Spectroscopy equipment

Michael, Thanks for your info, I may take you up on that offer when I get my rspec

Eamonn, I am truely amazed by all the different techniques and methods you have done. When you say "similar resolution to the best spectrographs", what kind of prices are we talking about with this technique?

Also, have you done Exoplanet doppler shifts with this technique, I am hoping to study Exoplanets in my Masters so it is a bit of an obsession of mine!

Also, what other software could you recommend to extract more detail than the Rspec software.

I am quite excited about the prospect of spectroscopy now! Thanks guys!

John,

I haven’t done Doppler shift measurements of exo planets, except exo planet transits.
You could look at the spectrographs I’ve built that may be applicable for exo planet observations. You’ll realise that all the systems I have designed and built are for wide field of views taking in multiple objects, except No.4. In your case you may only need a one star through the slit type. No. 4 may be suitable as it uses a grating 1200 l/mm (high res). This is fibre fed to a 0.4m telescope.
I’m not sure if No.1 is suitable as it uses a large grating size (5” x 4”).(medium res)
Its all down to the aperture size of the telescope/ spectrograph to collect light and to provide ever increasing resolution.

Software:

User friendly versions are BASS (Basic Astronomical Spectroscopy Software), ISIS (Integrated Spectrographic Innovative Software), More complex for extraction is SPECTOOL from IFAF is a GUI Spectrum Display and Analysis Tool, other user friendly ones are VisualSpec, SpIRIS, SpcAudace, PRiSM, Astro-Linux.

In order to give you more choice and costs I have built 4 types of wide field spectrographs.

1. Own design as mentioned references. Reflective grating at 400 l/mm ($1.2K)
2. Own design Slit-Free Multiplexing Spectrograph reflecting grating 300 l/mm and high speed optics. ($500)
3. Conventional using a ROS 200 l/mm transmission grating within an f/5.6 telescope ($200)
4. Czerny Turner design. ($1K)

If you need more technical details I can send on to you.

Optical Spectroscopy Considerations really depends on your application. I’ll give you some idea and resolution:

Trade-Offs Encountered With Traditional Spectrographs
Field of view
Whatever the field lens “sees” is focused onto the
entrance slit, creating a summed spectrum of all
objects, or selected object if field lens is a telescope, and
unable to distinguish multiple objects from each other

Big advance in 1980s: Replacement of exit slit with CID/CCD Array detectors –
Creates simultaneous multiple wavelength ability

Spatial resolution: If the spectrograph is an imaging spectrograph, with no
entrance slit, e.g. camera with ROS or Star Analyser type transmission grating,
then the spectrograph sees the whole field of view as set by
the field lens and its focal length.

The State Of The Art Multiplexing Spectrographs are Multi-slit WFCCD spectrograph at Las Campanas.
Fiber-fed multi-object spectrograph: Sloan Digital Sky Survey
Spectrographs at Apache Point Observatory

Each are complex, and capture generally less than 1-degree of sky

Slit-Free Multiplexing Spectrograph Design is an
Off-Littrow Reflection Grating Design for
both Echelle and Non-Echelle, inducing
astigmatism to form slit-like images of
point sources at the tangential focus
No Slits – provides wide field
Field of View set by Entrance Lens, which
is very low f/# to form highly reduced
image of wide field.

Off-Littrow Mount provides high spectral resolution, wide bandpass, and increased
line intensities.

Eamonn

Wow, that is truly a treasure trove of information Eamonn. Thanks so much.

I will look up those software you mentioned and compare them to the Rspec software

Thanks again,

clear skies,

John