Preparing for an AAOmega observing run

Contact your support astronomer (see the Schedule) and confirm your requested gratings, central wavelengths and blaze angles.
Fill out your AAO visitors travel form, and make your ANU lodge reservations directly with the ANU.
Check the software page for the latest version of Configure and download the relevant astrometric and fiber files from the FTP site.
Read the guide to using the Simulated Annealing Configure software.
Read the guide for making Complex Configurations (note compact fields or fields with +800 targets are complex).
Read the Frequently Asked Questions and Frequently Made Mistakes pages.
Chose your central observing wavelength to which fibers will be positioned. You may need to review the CVD web page to follow why this is required (CVD - Chromatic Variation in Distortion, an optical effect of the prime focus corrector optics).
Create a number of .fld files for the Configure software. Test them in Configure. e-mail a few example fields to your support astronomer to confirm the format and contents are okay.

These must contain

Science targets, with a sufficiently small range in target magnitude (less than 3mags is the standard constraint, but talk to your support astronomer if you require more detail here).

Sky fiber positions. You will need 20-30 sky fibers in the observation, and so 50-100 possible sky positions should be enough.
Guide stars, 14-14.5mag (B,V or R mags on the Vega or AB system are typically good for dark sky conditions, up to 12th magnitude may be needed during bright-of-moon, and do check the location of the moon relative to your fields). AAOmega has 8 guide bundles available. You should aim to use at least 4-6 and preferable all 8. This will require a good spread of candidate guide stars across the field plate to prevent guide star selection compromising science fiber placement.
Guide stars MUST be on the same astrometric system as your targets.
Guide star spatial distribution must match that of the stars. Typically, around 20-30 guide stars, distributed roughly uniformly across the field, is sufficient. One should avoid using only guides on one side of a field and trusting this to pull the field in, experience shows it typically does not.
The range of guide star magnitudes should be small, preferably less than 0.5mag spread. A greater spread will cause problems due to the dynamic range of the camera used to guide.

Notes:

Simply selecting some bright guide stars from SIMBAD or GSC is NOT going to work, your astrometric solution MUST be the same for the guide stars AND the targets, and good to 0.3arcsec or better. This is a requirement for AAOmega observations.
UCAC-2 and 2MASS sources have proved successful in recent years, although the USNO survey seems to be somewhat inconsistent (probably due to plate boundary effects).
SDSS is an obvious source of guide stars. However, all stars need to be eyeballed as SDSS has many funny artifact at the magnitudes required here, which are close to or marginally saturated. Marginally saturated stars, which do not suffer obvious defects on examination, have been found to still give excellent results with AAOmega (the SDSS astrometic data for these objects actually comes from smaller edge CCDs so the stars don't actually saturate in their astrometric reference frame.).
Eyeball your guide stars. Reject galaxies, reject binaries, reject objects with junk magnitudes. Stars should NOT be used blindly (guide globular clusters are next to useless and stars should not have spiral arms).
The target and guide star astrometry MUST be on the same system. Simply using two different catalogues that independently claim to be J2000 will result in poor acquisition and low sensitivity.
We have had some success recently in including a small number (1-2 objects per configuration) of standard star calibrators in each AAOmega field. These must be chosen to be faint, to avoid contaminating science spectra. Drawing the calibrators from the recent sample of White Dwarfs and Hot Sub-Dwarfs of Eisenstein et al. 2006 arXiv:astro-ph/0606700 from SDSS has worked well. Absolute flux calibration is not possible with a fibre system such as 2dF/AAOmega, due to the unquantifiable aperture losses in any given observation, but including a standard star in each field plate observation can improve the quality of internal spectral calibration, and monitor data quality during a run. All caveats relating to astrometric accuracy apply to calibrator data as well as science and guide data.
An interesting paper on the effects of poor astrometry on Signal-to-Noise is Newman P.R. 2002 PASP 114 918

Forward these files to your support astronomer who will check the format and look for possible problems.

Once problems have been fixed, prepare your full set of .fld files. Experiment with configure to determine the best options for your program. Forward the completed set of file to your support astronomer along with any relevant information on observing strategy, priorities and exposure times.

A note on observational wavelength:

Like all optical system, the 2dF prime focus corrector is a compromise. In order to achieve the wide field of view and acceptable image quality over that entire field of view, and all for an affordable cost, the corrector suffers from rather poor Chromatics Variation in Distortion (CVD). Put simply, this means that while the ADC accounts for the effect of the atmosphere on your target objects white light apparent positions, the prime focus corrector moves your target on the field plate as a function of wavelength. The effects can be quite large, up to 2arcsec in the worst case when considered over the full wavelength range accessible to 2dF and over the full 2degree field. 2dF knows about CVD and so you must specify for what wavelength you want 2dF to put the fibers in the correct position. This must be the compromise which best suites your programs goals (e.g. 4000A for Ca H+K and the Balmer lines, 8600A for Ca Triplet work or 6000A for low-res broad band redshift measurements).

Data reduction

AAOmega data is reduced using the 2dfdr software environment. Reduction facilities are available at the AAT, but users may wish to download and run the software on a laptop or at the home institute. The software can be found on the software page and a data reduction CookBook is also in preparation.

Rob Sharp (rgs@aao.gov.au)