| Do you have the impression that environmental effects (weather, dust storms, wild fires etc.) are more frequent than you've experienced it before such that your astronomy suffers from it? | |
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| Yes | |
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I know it's a bit of a strange title, so let me explain: Since Jan. 2021 the weather in Germany appears to behave according to this pattern: 1-3 good days with clear nights followed by 2-4 weeks of rain and cloudy (beyond any acceptable coverage for AP) nights. It's totally annoying and the equipment here collects more dust than photons and the hobby came effectively to a halt. My personal guess is that we observe the effects of climate change but that's not the question here. Some folks in Germany agree with my observation and I wanted to start this poll to see if my impression is totally wrong and also if people around the world experience similar situations for this year or at least for a prolonged time until now. I'm not just restricting this poll to weather but I'd also include all environmental impact which affects your AP time and seems to be more frequent than you'd normally experienced it. I planed to use the geographical subregions of the world according to the UN in this poll but AB currently allows 10 possible answers. Therefore, I am just starting with a yes/no poll. Maybe you can add a post and let us know where you (actually your observatory) are roughly located. Feel free to comment. CLEAR SKIES! Björn |
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| Personally, I think that this subjective question (Do you have the impression that...) in an astronomy forum will be heavily impacted by selection bias. I'd be curious, instead, to look at historical data of cloud coverage... Perhaps this information is available in some public archives of meteorological institutes? |
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I agree that there is a selection bias but I‘d say that’s considered in the question? („Given you’re an astronomer, do you have the impression/think/believe…“). I didn’t intend to sample from the world population but from the astronomers (which are members of AB). Also the frequencies of the answers aren’t too important. I’m rather curious to hear the opinions around the world. I talked to several German APers and they agreed. Nevertheless, maybe somebody here has some meteorology background/connections? |
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| Sure we don't want to have a conversation about the soon to be tens of thousands of satellites going up there for telecom purposes? |
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| Data is data and never lies. On the average for over 10 years and the average of the past year (clear nights good enough for observing vs. total nights) I can confidently say that this year is within 1 sigma of the average distribution for the years 2001-2012. "Having the impression of" isn't the way to go about measuring the actual outcome of a test. Full disclosure, in case is needed, I live in England, east side. |
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Sure we don't want to have a conversation about the soon to be tens of thousands of satellites going up there for telecom purposes? I wouldn't have considered it, although it's an environmental impact. What I had in mind is rather effects that are not *immediate* man-made effects. On the average for over 10 years and the average of the past year (clear nights good enough fior observing vs. total nights) I can confidently say that this year is within 1 sigma of the average distribution for the years 2001-2012. What source did you use? Maybe I can find some numbers for my location. I don't have sufficient personal record to but numbers behind it. General comment: In case I gave this impression, I want to clarify: It's simply a question what impressions people have about something. If someone has data available, even better. In no way did I intend to conclude from the numbers of the poll to the validity of a hypothesis or not. Besides this, very often the null-hypothesis (or theory) is just a *guess*; sometimes good, sometimes bad, sometimes well-informed, sometimes fully ignorant. The data will help to shed light on it. And still the conclusion may remain subjective - keyword: p-Value. So I don't see anything wrong in asking people about their opinion or impression in order to develop a possible null-hypothesis for testing? Cheers! Björn |
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I am in AP since October 2020, and I wonder wether weather has hidden stars in the past like this year. Here near to Heidelberg it is exactly like Björn writes: 2 to 3 fair nights and the rest is a feast for cloud lovers. |
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Well this thread is somewhat funny because I just had this conversation with a couple of my astronomy friends a week or two ago here in Auburn, Michigan, USA. - Penmitlaw Observatory. Latitude: 43º 25’ N Long: 84º 9’ W While our weather here in Michigan has never been perfect for visual observations or AP we have noticed that the winds here have been higher then in recent years. At least thats what we have noticed anyway. And clouds have certainly been an issue as well. Very rarely do we ever get more then 2 consecutive clear nights (if we do we feel blessed) so observations/imaging that is a multi night project is for the most part a long term project. I’m appx 15 miles off the coast of Lake Huron and depending on the time of the year lake effect is always an issue. In the late fall early winter we have clouds for 2-3 months staight until the lake freezes over and then we may get a couple of clear nights here and there. We always joke around saying, “Ok who bought some new equipment!” Which I’m sure is a standard joke around the astronomy community world wide. Anyway thats my input. Dale |
