README web version of /home/usg/OPS/MTS/readme_xml/readme_80500507

Principal Investigator Email Address

• lenzen@mpia-hd.mpg.de

Estimated Total Execution Time (hours, including overheads)

• 03:55:19.000

General Description

• README for CenA observations
  
  General remarks:
  The object to observe is the circum-nuclear region in CenA in J-, H-, and K-band.
   We want to get deep images on the star clusters close to the AGN, detected in our
   medium-depth K-band image, which I attached for your reference (K-clumps_with_jet.jpg).
  Moreover, I attached a finding chart for Cen A, and the according sky exposure (Finding_CenA.jpg).
  The brightest object in the field of view is the nucleus/AGN of Centaurus A. It
   has a magnitude 10.6 in K-band, 13.5 in H-band, and 15.2 in J-band.
  
  The priority list for this run is:
  
  		  1. K-Band imaging
  		  2. J-Band imaging
  		  3. H-Band imaging
  
  Choice of AO-reference - PARSEC:
  The observations should be taken with the Laser Guide Star.
  
  Choice of tip-tilt reference:
  The tip-tilt star given in the aocfg file is marked as R1 in the FC. 
  It was identified from the 2MASS point source catalogue (2MASS13252384-4300537)
   and has a J-band magnitude of 9.9.
  
  The time: 
  We have a total of 4 hours to observe CenA.
  The OBs are designed to get approx. equal total on-source exposure times of ~30
   min per filter. The DIT is chosen according to the two constraints: 
  1) not to saturate the detector with the bright AGN (especially in K-band 10.6 mag)
  2) get enough flux from the extended emission (i.e. the clusters that we want to
   see) to be above the background/read-out-noise
  !!! We are interested in the stellar light around the AGN, not the AGN itself! If
   the AGN is above the linearity limit or even marginally saturated, it's fine...
   as long as it does not affect the quality of the images. If necessary, please adjust
   the DIT accordingly.
  		
  The choice of the camera:
  We chose to use the S27 camera for all filters. The K-band will be Nyquist-sampled
   in the diffraction limit, while H- and J-band will be slightly undersampled. However,
   in previous runs we experienced that in H- and J-band we could not reach the diffraction
   limit. Moreover, we want to take advantage from the larger field of view of S27.
   
    
  The observing strategy:
  
  The acquisition for all filters is done in K-band, since the nucleus is best visible
   in this band. Please move the AGN to a central position on the detector. For the
   science template we chose NACO_img_obs_GenericOffset and we jitter the object on
   5 positions on the detector to remove bad pixels and cosmics. In order to remove
   the sky background, we plan to take sky exposures (S) in beween two object (O) exposures,
   i.e. observe a sequence "OSO". Since Cen A fills a large area on the sky we need
   a telescope offset of ~8.5' to get clear sky exposures. The position of the sky
   exposure is fixed in the template. When taking sky exposures we only jitter on two
   positions. Could you please make sure that these two sky fields do not contain very
   bright stars, and if necessary offset them accordingly.
  
  The priority list:
  		  1. K-Band imaging
  		  2. J-Band imaging
  		  3. H-Band imaging
  
  Please use PARSEC as AO reference, and put it as close as possible to the nucleus
   of CenA, in order to get the best possible AO correction close to the centre. 
  
  CenA-K	- DIT=15s, NDIT=1, #NEXPO=4, #OFFSETS=5
  Please adjust the DIT according to the above mentioned criteria.
  The total on-source integration time should be about 30 min. So, the OSO sequence
   should be repeated 3 times
  
  CenA-J - DIT=75s, NDIT=1, #NEXPO=1, #OFFSETS=5
  Repeat 2 times, i.e. OSO OSO 
  
  CenA-H - DIT=30s, NDIT=1, #NEXPO=2, #OFFSETS=5
  Repeat 3 times, i.e. OSO OSO OSO
  
  I have prepared two OBs: one for K-band and one for J- and H-band, where the filter
   is changed in the middle of the OB. The execution time is ~1hr51min for the first
   one and 2hr4min for the second one. I have a waiver approved that allows OBs with
   a total execution time of more than 1h (this waiver request was submitted and approved
   on Sep 9, 2008).
  
  Thanks a lot for carrying out the observations and best of luck!!!
  
  Nadine Neumayer (nneumaye@eso.org)

Waiver Requests

• A waiver request 280.C-5005(H) was approved that allows OBs with a total
   execution time of more than 1h (this waiver request was submitted and approved on
   Sep 9, 2008).

Critical Observing Condition Constraints

• N/A

Time-Critical Aspects

• N/A

Special Execution Requirements

• No.

Special Calibration Information

• No.

ToO Information

• N/A

ToO Activators List

• N/A

Is this a Pre-imaging run ?

• false

Pre-imaging Requirements

• N/A

Source(s) of Pre-imaging

• ---(Empty)---

Pre-imaging sources not listed above

• ---(Empty)---

Do all your OBs comply with the instrument-specific requirements listed
 on the instrument-specific Phase 2 web page ?

• YES

If this is a pre-imaging run, did you select PRE-IMAGING for the Observing
 Category for each Observing Template ?

• N/A

Do all your finding charts comply with both the general and instrument-specific
 Phase 2 Web Pages ?

• YES

If you submitted OBs for standard stars, did you specify the magnitude
 and spectral type of all standard stars in the OBs ?

• N/A

Have you included OBs for any calibrations that you need but which are
 not part of the Calibration Plan ?

• N/A

If you are observing Moving Targets, have you attached suitable ephemeris
 files to your OBs?

• N/A

If you have preferences which OBs should be executed first, did you make
 use of the User Priority field in the OBs ?

• YES

If this is a run that requires coordinated observations with other facilities,
 did you give proper instructions in the Time-Critical Aspects Section ?

• N/A

If you have PSF reference star OBs, do the names of those OBs begin with
 PSF_ ?

• N/A

If there are Finding Charts attached to your OBs, is the field-of-view
 of at least one of these charts 2' x 2' (with clearly labelled field orientation)
 ?

• YES

Have you clearly marked and labelled your wavefront reference objects
 R1, R2, R3, ... (as specified in the NAOS Preparation Software) on your Finding
 Charts ?

• YES

Have you specified the magnitude of the brightest object in the field-of-view
 for each OB ?

• YES

Are there objects in any of your fields (including standard stars) which
 are brighter than the limits specified in the User Manual and on NACO web Pages
 ?

• NO

If the previous answer is yes, have you given a list of OBs and a justification
 for the brightness limit violation in the general description field ?

• N/A