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Showing results for tags 'light pollution'.
Found 27 results
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Just found this. https://www.bbc.co.uk/newsround/amp/49836623 Let's hope it is a success and the good folk of Switzerland enjoy some clear dark skies. -
Hello, I am a fourth-year Interior Design Student. For my Final Major Project I am hoping to design an observatory and lecture space designed to encourage more people to engage with stargazing. I am currently researching the best location for this type of building. Naturally the darker the site the better it is for observing but I would like to know if there is a limit or maximum recommended level to the lighting radiance level or lux level of the surrounding area. Attached is a photo of a lighting radiance key that may help to determine the answer to my question as it breaks the radiance levels down into sections. I would be grateful for any opinions, knowledge or information relating to this J Thank you in advance for your help Larissa -
I read a comment made on here the other day about the maximum magnification you can realistically use in UK skies (250x apparently). Therefore I was wondering what everyone else thinks this is, especially for you guys with 16" plus, apertures. I'm still fairly new to this game (only being observing for about 7 months), and only have a 5" Newt at the moment (but am about to replace with a 10" Dob) so I don't get any higher than 159x (6.3 mm).- 38 replies
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Last year I was given a Unihedron SQM-L, the narrow field of view version of their gadget for measuring night-sky brightness. Since then, I’ve nipped outside to take zenith readings whenever I’ve been able, often a few times per night. As a result I now have 85 data-points, all from my back garden in Sunbury on Thames which rates a 19.04 on www.lightpollutionmap.info . As it turns out, this agrees well with the data I’ve collected. The darkest I’ve measured at this location has been 19.13, with 4 records better than 19.05 and 10 better than 19.00. Plotted against Moon altitude, it looks like: One thing I noticed very early on was that the reading generally gets darker and darker as the night goes on. The chart below suggests the data agrees, but how strongly I’m not adept enough yet with my statistics to work out. If anyone fancies doing this for me, I’d be grateful, I’ve attached the data .csv file I think to the end of this post. The data itself: each record contains date, time[GMT], SQM value, Moon phase, Moon altitude . For the purposes of my analysis, I’ve converted the time value into hoursafter6pm, which allows the intercept of the regression solution to be loosely considered as the “6pm starting point” for the darkness estimation, which is OK for this dataset as my data is all from this latest Autumn/Winter. I’ve done an “ordinary least-squares” regression with multiple input variables. At first glance it seems to me that the SQ vs altitude chart above should not behave well with that: there’s a clear kink, intuitively obvious I guess, at the point the Moon altitude goes negative. To cope with that, I divided my data into two and did three separate regressions: “Moon up” data, “Moon down”, and “All data” but treating phase and altitude as zero if the Moon is below -5 degrees (I chose -5 degrees arbitrarily). With Moon up, I decided the SQM value will depend on Time of Night, Moon Altitude and Phase. With Moon down, it only needs to depend on time of night. Thus my regression model is: SkyQual = a + b.timeafter6pm + c.phase + d.altitude + residual or rearranged residual = a + b.timeafter6pm + c.phase + d.altitude – SkyQual The analysis involves minimizing the sum of (the squares of the) residuals, by hunting around for the appropriate values of a, b, c & d which yields this minimum. I used MS Excel’s built-in Solver to do the “hunting around”. The following table summarizes the results: In words, using “Moon Up” as my subject, my Sky Quality, in magnitudes per arc-second, can be estimated as 19.28 mags/arc-sec plus 0.0314 /hour minus 0.864 /full-phase (or 0.216 /quarter) minus 0.0186 /degree above horizon (or 0.186 /10 degrees). This is a pretty simple analysis. I’m sure there’s theory and formulae available relating Moon-altitude and -phase to extra sky brightness, but I haven’t used any of that here. And the “error model” I’ve used implicitly assumes that the relationships between SQM-reading and the variables are linear. If anyone is curious and wishes to do their own analysis, my raw-ish data is available as a .csv file attachment at the end of this post. Cheers, Magnus A note about the data collection: each reading is an average of a few readings at a given time, with outliers rejected. For instance, often the first press yields an outlier, and over the following few seconds subsequent ones tend to settle down. So the series of readings 19.05 (me getting excited), 18.85, 18.86, 18.86 , which is a quite typical pattern, would cause me to record 18.86. My highest recorded reading, 19.13, was indeed where it settled down. Other “one-on-one” charts: SQMLdata201903.csv
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I gave a demonstration/workshop at my local Astro Group* about a simple way of removing light pollution from an Astro Photo. The description I gave was deliberately for beginners, using a wide angle tripod shot photo and using one of the easiest packages to get to grips with (Paint.net). The attached pdf covers the basic technique. I'd appreciate any feedback on it. * The Mid Cheshire Astronomical Group - all welcome, we meet on the last Friday of the Month. LP MCAG.pdf
