Boxed Place

Obtaing a Spectrum by using a CD and a Cereal box aslike a Prism Spectrometer

A simple spectrometer can be built from a CD and a box. Cut a slit on one side of the box. Place the CD on the other side with about 60 degree angle. Look down into the openning on the box. The slit should not be too wide, otherwise the spectrum lines will be blurred. It should not be too narrow either, otherwise the spectrum is too dim. I use a 0.2mm wide slit.

                   structure of the CD spectroscope

my cereal box spectroscope (arrow: the slit)   viewing the spectrum

 

Let's look at the spectra of some common light sources. All photos by the authors with a Nikon coolpix 995 camera.

(1a) afternoon sun, altitude 24 degrees           (1b) setting sun, altitude 0.5 degree

 

(1c) high Sun spectrum                                 (1d) low Sun spectrum

 

I took this photo before the total lunar eclipse of 2004 . Moonlight from a full moon was collected with an 8" Dob telescope. The spectroscope was held behind the eyepiece. As moonlight is nothing but reflected sunlight, the spectrum looks the same as a solar spectrum (1). It is continuous with dark absort lines, i.e. the Fraunhofer lines (some of them are marked).

    The moon                                                         Use a telescope

 

Lunar spectrum

LIKE THIS YOU CAN USE THIS SPECTROMETER FOR FIND THE DIFFERNT SPECTRUM FOR DIFFERNT LIGHT'S.

FACTS

 Brace's Spectrophotometer Prism #10565
Unsigned

In D.B. Brace's research work he made use of spectrophotometers of various kinds. Not satisfied with them, he invented a simple, but effective new type that utilized two 30°-60°-90° prisms cemented together with a silvered strip between them. His device was subsequently manufactured by Schmidt & Haensch in Berlin, Germany and Gaertner in Chicago and was used, e.g., at the Yerkes Observatory. Several of his prisms remain in the department.

References: D.B. Brace, "Description of a new spectrophotometer and an optical method of calibration," Philosophical Magazine 48, 420-30 (1899); D.B. Brace, "On a new system for spectral photometric work," Astrophys. J 11 (1900): 6-23. Schmidt & Haensch Katalog II: Spektralapparate, 1900 and Katalog II Spektralphotometer, Pyrometer, etc., 1914.
  Large Prism Spectrometer #10060
Franz Schmidt & Haensch, Berlin, S.

The Schmidt & Haensch Company of Berlin offered this spectrometer for use with D.B. Brace's spectrophotometer prisms. The main scale is calibrated in units of 10 minutes of arc and with the vernier it can be read to 10 seconds of arc. In addition to the usual telescope for viewing and the collimator for the light source, this instrument has a second collimator tube to utilize his new spectrophotometric system which Brace described in the literature. He attached the department's 4-inch Brashear telescope, directed at the star Capella, to one collimator and a standard light source to the other. This enabled him to make quantitative measurements of the spectrum of the star.

References: Schmidt & Haensch Catalogue No. 55 (1896); D.B. Brace, Philosophical Magazine and Journal of Science, 48, 420 (1899); D.B. Brace, Astrophysical Journal, 11, 6-23 (1900).

 

About the Author

THIS PROJECT WAS CREATED BY G.ANGEN CLETUS,INDIA,TAMIL NADU,TRICHY.

IN 23.5.2010

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Where would be the best place to find info on a royal mint boxed gold coin i have just gained?

it depicts 'The yeoman wardens of the tower of London' on one side and the other side is a pic of 'HM royal palace and fortress of the tower of London'

The item would more properly be called a medallion, and the study of objects of this type is called exonumia. It appears to be gilt or gold-plated, and there is likely a year stamped on the edge (rim). I hope this helps.

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