Buying Spectral Instrumentation
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GOTO Star Spectroscope -
This was the first visual spectroscope generally available to the amateur
market. It was introduced in the late 1960s and was sold in the U.S. by
Edmund Scientific Co. Unfortunately, it was not marketed very well.
It is a prism eyepiece mounted instrument that has three interchangable
cylindrical lenses that allows for
varying spectral spread of different magnitude stars.
The barrel is designed to thread onto the GOTO eyepieces
for efficient mounting. It is a very good visual instrument, particularly when used with
a moderate to large telescope. Since it is no longer being manufactured,
it only resides on the used market. It occasionally may be found on the
AstroMart
web pages for $100-200.
Update: I was informed on Jul/4/99 by Olshausen@aol.com that:
"The Goto prism spectroscope may still be bought, directly from Goto. The
price is 40,000 Yen. Inquire through their web site:
http://www.goto.co.jp
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Rainbow Optics Spectroscope -
The first transmission grating instrument available at a reasonable price, this
eyepiece mounted spectroscope is a very good buy in the $200 range. The grating
provides a linear spectrum and is comparable in efficiency with the GOTO instrument.
The grating is blazed to allow the majority of light to diffract at the required
angle. It comes with an informative manual and a newsletter is also available for
those interested in sending in data.
A
review
of the instrument appeared in the Vol. 7 No. 2 - 1996 issue of
The Practical Observer Magazine which can be found on the author's website.
Another review entitled "The Colour Purple - (Indigo, Green, Yellow, Orange and Red)"
by
Doug Welch (welch@physics.mcmaster.ca),
appears in Event Horizon - Volume 1 Issue 8 June 1994, as well as one in the October
issue of Sky & Telescope magazine.
The instrument is available from Rainbow Optics, 1593 "E" Street, Hayward, CA 94541.
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Sivo Spectrograph -
This reflection diffraction grating instrument was recently unveiled at the
Rockland Astronomy Club's Northeast
Astronomy Forum (April '98). It is a grating spectrograph designed to be used in
conjunction with a CCD camera. As such it is the only such instrument affordable
to amateurs which will allow data to be collected, not only on stellar objects,
but on galactic, nebula and cometary objects as well. It has a fiber optic bundle
that brings the light from the eyepiece to the spectrograph in a unique way. The bundle
is circular at the eyepiece end while slit-like at the spectrograph end.
Its cost is about $2000, certainly at the high end for the amateur market, but
very low when compared with laboratory spectrographs on the market which would also
have to be adapted. It is also computer
interfacable and it comes with computer software for displaying the data. The
spectrograph is available from
Sivo Scientific,
1404 Manhattan Ave, Union City,NJ 07087-5414.
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SBIG High Resolution Stellar Spectrometer -
In February 1999, the Santa Barbara Instrument Group (SBIG) introduced its new
High Resolution Stellar Spectrometer
(with their latest informational update on June 29, 1999)
This stellar spectrograph is a research quality, high resolution instrument designed
specifically for the ST-7 and ST-8 CCD cameras. Like the Sivo instrument, it is a
reflection grating instrument. It has several gratings available (10 or 38 angstroms per pixel).
Also available is a grating having a dispersion of 1.07 angstroms per pixel which is
capable of measuring large redshifts (galactic objects) with a moderate sized telescope (10-inch).
Although the instrument yields the highest resolution for "amateur" applications,
it's hefty price tag, of almost $4000 for the basic unit, does put it at the fringe of
affordability to most individuals wishing to delve into the subject.
SBIG,
P.O. Box 50437, Santa Barbara, CA 93150.
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An Objective Prism Spectrograph
The Practical Observer Magazine - Vol. 6 Issue 3 - 1995
The construction of an objective prism spectroscope for use during solar eclipses
and for stellar observations.
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