Target of Opportunity¶
ToOs are normally arranged at the 4pm Run Manager's phone con. The normal procedure is that someone (depending on who is available) prepares a .json file with the observing script. During the night, the script is run, either in twilight before starting obstac, or sometime during the night. If necessary, the observations can be done by hand (see instructions below).
Starting in year 3, the DESGW (DES Gravitational Wave) ToO program may be invoked. .json scripts will be provided. Additional instructions may be added in the future.
If you are contacted for a TOO after the 4 o'clock meeting, you better reach Tom Diehl or Josh Frieman.
Use Tom's cell phone and home phone number until you reach him. Be persistent. The numbers are in the expert call list.
DES Operations (Tom, Josh, Doug Tucker) will send an email to firstname.lastname@example.org if there is expected to be TOO data.
Manual followup of PHAs¶
This procedure can be done if no .json file is available.
A typical scenario might be that you are asked to obtain images of a nearby asteroid in order to measure its orbit. For this scenario, you will want to obtain ~5 exposures with the pointing dithered between each one to ensure that that gaps between the CCDs are covered.
- Determine that a ToO observation should be scheduled. Generally this is done by agreement with the DES director and the run manager/observers at CTIO.
- Get the desired exposure time, filter, and prop-id.
- Obtain coordinates. The following is an example ephemerides:
Date UT * R.A. (J2000) Decl. Elong. V Motion Object Sun Moon Uncertainty h m "/hr "/hr Azi. Alt. Alt. Phase Dist. Alt. ... <suppressed> ... 2014 02 04 0000 02 23 26.9 -12 06 55 75.8 21.8 -112.0 -12.29 119 +59 -05 0.22 032 +27 Map/Offsets 2014 02 04 0030 02 23 23.2 -12 07 01 75.7 21.8 -111.2 -12.03 111 +53 -11 0.22 032 +21 Map/Offsets 2014 02 04 0100 02 23 19.5 -12 07 07 75.7 21.8 -110.4 -11.80 105 +47 -17 0.22 032 +15 Map/Offsets
The necessary exposure requests can be generated using the "Dither Control" tab on the Observer Console. The following is an example:
- You enter information the same as you would using the "Exposure Control" with a couple of extra steps. On the right is a checkerboard where you can select the dither pattern to be used. The example shows 5 positions - one at the center and 4 at various offset positions. Many patterns work - the goal is to make sure that each position is in its own unique row and column. 5 positions guarantees that an object will be observed a minimum of 3 times.
- The "RA Step" and "DEC Step" fields should be set to 60 and 60 (arcsec). This step size is big enough to cover the largest gap size between CCDs plus a margin for glowing edges.
- Once you are satisfied, click "Add" to add the exposures to the queue.