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Hi Bjorn, As an Athenian, I must confess 1-2 good nights followed by weeks of clouds sounds pretty normal to me for the rest of Europe, including the western half of Greece. Here, clear skies are pretty much guaranteed between late June and early November. And most other months are okay, many a winter day is considered cloudy or rainy by normal people standards but I still get 2-3 clear hours in the night. I think artificial light pollution and man made "clouds" (wildfires in the summer and fireplaces in the winter) are a much bigger problem than the climate, here at least. Especially light pollution. For what it's worth, I don't think the projected changes for the greater North Sea region are in the direction of worsening things for AP. I believe it is projected to become more "Mediterranean-like" so more like Athens. I must also note that despite the weather being pretty much the same, I find myself having fewer good nights than say 5 years ago. The reason is that my imaging has become more demanding. When I started I had a pocket sized tripod which I used to point the D3300 with the 35mm lens at the general direction of Andromeda and take 3 second shots, untracked. At some point I was using a 1050mm scope and a guider and a heavy mount and needed 1 hour to assemble, focus and calibrate the whole thing. On one hand sky that is perfectly good at 35mm might be worthless at 30 times greater focal length, e.g. because of high (as in higher up the atmosphere) winds. On the other, the 2-3 hour clear sky window isn't so accessible if you have 1 hour setup overhead. This is the prime reason I simplified my setup and went unguided/short exposures with more moderate FL, which so far has made 2021 a much more productive year than 2020 or 2019. It is also the prime reason professionals and dedicated amateurs go to isolated mountain tops and deserts, or isolated mountain tops overlooking deserts. I mean, perhaps what you guys are noticing is the result of the whole community having moved towards more ambitious projects and types of imaging which are hitting the limits of what a "standard inhabited region" can support. Cheers, Dimitris |
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Weather in Northern France was excellent in 2021 so far, as it was in the first half of 2020. Only lockdown prevented me from taking dozens of pictures during spring. I think this is the usual flucutation with good periods and less ones. However I feel big concern about satellite trails. They were exceptionnal until end of 2019, now I have 60% of my pictures with 2-4 trails, wide field with longer exposures might become a problem. I would not be surprised if in the future amateurs will adopt remote on satellites or even on the Moon, no kidding, it is only a question about offer and demand and ratio weight/price. |
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I've posted a taste of satellite future here: https://www.astrobin.com/0k3ex1/ A single satellite trail is a little problem compared to the line of Starlink satellites. They make no trail in the pictures, it's rather a broad highway. And their number is growing every year. So we have two enemies: clouds and satellites. Maybe we are the last generation which is able to do AP? |
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| well for me, i live in California, and im sure sick of smoke from fires filling the skies for 3 months out of the year. it wasnt always like this. it hasnt started this year but we are much drier than last year already |
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Well, so far, 2021 has been quite bad, and we are going through to, perhaps, the worst drought of the decades, and that do not means less clouds but more instabilities, more wild fires and more extreme events, like having in one week almost all the rain that correspond to the year....causing huge disasters, due to flooding, and later due to dryness...so it is complicated. Two years ago we were covered by smoke for nearly two month, due to the wild fires, and this years, a lot of clouds an almost no rain. If someone likes statistics, ok, you can observe how fast vine crops and wineries are moving south, no kidding but soon you will get wine from Patagonia, and this has speed up during the last 10 to 15 years. Also peach production and many more fruits are being planted in southern latitudes each year, and the desert moves south faster. The data of the crops/latitude moving south is available, and is quite impressive, so that is a figure one can use, but, again, it does not mean better sky, I would say it means more clouds with higher temperatures and larger day-night fluctuations (this leads a lot of times to fog formation by midnight  ). One of my colleagues is in charge of meteorology at the university and he has explained many times, how fast we must expect more changes to occur, but it is a complicated subject, well... climatology is a rather complex field. Since non linear phenomena is one of my areas, I do understand that predictability will be a real challenge in these complex systems, particularly that good quality and comprehensive data is only available in recent years, so how to predict nice and clear skies...that is just a dream so far, but I could only say that fluctuating years (between good and bad ones) may not be rare, with low chances to predict them. Wishing CS ! for all Oh, as you may guess I am located in the southern hemisphere, latitude 35_S and 71_W (Chile). |
