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Post by woodstockahem on Apr 18, 2017 11:15:19 GMT
Hi All,
I know this has been discussed here in the past. What are the views on LPR filters? I am confused by different terminologies (UHC, Neodymium, O-III etc).
The price ranges from £20 to Over £300. And it also seems there's a difference between normal visual filter and one for astro-imaging.
My query is, is there any one filter below £50 which would be acceptable for all-round performance?
Thanks, Sameer
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Post by stevie on Apr 19, 2017 21:38:41 GMT
Hi Sameer An LPR filter is usually understood to mean a Light Pollution Reduction filter. These are filters which are sold to reduce the effects of light pollution from street lighting. If you hold the filter up to your eye and look at an orange streetlight, it removes the bright orange glow and all you can see is a dull red glow from the element in the light. Great, you may think. However, the problem with this type of filter is that they also reduce the light from the object you are looking at in the telescope, to such an extent that you often cannot see it at all. It must be said that LPR filters are not so common nowadays, as many people seem to have caught on to them. I know all this because I once drove to Dublin to buy one. A total waste of money, both for the eyepiece and for the petrol. The guy in the shop even warned me I was wasting my money, but, of course, I knew better. I cannot comment on whether this type of filter would have any sort of use in astrophotography, a subject I now nothing about. UHC and O111 filters are designed to enhance nebulosity, by blocking out some of the light, but enhancing other parts. They are useful on both large areas, like the Orion nebula and the Veil Nebula, and on small planetary nebulae. A UHC is a good all-rounder, while an O111 would be slightly more specialized. They are of no use on things like star clusters and galaxies, although they can sometimes be used to enhance gaseous star forming regions within nearby galaxies like M33. It can take a while and a bit of practice to fully appreciate the effect, but it is well worth it, and most of the regular observers in the society use UHC filters. Neobdynium filters are said to increase contrast on things like the Moon and planets. They are also supposed to reduce skyglow and light pollution. I've never used one so again cannot comment. You can also buy coloured filters for use on planets. These are often supplied as part of eyepiece kits. They have gone out of fashion in recent times, although I would occasionally use them for things like enhancing the equatorial belts or great red spot on Jupiter or dark regions on Mars. You do not need to spend a lot of money on filters. A good 1.25" UHC can be bought for around £55, and that is probably all you would ever need. Something like these would be perfect www.firstlightoptics.com/uhc-oiii-visual-filters/baader-uhc-s-filter.htmlwww.firstlightoptics.com/uhc-oiii-visual-filters/skywatcher-uhc-filter.htmlIf you have either a refractor telescope or an SCT-type telecope, you can screw the filter into the diagonal and use it for all your eyepieces, rather than having to swap it between eyepieces. If you own either a refractor or an SCT which has a 2" diagonal, you could buy a 2" filter, which will be a bit more expensive.
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Post by woodstockahem on Apr 20, 2017 13:36:48 GMT
Thanks very much Stevie for your detailed explanation !
I've decided to put this on hold for few months and get more comfortable with my scope and observation in general first. Street lighting is an issue where i live, so will see how it goes. Mine SCT has a 1.25 inch diagonal so might save me few quids as you mentioned.
Thanks, Sameer
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Post by woodstockahem on Apr 23, 2017 7:40:13 GMT
Last night i used a dew shield and it seems to help a bit in reducing light pollution.
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