P2PP: SINFONI Information

P2PP:SINFONI Information

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The Laser Guide star is offered for AO observations. During commissioning runs, corrected Strehl in the 10-20% range has been achieved under median-to-excellent seeing conditions, respectively. Acquisition of the Laser Guide Star induces an additional overhead of 10 minutes (which is included in the execution time reporting module, ETRM).

Introduction

SINFONI is offered since April 2005 (P75) in seeing limited and diffraction limited mode. SINFONI is a very user friendly, efficient and reliable instrument. Nevertheless we would like to highlight a few topics which we find essential for the success of the service mode science operations:

Adaptive optics observations will in most cases require good or excellent seeing conditions. Any other observation constraints (Moon phase, sky transparency) should be relaxed whenever possible, minimizing the risk that the respective observation blocks may never find a scheduling window.
AO users are requested to specify on-axis K-band Strehl ratios and seeing in the constraints sets for the adaptive optics observations (NGS mode). The Strehl ratio as given in the observation block (p2pp), or the ETC, must be strictly consistent with the seeing which was specified in the proposal and the visual brightness of the natural guide star.
Saturation of the detector array can under no circumstances be tolerated. The remnance effect would seriously compromise the observations taken later in the night. Targets and natural guide stars must not be brighter than 5th magnitude in the J,H and K and 6th magnitude in the H+K setups.

This page contains information specific to the creation of SINFONI Observations Blocks (OBs) for Service Mode programs. For more general OB creation information, see the P2PP Web page.

Requirement Compliance Policy: Observing runs which do not adhere to the procedures and policies presented in this document will not be scheduled for execution. If you feel you must violate one of these procedures or policies, you must submit a Phase 2 Waiver Request before submitting any Phase 2 material.

Read the Manuals!

Prior to starting the preparation of the OBs, you MUST become familiar with the content of:

The SINFONI User's Manual

The P2PP User's Manual

Further useful information and tools for the Phase II preparation can be found on the User Support Services and Tools Web page (object visibility, ephemerides, catalogues, ETC, etc.)

A tutorial page has been prepared to help you in the preparation of the SINFONI Observing Blocks (OBs).

SINFONI Observation Block Requirements

Observing modes not offered for service mode observations:

observations with the sky spider
service mode observations with spectral dithering

Selected DIT Values

In order to prevent daytime calibrations (dark frames) to run over a reasonable execution time, it is recommended to limit the use of different DIT values to a minimum set (0.83, 1, 2, 5, 10, 15, 20, 30, 60, 100, 150, 300, 600, 900 seconds). It is mandatory to select one of these values for DIT values of 150 seconds and longer.

Magnitude limits for targets and natural guide stars

The SPIFFI detector has a persistence effect that can last for many hours if the observed sources are too bright. In Service Mode, this problem can affect subsequent observations of other programs. Observations of point-source targets brighter than J/H/K/-band = 5mag or (H+K)-band = 6mag are therefore not allowed in Service Mode, except if acquisition is performed via SINFONI_IFS_acq_NGSfast, which requires the submission of a Phase 2 Waiver Request.

Star brighter than R-band ~ 2mag cannot be used as AO reference because they would exceed the 10^6 ADU saturation limit for the APDs.

The AO system will deliver correction for natural guide stars down to limiting magnitudes of R-band ~ 17mag. Observations using an AO reference star fainter than R-band ~ 14mag are however only possible under tight weather condition (Clear/seeing<0.6").

Angular Size of the AO Reference Object

The WFS FOV is 3.6" on the sky. Therefore, the angular extent of the AO reference source should not exceed that limit. If the source is extended beyond this value, it should display a very contrasted core at visible wavelengths whose angular size is smaller than the 3.6" limit.

OB Naming Conventions

Please refer to the general requirements for OB names convention.

P2PP Constraints Set

Users must enter the seeing/FWHM (noAO mode) and the seeing together with the on-axis K-band Strehl ratio (natural guide star - NGS mode) for all observation blocks.

Seeing/FWHM AND on-axis K-band Strehl ratios - for adaptive optics observations (NGS mode):

For closed loop AO observations we request the users to enter the seeing/FWHM as indicator if the respective observation block can be scheduled at the current observation condition. In addition we request for all closed loop AO observations to enter the on-axis K-band Strehl ratio in the constraint set. The later is compared with the real time AO performance estimator which derives this value from the wave front errors. Seeing and Strehl ratio must be strictly consistent for the given brightness of the natural guide star. The off-axis performance on the target in the user selected bands can be estimated with the SINFONI exposure time calculator.

Seeing/FWHM in the respective JHK bands for seeing limited observations (noAO mode):

For seeing limited observations the FWHM shall be specified for the respective bands of the science observations. The constraints sets and definitions are the same as for all other seeing limited VLT instruments. (The input field for the Strehl ratio should remain unchanged).

Lunar constraints

Do not overspecify the Moon constraints! The Moon does not directly affect infrared observations, but it does affect the quality of the active and adaptive optics corrections, in particular if the reference stars are too faint. It is recommended not to observe objects when they are closer than 30 degrees from the Moon. For SINFONI, the Moon illumination (FLI) can be entirely relaxed in most cases by selecting FLI=1. If the source used for AO correction is fainter than R=15, it is recommended to increase the Moon constraint by selecting FLI=0.7 and a Moon distance of about 50 degrees.

SINFONI Readme Files

In addition to the general requirements for README FILES, you should follow specific recommendations for SINFONI and clearly specify:

Near-infrared magnitudes of the science target (for the filters used), and angular size if extended.

For AO observations:
- R-band magnitude of the AO reference object, and if extended the angular size in in R-band in which this magnitude/flux was measured.
- Angular separation between the science target and AO reference (if they are distinct).

Here is an example:

       OB names       R (NGS)    target       separation     comments
       --------------------------------------------------------------------
       SDor-***       ~10.5      J~8.5        target = NGS    variable!
       Hip024612-***    7.1	 J=6.9        target = NGS    telluric
       Charon-***     ~14.0      K=16.0       0.8 arcseconds  moving object

       None of the NGSs and targets is brighter than 6th magnitude in the NIR.

SINFONI Finding Charts

In addition to the general requirements for FINDING CHARTS, you should also follow these SINFONI specific recommendations:

You should typically provide two finding charts, both with a clear indication of the field orientation. In case of AO observations, the finding charts must include the location of AO reference object:
- A wide field finding chart should be 1' by 1' in size. It will be used to characterize the surroundings of the region of interest. The field of view (FOV) of the 250mas SPIFFI platescale (8"x8") must be drawn.
- A high magnification finding chart with the FOV of the 250mas SPIFFI platescale (8"x8"). It must also show the FOV of the respective smaller platescales (100mas, 25mas) if used for the observations. This is typically not required in case of point sources, if only the 8"x8" scale is used and if all details of the target geometry are well resolved on the wide field charts.