DUTCH OPEN TELESCOPE Report for NOVA ISC meeting nr. 11 March 19, 2002 R.J. Rutten and F.M. Bettonvil Overall status -------------- A three-year ``DOT science exploitation period'', following the past three-year ``DOT science validation period'', has obtained green light from the Utrecht Faculty Natuur- en Sterrenkunde on the basis of negotiations conducted by SIU director A.~Achterberg. The budget includes substantial grants from NWO and NOVA (see below). A renewal proposal to continue the Utrecht-led TMR network on ``Solar Magnetometry'' as a Research Training Network ``Solar Magnetism'' has been selected by the EC for funding. It combines eleven solar-physics groups across Europe and will fund eight postdocs, one at Utrecht. Multi-channel DOT science observing has started combining G-band and continuum passbands in synchronous speckle mode. The initial sequences have been speckle-processed (a time-consuming process) and are available as movies at http://dot.astro.uu.nl. A DOT ``White Paper'' was written, formulating long-range plans to turn the DOT eventually into a facility for solar physics world-wide rather then for Utrecht-only research. The key step is the realization of large-throughput on-site parallel speckle processing. This White Paper is supplied as annex to this report and is available at http://dot.astro.uu.nl under "DOT Documents". Project management ------------------ The SIU directorship shifted from A. Achterberg to N. Langer. The DOT project itself remains without project manager. Progress since ISC 10 --------------------- The major technical advance was the successful installation of the first imaging channel branching off from the telescope axis to a platform mounted besides the incoming beam at the telescope top, where all filters and cameras other than the on-axis G-band channel will eventually reside. Presently, it adds a continuum channel at 432 nm near the G band (430.5 nm) to enable subtractive separation of magnetic elements (intergranular bright points) and convective patterns (granulation) in the photosphere. Initial two-channel image sequences were taken in autumn, have been speckle-processed in the meantime, and are being analysed in collaboration with A. van Ballegooijen (CfA), searching for the convection-induced magnetic-element buffeting that is believed to contribute a sizable fraction of coronal heating through wave excitation. Other technical work: - automation of the canopy opening and closure (a key item in DOT operation safeguarding) started and nearly complete; - third wavelength channel (Ca II H or K) design completed, optics in house, hardware being realized (IGF); - camera software upgrade (cadence increase from 6 to 12 fps) halfway (IGF); - auto-focus system designed and nearly completed; - design of 455.4 nm optics (Ba II line) completed but hardware realization postponed adhering to the advice of the DOT Evaluation Committee. Major meetings -------------- The pivotal meeting was an extensive presentation of the DOT project and DOT science prospects to the Utrecht faculty dean and director (in fact the first such in history) in the presence of most senior SIU staff, on the basis of which the Faculty accepted the next three-year plan including a generous allocation of IGF (workshop) time. Milestones ---------- The DOT project was presented as the initial review talk at the Silver Jubilee meeting of the Udaipur Solar Observatory, which presently seeks funding to realize a one-meter class telescope incorporating DOT innovations. The DOT figured extensively in a TV program "De Grillige Zon" in the VARA series "De Ontdekking", broadcast in December. An advanced international spring school on ``Solar Magnetism'', copying the format of the NOVA Herfstschool in all detail except timing, will take place at Dwingeloo April 2-6. It is organised by the DOT team as part of the TMR-ESMN programme, jointly with the theory-oriented TMR-PLATON network. The 21 students (from 9 countries) were selected from 36 applicants. Relations with collaborators ---------------------------- The NSST (New Swedish Solar Telescope), which succeeds the SVST (Swedish Vacuum Solar Telescope) in the building from which the DOT is operated, saw first light on March 2. This is now the largest solar telescope in Europe and the second largest worldwide. Hammerschlag participated in the design and fabrication of the new turret (2 alt-alt mirrors at the top). Bettonvil and IGF contributed DOT camera control software and fiber links for the NSST guider telescopes. These are in-kind contributions, repaying the Swedish hospitality in housing the DOT team free of charge. A joint NSST + DOT + TRACE + SOHO observing program initiated by the DOT team is scheduled for April 20 - May 4 and is likely to yield the very first NSST science data. The aim is to combine phase-diverse with speckle reconstruction to study bright point dynamics. In the future, with the NSST equipped with adaptive optics, the two telescopes will often co-observe similarly in complementary fashion. Hammerschlag and Bettonvil also supervise the construction (at Delft) of the DOT-design clamshell canopy for the new German GREGOR telescope on Tenerife (open 1.5 m aperture, first light around 2005). Critical areas -------------- The smallness of the DOT team remains a serious drawback. Even the continuation of the present team, in which the efforts of Bettonvil and Suetterlin are indispensable (as emphasized by the DOT Evaluation Committee last spring) was in jeopardy until funding was obtained from NWO to continue Bettonvil's appointment through ASTRON and permission was obtained from NWO to turn the allocated OIO into a 2-year extension for postdoc Suetterlin. Budget ------ The funding for the coming three years as drafted by A. Achterberg and eventually agreed to by the Utrecht Faculty is, in overview: SIU 180 kf + AIO Faculty 780 (= IGF time) NWO/GBE grant 501 + OIO (= Suetterlin extension) NOVA 300 and covers some of the high-priority actions advised by the DOT Evaluation Committee: - completion and installation of the multi-channel optics; - safeguarding the DOT operation to enable trained-person observing; - vigourous DOT science exploitation, but not the speedup of the image reconstruction procedures recommended also. Realization of the latter will enable more frequent observing than just a few weeks per year (which is sufficient for the Utrecht research capacity, but wastes much potential solar physics by others). An initial proposal for funding high-volume observing and processing to a major Anglo-Dutch company was unsuccessful. Items for specific consideration by the ISC ------------------------------------------- The ISC is invited to read and comment on the appended White Paper on future DOT observing strategies, but none of the steps outlined there requires urgent ISC attention.