74 replies to this topic

[Sebastian_Sajaroff]

To be sincere, I don’t think that Canada has better skies than USA, specially the populated band (95% of the population lives within 200 miles from the border).
The Great Lakes and Saint-Lawrence area has brutal light pollution, putrid seeing (jet stream) and clouds at large.
I have to drive 3 hours from Montreal to reach a Bortle 3-4 spot, and an extra hour for Bortle 1-2.
In all cases, weather is very unstable and I’m still under jet stream.
Atlantic Canada weather is even worse, though they have lower LP levels.
British Columbia (Vancouver and Victoria) coast is similar to Seattle : lots of rain and fog. But, if you drive 200-300 miles inland from Vancouver it’s MUCH better.
IMHO, the Prairies (specially Saskatchewan) offers the best conditions for astronomy in Canada.
Sadly, I don’t know any amateur community from the Canadian Arctic

[vsteblina]

https://yukonastronomicalsociety.com/

 

not quite the Canadian arctic but close.  Viewing was awful, as was the weather that summer.  

 

Great town.

[Sebastian_Sajaroff]

https://yukonastronomicalsociety.com/

not quite the Canadian arctic but close. Viewing was awful, as was the weather that summer.

Great town.

Good to know we have some fellow amateurs in Yukon.
Thanks!

[GeorgeLiv]

I think wherever you are, if you're not adaptable or versatile you're simply bound to be disappointed with what you get weather-wise. I can see how this tropical air can be agonizing, astronomically or not,..that is if you don't have a garden.

 

What I want right now is at least another month of hot 90°+ F temperatures (32°C) to grow my cantaloupes & honey-dew melons. But if some crisp cP air descends my way I'll head off to the cabin. If cold arctic air hits in January or February I'll hop on a plane to Vegas (cheap flights) rent a car and drive around to see the sights (Meteor Crater, Arizona, Death Valley, Cal). Being all-around multi-talented has its advantages.

[GeorgeLiv]

Having said the above, I must admit that as time marches on, we need to adapt more & more, because we probably haven't seen the worst of things to come, weather-wise.

Edited by GeorgeLiv, 09 July 2024 - 05:14 PM.

[Tony Flanders]

I think wherever you are, if you're not adaptable or versatile you're simply bound to be disappointed with what you get weather-wise. I can see how this tropical air can be agonizing, astronomically or not,..that is if you don't have a garden.

Disappointed is not the word that I would use -- nor agonizing, for that matter. The first word that comes to mind is "debilitating."

During the current hot, humid spell I only feel fully alive first thing in the morning. Somewhere around noon, both my body and my mind seem to shift into low gear as a precaution against overheating.

I am an outdoor person to the core of my being, never really happy when I'm inside. But when the dew point approaches 80F (27C) and the temperature soars above 90F (32C), my outdoor activities tend to be reduced to lying panting in the shade -- or maybe walking as fast as possible from one shade patch to another, and then lingering there as long as possible.

Summer is by far my least favorite season in terms of comfort, here in the eastern U.S. On the other hand, summer is where the action is -- it's the season that makes all other seasons possible. The world is simply bursting with life of every kind.

[Jon Isaacs]

I think wherever you are, if you're not adaptable or versatile you're simply bound to be disappointed with what you get weather-wise. I can see how this tropical air can be agonizing, astronomically or not,..that is if you don't have a garden.

 

What I want right now is at least another month of hot 90°+ F temperatures (32°C) to grow my cantaloupes & honey-dew melons. But if some crisp cP air descends my way I'll head off to the cabin. If cold arctic air hits in January or February I'll hop on a plane to Vegas (cheap flights) rent a car and drive around to see the sights (Meteor Crater, Arizona, Death Valley, Cal). Being all-around multi-talented has its advantages.

