OIII filter and galaxies

[Halcyon]

Daft question I'm sure, but I've been considering a OIII filter. I use a skywatcher 300 truss auto dob with various eyepieces including a 32mm 2inch panaview and 15 and 7 mm panorama eyepieces. All give excellent views. My question...I realise that these filters help with finding nebulae but do they help with the viewing of galaxies. For example andromeda we mainly see the core of course - would more of the outer parts of this become visible with such a filter?

Sorry if that's a dumb question!?

Thanks

[swamp thing]

They can help pinpoint extragalactic nebulae in some Galaxies yes.

It won't make the outer arms of M31 easier to see as most of that is comprised of unresolvable stars not H11 regions.

I've used my O-III on both M33 & M101 with pretty reasonable results. Not done any research into H11 regions in M31 as of yet. No doubt there are some, but I have'nt tried hunting for them to date.

Hopefully someone else on here has.

[cotterless45]

I prefer to use the UHC filter, a most excellent review from astro- baby will clarify,

http://www.astro-baby.com/reviews/O111%20and%20UHC%20filters/O111%20and%20UHC%20Filter%20Review.htm

Nick.

[lensman57]

Daft question I'm sure, but I've been considering a OIII filter. I use a skywatcher 300 truss auto dob with various eyepieces including a 32mm 2inch panaview and 15 and 7 mm panorama eyepieces. All give excellent views. My question...I realise that these filters help with finding nebulae but do they help with the viewing of galaxies. For example andromeda we mainly see the core of course - would more of the outer parts of this become visible with such a filter?

Sorry if that's a dumb question!?

Thanks

Hi,

A UHC or a Neodymium filter may be of help.

A.G

[swamp thing]

I prefer to use the UHC filter, a most excellent review from astro- baby will clarify,http://www.astro-baby.com/reviews/O111%20and%20UHC%20filters/O111%20and%20UHC%20Filter%20Review.htmNick.

You may find Mel has changed her mind since she wrote that. We compared filters on the veil.......somewhat different findings.

[John]

I've never found O-III filters to be much help on galaxies to be honest. A good example is the Owl Nebula in Ursa Major which has the galaxy M108 in the same low power field of view. The O-III filter does a really good job enhancing the contrast of the nebula but the galaxy more or less vanishes !

I do recall a night when a Baader UHC-S filter seemed to show M31 a bit better than without the filter so there might be some mileage in one of those.

[acey]

Like Swamp Thing I've tried a filter (UHC) on M33 and M101, which are just about the only galaxies likely to benefit since they have large HII regions (some with their own NGC number) - the effect is marginal, and only worth trying at a dark site - a filter certainly wouldn't enhance views of those galaxies at a light polluted site, just make them even harder to see. I've never tried it on M31 but wouldn't expect it to do anything - the most prominent DSO in M31 is NGC 206, which is a star cloud. Other DSOs in M31 that are worth hunting for with a 12" are globular clusters - all but one appear star-like in the telescope, the exception being Mayall II, which can be seen as a tiny fuzzy spot.

Map of M33 HII regions: http://www.astronomy-mall.com/Adventures.In.Deep.Space/M33.HII-Star.Clouds.html

Map of M101 regions: http://cs.astronomy.com/asy/m/galaxies/488852.aspx

NGC 206 in M31: http://messier.seds.org/more/m031_n206.html

Mayall II (aka G1) in M31: http://deepsky.astroinfo.org/And/g1/index.en.php

Some threads about the above:

http://stargazerslounge.com/topic/79872-g1/

http://stargazerslounge.com/topic/164237-ngc206-a-star-cluster-in-m31/?hl=%2Bm31#entry1661107

http://stargazerslounge.com/topic/63164-study-of-m33/?hl=%2Bm33#entry617915

[Halcyon]

Thanks guys pretty comprehensive answers.