L filter or light pollution filter? - Forums

Topic starter

Jun 2, 2017

Hi guys,

I see a lot of guys out there imaging with a light pollution filter in place of the L filter. I live in an orange zone…should I consider doing that? woukd I have to expose longer with the light pollution filter compared to the L filter?

I don't have the ASI1600MM yet as I am still saving my pennies but I am learning as much as I can in the meantime since I know I will acquire it by the end of the year (that's my hope).

thank you all!
Sebastian

Engaging

John E.

Jun 2, 2017

Hi Sebastian, I live in a White Zone and imaging with an L filter is difficult. My clubs site is orange/green and an L filter works better there. I also have a 2" LPS D1 filter that I used exclusively with my DSLR. I do want to try with my ASI1600mm-c but need to adapt for it. But for me, the best move was to move to NB as doing LRGB from my home site has too many problems. As far as exposure, the LP filter ALLOWED me to expose longer as it gave me better data. A very knowledgeable imager mentioned that I should definitely use the LP filter in our orange/green zone for everything but galaxies.

Helpful

georgian82

Topic starter

Jun 2, 2017

John E.:
Hi Sebastian, I live in a White Zone and imaging with an L filter is difficult. My clubs site is orange/green and an L filter works better there. I also have a 2" LPS D1 filter that I used exclusively with my DSLR. I do want to try with my ASI1600mm-c but need to adapt for it. But for me, the best move was to move to NB as doing LRGB from my home site has too many problems. As far as exposure, the LP filter ALLOWED me to expose longer as it gave me better data. A very knowledgeable imager mentioned that I should definitely use the LP filter in our orange/green zone for everything but galaxies.

Hi John,

Thank you very much for your input! I appreciate it.

Cheers
sebastian

Well Written Respectful

Edward Overstreet

Jun 3, 2017

Depending on what OTA I am using but I either have a LP filter screwed on the Coma Corrector (Newt) or field flattner/reducer refractor and SCT. So all filters, LRGB are shooting through the LP filter. This may be all wrong - but what I am doing regardless - I live in an orange zone. I do take the LP filter off when using NB.

georgian82

Topic starter

Jun 3, 2017

Very interesting @Edward O. I didn't think it was possible to use the LP in front of all LRGB filters. Thank you for your input!

Cheers

Edward Overstreet

Jun 3, 2017 · Edited: Jun 3, 2017

I would recommend that you take an adequate number of flats to deal with any vignetting that may happen because of the distance between the LP filter and LRGB filters. Personally, I cannot tell a difference in the vignette, with our without the LP filter but others have mentioned it and it may affect your setup.

However, placing the LP filter in front of LRGB filters should be no different than putting one on an OSC.

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bobzeq25

Jun 4, 2017 · Edited: Jun 4, 2017

Are you doing gradient reduction in processing? If not, that's the first step, the LP filter the second. Going from one shot color to RGB or LRGB also helps.

The stronger the LP filter, the more you have to increase exposure, the more it distorts the color balance, which then needs to be fixed.

Concise

Edward Overstreet

Jun 4, 2017

I use Dynamic Crop - for all LRGB - HaOIIISII so they will be identical - I can't think of any time in the as 3 years (when I started attempting this challenging hobby) that I didn't have to crop. Also, using PixInsight for most of the heavy lifting then PSCC for the rest.

Once all images are identically cropped - I then use Dynamic Background Extractor. This does a great job of removing all unwanted gradients….I use the Automatic version on clusters and most galaxies…..and the manual version if there is a lot of nebulosity regardless of the target.

Chris Sullivan

Jun 6, 2017

I live in a white zone near John. I've been using a Baader Neodymium (Moon & Skyglow) filter for luminance in my last couple of galaxy images. I think it helped a lot. The spectrum between the L and Neodymium filter isn't all that different - they both cut off at the same point, but there are 2 or 3 gaps in the middle. My main problem with it is that it isn't parfocal with my other filters. I had been using a 2" Orion Skyglow Astrophotography filter in front of my coma corrector, but I believe it caused some weird reflections in some of my images. Right now, I plan on continuing to use the Skyglow filter in my OSC, but not for monochrome.