Advice on filters

John Saunders · #1 12-02-2007, 06:26 PM

Hi folks.

Being only a newbie to astronomy, I am looking for some advice on coloured filters.

The other night I managed to "wow" my 14 year-old budding astrophysicist son with the Great Nebula in Orion...along with Saturn and Sirius. I believe that it is possible to use filters to enhance the colour of the nebulae etc rather than just viewing the blandish image (if you can call the Orion neb "bland"!) I get through my 8" SkyWatcher reflector, so it looks more like the pictures in books and from astro photos.

Suggestions...comments...advice...?

astro_south (Andrew) · #2 12-02-2007, 08:16 PM

John

Unfortunately there are no filters that make Orion's nebula come alive with colour. There are filters that restrict certain wavelengths of the light spectrum and result in an "enhancement" of other wavelengths, such as those emmitted from nebulas. These will make some of the fainter nebula in the eyepiece easier to see. Google search for 'light pollution filters', and 'narrowband filters'

You can purchase colour filters that can be used on planets to highlight certain features (such as the polar caps on Mars and the Great Red Spot on Jupiter) and there are websites you can find through Googling that will tell you what colours enhance what features.

If you are new to astronomy and want to learn there is no better way than going along to a star party and getting some 'in the field' training. There is a party planned for this weekend at Cambroon and depending on what side of Brisvegas you are on, it is between 1 and 2 hours drive. See this thread:

http://www.iceinspace.com.au/forum/s...ad.php?t=17042

Here you will be able to talk to people and it is a good oportunity to test out other peoples equipment - such as some of the filters I mentioned.

good luck, and maybe we will see you at Cambroon soon.

John Saunders · #3 12-02-2007, 10:09 PM

Thanks, Andrew.

This weekend is already bookmarked for my wife's birthday...a date not to be missed/forgotten/utilised for a star party. Having said that, I would be interested in going to such events in the future. I live on the north side of Brissy, and I do know the area. Where exactly do you go?

astro_south (Andrew) · #4 12-02-2007, 10:29 PM

John

I get around a bit. I am a member of the Southern Astronomical Society and we have our dark sky site at Leyburn (Other side of Toowoomba) so this is my primary site. I also go up to Ron's at Cambroon (though haven't been for a while), I also have a site in the Lockyer Valley - (short drive) for those last quarter moon weekends when I pack up around midnight and drive back to Brisbane, and just recently I went south to Casino.

JethroB76 (Jeff) · #5 12-02-2007, 10:47 PM

You could do worse than use the search function on this site for the same terms. There are a number of gurus who have provided similar advice in the past, I'm not one though

Gargoyle_Steve (Steve) · #6 13-02-2007, 02:19 AM

John here's the link with precise details as to how to find Ron's place- it' a sticky thread, ie you can always find it in the top section listed under "Star Parties and Observing Sessions" area:
http://www.iceinspace.com.au/forum/s...ead.php?t=8808

rmcpb (Rob) · #7 13-02-2007, 10:05 AM

John,

Take care with filters to make things colourful as they actually reduce the amount of light getting to your eye and can reduce the observable details. They work on planets to selectively see some features but not on nebulae, etc.

Have a look at:

The Hubble site filter page and toggle the filters on and off to get an idea of what happens. Remember that these photos are taken with a MUCH larger scope than yours and have been enhanced.
And the Astronomy for Everyone filter page, its really helpful.

Cheers