Light pollution filters

[Mike_S]

Hi,

just looking for a filter to improve visual observing of Orions nebula if possible.

i have a 10 inch F4.7 dob.

i have seen on FLO the Baader neodymium? Or the Explore Scientific CLS? Or something else?

 

https://www.firstlightoptics.com/light-pollution-reduction/baader-neodymium-filter.html

 

https://www.firstlightoptics.com/light-pollution-reduction/explore-scientific-cls-nebula-filter-1-25-2-inch.html

[Louis D]

I use an older Lumicon OIII filter to get the best contrast on the Orion Nebula.  I understand the Astronomic OIII is considered very good as well.

[Mike_S]

Heard a few mentions of the oiii now. Thanks. 

[ronl]

I tend to use a UHC filter, flo has a good range to choose from, it depends how much you want to spend.

[Ricochet]

In my opinion Neodymium filters are not effective against light pollution. What they are though, are the best filter to improve contrast on the Moon, Jupiter and Saturn, so you may still want to add one to your collection.

A light pollution filter that I have found to work, but that will become less effective as LED lighting increases, is the Astronomik CLS filter. However, the Explore Scientific CLS is manufactured to a lower price point and has a wider band pass, meaning that it lets in more unwanted light and contrast will be lower. I've not tried one to know if it is still effective or not.

As the Orion nebula is an emission nebula, it is an object that UHC and OIII filters will be useful for. There is a well known comparison of filters on nebulae which gave UHC the lead but with the levels of light pollution that I have at home, I have found a good OIII filter to actually be the best option. I think that the key here, again, is to choose a high quality filter that has a narrow band pass as this filters out the most light pollution and gives the best contrast. Astronomik are again the current top tier choice, but the Baader OIII, which has a band pass that is "too narrow", is going to be a much better choice than the brands that have band passes that are "too wide".

[Mike_S]

Thanks so how to I decide between an oiii or ufh for M42? Just try both? Or is one definitely preferred over the other?

[Ricochet]

I think you would have to try both to find out which is better from your location, but buying either will show an improvement compared to the unfiltered view.

[pregulla]

I live in a place where most light pollution comes from sodium lamps, which are easier to filter out than LED, yet the improvement is very minor using Optolong UHC on Orion Nebula. Based on that I would expect light pollution filters be of no help at all as they have even wider bandpass and let more undesired light through than my cheap UHC. Quality narrowband UHC or OIII (Astronomik/Lumicon/TV) might be more effective (on nebula only), but there is no substitute to darker skies.

Blocking stray light also helps. I see significant improvement using a shroud compared to observing without one.

 

[Louis D]

13 hours ago, pregulla said:

Quality narrowband UHC or OIII (Astronomik/Lumicon/TV) might be more effective (on nebula only), but there is no substitute to darker skies.

An example of nebula that benefits greatly from an OIII filter is the Veil Nebula.  Even in my 15" Dob, the nebula is little more than hinted at without filtration.  With the OIII filter, the various parts of it come alive in all their glory.  This from a suburban backyard with moderate light pollution.