DUTCH OPEN TELESCOPE Report for NOVA ISC meeting nr. 22 September 29 2007 R.J. Rutten and F.C.M. Bettonvil DOT website: http://dot.astro.uu.nl Project management ------------------ The DOT efforts are part of the Sterrekundig Instituut Utrecht (SIU) which is part of the Department of Physics and Astronomy (DepNS) of the Faculteit Betawetenschappen of Utrecht University (UU). The DOT efforts were/are funded during 2004 through 2007 through a DepNS guarantee including support from NOVA. This funding covered/covers the salaries of Bettonvil and Suetterlin, DOT exploitation including travel, IGF (DepNS workshop) effort, and on-site student training. Additional funding came/comes from the EC for observing (OPTICON). Additional EC funding for solar physics at Utrecht came from an MC/RTN grant to the ESMN network, now terminated, and presently comes from an MC/EST grant to the Utrecht-Stockholm-Oslo USO-SP graduate school (AIO's C. Fischer and N. Vitas, plus a number of six-month trainees) and an MC/RTN grant to the Solaire network (postdoc and AIO, both selected and starting soon). DepNS funding completes these grants into standard durations. The DOT core team consisted during the report period of R.J. Rutten (DOT scientist), R.H. Hammerschlag (DOT builder), F.C.M. Bettonvil (DOT project manager), and P. Suetterlin (DOT observer and data handler). In addition, G. Sliepen (UU graduate in informatics) and A.P.L. Jaegers (engineer) work through STW funding on DOT-related technology, in particular DOT-type foldaway canopies. C.U. Keller and various UU AIO's have partial DOT interest. Postdoc J. Koza (EC/MC-EIF funding) completed his two years at Utrecht on DOT-oriented research and returned to Slovakia. J. Leenaarts obtained his PhD cum laude in September and goes as Solaire postdoc to Oslo. Six-month USO-SP trainees have been J. Palacios and R. Melich while H. Bengtsson has recently started on such a traineeship and Z.F. Funda Bostanci will start in january. R.J. Rutten retired this spring formally and mandatorally but continues both DOT research and education as emeritus. Rutten's successor A. Voegler started in January 2007. He is an expert in numerical solar physics and presently concentrates on radiative MHD simulations of magnetized stellar atmospheres. From January 1 2008 onward, P. Suetterlin will be employed by the Swedish Royal Academy of Sciences to become the on-site SST Support Astronomer. He leaves the DOT team, but since he remains in the SST building from which also the DOT is operated he will remain around for advice. Similarly, F. Bettonvil will no longer be funded by UU for DOT work but transits to the STW and EST grants (see below), also remaining on-site. Obviously, these moves have DOT ramifications discussed below. European Solar Telescope ------------------------ A major new development in solar physics is the Europe-wide initiative and commitment to build a 2.5-m class "next generation" European Solar Telescope (EST). The science driver is that increased spatial resolution but also ample photon collection is required for sensitive photospheric spectropolarimetry, chromospheric polarimetry, and fast-cadence narrow-band chromospheric imaging. The technological motivation is that the advent of adaptive optics and image restoration now enable solar physics at much larger aperture than the Fried parameter (at best 15 cm on La Palma), and that the DOT's open technology has demonstrated that the one-meter window limit for traditional solar-telescope evacuation can be avoided. In this project DOT technology, the DOT as testbed for experiments, and possibly mechanical parts of the DOT itself are likely to play an important role and make Utrecht a key partner in this project. An EC-funded EST Conceptual Design Study has entered the stage of contract negotiations, with a project duration of three years. UU will take a major role in the designs of the dome, building and mechanical telescope structure, with F. Bettonvil as UU project leader. Progress since ISC 21 --------------------- 2007 becomes again a succesfull year in terms of DOT observing. Five international multi-telescope campaigns were performed so far, totalling 94 observing days. They include assignments on Spanish, OPTICON, ITP, and Slovak time. The presently ongoing Spanish-time campaign encompasses all solar telescopes in the Canary Islands and the major solar space missions including Hinode. The DOT database, stored on a high-volume data server in the DepNS computer room and containing all high-resolution image sequences collected with the DOT since the autumn of 1999, grows rapidly since the installation of the high-volume 70-CPU DOT Speckle Processor on La Palma. It has a user-friendly