This page presents a dedicated software that computes reliable seeing from star image. This is a "doubled star" created by adding a two holes mask and wedge prism at the telescope entrance pupil.
A digital video camera can be used to acquire the data, and thanks to their frame rate (up to 30 frames per second, depending on the model), it is possible to perform a real time analysis and compute the seeing based on the method explained hereafter :
Measuring Astronomical seeing: the DA/IAC DIMM (J.Vernin,C Muñoz-Tuñon) PDF
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Wavefront outer scale and seeing measurements at San Pedro Martir Observatory (R.Conan, R.Avila and all). PDF
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Influence of defocus on DIMM A. Tokovinin September 14, 2004 PDF
A digital video camera can be used to acquire the data, and thanks to their frame rate (up to 30 frames per second, depending on the model), it is possible to perform a real time analysis and compute the seeing based on the method explained hereafter :
the whole system, or part of it, as an automated DIMM system, such as :
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The software : manual or automatic software that can gather data from dusk to dawn, 24h service Provisions and special designs are possible to make it work during the day, with Sun presence allowing 24/24 service.
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The DIMM mask, the digital video camera to record the image of the doubled star
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Optical telescope tube from 250 mm to 400 mm, RC or cassegrain type, Fratio>8
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Telescope robotic mount, either classical gear/worm mounts, or directdrive mount
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Mount pier, tailored to your requirements.
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Electronic camera finder, beam splitter for easier aiming on start up
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System enclosures such as dome or clamshell, and all the electronics that come with to allow automated operation
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Complete Weather stations, all sky camera, cloud sensors
The double image of one star recorded by the digital video camera
The DIMM mask attached to various kind of telescopes.
One of our complete automatic systems, 12" telescope, absolute encoder telescope mount. Despite this is a "German mount", it has a pointing model and can slew in all sky locations. The pointing accuracy is less than 15 arcsec. This system has an electronic finder to monitor weather, and pointing accuracy.
The imaging train embeds high speed video camera and a flip mirror for starting up the system, when moved in his location, or to a new one in order to tune the mount.
The seeing result as measured by this system, the data is output as a text file, and the current result can be retrieved by a simple TCP client.
Many worldwide class institutes had purchased our complete system, as ready to go. Please contact us for a list of reference institutes.
Chinease academy of science has ordered by us 8 systems to perform seeing measurements in order to achieve site selection for their Optical/Infrared Telescope (LOT) to be sited in western China. The costs of construction are estimated to $220 million. Site selection stakes are high in this case.
