Search the Community

This video presentation examines multiple factors affecting Astrophotography System sensitivity (i.e. the Limiting Magnitude), and see how much they individually contribute to overall system degradation (actual data in magnitudes). The presentation quantifies the dependence on Aperture, OTA type, Optics Coatings, Camera QE (with imager comparisons), Seeing, Light pollution, Extinction… https://nlobs.com/acad-intro/ https://youtu.be/8RN_uc2f6NM This is a must see for all astrophotographers, beginners and experienced alike. PDF of this presentation and other goodies are available from: https://nlobs.com/resources/ ~Chris K.

Hi everyone. Looks like I will get some favourable weather in the coming days, but the moon is out and full. I finally have a car so I can get away from light polluted Weymouth, and tonight I took a drive and found a great spot to shoot (see image). So to the point, I want to shoot Andromeda during these moonlit nights since the moon will be directly behind me. How much will it still affect my images? I'm still a beginner, using a Nikon Z50 and the 50-250mm kit lens @250 (F6.3), but I do have a Star Adventurer now, so I'll go out and shoot if nothing for the practice (my polar alignments have been pretty good).

Hi guys, LED Streetlights were installed on the road next to my garden and.... Of course, they are not shaded, so my garden and even further neighbors gardens are strongly lit. Without any serious expectations I dropped a short email to the local council, however, they even called me today (only 3 days later) asking to clarify more details. Lady, Environmental Protection Technician, who spoke to me, was kind and was sure LED lights bring only benefits, she agreed to some of my statements about Light Pollution and asked me to describe the negative impacts in the email, so she would be able to forward the issue to the higher entities/authorities. I am not a native English speaker and struggle to express myself properly in official manner and hope you guys will help me out to draft one. Further more, - we could create a standard letter/email which would help others in this field. You can see the email text I received after our telephone conversation (as I understand she copied and pasted most of it from the council's website). I will start drafting my answer in the post below and hope some ideas and help from you guys. ********************* It was lovely to speak to you earlier and to clarify the concerns which you raised due to the scattering of light from these LED which disturb the environment of nocturnal wildlife. We both agree on the benefits of LED lighting. I have included excerpts from the Medway Council Website below:- Benefits of LED lanterns The benefits to residents include: reducing the amount of money spent on electricity per year less glare and intrusion into homes saving roughly 50% in energy less maintenance work improved visibility with a white light easier to see colours making it safer for residents driving, walking or cycling improved safety to residents The new lanterns are better for the environment as they: use less electricity than other lamps or bulbs have less light spillage with lights directed towards the pavement to create better environment for wildlife produce less carbon emissions reduce light pollution and sky glow work well in hot and cold environments have longer lives compared to traditional lights light up immediately I would be grateful if you could send photographs of the light scattering from the LED lights on your street which affect your home. Yours Sincerely, Environmental Protection Technician

Hi, I'm a beginner and I want to buy something for my telescope. I have a Bresser 6 inch Newtonian(750mm focal length) I have 2 lenses, 9mm, 25mm, a moon filter and a 2x barlow. What would be the next thing to get? I was thinking maybe a solar filter, a light pollution filter since i am stuck at home, idk. What are your thoughts on this?

I'm not experienced with LRGB imaging, so thought i'd give it a go on M81. However, when i combine the 4 individually processed integrations i end up with horrible colour hues across the image - they're all aligned and wotnot. Am i running into the issues of light pollution (inside the M25), which i can only remove with aggressive DBE application? Individual files attached.

Hello, Unfortunately, I will be moving from my Bortle class 3/4 skies overlooking the Cotswolds, to somewhere with class 6 skies 😫 Does anybody with any local knowledge around the Stotfold area have any observation site suggestions? Away from any local light pollution at least. It would seem driving east maybe productive according to https://www.lightpollutionmap.info Thanks Mike

Chatting on here about possible darker sites near me and came across the CPRE light pollution survey which you can contribute to this week. I’m going to rope the kids in & thought I’d share the link: https://www.cpre.org.uk/what-we-care-about/nature-and-landscapes/dark-skies/star-count-2021/

The view from my centre of town garden is both physically & light-pollution restricted. Anything below 25 degrees is out of the question, anything West below 60 degrees behind bright buildings and a huge South-Easterly sycamore tree combines with a neighbour’s security & outdoor fairy-light obsession to make a fairly narrow observing window to say the least. The local park about 5 mins away potentially offers a darker & wider alternative which I confirmed this week on a late night dog comfort-break excursion. All of a sudden, from a spot around the 22 on the rugby pitch, a break in the cloud presented a full vista of Orion, Taurus, both Canis, Auriga, Gemini, Perseus & Cassiopeia- I was star-struck to the point where my furry companion thought I’d lost it. Messier clusters in Auriga I’d struggled to get in the eyepiece from the garden were immediately visible as naked-eye diamond-dust, the Pleiades sparkled and M42 glowed. It was ten minutes of magic. Inspired by my mid-week bonus I hatched a plan to head to the park the next time a clear-sky coincided with a non-school night. Tonight promised a couple of clear hours around midnight but dodgy weather earlier in the evening combined with the feeling that lugging the Mak and tripod to the park might be tough to justify as a lockdown exercise break, confined me to a late night stroll armed only with my trusty 10x50s. Having overcome the nagging sensation I might be mistaken for some kind of lurking pervert, I set off for the park. In the end I got about 15 minutes before fog bubbled up from the river. But even this fleeting glimpse allowed me to confirm I can now easily find the Messier clusters in Auriga and put my bins straight onto the double cluster in Perseus, things I’d never seen before lockdown. As the fog closed in I took a sweep of the alpha Perseii cluster and Pleiades, my current binocular greatest hits, and headed home happy.

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

HI All, I have an entertaining video to share with you which is perfect for those just starting out and wanting to taste a bit of astrophotography without spending a lot of money. I image from London and managed to get a pretty good shot of Orion for just £150. This video runs through where I bought the equipment, why I bought it and how I used it to capture a Orion and some of the trials and tribulations I had to deal with on the way. Any questions please ask! Enjoy! FYI I shot this last year but with Orion now beginning to rise over the rooftops of London I thought this would be a good time to share it.

https://www.bbc.co.uk/news/uk-england-dorset-45180494

I was told by a friend who has close ties with the council that Basildon District are abandoning their part-night lighting in a few weeks. Apparently the street lights which currently go off at 1am are going to be left on at cost of circa £275,000 per year. They are supposedly going to fund this from reserves. Anyway, did a bit of googling and found this https://www.basildon.gov.uk/article/7711/In-the-news-Councillors-united-behind-plan-to-switch-street-lights-back-on-through-night I wonder how many people will notice!

Hey guys, I'm new here and thus question has been on my head all day. Tell me your thoughts! The light pollution is p******* me off!

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).

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.

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?

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.

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

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

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

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.

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

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.

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