 

Not to brag too much, I think everyone takes pride in their home state or province... But one has to be quite inflexible to be disappointed in the weather here in San Diego..  Cool in the summer, warm in the winter.. One can live outdoors just about all the time...  And one has access to a great variety of climates.. nearby mountains and deserts. drive 100 miles and one can be at 10,000 feet or one can be below sea level..  Cloudy skies along the coast, hop in the car and clear skies are with an hour's drive.. 

 

Jon

Edited by Jon Isaacs, 10 July 2024 - 06:13 AM.

[CharLakeAstro]

I take pride in my home province, and in particular my local area... however not from an Astronomy weather perspective.

There are many places with better weather for astronomy, but we chose this location for other reasons. Dark skies and sky glow did factor in... but not cloudiness,  nor seeing, nor length of night in summer and certainly not winter temperatures. 

 

San Diego sounds ideal for astronomy pursuits.

 

Not to brag too much, I think everyone takes pride in their home state or province... But one has to be quite inflexible to be disappointed in the weather here in San Diego..  Cool in the summer, warm in the winter.. One can live outdoors just about all the time...  And one has access to a great variety of climates.. nearby mountains and deserts. drive 100 miles and one can be at 10,000 feet or one can be below sea level..  Cloudy skies along the coast, hop in the car and clear skies are with an hour's drive.. 

 

Jon

[GeorgeLiv]

Recently in many places around the world near the mid-latitudes (10° or so near 45° N. & S. latitudes), it has become an "either-or" situation. For a given climactic zone, a lingering pattern of no change in weather will set up at one extreme or the other for that area, the pattern locking for at least a week.

 

I remember in the 1970s when a heat wave with temperatures at 30°C (86°F) or more would hit the Montreal area. It happened only once or twice a year, and as kids we'd spend all afternoon at the Jarry park municipal pool frolicking & cooling while in the adjacent MLB stadium the Expos would practice batting before games. "Splash-downs" in the pool were rare, only a few batters could make it, like Willie Stargell or Rusty Staub. In the evening we'd linger by the stadium's rear fence, just a few dozen feet by the pool, hoping to catch some not-so-far homers. In the 1970s I started astronomy near that stadium, bagging at least 90 Messier objects by the end of the decade with a good pair of 10x50 binocs.

 

Today, heat-waves and associated bright night skies (maritime tropical air) are common. In 2019, July had a record of 13 days hitting 30°C (86°F) or more. While June & August of the same year, oddly, only had one each. That was unusual because 30°C days are typically spread out the 3 months of summer. Last year's July was a bust, with only two days of 30°C or more, none in August, but the 2023 summer was historically more normal (except for the hot & dry May 2023).

 

On the cold extreme, in February of 2015, polar & arctic air set in over Montreal with a record of 15 (out of the 28) nights with the temperature going -20°C (-4°F) or below. In that year the temperature never went above freezing from January 19 through to March 4th. The winter of 2015 had little snow, but to me, that was brutal, and costly heating wise.

 

Jet streams are doing looping patterns now. This is probably the result of mixing for equilibrium, so that west-to-east "zonal flows" are less common than south-to-north flows. Currently in the SW and West US, a ridge has locked-in with temperatures soaring above 35°C (reddish shade) now expanding. Indeed, continental tropical air-mass being created. Let's see how long this will last, and I do hope this comes our way to the north-east. Very comfy at night. The polar & sub-tropical jets have also come together, meaning that there's a lot of air masses & systems being squeezed in the north-central portions of Canada. Today's IR..

 

 

[GeorgeLiv]

During the current hot, humid spell I only feel fully alive first thing in the morning. Somewhere around noon, both my body and my mind seem to shift into low gear as a precaution against overheating.

I am an outdoor person to the core of my being, never really happy when I'm inside. But when the dew point approaches 80F (27C) and the temperature soars above 90F (32C), my outdoor activities tend to be reduced to lying panting in the shade -- or maybe walking as fast as possible from one shade patch to another, and then lingering there as long as possible.

