PowerPoint

The Observations of LAMOST Jianrong Shi

NAOC1/7 2014

The Observation of LAMOSTJianrong Shi(NAOC)OverviewThe structure of LAMOST

The observation preparation

How to select the plate

The results from one year Pilot and two year standard surveysStructure of LAMOST

MB mirror6.67 m6.05m4000 Fiber Positioning4000FibersMA mirror5.72m4.4m16 Spectrographs32 CCDsCharacteristics of LAMOST A horizontal meridian reflecting Schmidt telescope with an active correcting plate

large field of view (5 deg) + large aperture (4m) Active optics on thin-mirror & segmented mirrors

4000 optical fibers on focal surface Parallel controllable fiber positioningThe observation preparationFocus the MB ( Shack-Hartman MA) ~5mintues

Focus the MA and four guiding stars (center star V < 8 mag. ) ~25mintues

Moving the fibers to the accurate positions (9mintues)(Which can be done during the focus) MB 6.67m6.05m Focal length 20m 37sub-mirrors

Segmented Active optics for 37 sub-mirrors of MB

#MA 5.72 m4.4m (24 sub-mirrors)

Segmented and thin mirror active optics for 24 sub-mirrors of MA

#4000 fiber positioning units (1.75m)

GuidingCCDsS-H sensorfor MA#4000 fiber positioning units

The site conditions The statistics of the number of hours of BATC observations per night from 2004-01-01 to 2007-09-30. The dashed line shows the theoretical available time.

Sky brightnessThe sky brightness in V band obtained from BATC Polaris monitor data, as a function of time from 1995 to 2011.

Telescope Seeing: 3-5 arcsec (dome + site)Site seeing: < 2 arcsec ; Fiber size: 3.3 arcsechas a field of view as large as 20 square degrees, the effective aperture varies from 3.6 to 4.9 meters in diameter (depending on the pointing). Enables it to take 4000 spectra in a single exposure at resolution R = 1800.Declination-10o60o90oEffective aperture4.9m4.2m3.6mField of view5 degree3 degree

SeeingComparing the seeing from guide star and DIMM during Pilot Survey (Oct. 24, 2011- Match 30, 2012 )Throughpot (Oct. 1 2011)

Signal to Noise Ratio

Signal to Noise Ratio

Signal to Noise Ratio

Signal to Noise Ratio

Signal to Noise Ratio

Throughpot (Oct. 1 2011)

Throughpot (Oct. 2 2011)

How to select the PlateObservational conditions: (240m)weather, Moon phase, left time and seeing etc. VB(9.0