LRGB filters - which ones?

From what I have read and seen, the narrowband filters from Baader are excellent. Time will tell when I get my first results.

From the CCD Tech forum, one particular contributor who I would trust implicitly (he backs everything up with *actual* data) swears by Baader - especially as they a re significantly cheaper than competitors.

Dunno what their RGB set is like though...

Dont be temped by ordinary dyed filters.

Dave,

Are the Baader LRGB filters just dyed filters? :oops: :shock:

From what I have read and seen, the narrowband filters from Baader are excellent. Time will tell when I get my first results.

From the CCD Tech forum, one particular contributor who I would trust implicitly (he backs everything up with *actual* data) swears by Baader - especially as they a re significantly cheaper than competitors.

Roland Christen (Astro-Physics) has produced some very dramatic narrowband results and it is his work that sold me on the Baader narrowband filters.

Dunno what their RGB set is like though...

Me too ... I am very happy with my SBIG (Custom Scientific) filters.

no filters are precisely parfocal

Dave,

This is something that has come up a number of times on the SBIG Yahoo forum and it is my understanding that filters are parfocal for telescopes with a focal length around 1200mm ... ex. AP160. :mrgreen:

I can certainly vouch for this claim (ie. 1200mm) since it is something I have observed repeatedly with my AP160+SBIG filters.

I dont know if the red green blue meade filters are good enough really, how would you know their relative weights in photoshop.

Hi Dave,

I would not worry about the weights for QE balance since this is a one-time exercise we must go through for any set of filters using a G2V star for calibration purposes: www.perseus.gr/Astro-Tips-G2V-Star-Calibr.htm

oh right, I thought this came specified with a good filter set.

I dont know if the red green blue meade filters are good enough really, how would you know their relative weights in photoshop.

Hi Dave,

I would not worry about the weights for QE balance since this is a one-time exercise we must go through for any set of filters using a G2V star for calibration purposes: www.perseus.gr/Astro-Tips-G2V-Star-Calibr.htm

oh right, I thought this came specified with a good filter set.

Not quite since the camera plays a role ... ditto for the transmission properties of the scope's optics.

It is a compound problem (filters + optics + CCD camera) and requires a one-time investment for each optical train. Just adding a Barlow (or reducer) is enough to change the net transmission and, thus, requiring a one-time calibration.