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How do filters enhance viewing?

Roosto

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nephilim

nephilim

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The key to seeing fine planetary detail is to prepare your eye properly beforehand. There is a trick involving a piece of while card and a while light torch. You stare at the illuminated card for a short while and this makes your pupil adjust to a state where your eye will perform better on picking out the subtle contrast / details on Jupiter, Saturn etc. It sounds odd but it does work.

The only filters I use are i) a full aperture while light filter for solar viewing and ii) an O-III filter for increasing the contrast of nebulae.

Thats an interesting bit of info, it goes against everything I know about optical dark adaption (Which isnt much really :grin: ) & i'll definatley be trying it out :smiley:

Steve

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nephilim

nephilim

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What filters help bring out galaxies ?

Can anyone please recommend a filter for nebula and galaxies , I have a skywatcher 200p dob ,

Budget around £20 per filter , Thanks

As i'm still fairly new to all this I cant advise on a 'galaxy' filter (there isnt one altho a lp filter may help.....could be wrong) for emmision nebula such as M42 then i'd recommend a uhc filter or a OIII (the OIII will darken the sky considerably though and are only recommended for scopes of 8"+ apperture altho some may disagree) Either way your looking at £30+ minimum for a decent filter as is usual with this hobby, you get what u pay for.

Steve

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acey

acey

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There's no question that looking at the moon, with or without a filter, will spoil dark adaptation. Full adaptation takes about half an hour, so it will be at least that long before your eye can be fully adapted again for the purposes of viewing faint DSOs. But if the moon is up then DSO viewing is going to be poor anyway. When viewing DSOs at a dark site, even Jupiter through a telescope will spoil adaptation. If you're observing at a light-polluted site with bright red lights and maybe a computer screen or smart phone (in "night" mode) then your eye is never going to adapt fully anyway, so it doesn't matter. Just do what feels comfortable. But if you're serious about dark adaptation then you don't want to look directly at any light source brighter than naked-eye starlight.

If I arrive at my dark site before moon-set then I'll maybe give the moon a look, because my eyes aren't yet adapted anyway, and if it rises at the end of a session then I might have a look before I go home. If the moon is less than half illuminated then I may do some DSO viewing while it's above horizon, but I'll aim at the part of the sky opposite to the moon, being careful not to look at the moon itself with naked eye. At a dark site with adapted vision, it's striking how bright even a partially illuminated moon is, casting clear shadows on the ground.

Regarding filters, I can concur with the previous post - the only filter I ever use is a UHC.

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yesteryeargames

yesteryeargames

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Are the skywatcher uhc filters good ? About £10 cheaper than the baaadr ones , unless someone can reccomfnd another one ?

Uhc would give me more objects to look at , but does it help at all on the oIII objects ? How can I find out which objects are and are not requiring uhc or oiii ?

Thanks

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yesteryeargames

yesteryeargames

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I own a Baader Neodymium Filter, I find it useless for my modern street lights , it does slightly help on glare and beings some detail out on Jupiter ,

Do I still need a uhc ? I am going to order one this week maybe try and get one for £49-50 which is best to go for ? Thanks

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acey

acey

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The Lumicon UHC (which I have) transmits OIII and H-alpha wavelengths, so it is useful on the sort of emission nebulae where you might use an OIII (e.g. Veil) or an H-alpha (e.g. Horsehead), though it is not as narrow-band as either of those, hence potentially lets through a bit more "unwanted" light" in some situations. For example, I may have had better results on the Horsehead with an H-alpha than with a UHC. But it's still good enough for me, and I regard it as a very fine all-rounder for emission nebulae. It has no effect on anything else (e.g. enhancing galaxies or cutting white-light-pollution, where the only answer is a darker sky).

I can't speak about other brands of UHC, but the Lumicon is excellent. I've successfully used it on all my scopes from 80mm to 12".

