The Official Publication of the Amateur Astronomers Association of Princeton Director John Miller (609) 252-1223 jmiller@princetonastronomy.org Assistant Director John Church (609) 799-0723 j.church@mindspring.com Treasurer Program Chairman Michael Mitrano Ludy D'Angelo 609-737-6518 (609) 882-9336 ... 273-1456 (732) 469-7698 and (609) 448-8644 kane@princetonastronomy.org editors@princetonastronomy.org Volume 38 From the Director March ... Please join us in Peyton Hall on March 10th. ...

ELT MASS/DIMM instrument for atmospheric turbulence measurements. ... 1.2 Principal geometry of MASS­DIMM device . ... The next chapter is a guide for alignment of the optical scheme elements ­ the op eration which is mandatory after the device assembly or while installing the device on the telescop e. Exit pupil optics tuning (MASS segmentator and DIMM mirrors), fo cusing and lateral p ositioning of the Fabry lens, checking the entrance pupil p osition are the sub jects of particular attention. ...