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Cloudy Day Spectrogram

Started by MarkS, Apr 26, 2015, 19:23:14

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MarkS

I experimented today with a slit (two Stanley knife blades mounted at the end of a cardboard tube) plus a diffraction grating (StarAnalyser 100) at the other end.

I was pleased to see that the Fraunhofer lines are clearly visible.



Imaged with the Canon 600D (unmodified) with a zoom lens at 200mm.

Mark

JohnP

Wonder how many people Googled Fraunhofer Lines after looking at this post... ☺ ;)

Did you mod your camera this weekend. ..?

MarkS

#2
Quote from: JohnP
Did you mod your camera this weekend. ..?

No, I may end up selling it instead.  My tests show it appears to suffer a "star eater" hot pixel suppression algorithm similar (or identical) to the infamous Nikon algorithms.  I'm still investigating this issue in detail and I won't mod it until I'm sure I'm going to keep it. 

With a bit more processing here is my spectrum of the today's cloud cover:



Mark

Rick

Interesting. Going to do a sunny day one (if we get one...) for comparison?

Mac

the sunny one will be interesting, just to see what lines are added by the compounds in the clouds if any.

QuoteMy tests show it appears to suffer a "star eater" hot pixel suppression algorithm similar (or identical) to the infamous Nikon algorithms.
Why cant they just add an astronomical mode which gives you warts and all.

Mac.

Fay

That diffraction grating has worked out well Mark
It is healthier to be mutton dressed as lamb, than mutton dressed as mutton!

The Thing

Very interesting. Maybe once you have a sunny day spectrum you could prepare a Frauenhoffer 'dark frame' to subtract cloud added lines from future cloudy day spectra :)

Carole

QuoteMy tests show it appears to suffer a "star eater" hot pixel suppression algorithm similar (or identical) to the infamous Nikon algorithms.
What a bummer.

Quoteyou could prepare a Frauenhoffer 'dark frame' to subtract cloud added lines from future cloudy day spectra
:lol: :lol:

Roy

Some cutting edge science?

Roy

MarkS

Hardly cutting edge. 

However, next time there's a comet I'd like to do a spectrogram of the coma to identify the elements therein.

Mark

The Thing

Now that sounds like an interesting project.

RobertM

Quote from: MarkS on Apr 27, 2015, 22:13:32
Hardly cutting edge. 

Were the Stanley knife blades blunt ?

Other than that, it's a very interesting topic.  I did a project on stellar spectra at the OU and vowed to do more when I have time; that and photometry.

Did you use vertical binning cleaned up version ?

Robert

The Thing

BTW PHD 2.5.n has a spectroscopy slit guiding function.

MarkS

Quote from: RobertM
Did you use vertical binning cleaned up version ?

Yes, IRIS has a number of very useful functions for spectroscopy.

mark