1. APEX (ATACAMA PATHFINDER EXPERIMENT) Heiko Hafok, Dirk Muders Max-Planck-Institute for Radioastronomy, Bonn, Germany

2. APEX collaborators: Max-Planck-Institute for Radioastronomy, Bonn, Germany (50%) European Southern Observatory (ESO) (27%) Onsala Space Observatory, Chalmers, Sweden (23%)

3. The site of APEX at 5105m: Pazifik APEX Quelle: Wikipedia Quelle: ESO

4. APEX is in regular science operation since July 2005

5. APEX Key Facts Telescope LocationLlano de Chajnantor, 50km east San Pedro de Atacama, Northern Chile Coordinates Latitude Longitude Elevation 23º00′20.8″ South 67º45′33.0″ West 5107m Telescope diameter12 m Total mass125 t Main reflector264 aluminium panels, average panel surface r.m.s. 5 µm Overall surface accuracy17 µm Pointing accuracy2“ r.m.s. over sky ManufacturerVertex Antennentechnik GmbH, Germany Optics: f/D Beam width (FWHM) Receiver cabins 8 7.8 ″ (800 / f [GHz]) 2 Nasmyth, 1 Cassegrain Instrumentation: Spectral coverage Frontends 200-1500 µm Heterodyn single-pixel + array receivers Large bolometer cameras BackendsFacility Autocorrelator New technology Fast Fourier Transform Spectrometer

6. ACS @ APEX APEX uses the same vendor-supplied control computers (ACU & PTC) and the same CAN bus interface (ICD 9) like ALMA It was thus decided to re-use the ALMA prototype telescope control software (TICS & ACS) and most of the corresponding control hardware setup

7. ACS / TICS Versions APEX is using TICS and thus ACS under VxWorks The ACS version in use has been determined by TICS (currently ACS 2.0.1) Preliminary work to port to ACS 6.x started, but currently on hold because of other commitments. This requires porting of both: –TICS under VxWorks (replaced in ALMA by a new Control System based on Real Time Linux) –The APECS layer (see next slide)

8. APECS (APEX Control System) Developed a number of generic instrument interfaces and C++ components using the U Bochum code generator, UDP socket DevIO and embedded system SCPI parsers Added Python Observing Engine, Raw Data (MBFITS) Writer, Calibrator, Monitoring Engine, Observations Logger, Observer CLI based on IPython and many more (see ADASS XV) APECS v0.8 is now used regularly for science observations

9. APECS Class Diagram

10. Deployment APECS is deployed at three locations: –Telescope (co-rotating) –Control room Chajnantor –Control room Sequitor 8 PCs with ACS/TICS/APECS, 1 VME computer, 5 embedded systems

11. ACS Experience General setup works as expected Distributed deployment without major problems Monitoring properties very valuable Notification channel (in ACS 2) is affected heavily by client behavior and can bring system to a halt Alarm system in ACS 2 not yet adequate No access control for critical components

12. @ www.apex-telescope.org cu…at the telescopewww.apex-telescope.org