Star Analyser questions

[Ags]

I am getting a new setup in the coming weeks, including an equatorial mount, a guide camera and an ASIAIR. I have wondered about getting a Star Analyser for years but with a guided setup I think it may be time.  I would be using it with a C6 reduced to 945 mm, or alternately with a refractor with focal length of 500 mm. The trouble is my ASI 485 MC is a color camera, and my incoming ASI 120 MM has a tiny sensor and larger pixels. Are either of these cameras viable for a Star Analyser? 

[lunator]

Hi Agnes

I think the website for star analyser can tell you if the scope/filter/camera are compatible. They say it works with a webcam so the 485 should be ok

[Ags]

Yes that suggests I could get away with the 485MC, but it looks like a tight fit. I may have an opportunity to pick up a mono KAF8300 CCD which I think will work better.

[robin_astro]

Hi,

I am the chap who developed the Star Analyser (Almost 20 years ago now !)  You can indeed use almost any camera and telescope but some setups work better than others if you have options. Mono cameras have  many advantages and although the sensor in the 120MM is small it is still  larger than the tiny sensors I originally used with the Star Analyser.  Just use the calculator on the RSpec website (the calculations behind it are mine)

https://www.rspec-astro.com/calculator/

to work out the distance to mount the grating to max out the space you have on the sensor.   The resolution depends on size of the star image relative to the length of the spectrum so a short focal length helps. What model is your 500mm fl refractor?  Well corrected APOs work well but achromats can give problems with chromatism which means the violet end of the spectrum goes out of focus.  The main thing is the SA was developed to get people interested in spectroscopy without spending a fortune  so whatever kit you have, you will get some sort of result and learn about spectroscopy on the way

Cheers

Robin

[robin_astro]

With a cooled mono 8300 you will be able to go much deeper. (No need to guide, just stack many shorter exposures) eg these on my BAA page

https://britastro.org/observations/observation.php?id=20230523_183229_5116a1a27f78a1ea

https://britastro.org/observations/observation.php?id=20210406_144443_9e1c6a4cf219d14d

https://britastro.org/observations/observation.php?id=20201216_234948_8cabda965bfe692f

Robin

 

 

[robin_astro]

I suggest as a starting point something like your 90/f5.6 APO with the 120MM and ~40mm spacing which will give good resolution, plenty of room to fit the spectrum and zero order and plenty of light on bright stars.

 

[Ags]

You can fit a lot on a 120MM sensor clearly!