Limits of light pollution

[Entropy]

Hey everyone,

I'm going through some serious imaging withdrawals.
I live in the centre of Sydney, pretty much (Kensington) and would really like to take my telescope out more often without driving for 4 hours to a dark site.

I was wondering how close to major cities do people image (Without a dome)?
What sort of results do you get?
Basically I want to find out how far I have to drive to get some semi-decent use out of my telescope to build up my experience (both in processing and acquisition) for when I do make long trips to dark sky sites.

Does anyone have any cool public spots relatively close to Kensington that they are willing to tell me about?

Thanks

[AG Hybrid (Adrian)]

Well, it depends on what you are imaging. If nebula's are what you are targeting you can do narrow band imaging. With the way it works you could do imaging from the steps of the Sydney Opera House.

Otherwise you're going to need a dark sky. You can image well enough from places like Linden or better Katoomba airfield if you image away from the Sydney light dome. I imagine the pony club is good too. These are far closer than 4 hours away.

[MrB (Simon)]

As Adrian has said, if it's nebula's you are targeting, narrowband is the answer.
I live only 10k or so from a very large industrial area which includes a BP oil refinery and its flare stack, CSBP and its flare stack, BOC and its flare stack, Alcoa alumina refinery, a large Nickel refinery, and about another half dozen large refineries/processing yards.

With no filter I would be lucky to get a 30 second exposure before the LP fogs everything out, but even with 'wide' (12nm) narrowband filters I can shoot 10 min subs with the same setting at full moon and get good contrast, at new moon I can get 15 minute subs with excellent contrast. I could possibly go 20 minutes.

The following link was a test image for an Astronomik 12nm Ha filter, it is 10 min subs at f6 and ISO800, during full moon with the above mentioned industrial light pollution.
http://www.astrobin.com/90125/

The other day I took another of the same region during new moon, everything else the same except 15 min subs at ISO1600 and the subs have much darker background, LP just isn't an issue at all anymore.
http://www.astrobin.com/full/98888/0/

[el_draco (Rom)]

Now, if you can work out how to do that trick through cloud, I'll sell you my soul...

[Entropy]

would something like this - Astronomik CLS EOS clip
Help with imaging in severly light polluted skies, or would you recommend the Ha filter specifically?

[MrB (Simon)]

The CLS will help, how much tho I can't answer.
I have a CLS-like filter (the Hutec LPS-P2) but I've not yet tried it, sorry.

[madwayne (Wayne)]

Hi

Sutherland Astronomical Society have a semi dark site at Waterfall, adjacent to the Royal National Park. Be about an hour drive off peak from Kensington. I've imaged from there before and you can image from there filter free. There are a couple of sodium lights that can interfere from the railway station if you image in that direction. It is an old cricket ground at the back of the school so it has clear views horizon to horizon. North is no good due to the light dome that is Sydney and while there is a bit of a dome to the South from Wollongong it isn't that bad that you can't see the SMC and LMC naked eye. They have viewing nights on Saturday nights on 3rd quarter and new moons. There is also a site at Bargo but there has been access issues to the site. It's a cracker of a site so close to Sydney but views are quite restricted East and West due to trees.

The Pony Club the Central Coast guys utilise may be of interest too. I haven't been up there but there are plenty of threads on here with maps etc.

Wayne

[Screwdriverone (Chris)]

Hi Entropy,

here is a shot taken of Eta Carinae through the horrendous light pollution south of me over Parklea and Blacktown, I can attest that the Eos clip filter works wonders with heavy light pollution in Sydney, just take a shot of a white piece of paper in clear sunlight and set this shot as the custom white balance in the camera and the blue tinge you normally get through this filter will disappear.

https://www.dropbox.com/s/lh28wc80c3...ilter-test.jpg

Well worth the money and so convenient to use

Cheers

Chris

[ZeroID (Brent)]

The CLS filter is a good bet. I'm affected by LP and the CLS made a huge difference. Widefeilds are impossible where I am at, image gets washed out with glare but I'm experimenting with another filter option to minimise it.

[solissydney (Ken)]

You might consider dropping in on SNAG's observing site, Dural Pony Club site in Bannerman Road, Kenthurst any clear Friday night.

Chris, we would dearly like you to drop in also once in a while.
My friends are all beginners and I would appreciate some support as I am getting rather forgetful and the technology has changed so much since my early days.