Is it worth using a LP filter in dark skies

[SimonJoubert (Simon)]

Hello,
I am considering purchasing a LP filter instead of a UV/IR filter for my imaging. I understand the obvious benefit of UV/IR for the reduction of aberrations for reflectors. While browsing these, I came across the Baader Neodymium filter, which I see is used to reduce the effect of light pollution. I live in Bortle 2 skies and while there is a streetlight nearby, my house blocks it and as far as I can see, it has no effect on my images. Is this filter worth using over the UV/IR filter even in dark conditions?
Thanks

[ausastronomer (John Bambury)]

Originally Posted by SimonJoubert

Hello,
I am considering purchasing a LP filter instead of a UV/IR filter for my imaging. I understand the obvious benefit of UV/IR for the reduction of aberrations for reflectors. While browsing these, I came across the Baader Neodymium filter, which I see is used to reduce the effect of light pollution. I live in Bortle 2 skies and while there is a streetlight nearby, my house blocks it and as far as I can see, it has no effect on my images. Is this filter worth using over the UV/IR filter even in dark conditions?
Thanks

Hi Simon,

If you have a streetlight nearby I wouldn't think your skies are even close to Bortle 2. Your address shows as "Kingsford", which is in Sydney. I am assuming you aren't talking about there. That would be closer to Bortle 6 to 8, not 2. Where abouts are you located at?

Cheers
John B

[SimonJoubert (Simon)]

Originally Posted by ausastronomer

Hi Simon,

If you have a streetlight nearby I wouldn't think your skies are even close to Bortle 2. Your address shows as "Kingsford", which is in Sydney. I am assuming you aren't talking about there. That would be closer to Bortle 6 to 8, not 2. Where abouts are you located at?

Cheers
John B

Hi John,
I live in Sydney for half the year, but have a holiday house on the edge of Loch Sport, Victoria, which is where I do AP. Lightpollutionmap says it is Bortle 2, so I went with that.
Thanks,
Simon

[sharkbite]

Hi Simon - other opinions may differ, and i'm a rank amateur at this - but this is what i have experienced.

My Obs (the driveway) is in a Bortle 5 area, and the nearby streetlight is obscured by a tree.

I did buy a LP filter, and would be happy to sell it to you - but it is a bit useless in my opinion.

It makes no difference to visual, and degrades the signal significantly for photography.

The photos all come out looking too "blue" and i have to up the gain or increase the time significantly.

I reckon keep your money in your pocket.

(prepares for rabid disagreement)

cheers,

P.S. best bang for buck purchase i made was the IR/UV filter....this largely got rid of 'blobby' stars in the photos

[AdamJL]

Hi Simon

What sort of camera do you have? DSLR or Astro? Mono or colour?
If you've got a mono camera, then I wouldn't bother with any filter at a dark site. When the moon pops up, it'll turn your B2 site into a B7-8 pretty easily and those moments you can switch to narrowband imaging.

[SimonJoubert (Simon)]

Originally Posted by AdamJL

Hi Simon

What sort of camera do you have? DSLR or Astro? Mono or colour?
If you've got a mono camera, then I wouldn't bother with any filter at a dark site. When the moon pops up, it'll turn your B2 site into a B7-8 pretty easily and those moments you can switch to narrowband imaging.

I have a ZWO ASI533MC, no mono cameras at the moment.

[SimonJoubert (Simon)]

Originally Posted by sharkbite

Hi Simon - other opinions may differ, and i'm a rank amateur at this - but this is what i have experienced.

My Obs (the driveway) is in a Bortle 5 area, and the nearby streetlight is obscured by a tree.

I did buy a LP filter, and would be happy to sell it to you - but it is a bit useless in my opinion.

It makes no difference to visual, and degrades the signal significantly for photography.

The photos all come out looking too "blue" and i have to up the gain or increase the time significantly.

I reckon keep your money in your pocket.

(prepares for rabid disagreement)

cheers,

P.S. best bang for buck purchase i made was the IR/UV filter....this largely got rid of 'blobby' stars in the photos

Thanks for the suggestion, mate. I'll just get a UV/IR filter

[Bart]

Originally Posted by sharkbite

Hi Simon - other opinions may differ, and i'm a rank amateur at this - but this is what i have experienced.

My Obs (the driveway) is in a Bortle 5 area, and the nearby streetlight is obscured by a tree.

I did buy a LP filter, and would be happy to sell it to you - but it is a bit useless in my opinion.

It makes no difference to visual, and degrades the signal significantly for photography.

The photos all come out looking too "blue" and i have to up the gain or increase the time significantly.

I reckon keep your money in your pocket.

(prepares for rabid disagreement)

cheers,

P.S. best bang for buck purchase i made was the IR/UV filter....this largely got rid of 'blobby' stars in the photos

I don't agree with this at all. I have successfully used an IDAS LP 2 filter from suburbia with little to no shift in colour, never had to extend my imaging times beyond my normal times. If you are doing colour calibration as part of your processing routine then it shouldn't matter. The one I was using was designed for astro photography. Never have I used one for visual, even in the city.



Here is one taken using that filter.


https://pbase.com/grahammeyer/image/146425724


And another


https://pbase.com/grahammeyer/image/146017157


If you are imaging from a dark site, it shouldn't be needed anyway, as the dark skies will cut your exposure time, more light from your object will reach your chip, thus reducing the "white out" time related to the back ground light eventually swamping your chip.