Photometry of a Sodium Laser Guide Star at the Starfire Optical Range

• Published in: Publications of the Astronomical Society of the Pacific Vol. 116; no. 817; pp. 278 - 289
• Main Authors: Drummond, Jack, Telle, John, Denman, Craig, Hillman, Paul, Tuffli, Andrea
• Format: Journal Article
• Language: English
• Published: The University of Chicago Press 01.03.2004; 01.03.2004
• Subjects: Apparent magnitude; Astronomical magnitude; Laser beams; Laser power; Lasers; Photons; Predetermined motion time systems; Sodium; Telescopes; Wavelengths
• ISSN: 0004-6280; 1538-3873
• DOI: 10.1086/382756

Measurements of a laser‐pumped sodium guide star produced over the Starfire Optical Range in 2002 November show that the brightness of the spot produced by 11.5 W of linearly polarized power on the sky was equivalent to a \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $V=8.0$ \end{document} mag star. However, taking into account that the transmission through aVfilter is only 55% at the wavelength of sodium, its corrected magnitude, \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $V_{1}$ \end{document} , was 7.4, or 800 photons s−1cm−2at the top of the telescope. In 2003 March, tests with linearly and then circularly polarized beams out of the telescope showed that a circularly polarized beam from 12 W of power out of the telescope produced a spot with \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $V_{1}=7.1$ \end{document} (1015 photons s−1cm−2at the top of the telescope), 0.7 mag brighter than a linearly polarized beam from 11.1 W of power out of the telescope. Over the 4 nights of experiments over two seasons, the apparent 2σ width of the spot varied between 3 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\farcs$\end{document} 6 and 4 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $\farcs$\end{document} 6, or 1.6 and 2.0 m at 92 km altitude, and its length through the sodium layer was 4.6–8.5 km, but no variation of spot size with power on the sky was seen.