Which filter to use?

[Manoocher]

I have two filters (L-Extreme and light pollution). My camera is 294c and I would like to take images of Nebulas and galaxies. I like to know which filter to use for different objects and if I need other filter types. Please comment. Thanks. Manoocher

[LewisM]

L-eXtreme is great but be prepared for significantly longer sub frames to make it effective. Hope your mount and guiding is good.

If you can guide for at least 240 secs or better, 5 min, and round stars you should be ok.

[Dave882]

+1 on the previous comment.

Also L-extreme is amazing for bringing out the Ha and Oiii complement of emission nebula. Especially effective when imaging in the suburbs or with full moon with an OSC as it does a great job cutting out light pollution. But do a bit of research on the nebula you plan to shoot as it will eliminate most of any reflection nebula and will not give good results there (eg m20). It is also not advised to use it for galaxies or star /glob clusters as these emit light over a broad spectrum. You will get weird colours unless you combine it with some rgb data later.

For these it’s best to use a broadband light pollution filter or just uv/Ir block filter, and try not to shoot toward moon or city light glow.

[toc]

Also depends on your scope as well - fast scopes like the RASA or hyperstar dont do well with the L-Extreme - I have had good results with the IDAS lp-z or Optilong L-Pro.

[LewisM]

Don't do what I accidentally did shooting a star cluster and leave the filter in. Was wondering why the images were so dim (1 min exposures for an hour that when combined looked like a single 1 min lol) and colourless.

[Startrek]

Long subs using the L Exteme filter is Camera and Focal length dependant
I use an L Extreme with my ZWO2600MC on my 8” f5 newt ( Bortle 3 skies ) and 6”f6 newt ( Bortle 8 skies ) with full moon or no moon and my subs range from 90 sec to no more than 3 minutes, with 1 to 3 hours of captured data) on Planetary and Emission nebula with fantastic results
Cheers
PS my 2600MC has an internal UV/ IR cut protective window