CCDSPEC Spectrometer - review

[athornett]

I have now completed the RELCO starter calibration light (240V version) and my first calibration spectra can be seen here:

https://roslistonastronomy.uk/first-calibration-spectra-from-relco-neon-starter-bulb-reclo-sc-480-s53993-taken-with-science-surplus-diy-spectrometer-9-9-2018

Andy

[athornett]

It has been quite an enjoyable project making this calibration light - just hoping I can identify the lines now!

Andy

Edited September 9, 2018 by athornett

[Demonperformer]

Looks like your project is coming along nicely, Andy.

Was originally confused by the apparent absence of the lines in the 'off' graph from the 'on' graph ... then I noticed the scale on the Y-axis!!

[athornett]

That confused me too - but like you I realised that the lines in the off graph had not disappeared in on graph but instead were simply less obvious due to much bigger scale on on graph. I think I might add something to that post to explain that!

I will load up my first neon/argon RELCO starter calibration spectrum is here showing many lines that I need to identify.

Andy

 

[Merlin66]

Andy,

I think you need more exposure to boost the signal. You can use a couple of images -one with line at 620 saturated to bring out the fainter ones and one similar to the above.

Walker's atlas will guide you through the maze.......

[Ben Ritchie]

After care from Dr Elliott has been nothing short of incredible. The poor soul has been bombarded with my e-mails and always promptly and politely responds with clear instructions and explanations. I wish every astronomer vendor was like this! He clearly knows his stuff and is happy to share his experience and skills with others.

He taught me spectroscopy when I was an Astronomy undergraduate, and was a terrific teacher. Nice to see he has kept busy

[athornett]

The problem with the neon and other lines on the RELCO starter bulb is that it is a lot of work to identify them. Not so for fluorescent bulbs which give a readily identifiable series of lines and with easily accessible online data on the wavelengths of those lines. Problem is that they run on 240V - not the safest or most accessible voltage outside in the dark.......but then last week Incane across someone selling off 12V compact fluorescent bulbs - I have purchased a pile before they sell out as they are in process of getting rid of old stock in order to replace them with LEDs!

Today, I have made myself a lamp with a 12V cigar car plug at one end in order to power these bulbs. Now I need a bit of Perspex to make a diffuser and I am away!

Andy

[robin_astro]

Hi Andy,

CF lamps can give you a rough calibration to get your eye in on better calibration sources like the RELCO etc but for precise calibration you need a wide range of narrow unblended lines.  It is worthwhile persisting with the RELCO because once you have identified a set of suitable lines, you can produce a file so that programs like ISIS will find the lines for you automatically and produce a very precise reliable non linear calibration  every time with a couple of clicks.

Cheers

Robin

[athornett]

What is the best way to identify the lines on the RELCO?

I think compact fluorescent bulbs are certainly convenient so I have taken the liberty of starting a conversation on them on this forum - but I would like to get the RELCO to work for me as well.

Andy

 

[robin_astro]

Hi Andy,

I think you need to address this issue with your spectrograph first. You need to be able to produce a clean spectrum image of the RELCO lamp similar to the one I posted here.

Robin

[Marcel]

Hello,

i am new in this topic.  The question i have is : what is the best option for spectography? Only a filter or a spectograph? Can someone tell me the pro's and con's?

Thank you.

Kind regards

Marcel

[Merlin66]

Marcel,

It really depends on what you want to achieve.

The SA gratings are a great way to start the journey, I call it "spectroscopy 101"

They allow you to acquire low resolution spectra which then leads to the calibration and processing tools you need to master. Once you are familiar with the processing you can consider analysing the results and determining what the various observed lines can tell us.

A slit spectrograph is a major leap forward, in resolution but comes at a financial cost in terms of the instrument and the supporting hardware.

I'd recommend one step at a time and start with a grating.

Our webpage may help you:
http://www.astronomicalspectroscopy.com/How_to.html