AMATEURSPECTROSCOPY By Keith Schlottman Presented at Texas Star Party 05/16/07
Have You Ever Used Spectroscopy? Used a Nebula Filter? Noticed that Vega is Bluish and Arcturus is Reddish? Seen a Rainbow? Viewed the Sun in H-Alpha?
The Spectrum Tells A Story • Stars • Stellar classifications / HR Diagram • Age of star • Surface gravity • Pressure • Surface temperature • Radial velocity • Identify spectroscopic binaries • Other Objects • Galactic and Quasar redshifts • Nebular compositions • Comets and Planets
Equipment – Visual Spectroscopy • Prism • CD-ROM • Project Star Spectrometer • Naked Eye (Rainbows & Moonbows)
Equipment – Telescopic Spectrographs • More Expensive • SBIG SGS • LHIRES III • Baader DADOS • Sivo Scientific Nu-View II • Moderately Expensive • SBIG DSS-7 • Less Expensive • DG Spectrum Filters • Rainbow Optics Star Spectroscopes • Rigel Systems RS-Spectroscope • Paton Hawksley Star Analyser • Build Your Own
Comparison of 4 Spectrographs Information based on my experience and manufacturer claims, may not be 100% accurate
Acquiring Data With the SGS • Use CCDSoft • Guide on Slit • Binning 1x4 • Note that images are monochrome!
Processing Data • Dark Subtract, Median Combine (CCDStack) • Rotate if Low-Res Mode (IRIS) • Wavelength Calibration (vSpec) • Flux Calibration for CCD Response (equivalent to Flat Field)
Wavelength Calibration - H Edmund Scientific Lamps are used
Spectral Types Spectra taken with The SBIG SGS on a 12” LX-200GPS from my Tucson backyard on October 16 & 17, 2006. BLUE RED
Emission Nebula The OIII emission lines were thought to be a new element in the early 20th century, “Nebulium”.
Pro-Am Collaborations Amateur spectroscopists were asked to obtain data on this star, which was a target for the COROT satellite.
T Tauri A very young star, still undergoing contraction.
Texas Star Party 2007 This data was obtained early Monday morning at TSP Upper Field. Blueshifted absorption feature provides a basis for calculating radial velocity of the expanding shell. Preliminary calculation from this data is ~ 200 km/sec.
DG Spectrum Filter • Zero and First Order on Main Chip Vega • Use Known Lines to Calibrate in vSpec
The Easiest Spectrum to Observe –No Equipment Necessary! For more information see: http://www.xanaduobservatory.com