Castell UHC filter

[adamh]

I've just received this filter, it's the first and only filter that I own so have little for comparison.

So I've got 2 crops of M27 from different nights, but everything else was the same. Same location (North London), same exposure 60s, and same ISO 1000. No processing other than crops from the jpg copy.

I think you'll be able to spot the difference.

[Moonshane]

nice one! I am visual only but have the Oiii version of this filter from the same company. really good value for money at£48 delivered for a 2". I'll certainly be getting the UHC in due course.

[adamh]

Visually it was harder to use. M57 which I can normally see directly I could only see with averted vision when the filter was in. It could have been that my eyes weren't fully adjusted, so I will check again.

The coma/poor collimation lines coming out of off centre stars were red.

[Moonshane]

I find that M57 is much brighter with the Oiii whereas M27 was not as good with this filter. I understand this is the usual way around. I have viewed M27 with someone else's UHC and it was excellent even in quite poorish conditions so looking forward to getting one.

[Doc]

Pretty impressive considering the cost. I wonder if they do a Hydrogen Beta 2"

[Nick]

Just read your post Adam, I recently borrowed a Baader contrast booster filter from someone in my local club. Previously I had been using a skywatcher light pollution filter, this filter did make a difference but the Baader filter transformed what I could see (and photograph). For example the North American Nebula is simply not visible through my 102 mm Vixen refractor, I could just about get an image in the murk with the SW LP filter, with the Baader filter I can clearly see the nebula. On this basis I will definately buy my own - question which one, I have seen the contrast booster in action I would expect the UHC to be even better - or maybe it would attenuate too much light to be as good - perhaps the semi Apo filter - any thoughts from anyone would be gratefully received.