Paton Hawksley Spectroscope StarAnalyser 100 - blazed diffraction grating for spectroscopy

Paton Hawksley Spectroscope Star Analyser 100

In professional astronomy, spectral analysis has been the means of choice for researching stars, nebulae, novae, comets and much more for over 100 years. With the Star Analyser, Paton Hawksley now offers a very inexpensive and easy to use system, which is aimed especially at amateur astronomers, observatories, schools and the general entry into the fascinating field of spectroscopy.

The Star Analyser is simply mounted like a 1.25" filter in front of a camera. In principle, any camera can be used for this purpose. For example, it is possible to use a telescope with an aperture of 80 mm and an unmodified webcam to spectroscopically capture stars up to the 4th magnitude. With 8" aperture and a sensitive astro CCD camera, hundreds of deep-sky objects are at your disposal to explore. Even the redshift of quasars can be detected in this way!

Tips from Teleskop-Service:

In principle, any telescope is suitable for spectroscopy. Reflector systems (like Newtonians and Cassegrain systems) as well as refractors with low chromatic aberration are ideal. With so-called rich-field achromats, however, a little caution is required, since their own color errors can make the spectrum obsolete.

For cameras with an integrated IR cut filter, please note that this cuts off the long-wave part of the spectrum. With pure reflector telescopes no IR cut filter is necessary anyway, this can therefore be removed.

When using it visually, please note that the Star Analyser 100 fans out the spectrum less than the Star Analyser 200, making it appear brighter. Therefore it is usually more suitable for this application. But the latter has a higher resolution and needs only half the distance in photographic use.

Valuable link:

The freeware program Visual Spec can be downloaded here:

Star Analyser field report - by H. Dr. Erik Wischnewski - Kaltenkirchen, 25 February 2013

Dear Mr. Ransburg,

some months ago I bought the blazed grating Star Analyser 100 (STA) from you and could achieve some results. I would like to report briefly on this.

The STA was used both as a lens grating in conjunction with my zoom telephoto lens 70-300 mm and slitless prefocal in the direct beam path of the 5" ED apochromat which I bought from you at the time (I still do not regret the purchase). I had Gerd Neumann make an adapter ring for me for use as a objective gratinge and now screw it into the filter thread of the lens.

I also used a Canon EOS 60Da. I mainly took pictures with the telephoto lens on a normal photo tripod. Bright stars up to 1 mag can easily be achieved at ISO 1600 with exposure times under 1 sec. The addition of 10-20 images, as known from general astrophotography, makes sense. Additions of 20-25 images at 2 sec. each (at ISO 1600) also enabled beautiful spectra up to the 5th magnitude.

With the 5" ED apochromat (f/7.5) at ISO 6400 and 30 sec. exposure time spectra of stars of brightness 11.0 mag are detectable. However, these spectra are very noisy and can no longer be used for line recognition. This succeeds on the same shot with stars brighter than 8.8 mag, which corresponds to the above estimate.

I was able to spectroscopy Wolf-Rayet stars as well as the famous Be stars P Cygni or Gamma Cassiopeiae. These stars show emission lines of concise clarity. WR and Be stars also show strong variations in the spectrum, making continuous monitoring interesting. The measurement of the equivalent width is one of the scientific tasks normally not attributed to an STA. I was able to achieve sufficiently accurate results here: for P Cygni an equivalent width EW in H-beta of -14.0 ±1.3 Angstroms and in H-alpha of -76.0 ±2.4 Angstroms was obtained on 6.10.2012.

The blazed grating StarAnalyser 100 is therefore more than just a demonstration part for school purposes.

Working with the STA has been a lot of fun for me so far. The blazed grating was definitely worth its money. As a side effect, it was important to me that unlike deep-sky photography, you don´t necessarily need many hours of clear air and dark skies. A short-term cloud gap is enough, light haze is not so dramatic and moon does not disturb as much as with deep-sky images of weak nebulae and galaxies.

I evaluated it with Fitswork and the possibility to create a pixel line. The determined values can be copied directly from Fitswork to Excel for further processing. But I wrote a small program with it.

In the appendix I have added some pictures without comment.

Many greetings

Dr. Erik Wischnewski


Spectra Star Analyser Wischnewski 1



Test result Staranalyser Dr. Wischnewski