P2PP: HAWK-I Information

This page contains information specific to the creation of HAWK-I Observation Blocks (OBs) for Service Mode programs. All general, instrument independent, instructions for service mode OBs are outlined on the P2PP Web page and must be followed as well.

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
Specifics for HAWK-I OBs
Additional requirements for Finding Charts
Additional requirements for ReadMe file

Read the Manuals!

It is absolutely essential that all users have read the following manuals:

A tutorial on the use of P2PP to prepare HAWK-I observations is also available.

Specifics for HAWK-I OBs

Saturation limits and persistence

Like many other infrared detectors the HAWK-I detectors show a persistence effect if the observed sources are too bright. In Service Mode, this problem would seriously compromise subsequent observations of other programs. Therefore, observations of fields containing objects brighter than K=8.6, H=9.6 & J=9.3 cannot be guaranteed in Service Mode and in shared visitor nights. ESO reserves the right to lower the overall priority of the OB in question in service, and not to execute the observations in shared visitor nights. As the saturation level on a given object also depends on the sky conditions, please use the Exposure Time Calculator to check the brightness of your objects.

The magnitude of the brightest object in the field, including standard stars, must be indicated in the "Instrument comments" field in each OB.

Requests for imaging observations not compliant with these limits must be submitted as a Phase 2 Waiver Request. If judged acceptable, ESO will try to devise operational strategies (e.g. observations at the end of the night, scheduling other BB imaging OBs after the observations in question).

Minimum Time between offsets

Rapid offsets of the telescope lead to a degradation of image quality and to excessive overheads (>> 100%). Therefore, the minimum time allowed between telescope offsets is one (1) minute. The integration time parameters (DIT, NDIT, NEXP) should be defined so as to ensure that this rule is strictly followed. Please consider that with large sky offsets and DIT * NDIT * NEXP = 60s, the overheads are already on the order of 100%.

Recommended DITs

In order to prevent daytime calibrations to run over an unreasonable execution time, the DIT values for long exposure times are restricted. In Service Mode it is therefore mandatory to select one of the following DIT values in case the DIT exceeds 120 seconds: 150, 180, 240, 300, 600, 900 seconds. For observations with broad-band filters please remember to define short DIT values, i.e. lower than 15 seconds, in order to avoid saturation on the sky background.

Detector gaps

Mind the gaps! The HAWK-I field consists of 4 detectors with gaps of 15" in between them. If you don't want your target to fall onto the center of the gaps, you should define an offset in the acquisition template.

Lunar constraints

Do not overspecify the Moon constraints! The Moon does not directly affect infrared observations. For most HAWK-I observations the Moon illumination (FLI) can be entirely relaxed by selecting FLI=1. Only for the shortest wavelength filters (<1.2mic) there is an increased contribution from the sky background, degrading the sensitivity of your observations. 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.

Additional Requirements for Finding Charts

In addition to the standard Service Mode finding chart requirements, the finding charts for HAWK-I must show a field of 10 arcmin x 10 arcmin, preferentially in the wavelength of your observations.

Additional Requirements for README Files

In addition to the general README file requirements, the following recommendations should also be followed:

If you have been granted a waiver for observations of a field that contains bright stars exceeding the limits given above, the justification for such observations must be provided in the README file.