ADIMM System Implementation Based On RTS2

The long-term monitoring of astronomical observatories is the importantresearch contents for researchers, it provides necessary technical supports for theefficiently astronomical observing. Hence, how to build a highly integrated andefficiency monitoring system of observatories become one direction of researchers’research topics. The monitoring system of astronomical observatories mainly includesatmospheric seeing monitoring, meteorological information monitoring, cloudmonitoring, et.al. The seeing monitoring is a very important part that it performs wellto estimate the observation condition of astronomical observatories.Atmospheric seeing is often denoted by atmospheric optic coherence length r0, itis the most widely application nowadays. There are many methods to calculate the r0,and the most representative one is the method of differential image motion. It’s veryefficiency that eliminate the influence of none atmospheric factors by the methodwhich calculates the r0value through measuring the relative position change of stellardot on CCD image, And Differential Image Motion Monitor–DIMM–is developedhereby. A stellar can have two dots on CCD image after through the two apertures onDIMM telescope, then the r0value can be calculated by measuring relative distancevariance of this two image dots. DIMM eliminates the influence of none atmosphericfactors, such as telescope’ shaking, and make the measurement results more credible.It becomes popular that more and more researchers use DIMM to measure r0, andit plays very important effect by acting as a tool of astronomical observatories’monitoring and astronomical site selection. Most observatories’ environments are verypoor because their locations are usually at remote area or plateau. This makes theobservation condition very hard that researchers watch over the observation especiallyat the South Pole. Thus, it becomes very necessary that researchers achieveautomation on DIMM (ADIMM) and make it to observe autonomously. Thetechnology of Robotic Autonomous Observatory is necessary for achieve ADIMM.Robotic Autonomous Observatory (RAO) is a telescope system that can executeevery observation task, and can adapt changing environment while nobody intervenes.It has the features of automation and unmanned. This technology is laying a goodfoundation of automation on DIMM, and automation is also a important developingtrend of DIMM.In order to control DIMM devices highly effective, we use an integrated and open source RAO control system based on Linux–Remote Telescope System2nd, RTS2–to proceed research of ADIMM. RTS2system’s developing goal also is automation, ithas merits of environment monitoring, observation targets’ selection, autonomouslyobserving and environment adapting, et.al. RTS2has very strong modularity insystem designing and can easily start or stop modules, it also can switch devicesquickly and its’ system response really fast. Achieving ADIMM by RTS2can take fulladvantage of this advanced system’ merits and control hardware highly effective. Alsowe can get hold of the key technology of RTS2system in order to achieve thebreakthrough on independent autonomous telescope control system development.According to the trait, the hardware configuration of ADIMM system based onRTS2may have these parts: environment monitoring part including meteorologicalstation, cloud sensor and dome; observing devices part including telescope,finder-scope and CCD cameras; control part including computer, RTS2andconnection of hardware. Also, the software control may have these parts: autonomoustarget finding, pointing, autonomous guiding, image processing and calculatingseeing.Refer to above contents, the meteorological station provides in real timemeteorological information to RTS2system, and the cloud sensor provides in realtime cloud information to RTS2system, in order to decide whether the dome can beopened. The finder-scope and CCD camera assist telescope to make accurate pointing.Firstly, the observing target can be centered in finder-scope’s FOV. Secondly, thetarget will be centered in telescope’s FOV. Then, Main CCD camera starts to exposurein order to get DIMM images. After installed RTS2on Ubuntu operating system incontrol computer, all the devices were configured in RTS2system in order to controlthese devices. Autonomous target finding system can synthesize a series of factors tocalculate weight for all observable targets, then select target with highest weight andfinish pointing. In the end, telescope CCD camera starts to exposure in order to getfits images, and execute guiding system, image processing and seeing calculating sothat we can acquire seeing data eventually.