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Whats your favourite visual filter


Coco

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I'm in bortle 6 according to the 'clear outside' app.

I'm thinking about OIII & LP visual filters and want to ask if you have a favourite particular filter.

Thanks ...

 

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For me it is the O-III filter. I do use UHC's as well which are useful but I have found that the O-III, when used on a receptive target, has the most impact. It is worth getting a good quality filter (eg: Astronomik) because they seem to have more effective band pass characteristics and deliver more of a contrast enhancement than lower cost filters.

I find my O-III filters  (I have a Lumicon in the 2 inch size and an Astronomik in 1.25 inch) work well with my 100mm scopes as well as my larger aperture ones so they are not just for 8 inch or larger scopes, as it used to be rumoured.

It will be interesting to see what others experiences are 🙂

 

Edited by John
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I have Orion filters and they do a reasonably good job.  As to a favorite, well it depends on what object i am looking at.  Sometimes is narrowband and sometimes its the OIII.  

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As mentioned above the OIII makes the most difference on suitable targets, the UHC has a more subtle effect but is great as a general purpose nebula filter, whilst my own personal favorite filter is the Baader Neodymium. It's very, very subtle and a lot of people think it doesn't do much at all but in my experience, as someone observing from less than ideal skies, I find it cleans up the sky background well and improves contrast on most objects.

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Depends on the usage and telescope for me:

  • Lumicon OIII (90s and modern versions in 2" and 1.25" respectively) for most nebula observing
  • Wratten #8 (480nm cutoff and no violet) or Wratten #4 (470nm cutoff and very slight violet) Light Yellow for fast achromats to cut violet fringing for general observing
  • Meade Green interference filter for best planetary/solar/lunar detail with a fast achromat, color cast be darned

Alternatively for easier to find/afford options:

  • The Svbony UHC is nearly as good as the Lumicon OIIIs on most nebula except under the most light polluted skies
  • Cheap, Chinese yellow filters on ebay are roughly Wratten #4 equivalents and thus cut almost all violet
  • The vintage Hirsch #12A is almost exactly a Wratten #4 if you can find one
  • Vintage 48mm K2 Yellow filters are exactly a Wratten #8 if you can find new old photography stock.  48mm is the same as an astro 2" filter
  • #56 Green or cheap Chinese green filters only pass half as much light, but have similar bandpass characteristics to the Meade Green
  • Vintage 48mm X1 Green filters are exactly a Wratten #11 Yellow-Green and have higher transmission than either of the above green filters and yet cut almost all violet/blue and red light

The modern GSO and other astro-specific yellow filters are either too weak (#8 cuts off around 440nm) or too strong (#12 cuts off around 500nm) to be useful as minus violet filters.  The modern #11 Yellow-Green filters pass too much red to be useful.  They're basically the same as a Hoya X0 Yellow-Green.

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I generally just use my Baader Neodymium filter when the moon is up to darken the background sky, other than that I do like the Astronomik UHC filter for emission nebula and the Astronomik OIII for nebula  receptive to that particular wavelength.

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I used my Astronomik O-III filter earlier this evening ........ to observe Venus !

It worked rather well at reducing the glare and the views were still crisp even at 300x. The downside was a blue / green tint to the field of view and the planet. Funny how quickly I got used to that and forgot about it though 😏

I didn't see any surface features for sure but I felt they were close to popping out now and then so maybe there were just suggestions of them visible during the moments of best seeing (and in between gusts of wind !).

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5 minutes ago, Mr Spock said:

I was thinking of picking up some inexpensive blue or violet filters for Venus to see if they have any benefit - what are other people using?

I find that the medium blue #80A is beneficial for Venus. Cuts almost all the excessive glare.

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7 hours ago, Coco said:

I'm in bortle 6 according to the 'clear outside' app.

I'm thinking about OIII & LP visual filters and want to ask if you have a favourite particular filter.

Thanks ...

 

Favorite Broadband: Baader UHC-S.  Best view of M20 in a dark sky.  Does well on reflection nebulae, which is uncommon in filters with this much contrast.

   Honorable mention: Lumicon Deep Sky.

Favorite Narrowband filter: DGM NPB. Best view of M8/M17/M16/etc.

   Honorable mention: TeleVue BandMate II Nebustar,  Lumicon Gen.3 UHC,  Astronomik UHC Visual, Orion Ultrablock (if you get lucky with QC)

Favorite O-III filter: TeleVue BandMate II O-III (my highest transmission O-III filter for BOTH O-III lines).

   Honorable mention: Astronomik O-III Visual 12nm

Favorite H-ß filter: TeleVue BandMate II H-ß (highest transmission H-ß filter I've owned).