graphical interface showing a thumbnail pictorial index of what was collected for every day with worthwhile data. An elaborate search engine has been developed by former DOT-student T. van Werkhoven and is now being tested. It will make the database yet more easily accessible to both the scientific community and the general public. Since the DOT is the only groundbased solar telescope with a rigourous open data policy and all its data web-accessible, DOT data are increasingly analysed by external scientists and DOT movies are frequently shown by solar physicists in their scientific and outreach presentations. The DOT education program also continues. Two DOT students are presently on La Palma for two-week on-site research training under R.J. Rutten's supervision. Rutten will also direct another US0-SP school for USO graduate students on La Palma in October. The H-alpha imaging channel and its companion red-continuum channel got new CCD cameras with better S/N, a larger field of view used at longer focal length. The results are satifisfying. The calibration unit was recently completed and is now in regularly use to help aligning the field of view of all cameras and to assist co-focussing them with high accuracy. The DOT focussing unit was upgraded. It now works more accurately especially at low-altitude pointings. The DOT got a new user interface in order to control the new H-alpha cameras. It has several new features. A H-alpha full-disk camera was also installed and is a great help in locating filaments. A prototype of a 3D optical sensor has been developed to measure deformations on the DOT and GREGOR canopies without interfering observations (STW). General maintainance was done on the concrete telescope foundation during the summer, including covering of the surface by metal gratings as protection against falling ice (a severe problem on La Palma). Meetings since ISC 21 --------------------- - STW canopy meeting, April: Hammerschlag, Bettonvil, Jagers, Sliepen - USO-SP School on radiative transfer and numerical magnetohydrodynamics, Oslo, June: Rutten (teacher), Fischer, Leenaarts, Vitas - CCI, Rome, June: Bettonvil - 2nd European General Assembly of the IHY, Torino, June: Hammerschlag (talk) - SOHO19/GONG2007 Workshop, July, Melbourne: Rutten (talk) - First Hinode science meeting, August, Dublin: Rutten (talk), Fischer, Vitas Milestones ---------- See "DOT publications" at http://dot.astro.uu.nl. A few more DOT papers are in press. The next paper in the "DOT tomography" series will be submitted next week. Critical areas -------------- The longstanding software issues pertaining to the telescope control and data acquisition systems developed over the years by the DepNS IGF are now largely solved thanks to the arrival of software specialist G. Sliepen in the team. The ending of UU's current funding of most of the DOT efforts per January 1, 2008 including the corresponding departure of P. Suetterlin to the SST and shift to EST design studies for F. Bettonvil obviously raises the question "what next". An important consideration in this context is that the Japan-USA-UK Hinode mission (a 50-cm telescope in space which in principle can furnish image sequences just like the DOT's but much more frequently and over longer durations) fails in one important aspect: technical problems with its tunable narrowband filter greatly limit its capability to deliver image sequences in hydrogen Balmer-alpha, the major diagnostic of the solar chromosphere. Since the chromosphere is becoming the major science driver for optical solar physics, this is a very unfortunate setback. At the same time, this failure implies that co-pointing in which the DOT adds Halpha imaging to Hinode's other diagnostics (photospheric imaging plus spectro-polarimetry and EUV coronal imaging and spectrometry) is scientifically very worthwhile. Thus, there is much more scientific motivation to keep the DOT running then was thought in 2004 when Hinode was expected to take over completely. Therefore, currently plans are being developed to keep the DOT functioning for two more years on a minimal budget. A major constraint will be that service-mode observing will no longer be possible unless funding is found to replace P. Suetterlin as on-site DOT observer. Plans for the coming half year ------------------------------ Continuing DOT observing at least in external-user campaign mode (see above). STW-funded tent measurements: wind- and deformation data during La Palma winter storms. Further safeguarding and automation of the DOT operation. Investigation of a proposed OPTICON proposal tool for solar telescopes. Further DOT-future deliberations including potential international partnerships and venues.