Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_comet_46p.thumb.jpg.9baae12eeb853c863abc6d2cf3df5968.jpg

Andrew*

Feedback on Filters primer

Recommended Posts

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

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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 :)

Share this post


Link to post
Share on other sites

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

mattifor

Share this post


Link to post
Share on other sites

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

Well done Mick.

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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

Hi Michael and thanks for the constructive comments.

Andrew

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

:rolleyes: .... may have done that on purpose!

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

Indeed - thanks for that correction.

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

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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...?

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×

Important Information

By using this site, you agree to our Terms of Use.