This section describes important changes which took place during Period 98 and 99, as well as changes expected to take place during Period 100.

Seeing and Image Quality:

• The seeing information to provide in Box 3 of the proposal form is the seeing in the V band at zenith. This ensures that the scheduling tool uniformly takes the seeing into account. Service mode users for approved programmes will enter the Image Quality for the airmass and wavelength of interest required for their observations as a constraint during Phase 2. The article by Martinez et al. "On the Dffierence between Seeing and Image Quality" describes the meaning of these two quantities and further information can be found on the Observing Conditions webpage.

The Exposure Time Calculators have been modifed accordingly and clearly distinguish between the two quantities, using a slightly modied version of the formula given in the above article. The ETCs also report on the chances of achieving the input seeing conditions and the resulting image quality.

Exposure Time Calculators:

• Exposure Time Calculators: All ETCs are now using a new sky model developed as part of the Austrian in-kind contribution (see Noll et al. 2012, A&A 543, 92, Jones et al. 2013, A&A 560, 91,  and The Cerro Paranal Advanced Sky Model). 
  

Designated Visitor Mode

• DVM has been offered in La Silla since Period 98. The 3-night minimum length per run remains. See the Call for Proposals for Period 99 for details.

Large Programmes

• Since Period 99, Large Programmes are offered again on the NTT

Instrument anf Facilities

• HARPS: Regular operations with the Laser Frequency Comb are expected to become possible during Period 100 Availability of the Laser Frequency Comb and instructions for its use will be announced in the instrument News page.
• ULTRACAM  is a high-speed imaging photometer designed to study faint astronomical objects at high temporal resolutions. ULTRACAM employs two dichroic beamsplitters and three frame-transfer CCD cameras to provide optical imaging with a field-of-view of 6 arcminutes and at frame rates of up to 300 Hz simultaneously in the u’g’r', u'g'i' or u'g'z' bands. This PI instrument is offered to the ESO community for up to 5% of the observing time at the NTT in Period 100. Large programmes will not be accepted. Operation of this PI instrument requires the presence of the instrument team so all ULTRACAM observations will be scheduled on fixed dates;  the exact dates in Period 100 have not been determined yet. For questions on the instrument and observation strategies, users shall contact the instrument  PI,  Prof. Vik Dhillon (vik.dhillon[AT]sheffield.ac.uk), at least two weeks prior to submitting their proposal. The ULTRACAM consortium commits to support the PIs and observers from the ESO community that have been awarded observation time with the ULTRACAM instrument during the execution of the observations and the subsequent data reduction to allow the scientific exploitation of the data obtained with the ULTRACAM instrument. Proposers must check that their planned observations do not duplicate protected observations for the ULTRACAM consortium for Period 100  in  the  page ULTRACAM protected targets.