Project

General

Profile

Standard Star Instructions » History » Version 25

Douglas Tucker, 08/29/2013 11:30 AM

1 14 Douglas Tucker
h1. Standard Star Instructions
2 14 Douglas Tucker
3 23 Douglas Tucker
_(Author:  Douglas Tucker, 29 Aug 2013)_
4 23 Douglas Tucker
5 14 Douglas Tucker
* Standard star fields are to be observed every evening and morning twilight that appear to be clear,
6 20 Douglas Tucker
  where "clear" is determined by a quick visual inspection of the RASICAM image, of the TASCA image, 
7 20 Douglas Tucker
  or (!) of the sky itself.
8 14 Douglas Tucker
9 14 Douglas Tucker
* If possible, for each twilight period, 3 standard star fields should be observed:  one at low airmass 
10 14 Douglas Tucker
  (X<1.25), on at medium airmass (X=1.25-1.65), and one at high airmass (X=1.65-2.10).  It is generally 
11 14 Douglas Tucker
  better to observe the high-airmass field first, since its airmass will be changing the most rapidly.
12 14 Douglas Tucker
13 20 Douglas Tucker
* For half-nights, 1 or 2 fields -- preferably a low-airmass field and a high-airmass field -- should 
14 20 Douglas Tucker
  be observed just before switchover.  (If only one field, a high-airmass field is preferred.)
15 14 Douglas Tucker
16 25 Douglas Tucker
* The list of DES standard star fields can be found here:  [[The Standard Fields]].  Note that they 
17 25 Douglas Tucker
  are broken into 3 types:  a "Golden" sample, a "Silver" sample, and a "Bronze" sample.  The "Golden"
18 25 Douglas Tucker
  sample fields, which have photometrically calibrated standards in all 5 DES filters (grizY) over the full
19 25 Douglas Tucker
  DECam focal plane, take precedence.  The "Silver" and "Bronze" either are missing calibrated Y-band
20 25 Douglas Tucker
  data or do not have calibrated standards just yet over the full DECam focal plane.  *Always make sure
21 25 Douglas Tucker
  that at least one "Golden" (SDSS) standard star field is observed each clear night.*
22 25 Douglas Tucker
23 14 Douglas Tucker
* For evening twilight, use the *DES/standard/Yzirg* scripts (which start with Y-band and end with g-band);
24 14 Douglas Tucker
  for morning twilight or pre-switchover, use the *DES/standard/grizY* scripts (which start with g-band and 
25 14 Douglas Tucker
  end with Y-band).   (For those rare nights when we also observe in u-band, please use the corresponding 
26 14 Douglas Tucker
  "DES/standard/Yzirgu" and "DES/standard/ugrizY" scripts.)
27 14 Douglas Tucker
28 14 Douglas Tucker
* There are several useful scripts in the StdStarPicker package in the DECamObserver account on observer2,
29 14 Douglas Tucker
  including decamStdFieldsTimeDate.py and decamStdFieldsQueryNextSet.py.
30 14 Douglas Tucker
31 22 Douglas Tucker
* *To get a full list of standard star fields that are in a good position to observe (airmass < 2.10, 
32 22 Douglas Tucker
  moon separation > 15 deg, within Blanco horizon limits), use decamStdFieldsTimeDate.py:*
33 14 Douglas Tucker
34 16 Douglas Tucker
<pre><code>
35 14 Douglas Tucker
  source ~/dtucker/bin/setup_StdStarFieldPicker.csh      (or .bash if you are using bash shell)
36 14 Douglas Tucker
37 14 Douglas Tucker
  decamStdFieldsTimeDate.py --help                       (for detailed help)
38 14 Douglas Tucker
  decamStdFieldsTimeDate.py --UT=now                     (for a list accessible right now)
39 14 Douglas Tucker
  decamStdFieldsTimeDate.py --UT='2013/09/17 00:43'      (for a list accessible at 00:43UT on Sept 17, 2013)
40 17 Douglas Tucker
41 16 Douglas Tucker
</code></pre>
42 1 Douglas Tucker
43 18 Douglas Tucker
* *To get a preferred triad of standard fields -- a low-airmass field, a medium-airmass field, and a
44 18 Douglas Tucker
  high-airmass field -- for a given time and date, use decamStdFieldsQueryNextSet.py:*
45 1 Douglas Tucker
46 1 Douglas Tucker
<pre><code>
47 17 Douglas Tucker
  source ~/dtucker/bin/setup_StdStarFieldPicker.csh      (or .bash if you are using bash shell)
48 17 Douglas Tucker
49 14 Douglas Tucker
  decamStdFieldsQueryNextSet.py --help                   (for detailed help)
50 1 Douglas Tucker
  decamStdFieldsQueryNextSet.py --UT=now                 (for a triad accessible right now)
51 14 Douglas Tucker
  decamStdFieldsQueryNextSet.py --UT='2013/09/17 00:43'  (for a triad accessible at 00:43UT on Sept 17, 2013)
52 1 Douglas Tucker
  
53 1 Douglas Tucker
  (Warning: decamStdFieldsQueryNextSet.py will output a default json file, "stdstar.json".  Just ignore it.)
54 18 Douglas Tucker
55 14 Douglas Tucker
</code></pre>
56 18 Douglas Tucker
57 19 Douglas Tucker
* *For simplicity, a look-up table of preferred triads for the nights of August 30-Sepember 30, 2013, 
58 19 Douglas Tucker
  listing the preferred triad for each 15-min interval throughout those nights, can be found here: 
59 14 Douglas Tucker
  attachment:listOfStdsByUT.Sept2013.txt*
60 6 Douglas Tucker
61 1 Douglas Tucker
62 25 Douglas Tucker
63 21 Douglas Tucker
64 21 Douglas Tucker
65 21 Douglas Tucker
h2. Attachments