Bonn Shutters

Background

As members of the former Instrumentation Group at the Argelander Institute for Astronomy (AIfA) of the University of Bonn we have continued the long lasting successful technical developments with our own private company "Bonn-Shutter UG". We cooperate with the University. Our focus is on high precision exposure shutters of various formats. Bonn Shutters with apertures from 60mm to 600mm are in use at CCD cameras for telescopes at major astronomical observatories around the world. Standard formats are currently square aperture shutters of 100mm, 125mm, 200mm and 280mm. We develop other formats on demand.

A design for a scalable large format exposure shutter for CCD mosaic cameras has been developed at the Astronomical Institutes of the University of Bonn (now the "Argelander Institute for Astronomy", AIfA) as part of the BUSCA project. BUSCA  the Bonn University Simultaneous CAmera is  based on 4 independent CCD systems (4Kx4K pixels each) for simultaneous imaging in four color bands (at the 2.2m telescope at Calar Alto). This first Bonn Shutter has an aperture of 110mm x 110mm.

The Bonn Shutter is a slit type shutter with a rectangular aperture. It is a low acceleration impact-free device. It consists of three main components --- mechanics, control electronics hardware and control electronics software --- which play together to achieve the shutter performance: Photometric accuracy of  the order of  1% at an exposure time of 0.1sec (i.e. timing accuracy of 1msec) at any position across the aperture. The table below gives typical specifications and performance parameters.

Bonn Shutter parameters and specs
Shortest exp. time About 1msec.
Exposure homogeneity Deviations <+-0.5% at 100msec exposure time.
Exposure  time accuracy About 0.3msec.
Expected lifetime >1 Million operations (Endurance test with 10**7 operations passed)
Dead time 0.2sec - 1sec depending on aperture size
Blade material Carbon fibre or sandwich
Movement control Microcontroller system. Software programmable velocity profile.
Exposure control External, TTL (but internal exposure timing provided).
Control Interfaces Control and status lines, RS232 line.