Will a filter of some kind help?

[sas]

Hi All,

I am in possession of a 12" dob and live approximately 13km out from the city centre (Melbourne), so obviously, seeing on the best of nights is punished from the amount of light pollution.

Are there filters i can get that will offer me a new view on the deeper / dark regions of the sky? Getting away from the light pollution is not so easy - so if there's something that will offer me a new set of wow's right from my back yard, that would be fantastic. I just don't know what to expect from them (filters)?

*edit* It may not even be a filter that will give me new wows... maybe an eyepiece?

Thanks all in advance.

- Michael

[renormalised (Carl)]

Grab yourself an UHC or nebular filter from Bintel or MyAstroShop. They increase the contrast of neb's by cutting back the skyglow and light pollution.

[sas]

Sounds ideal! Thank-you.

Will it come at a cost (visual)?

[wavelandscott (Scott)]

Originally Posted by sas

Hi All,

I am in possession of a 12" dob and live approximately 13km out from the city centre (Melbourne), so obviously, seeing on the best of nights is punished from the amount of light pollution.

Are there filters i can get that will offer me a new view on the deeper / dark regions of the sky? Getting away from the light pollution is not so easy - so if there's something that will offer me a new set of wow's right from my back yard, that would be fantastic. I just don't know what to expect from them (filters)?

*edit* It may not even be a filter that will give me new wows... maybe an eyepiece?

Thanks all in advance.

- Michael

If you get a chance, do a search on the topic of light pollution and you will find a fair bit of information on this topic here.

In summary, yes filters can help...but no, there are not nearly the solution that getting to a dark sky is.

Light pollution hurts the search for faint fuzzies two ways...

#1 The light makes it difficult to pull out the deep sky objects...a filter can help this.

#2 The light nevers lets your eyes dark sky adapt...filter can't help this.

I've owned and used Light Pollution Filters and others...in my opinion a UHC/Narrow Passband filter has the most utility.

My general advise for light pollution impacted folks is...instead of a filter use the money to buy petrol to get to a dark spot.

If that is not an option, concentrate on viewing things not impacted...moon, planets, double stars

Gotta run to a meeting! Good Luck...

[lacad01 (Adam)]

Hi Michael, feel your pain as I live about 8k from Sydney CBD. What's helped me a bit is to use some sort of shroud like what the early photographers used to do in the ye olde days. That way it'll also cut down on incidental light ruining your night or dark adapted vision. A large dark towel or something like that should suffice. But as Scott says, at the end of the day best observing is going to be out of the way of built up areas in a nice dark sky site

[rmcpb (Rob)]

As many of us live in light polluted areas this is a quite common question.

Some steps to help are:

• Make a light/dew shield for the front of your scope. This should extend 1.5x the diameter of your mirror in front of the focuser and will help stop ambient off axis light getting into your focuser and reducing contrast.
• Make a baffle for the rear of your scope if light can get around the mirror. A simple ring set up here will do and can be made of plastic. Again, it will stop ambient light getting ito the scope. Not so important as the light shield but easy to do so worth the effort. Make sure there is room for air to flow around the mirror still.
• Flock your scope's tube. If ambient light still gets in, and it will, flocking will reduce the effect on contrast.
• Make like a pirate. Get an eye patch and put it on your observing eye for a good half hour before observing. This will allow your eye to dark adapt.
• Make an observing hood that your head goes under when observing. This will stop the ambient light from ruining your dark adaption when observing.
• Take off and put on your eyepatch under the observing hood to preserve your dark adaption.

Give it a go, the results are really worth the small effort.

Cheers

[sas]

Some very useful suggestions Rob / Adam - next time the skies are clear i will give these a go!

Cheers Scott - I might try the freeby suggestions out to see what impact that has before i fork out cash for something. Filter might be the next step once all the light adaption techniques are in place.

[cookie8 (Vincent)]

Hi Michael
I use my 12" dob in my suburban Sydney backyard & I share your frustration. Nothing can beat a nice dark sky in the outback but unfortunately not always feasible.Bought a DGM NPB(narrow pass bandwidth) filter and very happy with its performance. Suppressed the skyglow making nebulae (both emission and planetary) appears a lot brighter. Cost:$200 plus

[rmcpb (Rob)]

If you go dowen the filter path you still need to make like a pirate and have an observing hood. Light pollution really affects your dark adaption and will reduce the effect of your filter.

[astroron (Ron)]

Try to cut down on as much exstranious light by putting some form of sheeting around your observing position,such as tarp or black plastic.
as other posters have said use a cloth or hood over your head ,and use higher mag on some objects which help to darken the sky.
Contrary to some posts I do not think any filters are any good for galaxies.
Colour filters such as a blue filter are fairly good for the brighter planets