[2014/12/09]
Attendees: Subaru staff members in Hilo, Instrument Planning Task Force members (Kashikawa, Masaomi Tanaka, Narita), and Mizumoto (from Mitaka)
Memo by Minowa-san
--------------------------- Iwata explained the reason why instrument planning is necessary now and a draft plan to be presented to Subaru Advisory Committee (SAC) and at Subaru Users Meeting in January. = Human resources and budget = * Assumption that NAOJ will try to keep the size of the Subaru operation at the same level as it is now until TMT is too optimistic (Arimoto) = PFS budget = * Where does the PFS budget come from? (Jovanovic) - IPMU has been raising funds for the development. NAOJ allocated additional budget for PFS starting from this year other than the Subaru operation cost. NAOJ managed to put some budget for PFS development (in addition to the telescope / enclosure modification required for PFS) this year, but is not guaranteed for next year. (Iwata) = NsOpt = *HDS presentation by Tajitsu-san ** HDS is the most reliable/stable instrument in the Subaru **The throughput of HDS at UV range (300-360nm) is the best among 8-10m class telescope in the world. ** Blue IMR at NsOpt needs to be relocated to keep the performance at UV. It costs about 1.5M yen. * Why is HDS better than VLT/UVES in shorter wavelength? (Imanishi) - UVES is using prism for derogating the image, while HDS is using K-type mirrors, which provides better throughput at extreme UV (Tajitsu). = Cs = * SWIMS/MIMIZUKU (new PI type instruments from IoA, UT) can be alternatives of MOIRCS/COMICS, but it depends on the reliability of SWIMS/MIMIZUKU. * Acceptance of SWIMIS/MIMIZUKU should be affected for the decision (or hibernation) of the decommission of the Cs instruments * What is the science case of SWIMS/MIMIZUKU at Subaru? Are they achievable during the short stay at the Subaru? (Arimoto) * To use SWIMS/MIMIZUKU as alternatives of MOIRCS/COMICS, they need to be evaluated their importance by using radar charts as we did for the other facility instruments. (Minowa) * Do we need to continue the operation of MOIRCS/COMICS while commissioning SWIMS/MIMIZUKU? The performance of these instruments should be verified (Imanishi) - There is no extra standby flange to keep both instruments (Takato). - We might need to bring MOIRCS or COMICS down to ESB while commissioning SWIMS/MIMIZUKU. That means we would have to judge SWIMS/MIMIZUKU performance without on-sky tests (Iwata). * If we decommission FOCAS, we will no longer use CsOpt. For S15A, among more than 20 times top-unit exchanges, CsOpt related ones are several. Does such reduction of TUE help day crew to reduce their workload? (Imanishi) - It will not help a lot (Hasegawa) * FOCAS presentation by Hattori-san ** In early years FOCAS has been used mainly for MOS observations of high-z galaxies, but now the usage of FOCAS is changing to more versatile science cases using all modes (imaging, long slit, MOS, polarimetry). It is also used to try some new observation modes (e.g., fast readout). ** Image Slicer IFU is expected to be implemented in 2015. * What is the uniqueness of FOCAS compared with the similar instruments at Maunakea? ** FOCAS vs. Gemini/GMOS - FOCAS sensitivity is higher than GMOS (Imanishi) - Some science that do not require sensitivity (such as exoplanet) may be done with GMOS (Iwata) ** FOCAS vs. LRIS/Keck I - Keck-I demand is oversubscribed because of MOSFIRE - Keck TAC requested us to use KeckII for Subaru-Keck time exchange - Since LRIS is attached to Keck-I, it might be difficult to absorb all request to FOCAS by LRIS (Imanishi) ** FOCAS vs. KCWI/KeckII? - Science case of the KCWI is narrow. - Although KCWI's capability is higher than FOCAS IFU, FOCAS is a more versatile instrument (Iwata) = General Discussions = * Evaluation of the operation cost for each instrument might be helpful to decide which instrument should be decommissioned first (Jovanovic) * Is there any technical risk to hibernate the instrument ? (Jovanovic) - If serious failure happens with the hibernated instrument, we will not try to fix the failure, but decommission the instrument (passive decommission). (Iwata) * Workload analysis - we might be able to consider the medium size development to reduce the workload for regular, but high load maintenance (e.g., Auto precooling system) or to prevent damage of the critical component (e.g., air flow to decelerate damage on blue IMR for HDS). (Walawender) * FMOS decommission ** FMOS decommission is postponed to the end of S15B or later depending on the progress of PFS project (Iwata) ** If we keep using FMOS, we cannot avoid PIR<-->POpt2 top unit exchange, which should increase the risk of the failure (Imanishi) ** It might be better to consider the decommission of FMOS at the end of S15B regardless of the progress of PFS to reduce the risk of the failure (Imanishi). ** It is important for the science strategy of the observatory to keep FMOS as long as possible and minimize the gap between FMOS and PFS. (Arimoto) * Upgrade plans for the existing facility instruments ** There are several upgrade plans for the instruments that are subjected to the discussion of the decommission. Is there any possibility to increase the competitiveness by these upgrade? (Walawender) ** FOCAS -- IFU, readout mode ** COMICS -- polarization mode ** MOIRCS -- new detectors, IFU ** HDS -- multi object unit * Possibility of the instrument exchange between the Subaru and the other observatory ** Is it possible to transfer the instrument to the other observatory at Maunakea? (Jovanovic) - There was a discussion to transfer HDS to Gemini, but it is suspended. Using fibre reduces shorter wavelength throughput (Iwata) - Interface between the telescope and instrument might be an issue (Walalwender) ** Is there any possibility to transfer the instrument to TAO? (Guyon) - It is not likely as TAO is trying to minimize the operation cost by limiting the instrument capability to ones that have merit at high altitude environment. * Subaru's strategy at 2020s ** Subaru's strategy at 2020s is to concentrate on wide field survey with HSC, PFS, and ULTIMATE and extrasolar planet study with PI type instruments. (Arimoto) * General purpose instrument in future ** There is no future plan for general purpose instrument to perform a wide variety of astronomical research. (Walawender) ** If we decommission the existing instruments, Subaru will loose general purpose instruments. Does Subaru's community agree with this? (Walawender) ** There is no strong objection at previous UM against the Subaru's strategy at 2020s. Director will ask community again at the next Subaru UM (Arimoto). * Global strategy of 8-10m class telescopes ** Is there any global strategy for the future of 8-10 m class telescopes (especially at Maunakea)? (Jovanovic) - Subaru is regarded as survey type telescope using HSC, PFS, (and ULTIMATE). The other observatory will avoid those capability for their future plan (Arimoto). ** Mauna Kea observatories basically agree the idea that we should avoid duplication of capabilities and share costs of instrument development through time exchange programs (Iwata). * If we decide to continue operation of some of existing facility instruments, does that decision affect the progress of ULTIMATE-SUBARU? (Guyon) - There might be some impact, but it should not be a primary reason of delay; development of ULTIMATE relies on contribution from outside (Japanese and foreign institutes). (Iwata) - Since ULTIMATE-Subaru is just a plan and has not funded yet, we also need to consider about the future without ULTIMATE-Subaru (new wide-field IR instrument). We might be able to reuse the existing instruments with the aid of the deformable secondary correction. It is better to postpone the decision of the instrument decommission until we have more solid plan of the ULTIMATE-Subaru. (Minowa) - Hibernation of the instrument is one of the solutions to such uncertainties in development of new facility instruments (Iwata) * Iwata asked if there's any objection to the draft plan to be presented in SAC and Subaru UM. No strong objection was expressed. Iwata mentioned that we need to continue discussions based on feedbacks from community and with updated plan of PFS. * Decommission of Cs instruments depends on acceptance or decline of SWIMS/MIMIZUKU carry-in proposals. We need to make decisions as soon as possible (iwata). * Next discussion - It would be better to have another internal discussion meeting after UM with some opinions from the Subaru community (Arimoto) ---------------------------