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Albireo with UHC filter


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Just a nooby-filter-user quickie, couched in strictly non-scientific terms!

 ...I very briefly tried out my Baader UHS-C filter last night (thanks FLO!)  on the Ring (nice) & then  - just to see - on Albireo....the blue star colour was intensified & it made a lovely sight!

My question is: was the richness of the blue the filter doing its work & enabling the colour to 'come through' for want of a better description, or was it , er, 'added' colour  from the filter itself?

(Hope that makes sense)

Thanks :)

Steve

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It was subtracted colour. The Baader UHC-S cuts out yellow light (550-600nm). The Albireo system owes its beauty to the contrast between the yellow primary and blue companion, so while the filter might make the companion bluer, it presumably cut the contrast between the two stars. Personally I'll stick to using my UHC filter on emission nebulae, the one type of object where it really makes a positive difference. But certainly no harm trying it on all sorts of targets just for fun.

post-1955-0-86336000-1410804212.png

Source: http://www.astrosurf.com/buil/filters/curves.htm

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http://www.astrosurf.com/buil/filters/curves.htm#Baader UHC-S

Hi Ya Steve - love the Nooby -  Filter User - Quickie

Check the link I have posted above - look to the left hand side for the relative transmission - if the line is at the top - this shows the amount of "wavelength of light" (the most) and if the line is at the bottom - this is what is "blocked" by the filter - you can see all the graphs for the different filters - the dashed vertical coloured lines give the point where the "colours" of the spectrum are at - so you can see that the filter passes the blue, green, red and violet

On a specific target like a star (just a pin point of light) you have only the colours that are passed through the filter - so very specific colours (visible to our eyes) are let through, with the majority (except about 775 Angstroms - not sure what colour this represents) blocked - so this tends to intensify the object in question, together with the darker background sky - this will make a lovely sight.

EDIT - http://cse.ssl.berkeley.edu/light/wavelength.html

This also explains the amount of "visible" light we can "See".

Paul.

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http://www.astrosurf.com/buil/filters/curves.htm#Baader UHC-S

Check the link I have posted above

Or check  the graphic from exactly that site which is in the previous post, together with link :)

Incidentally, the vertical dashed lines do not indicate "colours of the spectrum". As explained in the link, they mark the wavelengths of spectral emission lines: blue is H-beta, green is OIII, red is H-alpha, purple is SII.

And the spike you refer to as "775 Angstroms" (you mean 7750 Angstroms or 775 nm) is in the infra-red, hence has no effect on visual observation.

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It is by it's dimming-out the yellow spectra that UHC filters are commonly advertised as an aggressive light-pollution filter. But with many municipalities shifting over to using LED lighting - which turns a night-time sky into high-noon - this becomes a moot point. Los Angeles is an example of what this looks like, and buy sunglasses before going there.

Albireo is my favorite double-star, even though it is not a true binary. I find it interesting to hear people explain what color the two component stars are. People tend to see different hues in this system. I am convinced that human-beings ability to see all the colors most of us can see is a very recent development in our species.

Clear & Dark Skies,

Dave

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Thank you NSm & acey, not forgetting John & Dave of course (hey, sounds like a band... :) )

Really helpful for a thickie like me...I was more Eng Lit at school, maths was car-crash, was barely tolerated in General Science and thrown out of Metalwork so I've never been, um, at one with slide rule....

So I've never really understood those filter graphs (me, maths? Uh uh....'swhy I'll never be a grown up astronomer, merely a hopefully hip stargazer, lol) so thanks for helping me to at least begin to make sense of them. Afraid I have no idea about Angstroms - Anglo-Saxons, yep, Angel Fish, mmm, Angustora Bitters, yum... but wavelength/frequency of light? Something I'll have to learn!

I'm afraid I have no qualms about using any bit of kit inappropriately to see what effect it has!

But I am glad to hear that the blue was true - as I feared it may just an effect of the multicoatings or whatever - looking through the UHC in daylight throws up some interesting effects, for example. Now I know it's not for galaxies, but heck am I going to try it on M31!

Thanks for all your help & information, guys. Lots to learn :)

Steve

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