Feedback on Filters primer

Andrew* · (#1 (**permalink**))

I have written a primer about using filters for visual use, here. I hope it will help beginners to better understand visual filters.

Like it? Hate it? Please let me know why!

Cheers
Andrew

Astro_Baby · (#2 (**permalink**))

Think you forgot something

The link

Andrew* · (#3 (**permalink**))

Thank you!

AstroTiger · (#4 (**permalink**))

Andrew, that looks the business!
i will be taking a look at that later this evening.

cheers again!

Mark at Beaufort · (#5 (**permalink**))

Very good Andrew. Now that I have a 10" Flextube I think that I might experiment with filters to see the effect and hopefully improvements!!

Mark

mark skelton · (#6 (**permalink**))

a very good primer andrew, I'll be reading with interest.

Astro_Baby · (#7 (**permalink**))

I thought it was good - well done you.

AndyBooth · (#8 (**permalink**))

Great work, I've got a set of coloured filters stashed away in the loft. Never had the photons to do them justice.
Time to dig them out again

mattifor · (#9 (**permalink**))

Very helpful, being new to this stargazing I find this most instructive, thank you.
mattifor

mik · (#10 (**permalink**))

Very nice Andrew, very well put together and simple to understand.

Well done Mick.

Andrew* · (#11 (**permalink**))

Thanks for the comments - glad it's going down well

MikeA57 · (#12 (**permalink**))

As a new comer still awaiting the arrival of equipment your article is informative with some very useful links. Thanks for taking the time to publish.
MikeA.

robneath · (#13 (**permalink**))

Found the pimer very useful, especially for those, like me, with realtively small aperture

michaelmorris · (#14 (**permalink**))

Andrew
That's a really nice succinct primer of visual filters. Excellent.

I have a a few points.
- I think light at 400nm is violet in colour - I don't think I've ever heard of it it head butting anyone!
- Polarising filters - it's pairs of polarizing filters that act as variable neutral density filters, not single filters.

I think it the article could be made even more comprehensive by mentioning multi-wavelength contrast enhancement filters (blocks several discreet parts ofthe visible spectrum to make reds appear redder, greens appear greener and blues appear bluer - i.e Baader Neodymium filter) or colour correction filters (e.g. Baader fringe killer and minus violet filters).

Thanks again for a great article.

Andrew* · (#15 (**permalink**))

Mike and Rob - glad you got something out of it.

Hi Michael and thanks for the constructive comments.

Quote:

Originally Posted by michaelmorris

Andrew
- I think light at 400nm is violet in colour - I don't think I've ever heard of it it head butting anyone!

.... may have done that on purpose!

Quote:

Originally Posted by michaelmorris

- Polarising filters - it's pairs of polarizing filters that act as variable neutral density filters, not single filters..

Indeed - thanks for that correction.

Quote:

Originally Posted by michaelmorris

I think it the article could be made even more comprehensive by mentioning multi-wavelength contrast enhancement filters (blocks several discreet parts ofthe visible spectrum to make reds appear redder, greens appear greener and blues appear bluer - i.e Baader Neodymium filter) or colour correction filters (e.g. Baader fringe killer and minus violet filters).

Good points. I have also failed to mention anything about solar filters. I will get round to posting a follow up to include these. As for the Neodymium - I wasn't aware it was a colour enhancement filter - I would have put it in the "Light Pollution" catagory. You learn something new every day!

Cheers
Andrew

wulfrunian · (#16 (**permalink**))

Just the sort of thing I was looking for, and some great links, thanks

michaelmorris · (#17 (**permalink**))

Quote:

Originally Posted by Andrew*

As for the Neodymium - I wasn't aware it was a colour enhancement filter - I would have put it in the "Light Pollution" catagory. You learn something new every day!

Andrew
It was originally marketed as a broadband light pollution filter - it is quite good at removing the yellow glow of low pressure sodium lamps. The transmission curve for the filter has very distinct dips in the yellow and pale green parts of the spectrum. This means that the curve has three distinct 'peaks' one at the red end of the spectrum, one at the blue end and one in the middle (around blue/green). So, sort of by accident, baader came up with a nice contrast enhancement filter. One of the advantage of the Neodymium filter over conventional colour filters is that it maintains a good 'natural' looking colour balance. I have found that it works particularly well for Mars.

Mark at Beaufort · (#18 (**permalink**))

Is this the reason why they now recommend using this filter to view the great red spot on Jupiter?

Mark

astro_dt · (#19 (**permalink**))

Great primer Andrew, concise and useful.
Cheers
Danny

DavidB · (#20 (**permalink**))

Excellent primer for a newcomer like me. It brings together lots of information I have gleaned from other parts of the web and makes sense of it all. I particularly like the way you give the alternative names for these things. It is illuminating to now realise that OIII is oxygen III and that buying one would not be the first thing to do for my small telescope. Will now go for the alternative.

David B.

yeti monster · (#21 (**permalink**))

Spiffing stuff, but this means that I will now have to go and spend more money........

Saturnalia · (#22 (**permalink**))

Sorry for the (probably) silly question - I have read recently in a couple of different places about filters and one keeps being mentioned that I don't recognise...what's a CA filter...?

Saturnalia · (#23 (**permalink**))

No problem - chromatic abberation...I got to stop drinking.

darkly · (#24 (**permalink**))

very very handy, there's a lot more to this filter business than meets the eye ;-)

red dwalf · (#25 (**permalink**))

excellent ! you`ve made my mine up as i was undecided between a o111 or a uhc, wish i`d bought one at the astrofest yesterday now.
many thanks Rob