Presentation on theme: "By Keith Schlottman Presented at Texas Star Party 05/16/07."— Presentation transcript:
By Keith Schlottman Presented at Texas Star Party 05/16/07
Have You Ever Used Spectroscopy? Seen a Rainbow? Used a Nebula Filter? Viewed the Sun in H-Alpha? Noticed that Vega is Bluish and Arcturus is Reddish?
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 – 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 SBIG SGSSBIG DSS7LHIRES IIIDG1 FILTER COST$4,950$1,595~ $3,000~ $150 GRATING TYPEReflection Transmission GRATING Lines/mm 150 (Low) 600 (High) 100150, 300, 600, 1200, 2400 200, 500, or 1,000 DISPERSION Angst./pixel w/ST-7 4.3 (Low) 1.1 (High) 5.43.0 (Lowest) to 0.12 (Highest) Up to 0.5 RESOLUTION With ST-7 9Å (Low) 2.4Å (High) 16ÅUp to 0.4ÅVaries λ RANGETuneableFixedTuneableFixed GUIDINGInternal or External None or External Separate or External Internal or External BEST FORStars, Nebulae Nebulae, Galaxies Stars 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. RED BLUE
T Tauri A very young star, still undergoing contraction.
Texas Star Party 2007 Blueshifted absorption feature provides a basis for calculating radial velocity of the expanding shell. Preliminary calculation from this data is ~ 200 km/sec. This data was obtained early Monday morning at TSP Upper Field.
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