Astronomik RGB

[ebdons]

Hi All, just got some Astronomic RGB deep sky filters, do these filters come with a IR CUT built in, can't seem to find any info on this, I assume they don't have ir cut but wanted to make certain of this. all the best Tony

[andyboy1970]

They will cut IR which starts at 750nm upwards.

[ebdons]

Hi Andy, thanks for the quick reply, I assumed ( wrongly) that these would let it through so you could add your own ir cut or Luminance filter. ok thanks for that. all the best Tony

[ollypenrice]

You don't need to add a filter with these RGBs but if you want to shoot luminance you'd use a luminance filter which cut off the visible spectrum at both ends - ie beyond violet at the short end and beyond Ha at the long end.

Olly

[ebdons]

Hi Olly, Astronomic have some new L1 2 and 3 filters in place of the single IR/UV CUT, I have the standard IR CUT which blocks at a lower wavelength and  I want to use as a Luminance, which maybe not the best for use as a luminance but they also have the type 2c  filter, but I chose the standard RGB set. all the best Tony.

[andyboy1970]

I have a set of Astronomic RGB type 2 filters a Ha filter and a CLS-CCD filter for luminance, they seem parafocal to me when checked with a Batty mask.

[ebdons]

Hi Andy,  too late now to change, but is the type 2 filter better or the same or worse than the standard RGB? my filter set is the "new" version of the RGB type, which is why I asked about integral IR CUT/BLOCK which the type 2 have? all the best Tony

[andyboy1970]

The type 2 are higher quality, better light tranmission and each colour covers a slightly wider range.

From their website : Comparing Astronomik CCD Photographic Filters to our Visual Filters: Unlike Astronomik Visual Filters which do not require IR blocking, our Astronomik CCD Photographic Filters do include IR blocking filter layers to prevent any problems from Infrared Radiation (IR) when using CCD and chemical photographic devices.

I was lucky and mine came up on the second hand market.

[ebdons]

Hi Andy,  was going to use these filters with trius 825 mono or hypercam 174 mono, astrodon too expensive baader cheaper but have had issues with the glass coming loose in the holder and not tightening up so was put off them , so stumped up for new RGB astronomic set, still these filters will serve me well tho in the future, all the best Tony