do I really need a light pollution filter when narrowband imaging ?

[red dwalf]

Just been thinking about this over the last couple of nights is there any benefit or not ?

I'm using a baader 2 inch light pollution filter which isn't the most aggressive filter on the market.

What do you think ? Should I use one or not with narrowband filters.

[+Ibbo]

I'd leave it out Rob

[glider]

I'd leave it out.

 

It's another set of losses and potentially odd reflections if things are not mounted square.

[red dwalf]

thanks guys, it does seem to make sense leaving it out when narrowband imaging, will remove it for the next session.

[Guest whizzbang]

Late to the party, but deffo leave it out, i was NB imaging in the depths of Brixton and never used one with no adverse effects. you are only sampling a narrow spectrum of light 

[Guest Tweedledum]

Hi Rob,

 

Doc has just posted some links. Shamelessly copied! :-

 

http://www.prairieastronomyclub.org/resources/by-dave-knisely/filter-performance-comparisons-for-some-common-nebulae/

 

http://www.prairieastronomyclub.org/resources/by-dave-knisely/useful-filters-for-viewing-deep-sky-objects/.

 

Have suggested that these are pinned somewhere.

[Daz Type-R]

Done.

 

See http://www.eastmidlandsstargazers.org.uk/topic/8655-filter-performance-comparisons-for-some-common-nebulae/

 

I put it in the observing section as the links refer to filters for visual use only.

[red dwalf]

very useful reading, thanks very much

[Guest johnrt]

I have a permanently mounted 2" IDAS lp filter on the front of my reducer. It stays in place for both LRGB and narrowband, purely to preserve camera orientation. It doesn't improve narrowband one bit, as stated you are sampling a very narrow band of light. But importantly it doesn't reduce the effectiveness of the narrowband filter either. I use 3nm astrodons, and if it's too much hassle to remove you can just leave it in without worrying about it spoiling anything.

[red dwalf]

thanks John, 

i only use the 2" Baader Neodymium Filter which i screw onto the front of the reducer and is no where near as effective at cutting light pollution as the IDAS filters, but it does a fair job at cutting down the orange glow from street lights.

3nm filters, how on earth do you manage to focus those, i have enough problem with my 7 and 8 nm filters L.O.L.

[Guest johnrt]

thanks John, 

i only use the 2" Baader Neodymium Filter which i screw onto the front of the reducer and is no where near as effective at cutting light pollution as the IDAS filters, but it does a fair job at cutting down the orange glow from street lights.

3nm filters, how on earth do you manage to focus those, i have enough problem with my 7 and 8 nm filters L.O.L.

Ah I have a trick using the diffraction spikes from the spider vanes as I use an RC. Find the brightest star you can, bin x3 and a 10 sec exposure gets you some nice spikes to focus on

[red dwalf]

ah right