FORS Instrument Lunchtalk | ESO Garching | FORS1+2: The First of the VLT work horses – The User Perspective FORS1+2: The First of the VLT work horses – The User Perspective Mario van den Ancker – DMO/USD Gero Rupprecht - INS Instrument Operations Team: Ivo Saviane (PSO), Henri Boffin (PSO), David Jones (Instrument Fellow), Alfredo Leiva (LPO), Pedro Baksai (LPO), Mario van den Ancker (USD), John Pritchard (USD), Monika Petr-Gotzens (USD), Wolfgang Hummel (QC), Gero Rupprecht (INS)

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Is FORS2 the right instrument for your science?  VIMOS: More slits/mask (but limited grating options).  X-Shooter: Higher throughput for single-object spectroscopy.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Is FORS2 the right instrument for your science?  VIMOS: More slits/mask (but limited grating options).  X-Shooter: Higher throughput for single-object spectroscopy.  Observing Mode: Visitor or Service Mode?  All FORS2 modes with the exception of HIT-S offered in both VM and SM.  Instrument configuration limited to standard setups in SM.  Blue (E2V) CCD only offered in VM!  Maximum number of 10 MXU masks can be used within one night.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Is FORS2 the right instrument for your science?  VIMOS: More slits/mask (but limited grating options).  X-Shooter: Higher throughput for single-object spectroscopy.  Observing Mode: Visitor or Service Mode?  All FORS2 modes with the exception of HIT-S offered in both VM and SM.  Instrument configuration limited to standard setups in SM.  Blue (E2V) CCD only offered in VM!  Maximum number of 10 MXU masks can be used within one night.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Is FORS2 the right instrument for your science?  VIMOS: More slits/mask (but limited grating options).  X-Shooter: Higher throughput for single-object spectroscopy.  Observing Mode: Visitor or Service Mode?  All FORS2 modes with the exception of HIT-S offered in both VM and SM.  Instrument configuration limited to standard setups in SM.  Blue (E2V) CCD only offered in VM!  Maximum number of 10 MXU masks can be used within one night.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Is FORS2 the right instrument for your science?  VIMOS: More slits/mask (but limited grating options).  X-Shooter: Higher throughput for single-object spectroscopy.  Observing Mode: Visitor or Service Mode?  All FORS2 modes with the exception of HIT-S offered in both VM and SM.  Instrument configuration limited to standard setups in SM.  Blue (E2V) CCD only offered in VM!  Maximum number of 10 MXU masks can be used within one night.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.  Requested time should include overheads.

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.  Requested time should include overheads.  SM Observations: Are all necessary calibrations covered by the calibration plan?

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.  Requested time should include overheads.  SM Observations: Are all necessary calibrations covered by the calibration plan?

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.  Requested time should include overheads.  SM Observations: Are all necessary calibrations covered by the calibration plan?  Is pre-imaging required (if so, request this as a separate observing run and flag this as a pre-imaging run in your proposal).

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Use the FORS2 Exposure Time Calculator ( to estimate integration times.  Requested time should include overheads.  SM Observations: Are all necessary calibrations covered by the calibration plan?  Is pre-imaging required (if so, request this as a separate observing run and flag this as a pre-imaging run in your proposal).  Observing constraints for SM observations (sky transparency, seeing, sky brightness) requested at Phase 1 are binding!

FORS Instrument Lunchtalk | ESO Garching | Phase 1 Proposal Preparation  Select your targets wisely!

FORS Instrument Lunchtalk | ESO Garching | Phase 2 Observation Preparation  All observations prepared using p2pp.

FORS Instrument Lunchtalk | ESO Garching | Phase 2 Observation Preparation  All observations prepared using p2pp.  Advanced scheduling options introduced with p2pp version 3.3 (used for FORS2 as of ESO period 90).

FORS Instrument Lunchtalk | ESO Garching | Phase 2 Observation Preparation  Some observing modes (e.g. MOS, MXU) require use of another tool, FIMS.

