33 replies to this topic

[jacobfw]

So I'm aware that whenever possible, most professional observatories are built both in areas with very dark skies, and at higher altitudes.

However I haven't been able to find any examples of what I would see if I was looking at something like Jupiter through a telescope at several thousand feet, versus more at ground level.

 

Does anyone have any live video or unprocessed stills that show the comparison?

 

[Don W]

I don’t think a picture could show the subtle differences. I recently moved from Wisconsin at 700’ above sea level to the high desert near Sedona, AZ at 3200’ above sea level.

 

DonW

[havasman]

What Don said. Plus, there are WAY too many variables for such a video or other capture to be definitive or even much indicative. Often, as here, you pretty much just have to go look.

[Moravianus]

Observatories are also placed strategically where there is a high probability of good seeing, so visually, the object would be more steady and may reveal more details. Add the high altitude with better transparency but going really high like above 12000ft you need to be concerned about the physiological effect of hypoxia on the vision.

As Don said, you can get similar picture from low and high altitude, depends on the weather, seeing, jet stream, camera, scope skills etc.

I wish to spend once a night at a high peak in the Atacama desert.

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[Jay_Reynolds_Freeman]

On the average, expect better seeing and darker sky, and in some places the high sites are above local marine layers or other low-lying clouds that block local light domes, so those sites have a higher proportion of clear sky and particularly dark sky as well. I have observed a good deal at 8200 feet above sea level (the Bumpas Hell parking lot in the US Lassen National Park), and at 9300 feet above sea level (the Visitor Center for the Summit Observatories on Mauna Kea, on the "big island" of Hawai'i, USA), and my favorite site local to me now, in the area of Los Angeles, California, is at about 5300 feet above sea level.

 

Of course, higher sites are often chilly, so be prepared, but in my opinion the views are well worth it.

 

 

Clear sky ...

[jacobfw]

Interesting.  Would it still be possible to see some examples though?  I recognize the difference in person versus through a video can be drastic, but I would still like to see some examples.

[PKDfan]

Hi Jacobfw !

When i spent a few weeks at Mt. Kobau which is 1873m 6148feet in south central B.C. Canada i witnessed how sky darkness and seeing stability was a very fluid mechanism as fog formed down low -this area is famous Okanogan lake in dry desert Osoyoos. As it built up and rises with humidity the wondeful dark sky really starts to pop steadily getting darker and darker with some amazing seeing getting even better.

This site has visible the milky way seen to polaris. With my 58yo dark pupil near 8mm imagine a 25yo !

The naked eye was where i spent the majority of my time despite a C8 and my 15×70 Celestron fighting it out for the rest.
The topography of B.C. is unique with Vancouver on the coast and coast mountains then a very steep rise to a massive plateau 670,000 square kilometer 258,000square miles at the mighty Fraser river drops out of that & starts to fall away dramatically north to Kamloops and east it meets the very long deep Okanogan lake. Ogopogo our loch ness. Lol. The plateau is fabulous for seeing and is sparsly populated so very dark but so quick to get to below zero Celsius. Nothings free.

That fog build up was the indication for guaging sky blackness in the light pollution of this summer playground and if high pressure and little wind then if clouds thickened & build up slowly and i knew the seeing clarity would get better and better as it slowly and if just right thick enough to rise to 3-4000 feet eventually killing off all of the LP.

Sometimes just horizon to horizon stars and BLACK. Can't hardly see your hand.

Then all heck would break loose literally with a barometric drop.

Aside: I was up top in a Ferociously quick drop and it Raged for several Long hours before exhausting with a lightning barrage attack with numerous bolts flying about at once with not THOUSANDS but close to it one on top of another it was all out mother nature raging and i sat huddled in my jeep shaking uncontrollably both awed into utter inconsequence -i decided to tough it out and huddle in place but man wow Crazy stuff at the top of a mountain nonstop for a few weeks plus. Blue white flashes still ring in my memory. Not a good memory amid the Grandeur.

