{"id":34254,"date":"2022-07-19T12:54:32","date_gmt":"2022-07-19T12:54:32","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=110300"},"modified":"2022-07-19T13:22:14","modified_gmt":"2022-07-19T13:22:14","slug":"best-light-pollution-filters-for-telescopes","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/best-light-pollution-filters-for-telescopes\/","title":{"rendered":"Best light pollution filters for telescopes"},"content":{"rendered":"

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By Paul Money\n \t\t<\/p>

Published: Tuesday, 19 July 2022 at 12:00 am<\/p>

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If you live in or close to a city, you\u2019ll know how much energy our society wastes by shining light into the night sky.<\/span><\/p>\n

This is known as light pollution<\/a> and it drastically affects our view of deep-sky objects, making things like nebulae<\/a> virtually invisible through a telescope. <\/span><\/p>\n

Thankfully, there is help at hand for astronomers in the form of light pollution filters.<\/span><\/p>\n

These can partially compensate for the obliterating orange glow of light pollution by improving contrast.<\/span><\/p>\n

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M42 Orion Nebula by Mark Griffith, Swindon, UK. Equipment: Teleskop service 12\u2033 Richey-Chretien telescope, Skywatcher EQ8 mount, Atik 383L+ camera, Astronomik LRGB filters, Astro physics 0.67 reducer, Hutech IDAS light pollution filter.<\/span><\/figcaption><\/div>\n

What types of light pollution filter are there?<\/strong><\/h2>\n

Light pollution can be tackled using two different filter types: broadband light pollution filters and an ultra high contrast or narrowband OIII filter.<\/p>\n

Broadband light pollution filters attenuate the wavelengths of light associated with older mercury vapour and low pressure sodium lighting.<\/p>\n

Available from Orion, Baader and Sky-Watcher, these do an excellent job at improving contrast, although they all dim the overall view.<\/p>\n

Luckily this is not such a problem for lunar and planetary observation as the objects are already very bright.<\/p>\n

Another approach is to increase the contrast of objects you wish to observe by selecting the specific wavelengths you want to focus on.<\/p>\n

An ultra high contrast or narrowband OIII filter can be very effective on emission objects like nebulae.<\/p>\n

Below we\u2019ve tested a selection of light pollution filters that will help you get more out of your observing if you life close to the bright lights of towns and cities.<\/p>\n

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The Headphones Nebula by Jones-Emberson 1. PK 164+31.3 by Pete Lawrence, Lisburn, N. Ireland. Equipment: Skywatcher Quattro 200 CF, NEQ6 Pro, Atik 428EX Mono, Skywatcher ST-80, QHY5L-II, Ha OIII Filters<\/span><\/figcaption><\/div>\n

How we tested our light pollution filters<\/strong><\/h2>\n

We carried out our tests of light pollution filters by observing the Orion Nebula<\/a> in an area with bad light pollution caused by a nearby industrial estate.<\/span><\/p>\n

After screwing the light pollution filters into the backs of 1.25-inch fit 26mm and 10mm eyepieces, we used them with a 3-inch ED refractor and a 10-inch Newtonian reflector.<\/span><\/p>\n

We then looked at how well they suppressed the background glow of the light pollution and how adept they were at bringing out a selection of deep-sky objects.<\/span><\/p>\n

6 of the best light pollution filters<\/strong><\/h2>\n

Sky-Watcher UHC Filter<\/span><\/strong><\/h3>\n
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