Spectral Type

[robin_astro]

1 minute ago, Thalestris24 said:

They are over £3k! 

Louise

Yes but Gav asked what would be needed for detailed spectral classification. You can do a lot of other  interesting stuff with a Star Analyser and plenty of real science with a cheaper ALPY 600 core plus guider module for example

Cheers

Robin

[Thalestris24]

2 minutes ago, vlaiv said:

I was looking at lowspec and it indeed seems interesting.

In all of these designs, reflective grating can be replaced with transmission grating if layout is slightly altered - so SA can be reused in higher resolution instrument (it does require some way of easily mounting it and removing from spectroscope - like filter drawer or similar).

My SA100 is too deep to fit in a TS filter drawer and be able to slide the drawer in and out. Maybe something could be modified somehow...

[PhotoGav]

And to be fair, £3k is very reasonable for specialised Astro kit! Suffice to say that it will be on my Wish List, but somewhere near the bottom for now!

[Thalestris24]

5 minutes ago, robin_astro said:

Yes but Gav asked what would be needed for detailed spectral classification. You can do a lot of other  interesting stuff with a Star Analyser and plenty of real science with a cheaper ALPY 600 core plus guider module for example

Cheers

Robin

Still a lot of money! At least, for a poor person like me.

[vlaiv]

2 minutes ago, Thalestris24 said:

My SA100 is too deep to fit in a TS filter drawer and be able to slide the drawer in and out. Maybe something could be modified somehow...

Ah yes, that was one of the reasons I was happy with SA200 - it is low profile so will fit filter wheels / filter drawers ...

Depending on design, like "straight thru" version could need only t2 / 1.25" filter adapter - like one often supplied with ASI cameras. It does mean disassembling it each time you want to use SA "regularly".

[robin_astro]

1 minute ago, Thalestris24 said:

Still a lot of money! At least, for a poor person like me.

Sadly yes. Perhaps the downside of getting addicted through the Star Analyser is how it can lead to cravings for the harder stuff 😞

[Thalestris24]

1 minute ago, robin_astro said:

Sadly yes. Perhaps the downside of getting addicted through the Star Analyser is how it can lead to cravings for the harder stuff 😞

I may analyse the spectra I've already got but I probably won't do any more so won't be getting addicted!

Louise

[Nigella Bryant]

 

The Aply 600 is around £650 so is doable in the future for me. 

The Shelyak Alpy 600 is the core element of the ALPY product line, with a 600gr/mm grism (grating + prism), Alpy 600 offers compactness, low resolution (resolving power R~600) and a dispersion compatible with current CCD cameras in astronomy.

Specifications

F/4 spectrograph

slit/slitless modes (25µm hole; 25µm, 50µm, 100µm, 300µm slits; 3mm hole / 5µm tolerance)

R~600 (resolution around 10A)

light & compact: weight less than 200gr

M42 camera thread; backfocus 10.5-21mm

standard 1.25" telescope adapter with filter thread

A 1/2 inch or larger CCD camera with less than 21mm back focus and M42x0.75 thread is required for use with the Alpy 600. There is an optional C-mount adapter which replaces the M42x0.75 adapter of the Alpy 600 to work with a C-mounted camera. A Barlow lens element specially designed for the Alpy 600 extends the back focus to work with a DSLR camera; it enlarges the spectrum too.

[Stu Todd]

You may need the guiding and calibration module on top of that which bumps the price up - https://www.shelyak.com/categorie-produit/debuter-en/alpy-en/?lang=en

I'd look at 3D printing a UVEX, I think the optics come in at 400 quid or so, looks to be an excellent spectragraph too.

Edited October 9, 2019 by Stu Todd

[robin_astro]

16 minutes ago, Stu Todd said:

You may need the guiding and calibration module on top of that which bumps the price up - https://www.shelyak.com/categorie-produit/debuter-en/alpy-en/?lang=en

I'd look at 3D printing a UVEX, I think the optics come in at 400 quid or so, looks to be an excellent spectragraph too.

Yep the ALPY guiding module is a must but the calibration module is a nice to have. The spectrograph is very stable so you can calibrate using known lines in a reference star, even the sun using the daylight sky and  halogen lamp waved in front of the telescope is good enough for a spectroscopic flat.

More on the development of the UVEX here.  

http://www.spectro-aras.com/forum/viewforum.php?f=45

Deigned by world leading amateur spectroscopist Christian Buil,  it was principally designed to extend the range of amateurs spectroscopy into the UV but the the performance has proved to be  impressive across the full visible spectrum.  It is not quite fully developed yet (I think it is awaiting finalisation of the guider/calibration module, otherwise you need to use the one from the ALPY) and alignment is critical and tricky.  I can see this being a commercially produced instrument at some stage though. The lowspec is a very conventional design and might be more straightforward for someone new to spectroscopy.

https://www.thingiverse.com/thing:2455390

Cheers

Robin

[PhotoGav]

Next question - which processing software is best to use: RSpec or BASS? I haven't really investigated either, just aware that they both exist. Apologies for the rather lazy question, but I know you know!

[andrew s]

1 minute ago, PhotoGav said:

Next question - which processing software is best to use: RSpec or BASS? I haven't really investigated either, just aware that they both exist. Apologies for the rather lazy question, but I know you know!

I have used both. Unless you want to do real time spectra then I think BASS is the better package.

Regards Andrew 

[PhotoGav]

Thank you Andrew.

[robin_astro]

I use ISIS for all my Pro-Am work as I would say do the majority of amateurs doing research grade spectroscopy but it is not so easy for a beginner, particularly with the Star Analyser.   Another freeware alternative is Visual Spec which I "grew up with" though it is prone to crash.

[andrew s]

17 minutes ago, robin_astro said:

I use ISIS for all my Pro-Am work as I would say do the majority of amateurs doing research grade spectroscopy but it is not so easy for a beginner, particularly with the Star Analyser.   Another freeware alternative is Visual Spec which I "grew up with" though it is prone to crash.

Robin is right about ISIS but I think this is historical.  I am not aware of any  technical problems with BASS which would disqualify it from serious work.

I have used IRAF, ISIS, Visual Spec, Rspec and BASS unless someone can point out  specific problems with BASS for basic slit or slitless spectroscopy that's what I would recommend to new users.

Regards Andrew 

[Merlin66]

I've been using BASS project since its conception, and it continues to grow and is well supported.

All my ProAm submissions have been with BASS Project processing.

ISIS is great but is definitely focused on support for the Shelyak product range.....

[robin_astro]

18 hours ago, Merlin66 said:

ISIS is great but is definitely focused on support for the Shelyak product range.....

Hi Ken,

Shelyak have their own software (Demetra) that they are developing for their instruments  (currently only for the ALPY, I believe)

 Concerning ISIS, this predates the formation of Shelyak as a company. It is no secret that  as arguably the world leading amateur spectroscopist,  Christian Buil  develops ISIS primarily for his own use so it true that it has features that make it extremely efficient when processing spectra from the spectrographs that were designed by him but it has all the tools  to reduce the spectra from any spectrograph. As an example here are the various options for wavelength calibration ranging from fully manual line selection through to  a one click automated system based on either a built in or a user generated custom file of calibration lines for any specific spectrograph and camera combination

http://www.astrosurf.com/buil/isis/tutorial/calibration_us.htm