I'm the same, except that I'll chill in air conditioned stores or at home throughout the worst part of the afternoon. Then go out biking or gardening, but the mosquitoes are something else these past few evenings, so biking wins! Too many varieties out all at once, even on my roof-top 35 feet above ground. Later at night, if clear, I'll check out the sky, try to estimate the limiting magnitude. But nothing beats the right air-mass to do anything astronomical except urgent stuff if something shows up.

[Jon Isaacs]

I take pride in my home province, and in particular my local area... however not from an Astronomy weather perspective.

There are many places with better weather for astronomy, but we chose this location for other reasons. Dark skies and sky glow did factor in... but not cloudiness,  nor seeing, nor length of night in summer and certainly not winter temperatures. 

 

San Diego sounds ideal for astronomy pursuits.

 

Charles:

 

I like to make the point that while San Diego may be a nice location for amateur astronomy, it's a poor location for winter sports like ice fishing.

 

Jon

[Tony Flanders]

I like to make the point that while San Diego may be a nice location for amateur astronomy, it's a poor location for winter sports like ice fishing.

Indeed. I do love all the seasons of the eastern U.S., despite the fact that I often find the summers a little hard to endure. Each season has its own special, wonderful quality. Spring and fall are wonderful because they're the seasons of change. Summer is the season of abundance, and winter is the season of dormancy, when plants are slowly mustering their resources to burst forth again next spring.

 

But for me, personally, winter is my season -- the season of peace, solitude, and transcendent beauty. My very favorite weather even of all is the first snow. I would never be happy living in a place without snow.

 

Californians sometimes rejoin that they have ample snow in the mountains -- which is, or at least used to be, true. But having to drive to see snow is a sorry substitute for having nature deliver it on my doorstep.

 

By the way, I have realized what this thread really is. The title, as I have said before, is a complete and total misnomer. I care deeply about the weather; it affects me in dozens of important ways. And light pollution is not one of those. Obviously weather does in fact alter light pollution to a minor extent, but in my part of the world that is never, never, a significant factor in my astronomy experience.

 

This thread is really an excuse for members of the Light Pollution Forum community to talk about the weather.

[Jon Isaacs]

Tony:

 

I'm a native of San Diego.. Snow is a mild amusement, I get all the snow I need to visiting our son in the Missoula, Montana area. We do get snow at our place in the high desert but it's never more than 4 or 5 inches though the higher mountains get more.

 

I'll take the year around outdoor weather, close by mountains, deserts and beaches.. 

 

Snow in the mountains of San Diego. The photo was taken about 4 miles from the oceans.

 

 

A Spoiled San Diego wimp. 

 

Jon

[Tony Flanders]

I'll take the year around outdoor weather, close by mountains, deserts and beaches..

Yeah, speaking as a mountain lover, the situation in the eastern U.S. is pretty dismal. The things called mountains in Massachusetts would barely qualify as hills in California. And not a hint of a desert -- another terrain that I love. We do have great beaches, though.

 

As for "year around outdoor weather," what other kind is there? Do you think the weather moves indoors in other parts of the world?

[Jon Isaacs]

Tony:

 

"Year around outdoor weather"... 

 

Weather where one can live in relative comfort outdoors year around.  

 

Jon

[mountain monk]

Jon,

 

I remember visiting Palomar in the winter on school trips, especially the snowball fights. One winter it even snowed in Oceanside and the beaches were covered in snow. As far as year round weather goes…it reached 94 degrees here today and the lowest temp I’ve experienced here was -54. But I wouldn’t want to live anywhere else. 
 

Dark skies.

 

Jack

[osbourne one-nil]

If we could stay on topic it would be appreciated. Remember, we're not here to have fun...

[mountain monk]

Mea culpa. My apologies. I was struck down my a streak of nostalgia.

 

Dark skies.

