Which Light Pollution Filter is best for me?

[BJunge]

Hi,

I have a WO GT71 and use a QHY8L Colour camera for astrophotography. To get to dark skies I have to travel for over an hour, and with a two young children it is hard and I only get one chance a month to do it.

I live on the Gold Coast with a lot of light pollution. I need to purchase a filter that suits my setup so I can take photos from my back yard.

I have been doing some reading and it seems there are quite a few out there and just as many differing opinions.

Currently I am leaning towards an IDAS filter, but am more than happy to hear opinions from others who have an informed opinion and/or real experience with such gear.


Many thanks,


Brendan.

[skysurfer]

I have an Astronomik UHC-S filter which passes only Hbeta / OIII (greenish blue) and Halpha (red). This is suitable for nebulas, but will also work for broadband objects like galaxies and clusters.

Available in AU from https://www.bintel.com.au/product/astronomik-uhc-filters/

Even under LEDpollution it blocks something as white LEDs have a strong dip in OIII
/ Hbeta and Halpha light output.

[LewisM]

IDAS works superbly.

I use a Baader, and it works almost as well, but I think thre may be a small reflection issue - looking into that.

I tried the Optolong and some other cheaper ones and they do work also, but I found the blue gradient was harsher.

[BJunge]

Thanks for taking time to compose these replies.

Skysurfer, the Bintel site says the Astronomik UHC-S filter is more for visual application rather than astrophotography??

[skysurfer]

No, there are also XL clipin filters for Canon EOS available at Bintel, which I have and used with success. Faint red nebulas like the Heart Nebula IC1805 (https://www.skysurfer.eu/skypics1/IC1805-21x4min-ED110-20161205.jpg) I grabbed easily from a moderately light polluted Netherlands with an unmodded 6d, so it will work in Gold Coast.

[Don Pensack]

There really isn't a filter that you can use to photograph broad spectrum objects like galaxies or star clusters in a bright sky. However, you can take fantastic nebula photographs with very narrow filters, like:
H-α
O-III
S-II
N-II
and then combine them in stacking or image processing software. I have an acquaintance who takes 2 hour shots here in LA and gets fantstic images, even though a broad spectrum image is pure white in 10 seconds.
You want to keep the bandwidths of those filters to 7nm or narrower to avoid LP ruining the images.

Broadband filters these days are more of an enhancement filter for use in very dark skies. Unfortunately, with the advent of LED lighting, light pollution is very broad spectrum.

[beren]

Been happy with this one

https://www.cyclopsoptics.com/filters/stc-astro-multispectra-filter/

[bigjoe]

Think we'll be hearing more about this one!
bigjoe.

[Don Pensack]

That's a "notch" filter, and there are many more like it already on the market.
It's oriented to photography, though, where some of the others are oriented to visual use.
Interesting.
Then there's this:
https://www.cloudynights.com/topic/605235-new-cutting-edge-narrowbands-filter-stc-astro-duo-narrowband/

[AstroApprentice]

Graphical info on IDAS LPS filters can be found here:
http://sciencecenter.net/hutech/idas/lps-test/index.php

[chromus]

Can't find much literature on these, but they were released this week and cover normal Na and Hg vapour like the old version PLUS now LED street lighting.

http://www.ontariotelescope.com/LPS-D2-48mm-Filter_p_1454.html

[LewisM]

Never once got a reply from Ted Ishikawa at Borg re the IDAS LPS D2... which is disappointing considering he or his wife were always prompt to answer queries previously.

[Don Pensack]

LED lighting is fairly broad spectrum and has emission near the wavelengths you might want to shoot.
If your municipality has a lot of LED lighting, this may extend your ability to expose by a small amount but don't expect miracles.
Imaging is just plain difficult to do in a city.

https://en.wikipedia.org/wiki/LED_street_light

[chromus]

That Trevor guy from AstroBackYard has a youtube review and suggested it was cutting about 2/3 of the light pollution from his cities LED street lighting.

[that_guy]

I have managed to talk Brendan in to purchasing a ASI1600MM-C with narrowband filters ;) He shouldn't have any issues with light pollution anymore!

[Anth10]

Brendan,
I researched intensely before I decided buying my IDAS LPS V3 filter.
I have been quite pleased with the results it's been able to achieve from my near Red/Orange Zone where I live. It holds its colour nicely without introducing any false colour cast and does a fine job blocking stray unwanted light prevalent in the burbs.
No doubt narrowband filters is the best and most scientific way to producing best results but it comes with a steeper learning curve to use them effectively particularly with processing. But if it's an all in one solution with no fuss then this filter is a good place to start in my opinion.

Best of luck in making your choice,

Anth

I got mine shipped from Adelaide from a supplier that deals with them exclusively.
You can find them on the net.

[Camelopardalis]

Well, he will, it’ll just be less of an issue than before ;)