Milky Way often require 4 or 5 images, since there is a high probability of the target being involved with a star on any individual frame. Minor planet or comet photometry would require longer time series. Notes: If you request up to 4 exposures, we will either schedule all of them or not schedule your exposures. 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. 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	29-32	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 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. If the value of this field is -1, the scheduler chooses the time interval between successive exposures of the target according to its rate of motion, so that it moves a few pixels between successive exposures; this is convenient for detection purposes, and also ensures that meaningful rates of motion in R.A. and Dec. can be estimated from measured astrometric positions of the target. As discussed above, the spacing between exposures can vary by +/-15% with respect to its optimal value. Notes: 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. 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	34	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	36-38	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	40-42	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 ppp	44-52	These 3 parameters serve to specify a mosaic search for an asteroid or comet whose ephemeris uncertainty is larger than the field of view (14.8 X 14.8 arc minutes) of the Tenagra II telescope. This is often the case when one tries to recover NEOs and other minor bodies observed at only one past opposition and/or over a very short arc. You can obtain estimates of ephemeris uncertainty from NEODyS (NEOs with published orbits), from the Minor Planet & Comet Ephemeris Service (other unusual minor planets), or from the NEO Confirmation Page (newly discovered NEO candidates in need of confirmation). The ephemeris uncertainty region of a one-opposition object can often be approximated as a line (or a very elongated ellipse) in the sky passing through the nominal ephemeris prediction. The orientation of this line (which can be obtained from NEODyS for known NEOs or from the Minor Planet & Comet Ephemeris Service for other unusual minor planets) is specified by its position angle (PA). PA is measured from North (0 deg) through East (90 deg), up to 360 deg. A search mosaic is centered at the nominal ephemeris prediction, and consists of mm parallel rows of nn fields of view; the fields in each row have their centers along a line oriented at a position angle specified by the user in field ppp (this position angle should be equal to the position angle of the uncertainty line). The fields in a search mosaic partially overlap so that they cover a contiguous region of the sky without "holes" in between. The allowed values of nn (number of fields in each mosaic row) and mm (number of rows in the mosaic) are 1, 3, 5, 7,... For a typical one-opposition object, the uncertainty region is so well approximated by a line that one can use only one row (mm = 1) of partially overlapping fields covering the uncertainty line. The number of fields along the uncertainty line (nn) is chosen according to the estimated ephemeris uncertainty. For example, suppose you wished to recover the 20th magnitude one-opposition NEO 2001 TX1 on 2002 Sept. 17 UT:   The uncertainty line (blue) lies along PA = 72 deg and is about a degree long.  The red points represent the ephemeris positions of 2001 TX1 computed using a sample of alternative orbits which are compatible with the available observations as of 2002 Sept. 15. The object is likely to be found somewhere along the uncertainty line. The length of the uncertainty line is about 4 times the field-of-view (14.8 arcminutes ), so you would request a mosaic consisting of a single row of 5 fields-of-view (squares in the above figure) at PA = 72 deg (nn = 5, mm = 1, PA =72). Note that only odd numbers of fields can be requested, so to cover at least 4 fields one needs to request 5 fields. Notes: In most cases, the ephemeris uncertainty is smaller than the field-of-view, so it is not necessary to request a search mosaic; a single field centered at the nominal ephemeris position is sufficient. A single field is selected by choosing nn = 1, mm = 1, and leaving the ppp field blank. The number of exposures specified in columns 26-27 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. The exposure time, interval between exposures, binning factor, frame size, and filter will be the same for all fields in a search mosaic.
tttt	54-57	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	59-79	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: Dates are referred to universal time. 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. When the two date fields are the same, your observation request will be submitted to the scheduler for that night only. 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)	81-83	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)	85-87	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: If you leave this field blank, a default moon exclusion radius of 5 deg will be adopted. 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.

