TOPS 2003 Remote Obs 1 Karen Meech Institute for Astronomy TOPS 2003 Image copyright, R. Wainscoat, IfA Image courtesy K. Meech

How to Observe? The TOPS model The TOPS model Amateur “fun” Amateur “fun” TOPS 2002

How to Observe Professional Observing Professional Observing Request Telescope time Request Money Ultra-prepared Each nano-sec is precious Images, Courtesy K. Meech

Queue Scheduling Section of Targets Section of Targets Time critical? Time critical? Plan exposure times, filters Plan exposure times, filters Auto-scheduler Auto-scheduler Optimizes observing Optimizes observing Flexible for conditions Flexible for conditions No interactivity No interactivity Many chances for data Many chances for data Notification of data receipt Notification of data receipt Image, Courtesy K. Meech STScI

Types of Observations Brightness Brightness Hipparcos  magnitudes Hipparcos  magnitudes m = -2.5 log (B) + c m = -2.5 log (B) + c Brightness vs Time Brightness vs Time Intrinsic variability Intrinsic variability Other changes Other changes Wavelength Information Wavelength Information Position Position Morphology Morphology Size Size Structure Structure Photometry Photometry Measure of accumulated light arriving at detector Astrometry Astrometry Precise measurement of position Transformation of 3-D sky onto a 2-D surface Surface brightness Surface brightness Brightness per unit area Images, Courtesy K. Meech

Photometry Counting up how much light falls on the detector from star Counting up how much light falls on the detector from star Aperture Aperture How big to use? How big to use? Sky Background Sky Background Where to measure? Where to measure? How? How? Background objects Background objects Images, Courtesy J. Bauer

Surface Brightnesses Measure of brightness per unit area Measure of brightness per unit area Point sources Point sources Brightness does not depend on aperture size Brightness profiles Brightness profiles Dust activity Measure of amount of material Falloff  gravity field Missing mass Image, Courtesy K. Meech NASA, STScI

Surface Brightness Photometry Measure light in central aperture Measure light in central aperture Measure light in successive annuli Measure light in successive annuli Plot brightess (mag) versus area Plot brightess (mag) versus area Mag / arcsec 2 Mag / arcsec 2 Images, Courtesy J. Bauer

Some Examples Images, Courtesy K. Meech & J. Bauer

Beta Pictoris

Absolute Photometry Absolute Absolute True brightness Photometric (Eggen-o- metric) Requires standards “Know thy celestial sphere” “Know thy celestial sphere” Extinction; seeing HA = 0 Depends on declination Images, Courtesy K. Meech Copyright R. Wainscoat

Differential Photometry Relative brightness Relative brightness Tolerates some cloud Tolerates some cloud Corrects for extinction Corrects for extinction Airmass Airmass cloud cloud Measure many stars as reference Measure many stars as reference Noise & repeat measurements – S/N Noise & repeat measurements – S/N Images, Courtesy K. Meech

Differential Light curve Images, Courtesy K. Meech

Resolution Telescope Telescope Res = 1.22 /D Res = 1.22 /D Atmosphere – seeing Atmosphere – seeing Seeing depends on  Seeing depends on  Angular Size Angular Size S = r  S = r  Plate scale Plate scale Arcsec / pixel Arcsec / pixel

Resolution Images from Yerkes Obsty.

Resolution Know your observing site Know your observing site MKO  superb seeing Lowell  worse Conditions are time variable Conditions are time variable NASA Images

Astrometry Precise position meas Precise position meas Map 3-D sky to 2-D image Map 3-D sky to 2-D image Technique Technique Measure “centroids” of many stars Measure “centroids” of many stars Fit for plate center Fit for plate center Fit for scale, rotation Fit for scale, rotation Fit for warping, stretching Fit for warping, stretching Requirements Requirements Finding the objects Finding the objects Blinking Blinking Different color planes Different color planes memorization memorization 6.6’ FOV (1/2 CCD) [above] 40” section [lower] Images, Courtesy K. Meech

Astrometry Precise position meas Precise position meas Map 3-D sky to 2-D image Map 3-D sky to 2-D image Technique Technique Measure “centroids” of many stars Measure “centroids” of many stars Fit for plate center Fit for plate center Fit for scale, rotation Fit for scale, rotation Fit for warping, stretching Fit for warping, stretching Requirements Requirements Finding the objects Finding the objects Blinking Blinking Different color planes Different color planes memorization memorization 6.6’ FOV (1/2 CCD) [above] 40” section [lower] Images, Courtesy K. Meech

Colors & Spectroscopy Chemistry vs distance  origins Chemistry vs distance  origins Spectroscopy is best tool for composition Spectroscopy is best tool for composition Colors – a “poor man’s” solution Colors – a “poor man’s” solution Images, Courtesy J. Bauer

The Wild & Wonderful World of Filters Figure, Courtesy K. Meech

HST – Cone Nebula