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Congratulations to Welsh photographer Alyn Wallace for getting National Geographic Photo Of The Day for these pictures of the Elan Valley night sky. https://www.nationalgeographic.co.uk/photography/amazing-images-wales-starlight?fbclid=IwAR0hz92NXMnCh-ZaMw_MyFNkjKhRHYXIZLcygZGkTV_lHpNjjtvHWtNDXZg
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The Campaign To Protect Rural England are running another star survey to monitor the spread of Light Pollution- details here: https://www.cpre.org.uk/what-we-do/countryside/dark-skies/star-count-2019?utm_medium=email&utm_source=engagingnetworks&utm_campaign=campaigns-update-2019-jan&utm_content=Campaigns+Update+2019+Jan TAKE PART: 2 February - 23 February Help us reclaim our dark skies Dark, starry skies are one of the most magical sights the countryside can offer. But light pollution means many of us can’t see the stars. We want to reconnect people with the wonder of our glorious night skies. You can take part in #StarCount2019 and help us map light pollution, to ensure more of us can enjoy the most magical sight the countryside has to offer. Our Star Count will take place this February, when we’ll be asking you to look up at the night sky and tell us how many you can see in Orion. You can do this from anywhere in England. The results will help us to create a new map to show how light pollution affects everybody’s views of the night sky.
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Alright, my first contact with light pollution... i was able to rescue the picture to a certain extent. Level adjustment was made with cinepaint 0.24, basically a GIMP offspring that can deal with floating point and 16 bit TIFFs. It can even work with FITS, but it has some file export issues--
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In the battle against light pollution it seems moths may be our new best friend. This article is about the effects of light pollution on moths and the reduction in pollination that results. https://a.msn.com/r/2/BBSwdmN?m=en-gb&referrerID=InAppShare
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So I am not quite total beginner to astro images, but I am not hurrying to get to telescope range due to various factors and I did not find similar topic on several first pages of search, so this topic might be best suitable here. I have a camera that has a possibility to track astro-images up to 5 minutes, which is enough for me to take the Milky Way shots and even some Nebulae, clusters and similar level images. I have moved to the location that is a more light polluted than the one I lived before (from http://darksitefinder.com/maps/world.html : I lived close to the edge of yellow and all the dark orange, the city was light orange, now I live in the middle of red, the city is gray/white). It would be not so bad, as there are some empty fields around, so no very close light sources (same as in previous location), but the Milky Way is now directly above the city with way bigger light pollution opposed to the location where I had the MW in opposite side from the city. As nearest dark location is not for everyday drive (around an hour for a bit darker place), and even in red zone I get some recognizable images, I want to continue working on my technique and started looking to Light Pollution filters (I travel to some darker areas several times a year, but not too often). I found several 100mmx100mm filter brands, and several round ones, but I found no comparisons between them and very little to no sample images or reviews: PureNight Premium Light Pollution Reduction Filter by Lonely Speck – Lonely Speck - Lonelyspeck filter at the moment unavailable NiSi NiSi Natural Night Filter for Nighttime Light NIP-100-NGT Nisi filters Haida 100x100mm/4x4" Nanopro MC Optical Glass/ HD3702 B&H Haida filters IDAS Filters and Accessories IDAS LPS-D1 (round filter) Astronomik CLS Filter (round filter) I would prefer getting 100x100mm filter, as I can use it for multiple lenses (I have 49-86 filter thread lenses), but I could live with 77mm, if it is really worth it and possible to use with step-up/down rings. Any recommendations - is it worth to get any of these, or did I miss some good one, or any reviews? Are they worth buying? Clip-in filters are not an option because of camera brand (Pentax). Also, in the future I am considering modifying this camera after I will get a newer one (http://www.spencerscamera.com/store/store_product_detail.cfm?Product_ID=25&Category_ID=1) - any recommendations which modification type to choose and why (this is totally green part for me)? Also, will the chosen LP filter work with the modification? -
Fredogoto is happy to let you know that he updated the pan European Light Pollution Maps with the most recent datasets from Corine data land cover. Check here : http://www.avex-asso.org/dossiers/wordpress/?page_id=3273&lang=en_GB A Google map (KMZ) is also available to see the light pollution together with the 3D rendered views : Fred
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Hello, Just came across this new world map of the state of our dark skies, no good news I'm afraid. http://advances.sciencemag.org/content/advances/2/6/e1600377.full.pdf -