         1         2         3         4         5         6         7         8
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP (8034)        300.00  3   -1 1 FUL   R  1  1     32IN 2003-09-29 2003-10-01

The above is a request to take a sequence of three 300-second exposures of asteroid (8034) on the 32-inch telescope. The exposures will not be binned (0.87"/pixel), will use the entire chip (1024 X 1024 pixels) and will be taken using the R filter. The exposures will be centered at the asteroid's topocentric ephemeris position at each observation time. The time interval between successive exposures of (8034) will be automatically determined by the scheduler so that it moves a few pixels in that time interval. The request will be attempted between 2003 Sept. 29 and 2003 Oct. 1 UT. If for some reason the request is not carried out on 2003 Sept. 29 UT, it will be attempted until 2003 Oct. 1 UT; we will stop retrying if the request is carried out. Since the repeat field (columns 81-83) was left blank, the request will not be repeated. Since the moon exclusion radius (columns 85-87) 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
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP P/1996 R2     300.00  3   -1 1 FUL   R  5  1 152 32IN 2003-09-29 2003-10-01

The above is a hypothetical attempt to recover the periodic comet P/1996 R2, using a mosaic of five full fields of view (14.8 x 14.8 arcminutes) of the 32-inch telescope. The partially overlapping fields are arranged along a line passing through the nominal topocentric ephemeris position of P/1996 R2 (computed using the ephemeris provided by the Minor Planet & Comet Ephemeris Service); the line is oriented at position angle 152 degrees and moves with the comet. The central field of the mosaic is centered at the nominal ephemeris position at the time it is observed. The other 4 fields-of-view have suitable fixed offsets with respect to the nominal ephemeris position at the time they are observed, so as to cover a segment of the user-specified uncertainty line. The exposures will be of full resolution (0.87"/pixel), and will use the R filter. Each of the five fields in the mosaic will be imaged three times. The time interval between successive exposures of P/1996 R2 will be automatically determined by the scheduler so that it moves a few pixels in that time interval. The request will be attempted between 2003 Sept. 29 and 2003 Oct. 1 UT. If for some reason the request is not carried out on 2003 Sept. 29 UT, it will be attempted until 2003 Oct. 1 UT; we will stop retrying if the request is carried out. The observation requests for each of the five fields are treated independently by the scheduler, so that different fields might be observed on different nights between 2003 Sept. 29 and 2003 Oct. 1. Since the repeat field (columns 81-83) was left blank, the request will not be repeated. Since the moon exclusion radius (columns 85-87) 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
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP 2003 RW11     180.00 30  600 2 CTR   V  1  1     32IN 2003-09-25 2003-09-25

The above is a request for a photometric single-night time series consisting of up to thirty 180-sec exposures of asteroid 2003 RW11 with the 32-inch telescope. Successive exposures in the series will be separated by approximately 600 seconds. The exposures will use 2x2 binning (1.74"/pixel), will only use the central 7.4 x 7.4 arcminute field of the CCD chip (256 x 256 pixels), and will be taken with the V filter. Each exposure will be centered at the topocentric ephemeris position of 2003 RW11 (computed using the ephemeris provided by the Minor Planet & Comet Ephemeris Service); if the object is moving fast, the telescope will follow it along the night, so that it is always centered in the CCD field (provided the available ephemeris is accurate enough). Since the dates are equal, and the repeat field (columns 81-83) was left blank, the time series will be attempted only on 2003 Sept. 25 UT. Since the moon exclusion radius (columns 85-87) was left blank, the default value of 5 deg around the full moon (scaled down for other moon phases) will be adopted.

Note: Observations of photometric reference stars should be requested using the format for non-solar system objects.

         1         2         3         4         5         6         7         8
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP 2003 RW11     180.00 30  600 2 CTR   V  1  1     32IN 2003-09-25 2003-09-25   4

The above request is identical to the previous one, except that the repeat field (columns 81-83) was set to 4. This means that the time series will be attempted on the four nights 2003 Sept. 25, 26, 27, and 28 UT. Since the moon exclusion radius (columns 85-87) 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
123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
SSP (50000)       300.00  1      1 FUL   R  1  1     32IN 2003-09-25 2003-09-25 120  45

The above is a request for monitoring of minor planet (50000) over a 120-day period starting on 2003 Sept. 25, using the 32-inch telescope. On every night in this period, a single 300-sec exposure in the R filter is requested. This exposure will not be binned (0.87"/pixel) and will use the full 14.8 x 14.8 arcminute field of the CCD detector. The image will be centered at the ephemeris position of (50000) (computed using the ephemeris provided by the Minor Planet & Comet Ephemeris Service). The exclusion radius around the full moon 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.

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