Alpy_Info - Astrophotography and Spectroscopy

Astro-Imaging and Spectroscopy

Star Party  St Michel  Haute Provence (France)

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The Alpy600 consists of 3 modules. The Spectrograph, the  Guiding-Modul and the Calibration-Modul.
With the Guiding-Modul only a fixed slit of 23┬Ám usable. This is useful up to 2m focal length with a seeing disk of 3".
The Guiding-Modul is essential for guiding and taken spectras, because it is not possible or very hard to guide with
an additional telescope like in astrofotography. With the slit your are independed of the seeing conditions
and it is easy to substract the sky backround. The Calibation-Modul is optional and it is possible to calibrate with
the Balmer-Lines of a reference star spectral type B or A. But in praxis the Calibation Modul is very comfortable to  calibate
the spectrum and it is easy to take flats.
The spectral range from 3750 to 7500 A limited by a IR cut filter.  The spectrum is 9 mm long so only a small chip is necessary.
Backfocus ist about 21mm. For longer backfocus (DSLR) a balow lens for the Alpy is also available.
It is importend that the telescope has the nearly the same focal ratio then the collimator lens between f/4  and f/6.
The camera is a monochrome CCD Atik 414 ex.
The Guiding Cam is a ASI 120 MM monochrom CMOS camera.

The performance of the  Alpy600 is better then  most of Littrow-Spectrograph with a similar resolution.
The Alpy is good to detect faint spectras. The faintest object is a 16mag  quasar with a 200mm telescope.
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Copyright  Matthias Kiehl

October  2021
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