Informations useful for the observations: List of astronomical Target, Pako scripts, Observing strategies

List of Astronomical Target for Nika Jun 2012 run4

FXD: First version before run (27/05/2012)

Back to the NIKA run4 page

1. Planets Mars for photometric calibration (primary calibrators)

Here are the ephemeris for the planets

and the other objects LST Pointing quasars Strong galactic sources

2. Usual bright quasars

• for image quality and linearity checks

3. List of bright ultracompact HII regions

• for photometric calibration checks (secondary calibrators)

Here is the full detailed formatted list Source_list_fmt2012v1.0.txt with fluxes

Here is the catalog for Pako NIKA2012v1.0.sou.txt has to be RENAMED to NIKA.sou on the pako computer Here is a list of IRAM pointing sources with fluxes at 3mm and 2mm (I miss fluxes at 1mm, SL) ListAstroTargetNika3/IRAM_pointing_sources_with_fluxes.xls

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Interface with the telescope: Pako

Here is a short manual on useful "Pako for Nika" commands Pako_helpv9.1.txt

Here is a collection of Pako scripts that were used during the run

nini4.pako => run the initial series of commands that always have to be run at the beginning of an observing session, updated with choice of receiver and backend allowing to get fits files, updated with correct focus and correct nasmyth offset deduced from pointing model session from 17 to 18/10/2011 night.

ListAstroTargetNika4/OTF_pointing.pako => OTFMAP 100"x84" in 22 subscan x 10 s = 4+1 ~= 5 min (10"/s) with 2.6 samples (subscan step) per convolved 1mm HPBW (for pointing & focus). 10s = minimum subscan time possible (Pako doesn't authorizes less), hence the choice of subscan length. Scan height changed from 60" to 92" to have more margins for the useful pixels.

ListAstroTargetNika4/OTF_geometry.pako => OTFMAP 300"x220" in 56 subscan x 20 s = 19+3 ~= 22 min (15"/s) with 2.6 samples (subscan step) per convolved 1mm HPBW (for the array geometry = pixels map in sky)

ListAstroTargetNika4/OTF_faint_source2012.pako => OTFMAP 120"x90" in 16 subscans x 10 s = 3+1= 4 min (12"/s) 6 arcsec subscan step (for faint sources)

ListAstroTargetNika4/OTF_RXJ.pako => OTFMAP 360"x240" in 41 subscan x 20 s = 14+3 ~= 17 min (18"/s) with 1.7 samples (subscan step) per convolved 1mm HPBW (for faint sources)

ListAstroTargetNika4/OTF_15x10.pako => OTFMAP Crab

ListAstroTargetNika4/OTF_faint_sourcequick.pako => OTFMAP

ListAstroTargetNika4/OTF_geomfast.pako => OTFMAP 420"x210" (step 6) in 36 subscans x 14 s = 9+3 ~= 12 min. 30"/s

ListAstroTargetNika4/OTF_pointing_small.pako => POINTING

ListAstroTargetNika4/Crossplateau.pako => OTFMAP

ListAstroTargetNika4/Cross.pako => POINTING

ListAstroTargetNika4/OnOffJitter_quick.pako => ONOFF

Observing procedures and strategies for performances verifications and debugging

Observations procedure as discussed between FXD, RZ, NP & SL on 30/5/2012

1. Use the EMIR pointing model as the starting reference, setting Nasmyth offsets to 0.
2. Do a "classical" POINTING (cross)
3. Do a "NIKA type" OTF-POINTING
4. Implement Nasmyth correction to point on the central pixel
5. Check with POINTING
6. Idem using the WOBBLER (expected setup: SWOBBLER -25 25 ttphase 0.52 ; assymetric wobble impossible, must be wide enough w.r.t. beam, as fast as possible without being harmonic of something)
7. 1st crude FOCUS with wobbler ("classical" procedure): 6 subscans, 2mm shifts
8. 1st crude Focus without Wobbler: new NIKA style: one line OTF scan way and back; 3 scans, set focus between scans 2 mm shifts
9. 1st crude FOCUS with wobbler, 1mm shifts
10. 1st crude OTF-FOCUS (without Wobbler), 1mm shifts
11. 1st OTF-GEOMETRY (scan width = baseline x 2 + FOV + max pointing error = 1x2 + 2.5 + 1 + 0.5 = 5')

12. 1st OTF pointing session (as many quasar as possible in the 6 h slot, probably ~15 ?) => define the NIKA pointing model (15 is not enough stat for a clear determination, but should be OK at 1st order)

13. better FOCUS with wobbler ("classical" procedure): 6 subscans, 2mm shifts
14. better Focus without Wobbler: new NIKA style: one line OTF scan way and back; 3 scans, set focus between scans 2 mm shifts
15. better FOCUS with wobbler, 1mm shifts
16. better OTF-FOCUS (without Wobbler), 1mm shifts
17. better OTF-GEOMETRY (scan width = baseline x 2 + FOV + max pointing error = 1x2 + 2.5 + 1 + 0.5 = 5')

18. OTF-GEOMETRY for different foci => focus characteristics for all pixels

19. OTF pointing session => define a better NIKA pointing model

20. test skydip going at high airmass values (at least 3)
21. observe typical calibrators 1-20 Jy (e.g. OJ)
22. observe known fainter sources (e.g. Tau sources)
23. redo this procedure the next day

Note: good focus depend on geometry which depend on focus ==> iterative process.

How to find the elevation axis with the observation ? This is degenerate with the pointing model => Iterative approach => accumulate statistics. Due to the degeneracy one as to make a choice on the strategy for the definition of the center of rotation of the array (rotation with elevation of the sky image). After discussions the next days: at the start of the run we will choose the best of the 4 pixels at the center of the array and define it as the center for the pointing model.

For skydips: do a frequency sweep at each airmass step => up to airmass = 3 or 4. This will give the position of the resonance frequency = total power. Each step has to be done manually; in the future implement Pako script and CAMADIA to to the frequency sweep automatically at each step.

How to investigate the plateau, beam broadening etc. => gain of amplifiers and power on the tone are the hardware parameters that we will change => write the information in Wiki log pages (this is in the raw data anyway, but discuss with Alain to get all the info in the FITS).

IMBFITS format: keep same structure as before run (e.g. with a fixed number of pixels close to the maximum available, not a varying number of pixels), except the implementation of Wobbler information (TTL = 0 - 40, with numbers in between = blancking)

Strategy to investigate the Plateau

Since we see the plateau on 31/05/2012 pointing scans with crosses patterns, we will use these fast scans to investigate the plateau, the width should be larger than the plateau itself, that is to say bigger than the array with margins ==> 3 arcmin widths.

So far (01/06/2012) we identify 3 hardware parameters we could play on:

• Limit the total power in the acquisition line: play with 2 different values of the DAC => at least 2 scans

• Limit the number of tones generated (e.g. probe all pixels, or only one which means generating only one tone, or only one part of the array) => at least 2 scans

• Move the tones frequencies by a small amount to place them on a different location on the slope of the resonance => at least 3 scans

• Repeat the procedure at least twice to check repeatability => 14 scans minimum

==> This should allow us to determine whether the plateau is a pure electronic effect, and have ideas on what causes it.