Astronomical PhotometrySlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Astronomical Astronomical PhotometryPhotometryHow to get from thereto hereQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.Stars, sky, observing, telescope, filters, detector, noise, reduction, graphingApparent magnitudeApparent magnitude of a star will depend on:Luminosity Distance (F is flux)Stuff in between it and us (extinction; reddening)L 4r2T4F 1d2Definition of magnitude (visual wavelengths):mv(A) mv(B) 2.5[log Iv(A) log Iv(B)]Definition of “color” of a star:m(1) m(2) 2.5[log I(1) log I(2)]U B mU mB, B V mB mVV R mV mR, R I mR mIQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.Getting the effective temperature of a star using UBVRI FILTERS Color of star will also depend slightly on chemical composition(metal-rich vs metal-poor)B V RB V RQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.We always use filters. Original filter set was for a photometer, not CCDs. Telescopes may have different sets of filters (width and peak of band passes may differ, response may differ); may need to TRANSFORM magnitudes to a standard system.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.Antares/Rho Ophiuchus RegionQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.Reddening(“de-bluing”)QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.Find star hereExtrapolate thereColor ExcessColor Excess E(21) [m(2) m(1)]observed [m(2) m(1)]unreddenedSlope of the reddening line for stars earlier than A0:E U B E B V 0.72 0.05 B V For cooler stars, must use spectroscopy.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompress ed) decompressorare needed to s ee this picture.Bad, badder, baddest!QuickTime™ and aTIFF (Uncompressed) decompress orare needed to s ee this picture.sec z sinsin coscoscosHA 1X sec z 0.0018167 sec z 1 0.002875 sec z 1 2 0.0008083 sec z 1 3ZQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.CV’sCV’sQuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.FIG. 1.Light curves are presented for the six variable stars. Points represent observed data in B (filled circles), V (asterisks), and I (open circles). The dotted curves represent the best-fitting template to the observed data. The vertical axis in each panel spans 2
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