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News for Period 81

• As was the case for Periods 79-80, note that OBs using the laser can only be submitted by observers who explicitly requested it in the instrument configuration section of the proposal (Section 14; see also here).
• The acquisition template NACO_img_acq_Preset is no longer available. Normal imaging acquisition should be done using NACO_img_acq_MoveToPixel instead, with the Finding Charts indicating the correct field placement and orientation.
• The observation template NACO_img_obs_AutoJitterOffset is no longer available. Users wishing to jitter with independent sky fields should use NACO_img_obs_FixedSkyOffset instead.
• The new SDI+4 (SDI+ and 4 quadrant phase mask coronagraphy) is offered in Visitor Mode (only).
• FPI and observations which require chopping are not offered.
• The Wollaston prism oriented at 45 degrees is no longer offered.
• Coronagraphy with the semi-transparent mask and the S13 camera is strongly discouraged because of the small FOV available.

This page contains information specific to the creation of NAOS-CONICA Observations Blocks (OBs) for Service Mode programs. For more general OB creation information, see the VLT and ESO-MPI 2.2m Service Mode Guidelines 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.

This document has the following sections:

• Read the Manuals
• NACO P2PP Tutorial
• Additional Requirements for NAOS-CONICA README files
• Additional Requirements for NAOS-CONICA finding charts
• OB Naming Conventions
• P2PP Constraint Set
• NAOS-CONICA OB Recommendations
  • Moon Constraints
  • Telescope Offsets
  • Bright Sources
  • Editing the configuration file produced by the PS
• NAOS Preparation Software (NAOS-PS)

Read the Manuals

It is essential that all users read the following manuals:

• NAOS-CONICA User's Manual

• P2PP User's Manual

It is also useful to check the NAOS-CONICA Web pages for recent update and the NAOS Preparation Software Web page.

Further useful information and tools for the OB preparation can be found on the User Support Services and Tools Web page (for instance exposure time calculator, object visibility, catalogues, etc.)

NACO P2PP Tutorial

Additional Requirements for NAOS-CONICA README Files

In addition to the general requirements for README FILES, the following NAOS-CONICA specific recommendations should be followed:

• magnitude of the brightest object in all fields, including standard stars, and justification if the brightness exceeds the limits given below.
• For LGS mode OBs, the V magnitude of the TT star and its separation from the main target (in arcseconds) must be specified.
• For NGS OBs indicate the type of wavefront sensor used and the magnitude of the AO reference star (at the appropriate wavelength).

Additional Requirements for NAOS-CONICA Finding Charts

In addition to the general requirements for finding charts, the following recommendations should be followed:

• Starting with Period 81, at least one chart for each observation must be 2' x 2' in size, with additional charts showing more detail as appropriate.
• All wavefront reference objects must be clearly marked and numbered according to the way they have been ordered in the preparation software. They should be marked R1,R2,R3, etc.
• For imaging observations (including observations that use the wire grids), the field of view of the selected camera must be drawn.
• For polarimetric (with the Wollaston only) and coronographic observations, the field of view of the S27 or L27 cameras (28 x 28 arcseconds) must be drawn. Additionally, the target that is to be placed behind the mask (coronography) or centered within the transparent regions of the polarimetric mask (polarimetry) must be clearly marked.
• For long slit spectroscopy, the slit must be drawn.
• For slitless spectroscopy, the field of view of the S13 camera (14 x 14 arcseconds) must be drawn.
• For spectroscopic templates, the reference star used for preliminary slit centering must be marked and identified.

OB Naming Conventions

• For PSF reference stars, the OB name must be prefixed with the string "PSF_".

P2PP Constraint Set

Users should note that the seeing, airmass and Strehl constraints and the RA and DEC fields are automatically filled when the configuration file is loaded. Do not edit these fields.

NAOS-CONICA OB Recommendations

Moon constraints

The Moon does not affect IR observations with CONICA. However, the moon may affect the quality of the adaptive optics correction, if the source used for wavefront sensing is fainter than V=16. In these cases, reducing the FLI constraint to approximately 0.7 and increasing the distance to the Moon to approximately 50 degrees is generally adequate. Even here, it is important not to over-specify the constraints, as this reduces the chances of the Observing Block being executed. For wavefront sensing in the IR, these recommendations can be ignored.

LGS or NGS?

As mentioned above, only users who requested LGS in the proposal have the possibility to submit LGS OBs. But amongst those, there may exist borderline cases where NGS is an option. The limiting magnitude is currently 13.5-14 (in V, with zero color), i.e. with AO reference stars which are fainter than this limit one should select LGS mode and keep the star as a tip tilt reference. Brighter stars offer better performance in NGS mode. NOTE: As of February 28, 2008 (at 0818 UT) the NAOS-PS correctly predicts the Strehl performance for simulations using the LGSF.

Minimum time between exposures

Bright sources

Direct imaging of very bright objects results in residual images lasting for several minutes. In Service Mode, this problem can affect subsequent observations of other programs.

Brightness limits.

Observations involving fields with objects brighter than those specifed in the table below cannot be guaranteed..

Requests for observations not compliant with these limits must be submitted as a Phase 2 Waiver Request.

If the neutral density filters are used, subtract 4 magnitudes (Spectrscopic observations with the ND filters are not supported)

If the N90C10 dichroic is used, subtract 3 magnitudes.

Brightness limits: Acquisition

For acquisition of bright targets, the following filter settings must be used. Note that this applies not only to standard stars, but also to other bright objects in the field of view.

Important note: when the bright object in the field of view is not the science target, the target may become too faint to centre on slit due to the use of the Narrow Band filter(s). In this case offsets from a reference star should be used.

Editing the configuration file that is produced by the Preparation Software.

The PS produces an ASCII file with the extension aofcg which is required by P2PP and is used to set up NAOS. This file should never be manually edited. If you do, the execution of your OB will be severely compromised and your name will go on a yellow piece of paper on a big white board.

NAOS Preparation Software (NAOS-PS)

The NAOS Preparation Software (NAOS-PS) plays an essential rôle in the preparation of NACO OBs. In particular, NAOS-PS is used to generate configuration files that specify target acquisition and adaptive optics system setups for NACO observations.

A separate page describes what the NAOS-PS is, where to download it, and where to seek further help.

In addition, a detailed example of the use of the NAOS-PS can be found on the NACO P2PP Tutorial page.

Send comments to <usd-help@eso.org> Last update: 19 December 2007