Practical Spectroscopy Notes

[Merlin66]

I use various lecture notes when presenting spectroscopy as a subject worth considering for the amateur.

The attached general notes may be helpful for those considering spectroscopy.

 

practical_spectroscopy_notes.pdf

[CraigT82]

Loads of great tips, thanks for sharing!

[Merlin66]

Thanks!

It’s always difficult to make a start in a new area of endeavor......

Hope that helps.

Ken

 

[PhotoGav]

Very interesting - thank you for sharing. This is an area that I am about to embark upon and so these notes are very useful. It does look ever so slightly frighteningly complex though... Like all things involving telescopes, filters and cameras, there is a steep learning curve to clamber up!

[Merlin66]

Thanks.

I was committed to A-P for over ten years before turning to spectroscopy.

The challenge of science and technology I found met my needs.....after ten years I’m still 100% convinced that spectroscopy is an ideal area where serious amateurs can contribute to some serious research.

Try it, you may find it satisfying.....

 

[PhotoGav]

My plan is to introduce practical spectroscopy to the pupils studying Astronomy GCSE and Physics A level at the school I work in... I need to become vaguely proficient in it myself first though! I may have questions for you...!

[Merlin66]

Sounds good!

check out our website for ideas.....

We’re here to help and assist, just ask.

 

[robin_astro]

If looking to make useful scientific observations you might also find these presentations made at a BAA workshop of interest

https://www.britastro.org/downloads/15701

Amateurs are already contributing to real science and have been increasingly so over the past 15-20 years. The ARAS forum for example is very active in this area

http://www.spectro-aras.com/forum/

Cheers

Robin

Edited September 21, 2019 by robin_astro

[Merlin66]

Just a comment:

Although the page header says:

The files below are only available for BAA members to download.
Log in or join the BAA today to gain access to them.

It appears possible to download the various contributions.

Some good, useful material.

 

[robin_astro]

Yes this particular content was deliberately left open to encourage wider interest in spectroscopy. For the past few years the BAA has been supporting members interested in spectroscopy through assisted purchase of spectrographs and running  a series of workshops.  It also hosts a spectroscopic database for the wider amateur community  complementing its variable star database  

https://britastro.org/specdb/

where spectra of any object meeting the required quality standard  are welcome (4791 spectra at current count) 

Cheers

Robin

Edited September 22, 2019 by robin_astro

[robin_astro]

My contributions to  BAA workshops in 2008 and 2015 are also available on my website

http://www.threehillsobservatory.co.uk/astro/spectroscopy_10.htm

One day perhaps I will get round to adding some notes to the 2015 ones but if you have any questions on them, ask away !

Robin

Edited September 22, 2019 by robin_astro

[Whirlwind]

As a few thoughts.

It might be worth mentioning Echelle spectrographs as well - or more importantly that  these should be avoided to start with (they are generally expensive) but with "more money than sense" might be risked because of the potential higher resolution.

It might be worth mentioning that higher resolution (greater number of lines/mm etc) will give more detailed spectra but at the cost of more imaging time as the light is spread out more.

Also flats are needed if you want to completely flux calibrate your spectra.  The flat corrects for the response of the optical system.  In principle you can do this with the standard but relies on getting the standard spectrum on exactly the same pixel location as the target of object but that is nigh impossible.  It's better to flat this out and then apply the standard calibration (strictly speaking there should be both a normal flat and a sky flat but generally you can get away with just the former!).  If you are just looking at radial velocity changes etc, just a normalisation is fine.  But to get temperatures you should fully flat calibrate the image.

Yeah don't touch the grating, breath on it try and wipe it or otherwise anyway misuse it.  

You can use a filter to block out second order effects 

[robin_astro]

Hi Whirlwind,

I find the best advice is given by people who are already producing good data. It is difficult putting forum nicknames to actual people though. Are you active in amateur spectroscopy? What equipment do you have and do you have any results to show?  I've known Ken (Merlin) for a long time but I have yet to persuade him to actually publish any of his spectra 😉

Cheers

Robin

[Merlin66]

Robin,

Most of the Spectra I obtain is though the SASER group here in the S. Hemisphere and submitted to the ProAm campaigns we contribute to.

 

[Helen]

Thanks for this 🙂.   As Gavin says, quite a learning curve, but should be fun climbing it!  As with everything, it’s just getting the time to do it!!

Helen

[robin_astro]

Just to clarify, statements like 

"Never touch the surface of a grating – death is imminent"

"Yeah don't touch the grating, breath on it try and wipe it or otherwise anyway misuse it. "

Do not apply to the Star Analyser gratings as the surface is protected.  The instructions for cleaning can be found in the user manual

Cheers

Robin

[robin_astro]

15 hours ago, Merlin66 said:

Robin,

Most of the Spectra I obtain is though the SASER group here in the S. Hemisphere and submitted to the ProAm campaigns we contribute to.

 

Hi Ken,

I can't find any there in the current campaigns and no publications as co-author. 

http://saser.wholemeal.co.nz/

Just one in the BeSS database from 2017.

I try as far as possible to give practical examples from my own observations when explaining particular issues to beginners.

[robin_astro]

I must admit I found the notes rather confusing. Perhaps they work better with the presentation material. Anyway I have added some comments clarifications (in red) 

Cheers

Robin

Practical Spectroscopy K M Harrison_revisedRL.pdf