Service Observing at La Silla

Currently only Director Discretionary Time (DDT) observations are supported at LSO. Programs that are awarded DDT time must prepare their phase II material following the general instructions .

However no USD support is provided for LSO, therefore the observing strategy, or its implementation through OBs, must be discussed with the site astronomer via

Instrument characteristics are summarized in the instrumentation pages .

If DDT observations have ToO status, then the ToO Policy apply.

Standard Calibration Plan

We take care of the standard calibration OBs (defined in the table below): you don't have to define OBs for these (but you can), and you don't have to take them into account when computing your total time. Just mention in your README file (see below) that you want standard calibrations.

If you want more calibrations, or specific calibrations, you will have to prepare the corresponding OBs, and the night-time calibrations will be charged on your time credit.


+ Common:
we take care of all the "technical" OBs, including setup, focus...

+ Visible Imaging (EFOSC2) in UBVRI
- Biases, Twilight Flats (if possible, priority given to standard
filters) or Dome Flat fields.
- At least 2 Landolt Standard star fields at different airmasses
during the night, if it is photometric night and PHOT requested.

+ Visible Imaging (EFOSC2) in non-standard filters (not UBVRI)
- Biases, Dome Flat fields.
- NO STANDARD. You have to provide the OBs.

+ Visible Spectroscopy (EFOSC, FEROS, HARPS):
- Biases, Dome Flats, day-time wavelength calibration frames.
- 1 spectrophotometric standard star with broad slit during the night
(with the exception of HARPS for which standards are observed
upon request only).
Radial velocity, line profile, and other exotic standards are NOT
part of the calibration plan and have to be provided.

+ SofI Infrared Imaging:
- "Special Dome Flats" (cf manual)
- 2 photometric standard stars during the night for JHKs
(polarimetric standards are not part of the standard calib.plan; non
standard filters are not included, you need to provide the OBs).

+ SofI Infrared Spectroscopy:
- Dome flats, wavelength calibration
- 1 Hip standard stars during the night.

Note that User-supplied Calibration OBs are executed only once. This is valid both for the "on-sky" calibrations (i.e. those with a specified target) and the "dome" calibrations (flats, arcs...).

Total time and overheads

IMPORTANT NOTE: The total time of your OBs must not be larger than the time allocated to your program. The "execution time" report of P2PP is to be used.  To use them, press [Recalc Exec Time] for a given OB, or use the Report > ExecTime facility.


Wait for the acknowledgement from your support astronomer. He will check your OBs and will possibly suggest you some changes. When everything is done, your OBs will be marked at "ready for execution" in the repository. If you check them out, they will disappear from the repository, and will not be scheduled.

As long as you did not get an "OK" from your support astronomer, the OBs are NOT schedulled and will not be executed.

Data Distribution

We will notify you when the program is complete, and send you the data. The package will contain the relevant calibration frames for your program, acquired within the noon-to-noon period centered on the night of the science observations. So if you see that some calibration frames are missing, please check the ESO Archive. Usually you will find them in one of the calibration batches executed a few days after the science observations.

Data are also transfered in almost real time to, so you can download them from there, typically one-two days after the observations. Enter the ESO Observation Schedule with your program ID, and follow the "FileList" link.