RGB - green watten#? 56 or 58?

[Russe]

Which watten # does the green filter have in a typical setting?

What about blue and red's watten #?

[tom714uk]

See this entry on Wikipedia.

Tom

[tom714uk]

And also this guide to filters for use on planets, which has an illustration of the colour of each Wratten number. There's another guide in the Beginners' Help section of this forum as well.

Tom

[Macavity]

Strictly speaking, (L)RGB filters are (quite!) a "bit different" from old fashioned Wratten ones. A quick glance at transmission curves reveals this. Wratten filters were probably based on the *historical* availability of chemical dyes, more than (modern) "science" - And that, not meant in a derisory way.

Modern (L)RGB filters would undoubtedly be best, for serious excursions into imaging. Mine even include a gap in response, corresponding to the main UK Sodium Light pollution. That said, "pukka" imaging filters can be expensive, so nowt wrong "trying out stuff" with a fairly arbitrary choice...

There are now these, more exotic, narrow-band (Hubble) "pallets" etc. Some are indeed pretty too!

[Russe]

I just saw the Baader RGB filter set. That's quite steep! ~140£?