Turbulence (or seeing) is a great concern when recording images of the sky, because this is jeopardizing astronomical telescope resolution. Recording images during best seeing is really a big advantage, to do so, continuous seeing measurement is required to optimize image recording time. To get seeing measurements, the DIMM method is mostly used by professionnal observatories in order to measure atmospheric seeing (or turbulence) and allowing to optimize targets and observation programs.
Nevertheless, DIMM method requires a telescope with enough focal length (>3000mm) and enough aperture (>250mm), and to track bright stars the whole night. This is quite stringent and can be a quite costly approach. The telescope needs a shelter, and automatically jump from a star to another.
ALCOR-SYSTEM provides a method to overcome some of the drawbacks of the DIMM system.
In the northern hemisphere, a bright star called "polaris" that does not move so much in the sky and is bright enough.
Application fields of this system are (in a nutshell) :
Nighttime seeing and Ro, transparency monitoring. Site selection and actual seeing monitoring. No mobile parts
- Free Space Optics (FSO) communication
Nighttime seeing and Ro, Site monitoring, data provided at 1.55µm, bandwidth predictions
- Atmospheric studies
Atmospheric turbulence, Jet stream localization, passive optical sensing.
Atmospheric turbulence for remote sensing.
This product can be combined with our all Sky cameras.
The goal of this product is to measure atmospheric seeing condition in a continuous fashion, so this setup stays outdoor all the time 24h a day, and is aimed at the polaris star in a fixed fashion.
This system can only work in the northern hemisphere, at latitudes above 15° North, for southern hemisphere please contact us for solutions.
The fixed seeing monitor is a totally sealed system that can overcome all extreme weather conditions, and is not sensitive to wind gust due to its strong design. The software starts measurements automatically when the Sun is below the horizon and only when the stars are visible.
The system has four temperature sensors and two humidity sensors so that warming up of the entrance window is automatic (to prevent dew from forming), and also controls the cooling of the seeing detector.
The added value of this product compared to competitors are :
- better measurement accuracy because of more and smaller pixels
- the front window is heated against dew
- ethernet link to the host
- ability to measure very low seeing figure, whereas other systems are not reliable under 1.5 arcsec.
- strong and robust construction, that avoid measurements to be jeopardized by wind gust