In this page, you will find all the manuals needed to prepare and analyse your observations with FORS2. Please be sure to download the manual corresponding to the period in which the observations will take place.
All the manuals are in Adobe's Acrobat format.
- FORS2 User Manuals
All the information about the instrument itself, its modes and their characteristics is provided in the FORS2 User Manual (UM):
- FORS2 last User Manual with reference to HIT modes: Period 101.1
- FORS2 Template User Manual
Detailed information on the acquisition, observation, and calibration templates:
- FORS2 FIMS User Manual
Detailed information on the Instrumental Mask Simulator software tool to prepare precise target acquisitions at Phase 2:
- FORS1+2 data reduction Pipeline
The various pipeline recipes to reduce FORS data are available here. There, one can also find documentation for the pipeline and its use, including the pipeline manual and cookbooks for some of the FORS2 modes (see 'EsoReflex Tutorial').
- REFLEX Tutorial
Tutorial reflex workflows for FORS2 can be found on the VLT pipeline page here.
- Data reduction frequently asked questions
A list of Frequently Asked Questions on data reduction is also available.
- FORS2 Absolute Photometry Project (decomissioned in early 2024)
Detailed information on the FORS Absolute Photometry (FAP) project, whose goal is to produce a 3% absolute photometric accuracy,
if nights are photometric (see Freudling et al., 2006).
Nightly zeropoints and extinction coefficients are available at
and the description of the table entries and definitions can be found at
Due to the method used, the nightly zeropoints become available with a delay of about 4 weeks.
Important: Please note that the project will be decomissioned by early 2024. Please refer to the item from Dec 2023 in the News page for more details.
- Historical FORS1+FORS2 User Manual
The Period 82 version of the User Manual contains information on FORS1 and FORS2 prior to the merger of the two instruments in 2008.