Quote:
Originally Posted by MadMonk
Steve,
Some filter manufacturers recommend not using UHC or anything like it on scopes smaller than 8".
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Hi Tom,
I don't think this is something that is put forward by filter manufacturers. It is something that has snowballed on the internet because inexperienced observers continue to use UHC and OIII filters in small telescopes under light polluted skies, then continually express this opinion on the internet. No filter is a substitute for dark skies. The problem isn't the small telescope or the filter. It's light pollution and the observer.
Gary Kopff, Andrew Murrell and myself spent 3 hours observing with Al Nagler last evening at the TSP. We used his Televue NP127 (5" petzval refractor) with the prototype 13mm Ethos, with stacked OIII and UHC filters, to observe the Veil Nebula in Cygnus. We had the OIII on the diagonal and the UHC on the eyepiece. Keep in mind that an OIII is a lot "heavier" than a UHC.
Quote:
Originally Posted by MadMonk
I have also tried Astronomik CLS on both scopes, and for the 80mm I actually prefer it over the Ultrablock, also because it does not add the blueish hue to the colour of the stars.
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I would agree that an 80mm scope is getting too small to use a UHC or OIII filter with, but keep in mind that a 100mm scope has nearly double the light gathering capabilities of an 80mm scope. Personally, I think scopes over 100mm are fine with a UHC filter.
CS-John B