Measurements of atmospheric turbulence parameters at Vainu Bappu Observatory using short-exposure CCD images
|
摘要
We report atmospheric turbulence parameters, namely atmospheric seeing, tilt-anisoplanatic angle(θ_0) and coherence time(Τ_0), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of short exposure images of selected stars were recorded with a high-speed, frame-transfer CCD mounted on the Cassegrain focus of a newly commissioned 1.3 m telescope. The estimated median seeing is ≈ 1.85 " at wavelength of ～ 600 nm, the image motion correlation between different pairs of stars is ～44% for θ0≈ 36" and mean Τ_0 is ≈ 2.4 ms. This work was motivated by the design considerations and expected performance of an adaptive optics system that is currently being planned for the telescope.
We report atmospheric turbulence parameters, namely atmospheric seeing, tilt-anisoplanatic angle(θ_0) and coherence time(Τ_0), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of short exposure images of selected stars were recorded with a high-speed, frame-transfer CCD mounted on the Cassegrain focus of a newly commissioned 1.3 m telescope. The estimated median seeing is ≈ 1.85 " at wavelength of ～ 600 nm, the image motion correlation between different pairs of stars is ～44% for θ0≈ 36" and mean Τ_0 is ≈ 2.4 ms. This work was motivated by the design considerations and expected performance of an adaptive optics system that is currently being planned for the telescope.
We report atmospheric turbulence parameters, namely atmospheric seeing, tilt-anisoplanatic angle(θ_0) and coherence time(Τ_0), measured under various sky conditions, at Vainu Bappu Observatory in Kavalur. Bursts of short exposure images of selected stars were recorded with a high-speed, frame-transfer CCD mounted on the Cassegrain focus of a newly commissioned 1.3 m telescope. The estimated median seeing is ≈ 1.85 " at wavelength of ～ 600 nm, the image motion correlation between different pairs of stars is ～44% for θ0≈ 36" and mean Τ_0 is ≈ 2.4 ms. This work was motivated by the design considerations and expected performance of an adaptive optics system that is currently being planned for the telescope.
引文
Belen’kii,M.S.,Karis,S.J.,Brown,II,J.M.,&Fugate,R.Q.1997,in Proc.SPIE,3126,Adaptive Optics and Applications,eds.R.K.Tyson,&R.Q.Fugate,481
Breckinridge,J.B.,ed.1994,Proc.SPIE,2200,Amplitude and Intensity Spatial Interferometry II
Davis,J.,&Tango,W.1996,PASP,108,456
Fried,D.L.1965,Journal of the Optical Society of America(1917-1983),55,1427
Fried,D.L.1966,Journal of the Optical Society of America(1917-1983),56,1372
Fried,D.L.1975,Radio Science,10,71
Gerchberg,R.W.1972,Optik,35,237
Goode,P.R.,Wang,H.,Marquette,W.H.,&Denker,C.2000,Sol.Phys.,195,421
Hardy,J.W.1998,Adaptive Optics for Astronomical Telescopes(Oxford Univ.Pres),448
Hoffleit,D.1964,Catalogue of Bright Stars(3rd edn.;New Haven,Conn.:Yale Univ.Observatory)
Kellerer,A.,&Tokovinin,A.2007,A&A,461,775
Martin,H.M.1987,PASP,99,1360
Mc Clure,R.D.,Arnaud,J.,Fletcher,J.M.,Nieto,J.-L.,&Racine,R.1991,PASP,103,570
Sarazin,M.,&Roddier,F.1990,A&A,227,294
Sivaramakrishnan,A.,Weymann,R.J.,&Beletic,J.W.1995,AJ,110,430
Teoste,R.,Daley,Jr.,J.A.,Capes,Jr.,R.N.,Alves,J.J.,&Zimmerman,M.D.1988,Measurements of Tilt Anisoplanatism at the Firepond Facility,Tech.Rep.(Massachusetts Inst Of Tech Lexington Lincoln Lab)
Tokovinin,A.2002,PASP,114,1156
Tyson,R.K.1998,Principles of Adaptive Optics(Principles of Adaptive Optics,(2nd edn.;Boston:Academic Press)
von der Luehe,O.1984,Journal of the Optical Society of America A,1,510
Wilson,R.W.,O’Mahony,N.,Packham,C.,&Azzaro,M.1999,MNRAS,309,379
1https://www.princetoninstruments.com/userfiles/files/
2 ProEM EMCCD Camera Systems, ftp://ftp.piacton.com/Public/Manuals/Princeton
3 Princeton Instruments ProEMCCD, https://www.princetoninstru ments.com/userfiles/files/assetLibrary/Datasheets/ProEM-HS-1024BX3-and-1KBX3-10um-datasheet-P4-5-16-17.pdf
4Phase Unwrapping, https://scikit-image.org/
Breckinridge,J.B.,ed.1994,Proc.SPIE,2200,Amplitude and Intensity Spatial Interferometry II
Davis,J.,&Tango,W.1996,PASP,108,456
Fried,D.L.1965,Journal of the Optical Society of America(1917-1983),55,1427
Fried,D.L.1966,Journal of the Optical Society of America(1917-1983),56,1372
Fried,D.L.1975,Radio Science,10,71
Gerchberg,R.W.1972,Optik,35,237
Goode,P.R.,Wang,H.,Marquette,W.H.,&Denker,C.2000,Sol.Phys.,195,421
Hardy,J.W.1998,Adaptive Optics for Astronomical Telescopes(Oxford Univ.Pres),448
Hoffleit,D.1964,Catalogue of Bright Stars(3rd edn.;New Haven,Conn.:Yale Univ.Observatory)
Kellerer,A.,&Tokovinin,A.2007,A&A,461,775
Martin,H.M.1987,PASP,99,1360
Mc Clure,R.D.,Arnaud,J.,Fletcher,J.M.,Nieto,J.-L.,&Racine,R.1991,PASP,103,570
Sarazin,M.,&Roddier,F.1990,A&A,227,294
Sivaramakrishnan,A.,Weymann,R.J.,&Beletic,J.W.1995,AJ,110,430
Teoste,R.,Daley,Jr.,J.A.,Capes,Jr.,R.N.,Alves,J.J.,&Zimmerman,M.D.1988,Measurements of Tilt Anisoplanatism at the Firepond Facility,Tech.Rep.(Massachusetts Inst Of Tech Lexington Lincoln Lab)
Tokovinin,A.2002,PASP,114,1156
Tyson,R.K.1998,Principles of Adaptive Optics(Principles of Adaptive Optics,(2nd edn.;Boston:Academic Press)
von der Luehe,O.1984,Journal of the Optical Society of America A,1,510
Wilson,R.W.,O’Mahony,N.,Packham,C.,&Azzaro,M.1999,MNRAS,309,379
1https://www.princetoninstruments.com/userfiles/files/
2 ProEM EMCCD Camera Systems, ftp://ftp.piacton.com/Public/Manuals/Princeton
3 Princeton Instruments ProEMCCD, https://www.princetoninstru ments.com/userfiles/files/assetLibrary/Datasheets/ProEM-HS-1024BX3-and-1KBX3-10um-datasheet-P4-5-16-17.pdf
4Phase Unwrapping, https://scikit-image.org/