Astrotrac + DSLR + LP = Arrrrgg

[Scubapauly]

Hi Guys

I've been trawling through the threads here looking for some answers but I can't quite find what I'm looking for.

I'm using a Nikon D7000 with either 17-50 F2.8 or 70-200 F2.8 lenses.

For the plus part I live in the Oman desert. Trouble is the camp and surrounding area are floodlight. Unless I can get 20km (at least) away then the light pollution is dreadful.

Now, whilst I can find lots of solutions for LP filters for eyepieces and for Canon sensors I cannot find how to filter my lenses on a Nikon body.

Any help or suggestions will be greatly appreciated.

Paul.

[Leveye]

Astronomik makes blank disks you could fabricate a way or contact them to make you something custom possibly just a thought.

[Psychobilly]

I would hate to think how much they would be.... Hutech IDAS is already available in a range of front fit filter sizes but at a price...

What type of floodlighting are they using - what colours the light...?

Peter...

Sent from my GT-P7300 using Tapatalk HD

[lensman57]

Hi Guys

I've been trawling through the threads here looking for some answers but I can't quite find what I'm looking for.

I'm using a Nikon D7000 with either 17-50 F2.8 or 70-200 F2.8 lenses.

For the plus part I live in the Oman desert. Trouble is the camp and surrounding area are floodlight. Unless I can get 20km (at least) away then the light pollution is dreadful.

Now, whilst I can find lots of solutions for LP filters for eyepieces and for Canon sensors I cannot find how to filter my lenses on a Nikon body.

Any help or suggestions will be greatly appreciated.

Paul.

Hi,

For Deep Sky imaging you can always remove the LP at post capture process stage. Not using an LP filter is not such a bad idea as it will remove some of the light that is captured from the galaxies. The best solution is a dark sky location if u can find it.

Reagrds,

A.G

[DaveS]

FLO do IDAS up to 77 mm.

http://www.firstlightoptics.com/light-pollution-reduction-imaging/hutech-idas-p2-light-pollution-suppression-filter.html

Cost a bit though

[Psychobilly]

Hi,

For Deep Sky imaging you can always remove the LP at post capture process stage. Not using an LP filter is not such a bad idea as it will remove some of the light that is captured from the galaxies. The best solution is a dark sky location if u can find it.

Reagrds,

A.G

Removing the LP in the post processing is no where near as effective as using a LP filter to reduce it during the capture process...

As for the LP filter reducing useful signal, any decent filter will have narrow reject bands around the LP wavelengths and very high transmission at the astronomically useful wavelenghts...

Peter...

Sent from my GT-P7300 using Tapatalk HD

[Scubapauly]

Thanks for the replies. I took this from 5km away from the camp with 8mm fisheye just to show you

[Scubapauly]

try again

[edjrgibbs]

I use a Marumi Redhancer on my Tokina 12-24mm. Works well for orange glow light polution. £32 on Amazon http://www.amazon.co.uk/Marumi-MAHR77-Redhancer-77mm-Filter/dp/B00368CJRA/ref=sr_1_1?ie=UTF8&qid=1368791879&sr=8-1&keywords=redhancer

[Deus_Ex_Mamiya]

I agree with edjrgibbs - Didymium and Neodymium (aka Redhancer) filters are Nature's magic urban light pollution reducers. The combination of two rare-earth elements absorbs light at precisely the wavelengths of Sodium streetlights, and transmits almost all other wavelengths. Ok, that's physics, not magic: but it's a mighty convenient coincidence!

A few € on ebay recently got me a Cokin Redhancer on clearance. I used it in the left hand photo of southern Orion: Fuji S5 Pro, 2 minutes, Mamiya 55/2.8 at f/4, ISO 800, Astrotrac...cropped. An identical photo [including most importantly, an identical white balance setting), taken immediately afterwards without the filter, shows how the sky is washed out by scattered yellowish streetlighting, making the stars and nebulae much harder to see. The tree in my neighbour's garden, which is directly illluminated by a classic low-pressure sodium streetlamp, almost completely disappears in the filtered shot!

Although driving to a dark sky site is still preferable, there are times when I need to stay home in the 'burbs and I'll definitely be using this filter.

FWIW, the Cokin filter has a stronger sodium-blocking effect than my smaller-and-more-expensive 2" Baader Neodymium "Moon and Skyglow" filter. Holding them up to white light, the Baader gives a slightly blue tint, while the Cokin is yellowish, so they are somewhat different in their overall bandpasses.

Ray

[poogle]

Nice to see a side by side comparison. Do you know how these filters cope with LED-lights? Most of the street lights here in Stockholm have been changed from mercury to LED.

I guess light pollution filters will be less effective due to the broad spectrum of the LEDs?

/Patrik

[DaveS]

I think they'll be totally innefective.

You might have to bite the (Expensive) bullet and go narrow-band.

Pitty you can't charge it to the council.