 

Jack

[GeorgeLiv]

On topic:

 

Pretty much the entire population of the US & Canada are under a DEEP sub-tropical & hot air-mass, deep meaning in height to the stratosphere. It's a mostly modified continental tropical (cT) but also maritime tropical (mP) type. The modification of cT arises from pacific mP and gulf-coast mT air squeezed through the mid-USA exiting in the maritime Provinces. It's fine, it's July. You wouldn't want to be in northern Quebec, Ontario or Manitoba 'cause there's a ton of smoke. This will stay up north for the next few days.

[GeorgeLiv]

By the way, I have realized what this thread really is. The title, as I have said before, is a complete and total misnomer. I care deeply about the weather; it affects me in dozens of important ways. And light pollution is not one of those. Obviously weather does in fact alter light pollution to a minor extent, but in my part of the world that is never, never, a significant factor in my astronomy experience.

 

This thread is really an excuse for members of the Light Pollution Forum community to talk about the weather.

I took some time to think about this part of your reply: .."weather does in fact alter light pollution to a minor extent, but in my part of the world that is never, never, a significant factor in my astronomy experience." that I must reply.

 

If you lived south of Kentucky/Virginia were virtually all the weather (80%, now probably much more) is due to maritime Tropical air, your statement above would make a lot of sense to me. Only in the winter months would these residents experience cold Polar air. For me at 45° N, there used to be (and still is) a battle zone between Polar & maritime Tropical air. For clear nights, I not only think the difference in LP created over a bright city like Montreal is large, I can easily show the difference with photos. I can also confirm that there's often a full magnitude difference (sometimes more) via SQM and visual estimates, when clear, not when it's misty, hazy or with high cirrus. The difference is much less away from heavy light-polluting towns or cities, so I'm imagining that you're far from Boston because it would have been obvious (at least to me).

 

I'm saddened that the effect I tried to explain - temperature & depth of the air-mass over you playing a role in sky-glow - has been lost in a sea of off-topic replies. But it's really my fault for selecting such an ambiguous & apparently "gloating" title. The title simply should've been: In which "air-mass" is created the least LP. At least I have good appreciation in what I need to rectify for my (e-)book!
 

[Tony Flanders]

I said:
 

Weather does in fact alter light pollution to a minor extent, but in my part of the world that is never, never, a significant factor in my astronomy experience.

 
And George Liv responded:
 

For clear nights, I not only think the difference in LP created over a bright city like Montreal is large, I can easily show the difference with photos. I can also confirm that there's often a full magnitude difference (sometimes more) via SQM and visual estimates, when clear, not when it's misty, hazy or with high cirrus. The difference is much less away from heavy light-polluting towns or cities, so I'm imagining that you're far from Boston because it would have been obvious (at least to me).

I have roughly 100 zenithal SQM-L measurements covering a span of 15 years from the site in Cambridge, MA, where I did the observations for my Urban/Suburban Messier Guide. They're clustered strongly between 17.6 and 17.8 mpsas, but there are indeed some outliers as bright as 17.2 and as dark as 18.4. The overwhelming majority of that variation is due to time of night, the absence or presence of leaves on the trees, and the absence or presence of snow on the ground.

Mind you, these are nights that are pre-selected as being suitable for deep-sky observing -- in other words, nights when the transparency ranges from good to excellent. If I also included nights of poor transparency, suitable for lunar and planetary but not deep-sky observing, I would have a lot more bright nights.

 

But here's the kicker. Those exact same nights that are good for deep-sky observing near the middle of a major metropolis are precisely the ones that are good at my relatively dark sites (barring local variations in weather, of course). Whenever the sky is abnormally bright in the city, it means the transparency would be lousy in the country, and vice versa.

 

So really the only way that atmospheric conditions affect my observing experience is through their effect on transparency. The effect on skyglow is secondary, a side-effect of the variation in transparency. When the transparency in a city is poor, the sky is bright. When the transparency in a city is good, the sky is relatively dark.

 

So as I said in my first response, as far as I'm concerned, skyglow is a total red herring in this thread. What you're really talking about is the effect of weather on transparency -- which is every bit as important at a "dark" site as it is in the middle of a city. If you removed every reference to skyglow in the thread nothing at all would be lost.

