It is an instrument quite different
from the Star Analyser because it is a true slit
spectrograph. You can use extra-wide slit,
intermediate and very narrow slits for peculiar applications
(typically 10 microns). For advanced applications, a
small optional calibration module is available
(with a spectral lamp and a flat-field lamp).
The spectral resolution is near R = 550 with
a 23 microns slit. This is significantly higher
than a Star Analyser and lower than LISA
(R=800-900). The line shape is very uniform for
the spectral range 3700 A - 8000 A (I took care to optimize
the optics (a specific design) for the ultraviolet in particular
because it is of great astrophysical interest).
ALPY 600 can fully accept f/5 optical beam (and of course,
can be used with f/6, f/7,... f/10, ... telescope or refractor).
You can also adapt photographic objective lens!
This is not a multi-object spectrograph as
the Star Analyser, but it captures fainter objects
because the sky background is more dark. I think also it
is a very good spectrograph for spectroscopy of
variable stars, which can effectively replace
standard (U)BVR system. This is a potential fantastic
feature.
The spectrum below is typical of results
obtained with ALPY 600: the spectrum of Seyfert
galaxy NGC4151 captured using the guiding module
(with a 23 microns wide reflective slit). This
module provides a good quality field image (which
is essential for faint object spectrography).
The expsoure time is 20 minutes only. The redshift is
easily measured (a typical educational project!).
As always, I observe in urban conditions ...
Christian Buil