Blissful & bucolic or mean and nasty.

This was once considered the home for the Canada France and what turned out to be Hawaii 3.6m scope the seeing is so exceptional here.

Albeit at only little more than a mile high its a smallish mountain but with all that desert heat building up thunderstorms can be deadly serious.


CSS
Lance

[jacobfw]

That sounds beautiful Lance!  Hope I get to see something like that one day myself.

[Keith Rivich]

Planets are all about the seeing. Jupiter would look much better from Death Valley with sub arcsec seeing then from the top of Mt Everest with 3 arcsec seeing. 

 

Altitude mostly benefits sky darkness and transparency. Seeing is a bonus. 

[triplemon]

Interesting.  Would it still be possible to see some examples though?  I recognize the difference in person versus through a video can be drastic, but I would still like to see some examples.

Its hard to visualize that in a picture. It also depends a LOT on what elevation angle you look at things. So near the zenith the differences are small, but if you look at something deep down south near the horizon, the difference can be several magnitudes in extinction. I once viewed the southern cross from Haleakala at 10,000 feet and it was bright and seemingly "well above the muck". The next night, from sea level, I could barely see one star down there. The marine layer was to blame a lot for that as well.
 

But (there is always one, right) there is a limit for visual observation: Once your blood oxygenation levels start to drop, visual acuity and sensitivity are measurably affected. How much depends a lot on your physical condition and adaption to higher altitudes. As a rule of thumb - around 8000 feet it starts for some people and by 12000 feet almost all people have measureable issues, short of those staying for weeks at these elevations. Dark adapted sensitivity seems to degrade before you feel other physiological effects in thin air. https://pubmed.ncbi....h.gov/24479261/ and many other references there.
 

So that is why the general saying is - going from sealevel to 3000 feet gets you above the worst of the muck, 5000-8000 feet may be ideal for visual, above that it starts to depend on you more than the sky.

 

Edit:
I found an old geeky table I did to get some idea how much elevation vs altitude matters. To answer to myself  "do I better drive another 300 miles south or up a higher mountain instead" when trying to see the southerly goodies.

It tabulates atmospheric extinction (in astronomical magnitudes) as a function of elevation angle and observer altitude, based on airmass data only. Its kind of a minimum change you see if your skies are completely void of any moisture or dust all the way down to where you want to observe. A somewhat theoretical thing, as the actual atmosphere has moisture and dust in a (highly variable) layer close to the ground. So getting "high enough" so your actual line of sight goes just above that is a much bigger factor.

From the outlined boxes you can see that at sealevel, you loose a full magnitude at 15 degrees elevation.
But at 5000 feet you can get that same extinction down to 10 degrees elevation. So you can access "5 degrees more sky" in comparison up there.

Edited by triplemon, 19 March 2025 - 01:05 PM.

[Astro-Master]

I've had my best views of DSO's from altitudes of 8,000 to10,000 feet from dark pristine skies with transparency off the scale and good seeing, the skies are filled with so many more stars, and they look twice as bright.

 

Galaxies in the 18" Dob look like photos, Globular Clusters look better than photos, faint galaxy clusters just don't look that faint anymore, no way I'm going the screw up my night vision looking at a bright Planet, under skies like that.

 

I had my best view of the Planets from light polluted skies with excellent seeing from the city.  Take a trip to Mt Wilson, the skies are bright, but the seeing is often excellent!                              

[fishhuntmike]

I had my most memorable views of the universe at ~18000 ft in the Andes (I was somewhat acclimated). Perhaps it was the Southern hemisphere more than the actual elevation that convinced me. At the time all I had was an 8x20 binocular and "seeing" or planetary viewing was not on my mind at the time, and I was just purely awestruck!

[Tony Flanders]

I haven't been able to find any examples of what I would see if I was looking at something like Jupiter through a telescope at several thousand feet, versus more at ground level.