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I think objective data would show that there have been changes for the bad and for the good, even with climate change, but this would be dependent on location. As the question is worded, it would also have to be weighted depending on the number of observers within each location. Probably this is very obvious to everyone. So in three sentences I have said nothing! But since I moved to Oregon (north western coast USA) 6 years ago, the first few years we had pretty typical weather, though hotter than normal in the summers. As is typical in the pacific nw, our pattern is to be cloudy and wet in the months from later Oct. through April and May even. But spectacular skies in the summer. Starting 4 years ago, the wild fires have impacted that seriously in the summer months. While no wildfires burned close to my home, the smoke from as far away as California drifted north and impacted viewing for weeks on end. This has since not let up, but has gotten worse. Two years ago, the smoke got thick enough that I actually snapped photos of the sun (with sunspots) directly with an SLR and no filters. But last year we had days from closer fires that were pitch black during the day, the whole day. Those fires in Oregon last year burned a very high percentage of all trees in the mountains just west of my location. As of yet, no fires in the mountains of the coast range, which is where I live. But unless you are blind, the writing is clearly on the wall. BTW, I had lived in Seattle from 1993 prior to the move south to Oregon. For a decade, while there were fires, they rarely impacted the distant seeing. But in the few years prior to my move, say 10 years ago, smoke from both California and the Cascade range east of Seattle became more prevalent. But nothing like the current situation. Today, Portland Oregon hit 108 F. A daily record surpassed by 6 F. Tomorrow the forecast is for 111 or 112. 113 for my town. Portland also surpassed the all time temperature record by 1 F. Our climactic high temperatures typically arrive at the end of July through August. So "my answer" to the question is a definite yes! For those who do this work and have observatories in those areas and were threatened or destroyed the last number of years, the answer must be yes. But the debate will rage on that this is not an effect of environmental change. The climate will not pay attention to that debate, of course. The benefits to observing, if any, will be seen, again, dependent on where you live. To be a protagonist, I would argue that once all the trees of the western USA are completely burned and the climate stays dry here, then eventually we will have nothing but clear skies from then on! Alan |
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It depends. Usually everytime you buy something, the next couple of months will be cloudy *Yes this is an undeniable fact. I would also like to see objective evidence that finally shows that global cloud cover is less during the few days around the full moon than any other time of the month. In the US Pacific NW, we have winter skies that can be cloudy for months in a row. It is amazing how often you get to see a full moon during that time. Only exception is during an eclipse. |
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So far, 2021 has actually been quite good. I was able to collect data for a everal projects in the period of February until April, before summer recess (AP is a no go from May until late August up here). But when I look at what I've collected over the past years, there is the pattern that is described by the OP; about 2 clear nights per month, sometimes less, sometimes more. And excluding the nights with a full moon. Anyway: CS, Wim |
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Thank you for your responses. It's interesting to read all of your opinions and some of the responders have the impression that they struggle more with environmental issues than before. I've been trying to place my assessment on more solid grounds. Hence, I've downloaded cloud coverage data for a weather station near to my location. The data available reaches from 1949 until a few days ago. From 2005 until now, the data was measured on an hourly basis. I've filtered the data for data points from 9pm to 5 am (average observation time) and calculated the mean cloud coverage (in steps of eights, 0/8 = no coverage, 8/8 = fully covered) for each night. There are several ways to present it but I chose to create an aggregated statistics per year. The following graph shows a box-whisker plot for each year (hor. axis) since 2005 and the average cloud coverage per night on the vert. axis. If people are not aware about the box-whisker statistics: the box shows where the 25% (lower box bound), 50% (horizontal line within the box) and 75% (upper box bound) of the respective data are located. The whiskers are drawn to contain all data points not considered outliers (I will look up the exact mathematical definition for these whiskers if someone is interested). Above the boxes are the numerical values for the 25% , 50% (Median) and 75%. What I observe from this data is: While the median mean cloud coverage is 5,8, we can clearly see that the 2021 median mean cloud coverage has increased to 7,9 which means that 50% of the nights had a cloud coverage above 7,9/8. Also the 25% quantile mean cloud coverage is above 3,6 which is not that extreme as for the median but still above the average 2.9/8. Here's the graph: (Data basis: Deutscher Wetterdienst, Offenbach, Germany. Averaged over individual values.)  Feel free to comment. Björn |
