This is a summary of the things to resolve as a result of discussions at the NOT during Jan 13-15. ---------------------------------------------------------- Building: --------- When will it be ready? Thomas to investigate and provide answer medio March 2003. Temperature stability defined as deltaT < 1K peak to peak over 24h, seasonal changes can be much larger. We (John A./Preben N.) have to check the operation of the system regulating the white coffin. The T sensors monitoring the temperatures at different locations inside and outside the white coffin did behave strangely at the last installation visit to La Palma in february 2001. How do you access the building? How is the FIES instrument transported to the laboratory? Suggestion: make a liftable roof. Lift the optical table in and lift the roof on. (NOT crew to investigate) How do we mount the optical table? On special vibration damping legs? On automobil tyres (this was Bo's solution in Skellefteaa)? (Bo and Soeren's action item) What should be placed in the building? Preliminary list: - Optical table with all elements and the white coffin, which provide additional temperature stability. - Present calibration unit. - Cryotiger cooling unit (needs cooling water!). - Power supplies for FIES (we need power!) - The FIES PC with a net connection? Size of building: one room 3.5-4mX5m plus front room 8 sq.m. PC, calibration unit, Cryotiger go in the front room with aircondition equipment also. New fiber(s): ------------- Is it possible to run more than one fiber between the dome and the new lab? Yes! Do we make one or two fiber units or do we try to make a combined unit with the possibility to have a remotely controlled mechanism to choose between different fibers/modes? Suggestion 1: - Make a high resolution and a low resolution set. - The high resolution has a target and a sky fiber. - The low resolution only a target fiber. - The observer has to choose for the observing run, which set he wants. Suggestion 2: (our baseline right now) - make a fiber assembly with three input fibers at the frontend in a line: target(100mu), sky, target(200mu) - combine the sky and the calibration fiber into one and enter the spectrograph with three fibers on a line: target(100mu), sky/calibration, target(200mu), where the line is oriented in the cross dispersion relation. - make a movable mask just in front of the fibers that can block either the 100mu or the 200mu and in both possibly the sky fiber - make the fiber entry section with a flat mirror instead of reflecting the light off the fiber ends or the lens (FEROS style). How do we calibrate/flatfield the spectra? Can we use the existing flat field lamps in the adaptor? (Bo, John T., Soeren) How do we block the sky fiber, if needed? Do we introduce a mechanical mask? Or can we make a fiber connector to be undone to drop the sky signal? How do we arrange the input to the spectrograph? Have another look at the distance between the target fiber and the sky/calibration fiber at the input to the spectrograph. Do we have two separate lenses for the target and sky fiber? What distance on the sky should be chosen? Do we introduce a mirror in front of the fiber input to reflect light for fiber viewing to Stancam? This means we can place the lens on the optical input axis and enter the fibers in the perfect direction. Check the length of the fiber by running a fiber mimic from the new building to the telescope. Could we make a 50m mockup, that would behave identical to the real fiber? Then it could be used to test how much slack we need to take up the +- two rotations of the building and the 360 degree rotation of the adaptor. We could also check, whether there was a danger of entanglement with the present instruments while observations were done. We should make two copies of the fiber assembly to have a spare in case one breaks due to an accident. It is presumable cheaper to have that spare made simultaneously with the first unit, assuming that a fair part of the time spent is development and setup time. (One fiber solution prefered, Bo and Soeren to come with a design) Atmospheric Dispersion Compensator. ----------------------------------- Where do we put it? How do we mount it? The idea is to have a set of rotating prisms. How do we control them? There is room extending ~11 cm into the adaptor from the FIES frontend plate. If it is further away from the front plate, it will block light from guide stars. Another possibility is to place on a retractable arm in front of the adaptor in the telescope beam. The distance from the front plate to the optical axis is ~30 cm and the position in front of the daptor is 15-20 cm further up, so the position in front of the adaptor means it is a distance of 45-50cm from the fiber. (Bo and Soeren to come up with a design) The ADC needs to be controlled from the computers in the control room. We need a serial line output converted into an RS485 cable, on which we put one or two elements as used in the present FIES electronics. Then the FIES software can control the ADC by connecting to the computer in the control room using the communication protocol to be defined for the different control programs at the NOT (see the workplan under software). (Soeren, Peter S. and Jacob to suggest the setup) Upgrade of the optics. ---------------------- Where and at what costs can the optics be antireflection coated? REOSC seems to be able to do it at a reasonable cost. (Bo to get an offer) Do we replace the silver on the collimators with aluminium or do we put on a multilayer coating on top of the silver? Where and at what costs can this be done? (Bo, Soeren and Thomas to define process) Exposuremeter. -------------- Which light do we send of to the detector? A small fraction by using a clear glass plate reflecting ~5% or by using a dichroic beam splitter to redirect infrared (~1 micron) light to the detector. Do we use an avalanche diode detector? They are small and come as complete units including amplifiers. (Bo, Soeren and John A.) Cryotiger. ---------- How do we connect the cooling unit to the CCD to avoid any mechanical stress to act on the CCD, which might lead to small displacements of the chip position? (Preben N. and CUO CCD team)