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LP filters.

LukeSkywatcher

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LukeSkywatcher

LukeSkywatcher

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I dont reckon that my observing location is too badly affected by LP when i observe through my scopes or bins but when i take images of the night sky they are pretty horrible on anything above 10s.

I think i'd like to try a LP filter for my scope(s), just to see if there is any real difference. I dont want to spend a small fortune on one. I was thinking of maybe £60-80. I know that is pretty cheap as far as LP filters go and you get what you pay for. I would max out at £100 for one IF it is worth it. All my scopes (all 2 of them) have 1.25" EPs.

So for about £100.............what would be my best spent cash?. Is there a general all rounder LP filter for that price that will deliver?

P.S.~~~i'm not to worried about using it on my 90EQ scope. I am thinking more of my SkyWatcher 130P.

Thanks in advance.

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Astro_Baby

Astro_Baby

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Paul - I have a SkyWatcher 1.25 and found it to be not much use against my local LP (which is VERY excessive). Some other people report good results but I think a lot depends on what kind of LP you have and also individual eyeballs.

I mostly use mine with a neutral a density on the moon which is about the only object I can ever see from my location. LP is so bad around me now that even Jupiter is blanked out most nights.

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LukeSkywatcher

LukeSkywatcher

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Paul - I have a SkyWatcher 1.25 and found it to be not much use against my local LP (which is VERY excessive). Some other people report good results but I think a lot depends on what kind of LP you have and also individual eyeballs.

I mostly use mine with a neutral a density on the moon which is about the only object I can ever see from my location. LP is so bad around me now that even Jupiter is blanked out most nights.

Thanks AB. I'm pretty sure/possitive my LP level is nowhere near as bad as yours.

To be honest i am puzzled as to what type of LP i suffer (apart from the one security light behind my house). My observing location (that will be my back garden) is shrouded on 3 sides:

50 ft high trees at the east end of garden. My house blocking my west view and my north view obscured by next door neighbours boiler houses and my view south is PANTS due to a motorway about 3 miles away.

I really am stuck with observing east or straight up to zenith.

To be honest i have not a clue. I just figure if my SLR shows up so much LP in all directions apart from straight up.............that i cant go wrong by investing in a LP filter of sorts for my scope.

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LukeSkywatcher

LukeSkywatcher

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So.............so far, 2 out of 2 use a SW LP filter. Any links as to where to buy one?....cost etc.

As i said..............i dont wanna spend a fortune for something that i really am just curious about trying. A marginal difference will do me.

Every little helps.

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stev74

stev74

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Ok to what I've read it depends on the 'type' of light you have in your street - if it's the old fashioned steet lights ie. mercury-vapour lights which I think are the more orange coloured lights, the Skywatcher or other LP filters will be good. If like me you have the brighter yellow/white lamps in your street you need to find a dark site as I don't think there is a filter to help yet!! :hello2:

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riklaunim

riklaunim

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Baader Moon and SkyGlow may also be good, but it's not dedicated ALP filter. Using very cheap chinese filters isn't good too as they may not be made from optical, good quality glass.

Quite good for visual and imaging is Hutech IDAS LPS filter (~140$ for 1,25" filter) as it blocks terrestial light (Hg/Na) and try not to change the color of observed objects.

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James

James

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Thanks for your input. If it helps.............GREAT.

If NOT.....................it is less then 20 quid.

If it doesn't work for your location we'll happily take it back Paul - we appreciate that it's hard to predict which kind of LP you have and which filter will work. :hello2:

James

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glowjet

glowjet

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If it is any help mercury or to be correct MBF/U are fluorescent blue/white, LPS or low pressure Sodium units give out the customary orange glow. HPS high pressure Sodium which I can only describe as bright warm sunshine, these are mainly used on major roads and highways mounted at heights of 10 to 12 meters, you also have variants such as mercury/tungsten MBT/L with a colour leaning to wards white, then , of course there is flood lighting, tungsten halogen and HPS as well. LPS filters are better with LPS or orange lighting rather than any of the Mercury to white lighting,

hope this helps,

John.

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riklaunim

riklaunim

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You can buy hand held spectroscope (3 prism usually) from shool aids stores very cheaply (or make something simillar with a diffraction grating) and check the street lights.

I have high pressure sodium lamps all around me, and spectrum I got (spectroscope + telescope pointed on the lamp):

4222912162_6ce9d400e1.jpg

Then you can get best ALP filter, and/or check how good those filters are :hello2:

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LukeSkywatcher

LukeSkywatcher

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Thanks Rik but street lights are no my DIRECT problem. I cant see any from my observing location but obviously they play a part in the general scheme of things. My LP problem is the general skyglow problem with the added extra of one stupidly positioned security light on the house behind.

As i have said.....i have never noticed any ill effects when observing through a scope or bins (but how do i know there are no ill effects if i dont know any different!!!).

I only know it is there because of exposures i take with a DSLR.

NOW..........regarding the LP filters available on FLO. I can afford either one, but i am unsure if the Baader LP filter will fit a 1.25" EP. The SW one does.

Just one more Q:

Is it possible to buy a LP filter for DSLR's?. I mean one that attaches straight onto the camera lens for those of us who only image the night sky from a fixed tripod. I have no plans to get my camera "modded" because i mainly use it for every day imaging.

BTW....

Cool image of the light spectrum from the street lamp.

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LukeSkywatcher

LukeSkywatcher

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Hutech makes such filters for DSLR (IDAS LPS).

Thanks Rik. I have googled IDAS LPS and found good images/info. I havent read much so i am unsure if these attack straight onto the DSLR camera lens. I have NO plans to attach the camera to scope so will these work simply by placing them over the camera lens?

i.e: will they simply attach to any lens i use on my camera of do i remove the lens first and place the filter and then re-attach lens?.

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MishMich

MishMich

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Not cheap,

Hutech Light Pollution Filters

P31.7 £138 (1.25")

P48 £188 (2")

P48SCT £227 (SCT Version)

P52 £188

Looks like can get a 52mm camera lens fitting in the UK. The results look impressive.

I have to say that I have the 1.25" Skywatcher, which was OK except using a 1.25" adapter introduced vignetting to images. I got a 2" adapter and LPR filter, the filter cost about £40, but I can't remember the manufacturer. TBH, I don't use the 2" one because I don't like the resulting colour and makes things so dark it doubles the exposure time - the skywtacher one was better. I have heard the Baader UHC/LPR filters are better. I have the Baader fringe killer and the moon+sky-glow/IR-cut filter, both 1.25", and they are nicer to use (better colour, less loss of brightness). If I was starting again, I wouldn't go for a cheap light pollution filter - I'd wait and go for a good one. In my limited experience, the Baader filters seem worth the extra money. This goes against the grain for me, because I am usually dead against spending more money where possible - but in terms of filters, I suspect you do get what you pay for. Let me know what you get and what works out - otherwise I'll probably get a 2" Baader.

M.

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LukeSkywatcher

LukeSkywatcher

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Thanks peeps. I think for starters i will just go with the SW LP filter. James from FLO has very kindly offered to allow me to send it back and replace it with another if i find it does not suit my needs.

Those Hutech filters are a bit above what i want to pay just for something i want to try out and i'm sure Hutech will not allow me to send it back if i find it useless.

Sorry if i missed anyone who said either way if the Badder LP filter available on FLO is suitable for a 1.25" scope.

Is it?

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