How effective are the Light Pollution Suppression Filters?

[evilgeenius]

How effective are the Light Pollution Suppression Filters? Are they really worth it? Can anyone recommend a reasonably priced one?

Can someone show me a comparison shot of something with/without the filter?

Thanks

[rocketandroll]

Unless you're imaging from a REALLY dark/remote site... you need one.

I've only been imaging for four months now, and when I started an LP filter seemed like quite an expensive item that was quite low down my list of requirements... then I got one, and I can't tell you what a massive difference it makes.

Below are two images of IC1396 taken a few weeks apart with my 200mm f2.8 Canon L series lens and my modded Eos 350D.

The first was taken before I got an LP filter, it's about 45 mins of data IIRC. The second was taken WITH an LP filter from almost the same location and used longer subs and was about an hour and a half of data (so, if anything, should have been MORE affected by the LP).

The first one you can barely make out the nebula and where it starts and ends... the second one (despite being slightly out of focus) is quite obviously IC1396 and the elephant trunk nebula etc are clearly visible.

In all my images before I got the filter I seemed to spend most of my processing time trying to remove horid gradients and picking out feint fuzzy patches from a larger light fuzzy area. Now, things stand out pretty clearly.

I got one of the Astronomik clip filters that snaps straight into the EOS body... yes, they are over a hundred quid, but it's the only filter I can see me needing until I switch to CCD imaging.

Ben

[evilgeenius]

From what I've read it seems that they are only good for planetery nebula and they make everything else dimmer, such as galaxies, because they remove some of the light from those objects. Is this correct?

[rocketandroll]

From what I've read it seems that they are only good for planetery nebula and they make everything else dimmer, such as galaxies, because they remove some of the light from those objects. Is this correct?

Well, IC1396 certainly isn't a planetary nebula :-)

Nope, as far as I know they are pretty specific about what they cut out... I've certainly imaged galaxies and emission nebulae with my scope and with the lens since installing the filter and have noticed absolutely no reduction in light gathering capabilities on those targets.

They may cut a little useful light out, but you're talking a few percent... certainly from what I've seen the bennefits far outweight that slight loss.

Ben