SV StandardStar » History » Version 1
Thomas Diehl, 12/18/2012 08:10 PM
1 | 1 | Thomas Diehl | h1. SV StandardStar |
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2 | 1 | Thomas Diehl | |
3 | 1 | Thomas Diehl | To supplement the standard star fields that are setting at morning twilight, I've created json files for all the DES standard star "E region" fields: E1-A, E2-A, E3-A, E4-A, E5-A, E6-A, E8-A, and E9-A (E2-A and E4-A should just be duplicates of the previous E2-A and E4-A json files). I have placed them in the ~DECamObserver/ExposureScripts directory on observer2.ctio.noao.edu, as well as attaching them to the current message. (The file names follow the |
4 | 1 | Thomas Diehl | format: stdstarField_<name>.json.) |
5 | 1 | Thomas Diehl | |
6 | 1 | Thomas Diehl | Their coordinates have been adjusted to center them in the N4 CCD: |
7 | 1 | Thomas Diehl | Field RA(2000) DEC(2000) |
8 | 1 | Thomas Diehl | ----- -------- --------- |
9 | 1 | Thomas Diehl | E1-A 01:24:50 -44:33:40 |
10 | 1 | Thomas Diehl | E2-A 04:03:00 -44:41:45 |
11 | 1 | Thomas Diehl | E3-A 06:42:54 -45:05:06 |
12 | 1 | Thomas Diehl | E4-A 09:23:44 -45:21:02 |
13 | 1 | Thomas Diehl | E5-A 12:04:11 -45:24:03 |
14 | 1 | Thomas Diehl | E6-A 14:45:33 -45:15:34 |
15 | 1 | Thomas Diehl | E8-A 20:07:22 -44:37:01 |
16 | 1 | Thomas Diehl | E9-A 22:45:37 -44:22:47 |
17 | 1 | Thomas Diehl | |
18 | 1 | Thomas Diehl | |
19 | 1 | Thomas Diehl | I did some checks, and it looks like standard star fields E2-A, E4-A, E5-A, and E6-A -- in combination with the MaxVis and Stripe 82 standard star fields |
20 | 1 | Thomas Diehl | -- should provide adequate standard star field coverage through February 14 (although we *might* want to supplement with another field or two for February). |
21 | 1 | Thomas Diehl | |
22 | 1 | Thomas Diehl | Some suggestions for taking standard star field observations for the rest of the DES season (through mid-February): |
23 | 1 | Thomas Diehl | |
24 | 1 | Thomas Diehl | 1. For this first year of DES, it is very important to try to observe |
25 | 1 | Thomas Diehl | at least one Stripe 82 standard star field under clear conditions each |
26 | 1 | Thomas Diehl | night (and preferably the more Stripe 82 fields the better). Currently, |
27 | 1 | Thomas Diehl | these are the only DES standard star fields with calibrated standard stars |
28 | 1 | Thomas Diehl | covering all the CCDs over the full DECam focal plane. Since the Stripe 82 |
29 | 1 | Thomas Diehl | fields are getting hard to observe in the morning twilight, this means |
30 | 1 | Thomas Diehl | trying to hit at least one Stripe 82 field in the evening twilight. If |
31 | 1 | Thomas Diehl | sky conditions are not clear during evening twilight, one should try to |
32 | 1 | Thomas Diehl | observe a Stripe 82 field under clear conditions in the middle of night, |
33 | 1 | Thomas Diehl | before they all set too far into the West. |
34 | 1 | Thomas Diehl | |
35 | 1 | Thomas Diehl | 2. If no Stripe 82 fields can be observed during a clear period during the |
36 | 1 | Thomas Diehl | night, the MaxVis standard star field is a less-preferred-but-still-adequate |
37 | 1 | Thomas Diehl | second choice. |
38 | 1 | Thomas Diehl | |
39 | 1 | Thomas Diehl | 3. For some nights, due to clouds, #1 and #2 above will be impossible to achieve. |
40 | 1 | Thomas Diehl | Data taken on these nights will have to be photometrically calibrated at a |
41 | 1 | Thomas Diehl | later stage of the DESDM pipeline -- so, not a disaster, but a situation |
42 | 1 | Thomas Diehl | that we prefer to avoid if possible, since it causes more work on the |
43 | 1 | Thomas Diehl | data processing side of things. |
44 | 1 | Thomas Diehl | |
45 | 1 | Thomas Diehl | 4. To check which standard star fields are in a good position to observe |
46 | 1 | Thomas Diehl | (airmass < 2.10 and moon separation > 15 deg), use the decamStdFieldsTimeDate.py |
47 | 1 | Thomas Diehl | on observer2.ctio.noao.edu: |
48 | 1 | Thomas Diehl | |
49 | 1 | Thomas Diehl | source ~/dtucker/bin/setup_StdStarFieldPicker.csh (or .bash if you are using bash shell) |
50 | 1 | Thomas Diehl | decamStdFieldsTimeDate.py --help |
51 | 1 | Thomas Diehl | decamStdFieldsTimeDate.py --UT='2012/12/19 00:43' |
52 | 1 | Thomas Diehl | |
53 | 1 | Thomas Diehl | 5. It is usually better to observe your high-airmass standard star field |
54 | 1 | Thomas Diehl | first, since generally its airmass will be changing the fastest. |
55 | 1 | Thomas Diehl | |
56 | 1 | Thomas Diehl | |
57 | 1 | Thomas Diehl | Many thanks for your help, and best wishes for good observing! |