[GeorgeLiv]

My last post here. I read, then re-read replies directed to me, think about it for a while, and I'll respond if important. Please don't take any of the following personally if by chance they appear critical.

 

Responding to a deleted post: "..the same amount of LP is created by light sources regardless of the air-mass type".

 

I must disagree. Light-pollution is "created" by the air you're in, not by the lamp sources. These lamps have some portion of up-light. This up-light would be invisible in the absence of air (or an atmosphere), however, we'd see any lit ground. And absolutely, winter can bring the most "transparent" skies possible even with snow on the ground. An amateur being hardy enough to take advantage of that situation is another story altogether. Thanks for you comments btw.

 

 

Notwithstanding being a seasoned amateur, there are many new amateur astronomers attempting to observe in conditions such as above (the sky was clear on top), not just in conditions deemed good to "mature" astronomers. On the most part, these are the southern Americans and Britons that rarely experience "transparent" cP air. When I was young I observed in ANY clear condition I could find, tropical, polar or arctic. Years before any undergraduate studies I knew about the difference in LP over me. Eventually I understood why.

 

I find a lot of cliches in amateur astronomy which glance-over important concepts. One of these is transparency. Why is one night more transparent than another? Is it due to water?..smoke? industrial fumes? Is that all??

 

The following composite was done using the same exposure settings & equipment. There are no tricks involved, Photoshop or otherwise. Why is there a brightness difference? Why is there a shift in color? Answer: It's due to the properties of the air above.

 

 

Another cliche that truly irks me is "mercury lines in sky-glow". Even now in the 2020s the assumption is almost consistently that these are in sky-glow due to mercury-lamps. Not true after about 1985.

 

Anyways, I was going to accept that I failed in my attempt to connect sky-glow with the role of water via air temperature and the optical depth, but I believe it's alright. I'm good. It's harder to budge people from their inertial maturity.

 

Thanks for your input.

Edited by GeorgeLiv, 14 July 2024 - 03:51 PM.

[Tony Flanders]

I'm interested in the details of how the atmosphere affects light pollution.

 

My hunch is that the depth of the troposphere isn't relevant in most cases, since most of the aerosols are concentrated in the bottom few km in "normal" conditions. In any case, the vertical distribution of aerosols is never uniform.

 

It varies no doubt depending whether you're actually inside the densely populated part of a city, on the fringes, or at great distance. At great distance the aerosols near the ground might actually reduce a city's skyglow.

[GeorgeLiv]

On cue for September 1st, parts of the the mid-northern states have some cool Canadian air over them, even though modified by the lack of frozen lands. Air is streaming down from near the N. Pole. Maximum (sea-level) temperatures are near 65°F around the Great Lakes, dipping to 45°F by dawn Sept 2nd. Frost advisories are in place for a large part of mid-northern Ontario.

 

This is the infra-red (temperatures) satellite loop for most of this day September 1st. If in the blue, what you should be doing is putting your eye-glasses on and noting your visual limiting mags.

 

 

[GeorgeLiv]

I got up at 4 am this morning, Sept. 3rd '24. Stars once again were gorgeous over the city, including Orion's belt & sword as well as Sirius rising in the south-east.

 

Beautiful nights in the N.E. with what I'd like to call "fresh Canadian" air. Short-lived though, already pushed out over the Maritime provinces (in blue). From the north part of Montreal, with corrected vision (my driving glasses) my limiting magnitude was the star Nu Andromedae at 4.5 mag., adjacent to the Andromeda galaxy.

 

On September 2, again in the am hours, the limiting magnitude was 6.5 (M33 by averted vision) near Vannachar, Ontario.

 

Some yucky American air will return in a day or so, complete with Idaho smoke. I placed a red warm front to indicate the warm-air influx. Current frontal map, below, ..the temps are in Celsius.

 

 

Edited by GeorgeLiv, 03 September 2024 - 06:37 PM.