Presentation on theme: "Jozef Žižňovský Stakčín, December 2012"— Presentation transcript:
1 Jozef Žižňovský Stakčín, December 2012 PROJECT OF THE 130 cm TELESCOPEFOR THE SKALNATÉ PLESO OBSERVATORYJozef Žižňovský Stakčín, December 2012
2 The described system consists of a 1 The described system consists of a 1.3m alt-az mounted Cassegrain-Nasmyth telescope with two Nasmyth focal stations.Both Nasmyth focal stations are equipped with a field derotator.It contains a control system and a software communicating with the dome control unit and a meteostation.In principle it is a robotic telescope.Manufacturer and supplier: ASTELCO Systems GmbH, MünchenInstruments in the foci:CCD camera for near UV, visual and red spectral regionIR CCD camera for infrared regionEchelle spektrographIt will be provided in the frame of the European Regional Development Fundin three steps:1. Telescope: till the end of 20132. Dome computerisation : 20133. Focal instruments and infrastructure: Spring 2014
5 The primary mirror is a thin low expansion glass meniscus. Its shape and optical performance therefore has to be actively controlled duringthe observations.The active mirror support system consists of a combination of an 18 pointwhiffle-tree support and 9 axial actuators. The actuators are controlled bya Shack-Hartmann sensor unit as a part of the telescope system, like theautofocus thermal control.The Shack-Hartmann unit allows checking the online alignment performanceof M1 and M2 mirrors and helps to regain the collimation of the optics afterrecoating.The primary mirror is fixed radially by a 4 point preloaded spring pad system,which guarantees the permanent position of M1 during all telescopemovements between zenith and horizon positions as well as at high slewingrates of the telescope.The surface accuracy of the optical system will be proven by interferogramsat factory acceptance.At final acceptance, there will be on-sky tests carried out at the Observatorywith the supplied Shack-Hartmann sensor unit available at the Nasmyth focalstation.
6 2. Mechanics2.1 DimensionsMaximum height (tube in vertical position)*440 cm**Minimum height (tubus in horizontal position)*300 cm**Optical tube lengthsMaximum radius of movement (horizontal position)215 cm**Required concrete foundation diameterTotal weight of the telescope in basic specification~ 7 t* Calculated from the lower surface of the telescope basis ** Dimensions after the preliminary design phase
7 2.2 Telescope structureThe structure of the telescope is a special, super-compact “ASTELCO Design”.The telescope tube is a welded Serrurier truss design made from steel. This guarantees a minimal and predictable bending of the tube. All welded parts of the telescope are annealed to relax tensions. This very stiff and rigid design reaches high values for the eigenfrequencies of the system and therefore allows observing at wind speeds up to 15 m/s.The telescope’s central part connects the upper and lower truss sections and holds the combined motorized M1/M3 mirror doors. This section connects the tube assembly by means of two hollow flanges to the fork arms of the mount. Through these hollow flanges the light path of the telescope is sent to oneof the 2 Nasmyth foci.A motorized rotating and self-centering M3 unit is provided to reach both Nasmyth foci by software control. Rapid and precise focus change between the two Nasmyth foci gets a simple standard task to be able to use two different instruments at two foci at practically the same time.The lower Serrurier truss part holds the mirror cell with the M1 primary mirror. The mirror cell allows easy access for maintenance – for mounting and dismounting the primary mirror a special ASTELCO tool is supplied.
9 2.3 Telescope mount and drives The tube assembly is mounted between both fork arms of the alt-az mount.The fork arms are connected to the mounting base plate.On the upper end of the fork arms the bearing housings, the encoders andthe motors are located.The accuracy of the perpendicularity of axes is < 10 arc sec; residual errorsare corrected by the software.Slewing speed* 20°/sec20°/secAbsolute pointing accuracy< 5 arcsec RMSDifferential pointing accuracy< 0.2 arcsec RMSTracking accuracy without autoguider< 0.5 arcsec/10 minTracking accuracy with autoguider< 0.25 arcsec/10 minEffective encoder resolution328 increments per arc sec (0.003 arc sec / increment)
10 FOCAL INSTRUMENTS CCD camera for near UV to red spectral region Quantum efficiency in the interval of nm: 80%Sensor size 10k x 10k, class: 1Pixel size: 8-10 µmInterface for communication with the computer via fiber optic cable(1 Gbit)Dark current maximum: 0.01e‐/pixel/secReadout noise: less than 5e- (rms)16 bit AD converterCooling with cryotiger to < -100° CExample: Spectral Instruments 1110S
11 2. IR CCD camera for near infrared region Quantum efficiency in the interval of nm: 70%Sensor size 2k x 2k, HgCdTe technology, class 1Pixel size: 15 µmDark current maximum: 0.01e- /pixel/secReadout noise: less than 20e- (rms)16 bit AD converterCooling with a Stirling engine to 70° K (-203° C)without the necessity of liquid Nitrogen useExample: Teledyne Scientific(Manufacturer and supplier of detectors forthe Hubble Space Telescope and the James Webb Space Telescope)
12 3. SpectrographHihg-dispersion échelle spectrograph to the Nasmyth focus:R = for seeing 3"Spectral region: nmCCD camera 2k x 2kCalibration lamps for ThAr line spectrum and continuum lightInterchangeable slits (apertures)Software for remote control of the spectrograph and its CCD cameraManufacturer, contractor: Lasertechnik BerlinSubcontractor: Hamburger Sternwarte
14 Price (incl. VAT): Telescope 1 030 000 € Dome automatization 53 500 € Spectrograph €CCD camera €IR CCD camera €Coating unit for the 130 cm mirror €Fiber optic cable from Poprad €Data storage devices €Diesel-electric generator €∑ €Sponsored by:European Regional Development Fund, %