FORS Instrument Lunchtalk | ESO Garching | Phase 2 Observation Preparation  Some observing modes (e.g. MOS, MXU) require use of another tool, FIMS.  Astrometrically accurate images (or FORS1/2 pre-images) needed for mask preparation with FIMS.  32 bit Linux version (or 32 bit Linux running as a virtual machine) needed to run FIMS.

FORS Instrument Lunchtalk | ESO Garching | Do’s and Don’ts at Phase 2  Do not deviate from your Phase 1 proposal (constraints, targets, instrument setup).  Do use the standard instrument set-ups.  Do check the definition of offsets and rotator angles (instrument-dependent!).  Do not use offsets > 1’.  Do include a few bright stars in any mask.  Mind the gap!

FORS Instrument Lunchtalk | ESO Garching | Do’s and Don’ts at Phase 2  Do not deviate from your Phase 1 proposal (constraints, targets, instrument setup).  Do use the standard instrument set-ups.  Do check the definition of offsets and rotator angles (instrument-dependent!).  Do not use offsets > 1’.  Do include a few bright stars in any mask.  Mind the gap!

FORS Instrument Lunchtalk | ESO Garching | Do’s and Don’ts at Phase 2  Do not deviate from your Phase 1 proposal (constraints, targets, instrument setup).  Do use the standard instrument set-ups.  Do check the definition of offsets and rotator angles (instrument-dependent!).  Do not use offsets > 1’.  Do include a few bright stars in any mask.  Mind the gap!  Check for vignetting (HR collimator only).

FORS Instrument Lunchtalk | ESO Garching | Do’s and Don’ts at Phase 2  Do not deviate from your Phase 1 proposal (constraints, targets, instrument setup).  Do use the standard instrument set-ups.  Do check the definition of offsets and rotator angles (instrument-dependent!).  Do not use offsets > 1’.  Do include a few bright stars in any mask.  Mind the gap!  Check for vignetting (HR collimator only).

FORS Instrument Lunchtalk | ESO Garching | Science  FORS is essentially used for all types of science. A: Cosmology B: Galaxies and Galactic Nuclei C: ISM, Star Formation and Planetary Systems D: Stellar Evolution

FORS Instrument Lunchtalk | ESO Garching | Science  FORS is essentially used for all types of science.  FORS2 is currently the most popular instrument on the VLT.  Publication rate: 886 papers so far with FORS1 (of which 14 in Nature), 909 (of which 17 in Nature) with FORS2.  9/20 most cited ESO papers resulting from FORS data.  Five science highlights.

FORS Instrument Lunchtalk | ESO Garching | Science Highlights: 1/5  Derivation of the internal structure of a dark cloud on the verge of collapse. Alves et al. (2001, Nature 409, 159)

FORS Instrument Lunchtalk | ESO Garching | Science Highlights: 2/5  Discovery of a very energetic supernova associated with a long-duration GRB at redshift z = Hjorth et al. (2003, Nature 423, 847)

FORS Instrument Lunchtalk | ESO Garching | Science Highlights: 3/5  Discovery of clouds in the transmission spectrum of the transiting super-Earth exoplanet GJ 1214b. Bean et al. (2010, Nature 468, 669)

FORS Instrument Lunchtalk | ESO Garching | Science Highlights: 4/5  Measurement of the polarization signal from biosignatures in the Earthshine (sunlight reflected from the earth to the dark side of the moon). Sterzik et al. (2012, Nature 483, 64) Red line: data Black line: model Green: Error estimate

FORS Instrument Lunchtalk | ESO Garching | Science Highlights: 5/5  Non-spherical ejecta in Planetary Nebulae are due to binarity. Boffin et al. (2012, Science 338, 773) PN Fleming 1 in Halpha (red), [O III] (green) and [O II] (blue). Instrument: FORS2.

FORS Instrument Lunchtalk | ESO Garching | Conclusions  FORS1 and FORS2 are amongst the most successful ESO instruments ever.  After 13 years still in high demand and productive.  On the hardware side, no obvious signs of aging.  Good for the next 13 years?