A new study has been released looking at the spread of Light Pollution. http://advances.sciencemag.org/content/2/6/e1600377.full One of their conclusions is that most of the UK is in the zone with furthest distance to travel to reach a pristine sky. So according to the map above my skies in Mid Wales are in the Green Zone and are thus "degraded to the Zenith". I'll just check outside.... (Spring Milky Way- May 2016 EDIT SQM reading 21.8 this night) -
Hi all, thanks for reading this. We've just started an Essex social group here and its growing pretty quickly. One of the first things we've done is to look for a dark site ! Feeling pretty happy with ourselves (thanks to Simms who did most of the work) we found a pretty decent looking few sites. Then it was pointed out that the RSPB are doing this - http://www.rspb.org.uk/reserves/guide/w/wallaseaisland/ This at the moment means more and more high wattage lamps aiming upwards causing a nice orange glow ... PLEASE could you email this following note to - wallasea@rsbp.org.uk ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Dear Sir/Madam, I am a member of (state organisation or SGL) and am concerned about the large number of floodlights that have been installed at the Wallasea Island Wild Coast Project. The Dengie Marshes are just across the River Crouch, and it is a favourite location for Essex astronomers. The much lower levels of light pollution are favourable for visual observing and imaging the night sky. It is very difficult to find such an area in Essex. Some Essex astronomers travel large distances to find other suitable sites, so the whole Dengie area is important to us. At night, light glow from bright lighting carries for a considerable distance. From the Dengie Marshes the glow from Southend, Burnham, Maldon and Clacton is readily apparent. The much closer lights at Wallasea are a great concern to Essex astronomers. Please be assured that I am in full support of the Wallasea project. It will be a valuable resource for protecting wildlife and be a great place to visit. I wish the project all success. I do understand the importance of providing a safe working environment for those working at Wallasea, especially at night. However, as mentioned, the large number of floodlights at Wallasea is a concern. So I am asking if the number of flloodlights could perhaps be reduced, or at least pointed downwards. The horizontal positioning of the lights means that they will be very apparent for many miles. If they could be angled downwards, that would help to lessen the light pollution. On the safety aspect, horizontally mounted floodlights are just as likely to cause an accident as to prevent one. A bright light shining in a persons face can make it difficult to see a hazard. If the lights are aimed at the ground, then the area is illuminated, and workers less likely to be blinded by the flloodlight. Thank you for reading this. As already mentioned, I wish the Wallasea project all success. Very best regards (state individual or organisations name ) ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Obviously edit it a bit to make it 'your own' Thanks to Ed, NGC 1502 for bringing this to our attention and the letter / email draft Many thanks in advance Knobby
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Thought i'd share somethingpositive Last week, i saw new LED lighting being fitted in our town. I was mad about it, thinking "oh no-now those #'+*! are making the light pollution even worse with that!" But- although they don't look like it, the new lights are keeping the photons much more on the street, where they belong. And i have at least a dozen of them within 100 yards. So, not everything keeps getting worse! What are Your experience with new vs old street lighting? Best, Ulrich
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How good are revolvable polarising filters for reducing light pollution and moonlight from most affected areas of sky? Also for seeing bright objects and reducing brightness that covers near neighbouring objects?
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Im fed up with the frustration of trying to enjoy astronomy from my back garden. Before I begin I know that I am being unreasonable in expecting all of my neighbours and the population of Warrington specifically and Greater Manchester in general to consider me when they are turning outside lights on, but there isnt an intent ,interest , policy ,or a direction to reduce light pollution by governments, or in the wider population, outside of small groups of enthusiasts like you lot. Indeed they want more light because they are scared to death of violent crime. The purchase of a 200p Dobsonian has only made it worse as now I am interested in trying for fainter objects . My skies are not dark ...no where near dark , and as more LED street lights have been rolled out around Cheshire the skies are getting noticably brighter. ( maybe they are not and Im just noticing the existing issue??) Ive built screens , Ive added setting circles, to help to search in the gaps between the visible stars, but its never dark. Ive stopped planning my star hops before I go out because I know that my initial expectations will collapse into a Muttley like muttering of damning my fellow humankind . I know I should pack the van and drive out to a dark sight but just how often can you do that in practise.? Sad but Im losing the love.
