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star_chemist

Is it feasible to study the spectrum of daily light sources using DSLR & Star Analyzer 100?

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Hi, 

I am trying to understand the mechanism of spectroscopy used in astronomy, and the feasibility to use it to measure the spectrums of 

light bulbs, flames and lamps. 

With a black board with a needle hole, placed behind the light source to emulate a star, then use the SA-100, 105mm lens and a DSLR combo

to photograph the needle hole, will it yield the same effect as spectroscopy seen in this forum? 

SC

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In principle yes. Not sure about the specific optics combinations.

We use this kind of set-up to demonstrate spectroscopy indoors.  We set a small telescope up looking at a pair of pinholes ~20m away (with an eyepiece). They look just like a pair of identical stars.

Then we flip in an SA-100 grating; and hey-presto -- you clearly see that one of the pinholes is illuminated by an incandescent bulb (continuum spectra), and the other by energy-saving/CFD bulb (whole bunch of emission spectra). They're not identical at all, despite what they 'look' like!

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I seeand thank you. All i can lay my hand on is an 24-105 lens and 105mm is the best focal length. I see the telescopes usually use at least 500mm focal length. When doing telescopy does it require the light from the star to be parallel? Does the indoor telescope demo require dark ambient environment?

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Hi SC,

Take a look at my website here

http://www.threehillsobservatory.co.uk/astro/spectroscopy_14.htm

You could use a pinhole instead of the refection from a needle

note this work was done before the SA200 was launched. I would now recommend using the SA200 instead of the SA100 and a focal length ~half that used here. This will give a higher resolution due to the smaller light source image size and  also means the standard kit  zoom lens canbe used. You can also see more about this techniquue used on stars here

http://www.threehillsobservatory.co.uk/astro/spectroscopy_17.htm

http://www.threehillsobservatory.co.uk/astro/spectroscopy_11.htm

I have also used a similar setup for  over 10 years now during my astro spectroscopy talks using a webcam fitted with a 35mm lens  with an SA100 on the front aimed at "artificial star" pinhole light sources a few  metres away (incandescent and low energy lamp) to show live how spectroscopy can reveal hidden information in the light.  (The background where the spectrum falls should be black card or similar and the room light needs to be subdued)

Cheers

Robin

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