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Filters that work for galaxies

Started by Bill Steen , Feb 11 2015 10:38 PM

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63 replies to this topic

#51 faackanders2

Cosmos

Posts: 7,980
Joined: 28 Mar 2011

Posted 19 February 2015 - 11:42 PM

It appears that the Orion Mars Observation has a similar filter curve as the DGM GCE filter:

http://www.telescope...lter/p/5599.uts

Would the Orion filter work as a 'poor mans' galaxy filter? It's cheaper and seems like it does almost the same thing.

Looks like it would work, and better than the #8 filter. It seems to cut out more light, in a wider swathe than the DGO GCE or Orion's Moon and Sky Glow Filter. On the other hand, the DGO GCE might make a really good Mars filter. It might be worth saving a few more nickels and buying the better filter.

Never trie Orion Mars filter on galaxies, or DGM GCE filter on Mars yet. But now I will have to do it sometime.

P.S. Skyglow works really good on Jupiter to being out bands, red spot, and polar caps.

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#52 Wol

Vostok 1

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Joined: 26 Mar 2007

Posted 06 January 2017 - 09:40 AM

Just wondering if Bill did ever receive/test his filter and if it had a positive effect on his viewing.

regards

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#53 Procyon

Fly Me to the Moon

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Joined: 23 Feb 2009

Posted 06 January 2017 - 01:31 PM

I'd say the gas filter is the best bet.

What is a gas or gasoline filter? :shocked:

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#54 Miranda2525

Soyuz

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Posted 06 January 2017 - 01:40 PM

I'd say the gas filter is the best bet.

What is a gas or gasoline filter?

It's a trip in your car or truck to darker skies.

Dark skies is best for galaxies & deep sky.

Planets do not need this.

Edited by Miranda2525, 06 January 2017 - 01:41 PM.

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#55 Procyon

Fly Me to the Moon

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Posted 06 January 2017 - 01:45 PM

:lol: :lol: :lol: Ok thanks.

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#56 csrlice12

ISS

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Joined: 22 May 2012

Posted 06 January 2017 - 01:48 PM

There is no galaxy filter, and the person who invents one will make $$$ off all us CN folk.

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#57 Starman1

Stargeezer

Posts: 63,332
Joined: 23 Jun 2003

Posted 06 January 2017 - 02:15 PM

There is no galaxy filter, and the person who invents one will make $$$ off all us CN folk.

I have found, recently, in my testing of 29 different filters, that some of the "notch" type filters do help on galaxies if you are already in a dark sky.

They lower the background brightness a tiny bit without dramatically affecting the brightness of a galaxy.

A standard CLS/broadband filter may help you resolve H-II regions in M33 or NGC6822 or M31 as well, though the overall image will be dimmer.

Normally, though, the gasoline filter must be applied. :lol:

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#58 Redbetter

Hubble

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Joined: 16 Feb 2016

Posted 06 January 2017 - 03:25 PM

There is no galaxy filter, and the person who invents one will make $$$ off all us CN folk.

I recently saw some modest increase in contrast using a yellow filter on heavily obscured galaxies, although it wasn't a great test due to atmospheric conditions and dewing. These galaxies are ones hidden behind dust from the plane of our own galaxy: Maffei 1 & 2, Dwingeloo 1, some IC's in the vicinity. The dust knocks out most of the blue and green wavelengths with even the yellow highly reduced. Some of these would be showpiece objects if they were positioned out of our galactic plane. The remaining light from them that we can actually detect with our eyes is mostly red/orange with some yellow resulting in very low surface brightness. Using a yellow filter eliminated the shorter wavelengths from the background glow of the sky/light pollution without reducing the light from the galaxies significantly...but there wasn't much light to begin with. I was doing this from a moderately dark location.

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#59 Procyon

Fly Me to the Moon

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Joined: 23 Feb 2009

Posted 06 January 2017 - 05:18 PM

How come there's no dust seethrough type of filters yet? With Chandra telescope optics.

Edited by Procyon, 07 January 2017 - 02:21 PM.

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#60 faackanders2

Cosmos

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Joined: 28 Mar 2011

Posted 07 January 2017 - 02:06 PM

The only kind of filters that help galaxies at all are the so-called broadband "LPR" type filters (Orion Skyglow, Lumicon DeepSky, IDAS LPS filter, DGM Optics GCE, etc.), but the enhancement they may provide for these objects is usually fairly minimal even under skies that are already fairly dark. The effect of these filters is most noticeable on the larger and more diffuse galaxies, as on the smaller ones, a similar enhancment can often be achieved just by bumping up the power a little. Under moderate to severe light pollution, no filter will help galaxies, so your best bet is to find as dark an observing site as you can. Clear skies to you. BroadbandFiltersOnGalaxiesSmall.jpg