Astronomical Spectra L200 Spectrograph
Bench Testing
The astronomical Spectra L200 spectrograph is a kit designed and sold by Ken Harrison. A Littrow spectroscope kit, the Spectra-L200 is for amateurs moving from the basic Star Analyser/ Rainbow Optic grating to their first slit spectroscope. It is only available to members of the astronomical spectroscopy Y! group.
Ken Harrison is the owner of the Yahoo!
astronomical_spectroscopy Astronomical Spectroscopy for Amateurs group.
This web page shows work-in-progress of building and testing the Spectra L200. Below are photos of the unpainted Spectra L200 that was put together to check mechanical fit and optical alignment.
- R=3000+
- The 30mm x 30mm diffraction gratings is an Optometrics 600 l/mm ruled 500 nm blaze.
- Adjustable slit mechanism
- For use with telescopes above f7 (f7 to f12)
- For bench testing the objective lens is a
Mini Borg 45ED
f/ 7.2 (focal length 325) refractor.
- The Orion flip mirror is used as a finder.
- The astronomical spectrograph snaps on a tripod with the Bogen-Manfrotto RC4 Low Profile Rectangular Rapid Connect Adapter.
- The astronomical spectrograph mounts on a telescope mount with a Vixen dovetail.
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Major Components Mounted on the Spectra L200 Spectrograph
Going from the left side to the right side:
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The above test spectrum is dark rain clouds taken from inside the house with the Spectra L200 pointing out an open door.
- Screen capture of a uncalibrated spectrum image.
- Shorter wavelenghts are on the right side of the spectrum.
- H-alpha absorption line is the dark line at the far right where the white vertical tick is.
- The exposure time was 120 seconds.
- The white dots in the spectrum image are the hot pixels. Dark calibration will remove them.
- Dark round shadow in the spectrum image is dust on the CCD. Flat calibration should remove it.
- Horizontal tilted bands are from the uneven slit. Need to clean the slit with the tooth picks that came with the Spectra L200.
- The above screen capture image is half the spectrum image resolution.
- The CCD camera was aligned so the spectrum lines are vertical.
- Micrometer setting is 21.145.
- Spectrum order is 1st.
- Camera control software is Diffraction Limited MaxIm DL V5.07.
Spectra L200 Spectrograph
© 1998-2011 David Haworth