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Last night was the first night with a long moonless spell. Unfortunately it was also horribly murky. Those who have the luxury of being able to apply a counsel of perfection would immediately reject it out of hand. However, we're not so lucky, clear moonless nights are few and far between, so have to be taken anyway, even when only the bare skeleton of Cygnus is visible, and the milky way no more than a distant rumor. Herewith 2 hours of H-alpha in 10 min subs, Photoline 130mm f/7 Triplet / 0.75x APM reducer, 3nm Astrodon, Trius 694. ASA DDM60 mount / Maxim DL with 5 pixel dithering in x and y. Stacked in AA5 with Flats, and Bias (Need new flats, a dust bunny has appeared) Sigma Add. DDP followed by a moderate histogram stretch with curves to boost contrast a little. I may add to this and use it as the basis of a SHO or NHO image for the challenge. C&C welcome as always.
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From the album: Astronomical Equipment
To combat light pollution I have a telescope blind. To sensitize my left eye, I wear an eyepatch. It stays in the dark all night long unless it is looking through the eyepiece. -
Here is an animation from ESA showing how light pollution in Europe has increased: http://esamultimedia.esa.int/images/imageoftheweek/Europe-1992-2010-compare-subset_H.gif It was originally posted on Cloudy Nights, where there some debate as to whether the animation is "real." i.e. is one image simply a scaled version of the other. I suspect not, since not all areas brighten equally. Regardless, I think it's a good animation and worth including if you're writing letters to local government, etc.
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Apologies people for placing this in the lounge but I need some help if you live in Hertfordshire. There is an online petition to have the lights turned back on after midnight in Harpenden. This could result in the rest of Hertfordshire going down the same route. With London close by it's hard enough even with a goto scope to pick out the tougher messiers without lights being turned back on after midnight. Could you take a look at my petition to keep the lights off until a better solution is found. https://consult.hert...tition_id=58962 Thank you for reading this. I really do need your help.
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There's a petition to turn street lights back on after mdnight in Harpenden. This could end up with the whole of Hertfordshire being re-lit. http://stargazerslounge.com/topic/156722-harpenden-petition-turn-our-street-lights-back-on/ I've begun an opposing petition to keep the lights off until a suitable alternative is available. Herts CC has replied and approved the petition which goes live tomorrow. This isn't a selfish plea from an astronomer rather a plea from a resident that hates helping burglars, has a wife with cancer is also a stargazer and wants the community to benefit. I'll post the link to the petition tomorrow. I'd be extremely grateful for any support.
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I was wondering if any of you good folks might be kind enough to physically show me, and others, some examples of unprocessed LIGHT images from a DSLR (taken under medium light pollution), that can provide me with a point of visual reference? I'm looking for an approximate indication of the kind of 'look' I should be aiming to get on my DSLR screen at the end of a shot; Essentially trying to figure out where the threshold lies between a good, usable LIGHT image, and one that is over-exposed and has too much light pollution noise to be useful. At this stage in my learning, trying to read-up on it is making my brain ache, so some actual examples of what my unprocessed LIGHTS should physically look like, will be really useful. I live in a reasonably light polluted area (edge of a large Town). Thanks in advance- 19 replies
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Well, this is my first ever "proper" LRGB effort using my Star 71, from a rather light polluted garden in Portchester, Hants. Getting on for 10 hrs in total exposure time. Processed in PI (thanks Kayron) and PS (thanks Olly), but I still haven't worked out how to tease the colours out properly (Olly, I can't find your method on here - I must be searching with the wrong terms..) 51*180s luminance, 49*180s red, 45*180s green, 49*180s blue I'm actually very happy how it's come out, despite the various technical challenges along the way! PS - anyone on here able/qualified to collimate a 5 element astrograph for beer tokens? lol.
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https://www.bbc.co.uk/news/uk-england-dorset-45180494