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Helle everyone, I have also the impression it is getting worse, but what worries me more: if there are no significant clouds, the transparency is is getting worse and worse. I think it is related to the increasing humidity. So the cloud coverage is only one indicator among many. When I had started astronomy in 1984 there were plenty of dark and crispy nights. Real dark black sky. The last time I can remember seeing such a deep dark and clear night was 7 years ago. Now they are all washed out, misty or milky white illuminated.. I think the minimal increase of ever age temperature caused by the climate change has multiple impacts. Clouds are the most obvious, humidity, transparency and mist are the less obvious and probably not measured at the local weather stations, but also very much impacting our hobby. CS (hopefully) Rüdiger |
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Ruediger: Hi Rüdiger, The German weather stations operated by the DWD also measure humidity and visibility, amongst other values. If I find some time, I can also check this data. Cheers, Björn |
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Ruediger: What you see are the effects of increased LP, not increased humidity. When I was little kid I could see the Milky Way from my house in the outskirt of Rome. Nowadays you're lucky to see few stars. |
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Ruediger: Hi Björn, humidity they have of course, but whether they have nightly transparency? I have doubts they have that data, but would be quite cool. They often claim perfectly clear skies, but actually it has terrible seeing/transparency. CS Rüdiger |
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Ruediger: Hi, sure they have humidity, but I doubt whether they have a reliable information about transparency. Very often they claim perfect clear sky, but actually it has a terribly bad seeing resp. transparency. but anyway, would be cool to compare humidity. |
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andrea tasselli:Ruediger: Nope, I compare locations where is almost no LP. Sure LP has increased, but also at far off sites the nights are less transparent. I have the fortune to to live in an area where LP is not the biggest issue (except my neighbor at X-mas 🤬). Vice versa: a lot off laws and regulations were installed to reduce LP. E.g. nightly illumination of buildings is prohibited, also sky beamer, street lamps were replaced or dimmed at late night, and much more. |
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| While atmospheric water vapor (humidity) may be a contributing factor, it likely is not the issue alone. Some of the best seeing conditions that can be had are found in the dark sky sites of Florida and within the tropics. Here the humidity can be about as high as is possible. So it is noteworthy that as climate change is expected to increase atmospheric water vapor in mid and higher latitudes (with lots of evidence backing that up) something else has to be in play to work with that. Water vapor itself is transparent to visible light. The high water vapor content of those areas are also extremely deep and reach to high altitudes. But, high levels of water vapor can be condensed into droplets when there is an increase in particulates and other components such as airborne "pollution" both man-made or natural. Both of these may also be increasing due to climate change. So while you may well be experiencing a degradation of seeing in your area that can't be attributed to LP, the reasons may be a bit more complex that you think. It is my understanding that the world has done a much better job at reducing the amount of aerosol-type pollution over the past decades, primarily by a decrease in burning of coal for power. But I believe that far eastern economies are rapidly picking up the slack in coal burning. What you see in your area could be very local. Is there a lot of wood burning in the winter? Are there valleys and hills/mountains that create inversions trapping the particulates? If yes, have you noticed a significant decrease in night winds with an increase in inversions? Might be interesting to know. |
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Well, I found an article where the atmospheric extinction coefficient has been measure, and it is constantly been measured, in the Northern observatories in Chile, and one of the conclusion, apart of the effect of the amount of aerosol in the air, is that "transparency conditions have been worsening during the last 35 years". The main cause of this is not completely clear and still they believe is mostly due to a contribution to aerosols in the air, due to volcanic activity, but is not the only hypothesis. Now, the topic is also covered in this paper in Nature astronomy: "The impact of climate change on astronomical observations" , September 2020, and one of the reasons is atmospheric water vapour, they show a clear tendency to increase water vapour from 1980 to 2020, so it is very likely that a few of these parameters are getting worst, and making AP more complicated in the near future. The paper can be downloaded from arxiv.org, it is also clear that microclimate favours some locations, but even in the Atacama desert, they are not free from these effects, and there is another concern, the huge increase in light pollution in those areas as well. |
