In January 2004, a few but significant changes have been introduced at the Calar Alto Observatory. Most importantly and of immediate significance, Spanish and German astronomers now receive an equal share of observing time. The change in the telescope time allocation is the direct consequence of ongoing negotiations between the Consejo Superior de Investigaciones Científicas (CSIC) and the Max-Planck Society (MPG), concerning the joint operation of the observatory. The CSIC-MPG collaboration still awaits final signature but all major issues are agreed upon. In practical terms, Calar Alto is to be converted into an independent, legal entity which is fully embedded into Spanish Law. Scientific publications which result from observations after January 1st, 2004, should acknowledge this change in a footnote to the article. The new collaboration with CSIC has attracted this years Calar Alto Colloquium and the spring meeting of the time allocation committee, to the city of Granada.

Calar Alto forms part of the Opticon/COMET network which provides telescope access to international programmes from European member and associated states. Access time is granted at a level of some 5-10% depending on the facility within the network. Scientific programmes which qualify for the access programme will receive travel & subsistence funding from the European Union. A detailed description, qualification criteria and participating facilities is available via the Calar Alto portal at www.caha.es/wording.html and via the pages of the transnational access office which has been set up at the IAC ( www.otri.iac.es/opticon/). The long-term vision of the COMET network foresees coordinated instrumentation programmes, joint developments of data reduction pipelines and telescope operation strategies, and other collaborative efforts among European operators of 2-4m class telescopes.

A significant improvement has been achieved with LAICA, Omega2000, and PMAS. The first science runs scheduled with the 3.5m prime focus optical imager LAICA were severely hampered by malfunctioning detectors. From its 4 CCDs, three did not work properly. One suffered from a broken substrate, one died completely, and only half of a third detector was usable. In October 2003, the instrument returned to the 3.5m telescope with three new detectors. Final telemetry is presently being determined at the MPIA, and the full optical wide-field imaging capability will be restored for the autumn semester. During the October 03 commissioning run, an image quality of 0."7 has been measured on the detector.

During commissioning runs in 2003 it was found that the original 2Kx2K HAWAII detector of Omega2000 suffered from a pronounced non-linear behaviour and had to be replaced. In order to carry out the scheduled science runs of the autumn semester of 2003, the detector from LUCIFER has been made available for Omega2000. A new 2K HAWAII detector has been ordered and is to be received during the next few weeks. According to the data sheet that is already available, the new Omega2000 detector is of superb cosmetic quality. Problems with a number of narrow band filters persist, however. New filters have been ordered but delivery is suffering from large delays. The potential user of Omega2000 is advised to consult our webpages for updated information on the filters.
An example of the capabilities of Omega2000 is given in this mosaic of 12 H-band images toward the HIROCS 22hr field. The upper image covers a bit less than 1 square degree. Each image has a total integration time of 25 x 1 min. The limiting magnitude (S/N=5) for 50 min of total integration time in the H band is 21.2 mag. The image quality is of the order of 0."8.

An important instrument upgrade has been performed at PMAS. While PMAS provides a unique wavelength coverage, in terms of field of view the instrument has not been competitive. This was because the initial science cases were related to the spectroscopy of crowded fields and faint background limited objects. The 16"x16" lenslet array is, however, too small to be used efficiently for the study of extended objects such as spiral galaxies. Therefore, a new integral field unit has been developed which is based on a fibre bundle. The PPAK fibre bundle consists of a hexagonal, dense packed array of 331 object fibres, surrounded by 36 sky fibres and 12 calibration fibres. The individual PPAK fibres are 2."7 in diameter and cover a total FOV of 75". With PPAK, PMAS is competitive with VIMOS, the VLT integral field unit. For the study of objects fainter than the surface brightness of the sky, detection limits in low and medium resolution spectroscopy are determined by the incomplete subtraction of the bright and varying sky. In order to improve the detection limits, a nod and shuffle beam switching technique has been installed. The method is similar to beam-switching which is commonly used in infrared observations.

The highlights of this newsletter are, as always, the scientific contributions provided by the visiting astronomers.
López & Montes report on the results of their spectroscopic survey of late-type stars in young stellar kinematic groups. Among other results such as radial velocities, spatial motion and age determinations from LiI, the authors confirm a clear trend of increasing chromospheric activity with increasing stellar rotation as measured from photometric periods. Pascual and collaborators introduce their long-term study of star-forming galaxies at z=0.24, which suggest that the properties of their Halpha selected galaxies are very similar to those of local galaxies selected in the same way, which is an important result to understand the star formation rate at this redshift. Verdes-Montenegro presents the AMIGA survey, which aims at a detailed study and the characterisation of the different phases of the interstellar medium in a complete, unbiased sample of isolated galaxies. And last but not least, Fernández and collaborators discuss their multisite observing campaign of the WTTS V410 Tau.
It is remarkable that all scientific contributions in this newsletter are from Spanish astronomers, a clear indication that there is a high interest of Spanish astronomers in the use of Calar Alto facilities.