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nephilim

nephilim

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I use the the Skywatcher UHC in my 130 & 200mm scopes & it does the job well, some say the packaging isnt very good & looks a little cheap, but your not looking through the packaging :rolleyes: , the filter itself is fine and IMO works very well.

Steve

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michaelmorris

michaelmorris

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The thing to remember with all filters is that all they do is cut down the amount of light reaching your eye/camera. Neutral density filters cut out light more or less evenly across all wavelengths. Selective filters reduce the transmission more in some wavelengths than in others.

For example -

A white light solar filter will cut out all IR light, and almost all light in visible equally across al wavelengths. (Neutral density)

A H alpha solar scope will cut out all light in very wavelength except a tiny range at wavelengths around 656nm. (very highly selective)

An IR cut filter will let through all visible wavelengths but block infrared light.(selective)

An IR pass filter will block almost all visible wavelengths but will pass infrared and far red light.(highly selective)

I hope this helps

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DanH

DanH

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For DSO, I'm using those filters in my 4x2" Orion manual filter wheel :

- Baader skyglow filter

- Lumicon UHC-s

- Lumicon UHC

- Baader clear filter (full transmission, also in IR, to prevent a focus change)

SInce I have installed that filterwheel, I can change filters anytime without the risk of having those fall on the ground or having my fingerprints ont their surface.

This is a MAJOR improvement in comfort !

Of course, for astrophotography, I use the much more convenient Starlight Xpress USB filterwheel, with 7x36mm unmounted filters ! (LRVBHaSIIOIII)

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John

John

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The Lumicon UHC (which I have) transmits OIII and H-alpha wavelengths, so it is useful on the sort of emission nebulae where you might use an OIII (e.g. Veil) or an H-alpha (e.g. Horsehead), though it is not as narrow-band as either of those, hence potentially lets through a bit more "unwanted" light" in some situations. For example, I may have had better results on the Horsehead with an H-alpha than with a UHC. But it's still good enough for me, and I regard it as a very fine all-rounder for emission nebulae. It has no effect on anything else (e.g. enhancing galaxies or cutting white-light-pollution, where the only answer is a darker sky).

I can't speak about other brands of UHC, but the Lumicon is excellent. I've successfully used it on all my scopes from 80mm to 12".

I think acey means H-Beta above. H-alpha filtration is only useful for solar viewing I believe.

I've found a UHC or an O-III filter very useful to have for enhancing the views of some nebulae. Only some though and these filters do not get a lot of use to be honest. They are not "magic bullets" except with a handful of objects where they can make the difference between seeing something and seeing nothing.

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DanH

DanH

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Yes, I leave the filterwheel permanently connected. Unlesss I swith for the camera and the more advanced filterwheel.

So, I can swap eyepieces and filters in a snap !

I'm using the Orion manual filterwheel, but this one is made for 2" filters. There are cheaper FW for 1.25" filters.

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John

John

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Ah right the filter wheel will permanent installed while I switch eyepieces ? I could do with one , can anyone recommend a suitable wheel that would work with my scope , 1.25 eyepieces and a 8 dob ,

I will go for the baaadr or skywatcher uhc to start with :)

I think filter wheels use up some inwards focus travel so you may not be able to get eyepieces to focus with some scopes. DanH uses a refractor which has more focus travel than most newtonains.

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DanH

DanH

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Hi Acey,

An empty slot would have a different focus position, because of the thickness of the filters.

That's why I have a clear filter instead of an empty slot. It remains "in-focus" no matter the filter position.

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John

John

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Can't decide the skywatcher uhc for £39 or Baader £50 ? From first light optics unless there's a cheaper site

If it's the Baader UHC-S you might find the Skywatcher UHC more effective with your 200P. The Baader UHC-S is a nice filter but it's a little "gentler" than most UHC's and is designed for use with smaller aperture scopes. Your 8" of aperture gathers enough light to make a full blown UHC worthwhile, in my opinion, and it will have more effect than the UHC-S I feel.

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