A HANDY SPECTROGRAPH AND ITS APPLICATION IN ASTRONOMICAL EDUCATION

Abstract

I use a common educational spectrographic device (SV2100R) in order to obtain astronomical spec-tra after inventing a new adaptor for telescopes. Experimental classes and learning projects in schoolsand public outreach are well established regarding imaging and photometry observations. However, ex-periments using astronomical spectrographs are rather hard to nd because the procedures of spectralextraction and wavelength calibration is less convenient. SV2100R is a 1D CCD array and thus has theadvantage of not requiring spectral extraction. In addition, basic wavelength calibration is preformed bythe the provided software. It was adapted to a 12-inch reecting telescope in the Korea Science Academyof KAIST in Busan and a spectrum of the bright object, Arcturus, was successfully obtained. This meansone can provide educational programs on the topic of astronomical spectra. A few suggested projects arepresented.Key words: Spectroscopy; adaptor; education1. INTRODUCTIONLight gives important information and spectra play akey role in investigating stellar temperatures, chemicalcompositions and relative motions. Electromagnetic ra-diation is one of main objectives of education in as-tronomy as well as for Newton dynamics. Introduc-tory astronomy often teaches about spectral properties,Doppler shift, Wien’s law, Stefan-Boltzman’s law, andKirchho ’s law (Bardar & Brecher 2008; Slater et al.2001).Major learning objectives are 1) having an intrinsicinterest in science, 2) developing critical reasoning skillsand 3) understanding nature. Self-motivated learn-ing is thought to be an e ective learning process andproject based education is becoming important, as wellas lecture-based methods. Handling telescopes in astro-nomical observatories is a good tool for active learning inastronomy. Most educational programs using telescopesfor imaging or photometric observations at universities,schools for science and public outreach in astronomi-cal centers. Understanding and experiments for electro-magnetic spectra have an important role in educationfor introductory astronomy. The development of spec-troscopic experiments using telescope will be helpful fordeveloping knowledge of light and electromagnetic spec-tra for both introductory astronomy and self-motivatedscience projects.In schools, universities and public outreach programs,the prism or grating lm is normally applied to ob-http://pkas.kas.orgserve the spectrum of light sources. It is straightfor-ward, however it is not recordable. If the grating lm iscombined with a DSLR camera, the spectrum could beeasily recorded and spectra extracted. In this case, spec-tral extraction and wavelength calibration are requiredfor data reduction. Recently, an astronomical spectro-scopic device has been made for education in terms oflearning the structure of the device and the detection ofastronomical spectra Lee et al. (2013).As a result of the importance of spectral educationin astronomy, I developed astronomical spectroscopicobservations in education using a commercial spectro-graph attached to the telescope using a new adaptor.The spectroscope has been widely used for educationalpurposes, and is normally used in chemistry projects orlabs. The new adaptor xes the spectroscope to the tele-scope and makes detection through the telescope easy.It has obtained spectra of reected sunlight from brightplanets and bright stellar spectra.2. SPECTROSCOPIC DEVICE WITH NEW ADAPTORThe educational spectroscopic device, SV2100R, manu-factured by K-Mac, has been used. It contains a grat-ing of 600 lines/mm and uses a 1-D CCD array of 2,048pixels. Wavelength coverage is 250 ˘ 800 nm and hasa spectral resolution better than than 1nm. There is noneed to extract spectra from the spectral image becauseit is already a 1D array. The provided software makesit easier for to carry out reduction in terms of spectralextraction and wavelength calibration. Due to the 1Darray, there is no need to extract the spectrum from the757