Useful filter for Deep Sky visual observation

[Bamo]

Hello fellow visual observers,

Was wondering any of you uses filters for a better viewing of deep sky objects like nebulae or star clusters?.

Appreciate sharing your thoughts.

Regards,

Bamo

[Paz]

I find for me a UHC filter is the best general purpose filter for nebulae, but for star clusters there isn't a filter that really helps me, just as there isn't a filter to help with galaxies.

If you have light pollution then a light pollution filter may help slightly with clusters but only slightly - I have one but rarely use it, trying to go to a spot with darker skies gets (much) better results.

 

[Bamo]

I also found that website for better illustrations on how to choose filters.

https://agenaastro.com/guide-to-light-pollution-filters.html

[John]

Nebulae are best enhanced by either a UHC or O-III type filter. For smaller aperture scopes the UHC might be more versatile but the O-III has more impact on some objects including wonders such as the Veil nebula.

Star clusters and galaxies are best enhanced by dark skies !

This is a good piece from the US magazine "Astronomy" by Phil Harrington:

www.astronomy.com/~/media/import/files/pdf/8/c/7/0805_nebula_filters.pdf

Personally my favourite is the Lumicon or Astronomik O-III filter (my scopes go from 100mm to 300mm in aperture) and also the Omega DGM NBP filter which is a UHC type.

 

[Highburymark]

35 minutes ago, John said:

Nebulae are best enhanced by either a UHC or O-III type filter. For smaller aperture scopes the UHC might be more versatile but the O-III has more impact on some objects including wonders such as the Veil nebula.

Star clusters and galaxies are best enhanced by dark skies !

This is a good piece from the US magazine "Astronomy" by Phil Harrington:

www.astronomy.com/~/media/import/files/pdf/8/c/7/0805_nebula_filters.pdf

Personally my favourite is the Lumicon or Astronomik O-III filter (my scopes go from 100mm to 300mm in aperture) and also the Omega DGM NBP filter which is a UHC type.

 

How do you find the O-III performs in your 100mm 'scope John?  And would it be too narrow for Bamo's 80ED?

Btw - welcome to SGL Bamo.

[Highburymark]

Just seen that my question has been answered in the other current O-III thread - please ignore.....

[Bamo]

Cheers Highburymark!.

From what I read, I guess a narrow band filter is a good start. On the market they have a name of UHC apparently. As quoted on the website I've pasted "pass light from H-beta (at 486nm) and OIII (at 496nm and 501nm) where the human eye is most sensitive"

The Olll filters seem to make stars way dimmer. You can imagine what may happen with an 80mm aperture

[Stu]

 

Cheers Highburymark!.

From what I read, I guess a narrow band filter is a good start. On the market they have a name of UHC apparently. As quoted on the website I've pasted "pass light from H-beta (at 486nm) and OIII (at 496nm and 501nm) where the human eye is most sensitive"

The Olll filters seem to make stars way dimmer. You can imagine what may happen with an 80mm aperture

80mm will still work under a good sky with proper dark adaptation. Yes, the stars will be dimmed but it is the nebulae you want to see most.

This is a useful link regarding effectiveness on different targets

https://www.prairieastronomyclub.org/filter-performance-comparisons-for-some-c

[John]

11 hours ago, Bamo said:

The Olll filters seem to make stars way dimmer. You can imagine what may happen with an 80mm aperture

Some dim the stars more than others. The Astronomik O-III is one that I have used in small aperture scopes with success. The Baader and Celestron O-III's have a narrower band pass width so dim the stars quite a bit more which is OK in a larger aperture scope but not so good on small ones.

This might surprise you but not all UHC and O-III filters have the same band pass width or high overall pass % in the selected band widths, there is quite a bit of variation across the brands.

 

[Stu]

This site hasn’t been updated for a long time, but still contains some useful information, which backs up what John has just said.

http://www.astrosurf.com/buil/filters/curves.htm

[Bamo]

Thanks John,

Yeah I can see a lot of variation across the brands too (pricewise)!. 

Most likely I'll go for Astronomik UHC filter. My feeling  says 80mm aperture might be a challenge for O-lll filter as it's too narrow banded as you said.

https://www.astronomik.com/en/visual-filters/uhc-filter.html

 

 

[scarp15]

I think that it depends on your sky condition, eyepiece / exit pupil you are applying, subject targeted and to an degree observers skill / familiarity. An Astronomic UHC would be a good match for an 80mm refractor. Depending upon the subject you are aiming to gain contrast on, an 0-III and H-beta filter can also be employed, I have used each with a 76mm refractor and definitely plan to do so with my current 85mm.

[LukeSkywatcher]

For nebula...............UHC and/or OIII.

UHC makes the visible, more visible. 

OIII, makes the invisible, visible.

[jetstream]

My OIII's work well in the 90mm and 120mm fracs here, you need low enough mag to get them working- I use a 30mm ES 82 and the 42mm LVW.

[Bamo]

I'm waiting now for my UHC to arrive!. But I know what's gonna happen as soon it does!.

So apologies for any bad weather in advance

[LukeSkywatcher]

Bad weather I like. Good weather, no so much. 

[Bamo]

On 07/08/2018 at 13:49, LukeSkywatcher said:

Bad weather I like. Good weather, no so much. 

Hope you're enjoying today's weather Paul!. I don't know how is it in Ireland at the moment but in NL it's just the right weather for you.

 

All that rain and my filter hasn't arrived yet

[nigelg]

I found this web page helpful for choosing the filter for various targets

https://www.prairieastronomyclub.org/filter-performance-comparisons-for-some-common-nebulae/

 

Nigel