   Honorable mention: Astronomik H-ß

Favorite planetary filter: Baader Contrast Booster

   Honorable mention: Baader Moon & Sky Glow filter.

 

Note: Baader does not have visual filters in these categories except the UHC-S

The other filters they make are really oriented to astrophotography, not visual.

 

There are some discontinued filters I would add to the honorable mention lists, but since they aren't serial numbered, I could not recommend buying a used one because it could be from a different year.

 

What you're looking for:

>90% transmission at:

60-70nm for broadband

22-27nm for narrowband

11-13nm for O-III (dual band 495.9nm and 500.7nm).

8-10nm for H-ß

 

Edited by Don Pensack
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Observing from home, this past year has been the Baader Neodymium. Only other filter I might consider using from home is my (older version) Lumicon UHC. Pays to have a set of good visual filters if able to get occasionally to darker skies, thus an older Lumicon O-III and H-beta will receive use and the O-III being a favourite. Each in 2" format for versatility. 

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1 hour ago, Philip R said:

I don't think I have a favourite visual filter as such, as each one has it capabilities, expectations, etc. That said, I do like the Explore Scientific filter boxes... :thumbsup:

image.png.6b53d0107454efbf853bf9fdcb564f66.png

Agreed.  Too bad the filters in those boxes weren't very good.

Well, at least they're cheap.

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Chroma 3nm Ha is the best filter I’ve got for night vision nebulae from London. It also proved a good investment. About two months after I’d bought the 2”, prices doubled over night. This was even before COVID.

For night vision stars, globs and galaxies, Baader 685nm IR pass.

Baader Continuum and polarisers for white light. Occasionally Astronomik UHC, Lumicon O III, if I’m travelling.   
And biggest of all, a 120mm Baader ERF for solar Ha.

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The filters I use regularly are...

Solar white light - polarising filter and continuum filter and nd3

Ha - polarising filter

DSOs - I use UHC amd OIII about the same

Venus - ND0.9

Jupiter and Mars - atmospheric dispersion corrector (not a filter I admit)

Regular moon observing - dont often use filters actually

Moon and planets in daylight - polarising filter

Full moon - any colour filters are fun bring different features to the fore (I know the full moon isn't supposed to be worth observing - sorry to blight the forum with such a comment!).

I'd say overall the solar continuum filter is the winner for me.

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On 20/04/2023 at 22:51, Don Pensack said:

Agreed.  Too bad the filters in those boxes weren't very good.

Well, at least they're cheap.

The UHC and Olll are a vast improvement to the cheap ones I used to have before I joined SGL. 😜

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On 21/04/2023 at 07:15, niallk said:

O-III for sure on DSOs: makes elusive detail visible on a wide range of objects:

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

A wide variety of emission nebulae, you mean.

It serves no useful function for anything with stars, or dark nebulae, or reflection nebulae.

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3 hours ago, Don Pensack said:

A wide variety of emission nebulae, you mean.

It serves no useful function for anything with stars, or dark nebulae, or reflection nebulae.

Absolutely, yeah i phrased that poorly - meant lots of targets on which to use it, and it can give a dramatic enhancement; but it's all nicely covered in that famous link!

I use the Astronomik O-III, and also their UHC.  Next filter I plan to get is a Hb... and an Astrocrumb filter slide at some point.  I had a filter wheel for my 10" dob and it was very handy for flicking in - especially when using moderate to high mag and you don't wish to lose your target

Edited by niallk
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6 minutes ago, niallk said:

I had a filter wheel for my 10" dob and it was very handy.

How did you make that work?  Did you shorten your truss poles?  My Dobs have low profile focusers with about 25mm of in-focus from the primary focus point.  This was done to minimize secondary obstruction while maintaining decent illumination levels.

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2 hours ago, Louis D said:

How did you make that work?  Did you shorten your truss poles?  My Dobs have low profile focusers with about 25mm of in-focus from the primary focus point.  This was done to minimize secondary obstruction while maintaining decent illumination levels.

My 10" was a solid tube Skywatcher 250px, and there focuser travel wan't an issue!  Not so for my 15" truss dob... I'm very tempted to get the Astrocrumb filter slide which attaches to the threads on a Feathertouch - ie on the inner 'secondary mirror' side.  It encroaches a little into the light path.

I only had a cheapo filter wheel from TS, but it was the business in practice: it really became a joy to flick between no filter, UHC, O-III, and I had a neutral density filter in there too for the moon.

I'd like to get that sort of convenience back for the 15".

Edited by niallk
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