I'm never sure what "several" means. But barring local effects, the difference between sea level and 3,000 feet is negligible. At 3,000 feet just 10% of the atmosphere is below you, and 90% is above.

Of course local effects do matter. If you're on an isolated 3,000-foot hill (known as a mountain in my part of the world) above a sea-level plain, then that's likely enough to get you above the worst of the natural and artificial pollutants that hug the ground -- in which case it would make a big difference in terms of transparency (clarity of the air). But a plateau at 3,000 feet would be no better than a sea-level plain.

As for viewing planets, that's a matter of atmospheric stability -- called "seeing" by astronomers -- which is quite a different matter. In my part of the world, the seeing tends to be worse at high altitudes than at low altitudes. In general the best seeing is on the windward slope of hills and worst on the lee slope of hills.

[Sebastian_Sajaroff]

In my case, I get the best results between 1000 and 2000 m (3000 to 6000 ft).

Beyond 2000 -2500 m, altitude starts to hit me.

I feel my mind working in slow motion, difficulty to concentrate, exhausted after moving the tripod or telescope around. 

Brutal migraines arrive at 3000m/9000 ft, joy killers even if the sky is wow !

[mountain monk]

It also depends on your base elevation. If you immediately go from sea level to 9,000 you will feel it. If I go from my base elevation of 6,400 feet to 9,000 feet I won’t notice it. Since most of my viewing these days is about 7,000-8,000 feet elevation is not one of my concerns. On the other hand, seeing is always a concern. I spent years of my life above 10,000 feet and I agree with  Astro-Master—those were the best views of my life. In general, the higher you go the better it gets, assuming you are acclimated. The limit for acclimation is usually said to be 18,000 feet, although the U.S. Army claims 20,000 feet. World wide, people do not choose to live above 18,000. People work higher in Chile and Tibet, but they sleep and live lower. Mountaineers try to climb high and sleep low. On mountaineering expeditions your body deteriorates if you stay above 18,000 feet. Photographs of your retina will show the vessels and veins swollen with blood, and many climbers claim long term mental deterioration if they spent too much time above 18,000 feet. Fortunately, that’s not a problem for astronomers.

Dark, clear, calm skies.

 

Jack

[Refractor6]

  6000ft at the cascade lookout at Manning Park BC during the spring ,summer and early fall is the best high alpine deep sky observing I've had to date in telescopes and binoculars.

 

Very steady seeing and transparent sky quality and back then in the early to mid 2000's the ever growing sky glow of the lower mainland {Vancouver} wasn't as big of a problem as it is now. Given the distance of the park if you look on a map it shows just how much a big city can mess with the dark quality of the sky even from that far away.

[mountain monk]

Yes, that’s why I always say the best observing will be high, calm, and remote, conditions that, jointly, are rarely met. My first choice has always been northern Chile on the border with southern Peru and Bolivia. Southern Argentina is also excellent, and it is farther south than Australia and Namibia. Incredible!

 

Dark, clear, calm skies.

 

Jack

[Starman1]

So I'm aware that whenever possible, most professional observatories are built both in areas with very dark skies, and at higher altitudes.

However I haven't been able to find any examples of what I would see if I was looking at something like Jupiter through a telescope at several thousand feet, versus more at ground level.

 

Does anyone have any live video or unprocessed stills that show the comparison?

Your risk of pulmonary edema increases a lot over 8000-9000' (2440-2745m).

I've observed at 10000' (3048m), but the loss of oxygen didn't allow me to see any fainter than at 8000' (2440m).

I see a strong improvement in atmospheric transparency between 5400' (1646m) and 8350' (2550m), my two most-frequented sites, but my experience at 10,000' (3048m) was really not different at all.

But I can move around a lot easier at 8350'.

[rcooley]

Interesting.  Would it still be possible to see some examples though?  I recognize the difference in person versus through a video can be drastic, but I would still like to see some examples.

I live at 7000 ft now. Used to live at sea level in Los Angeles. I was out last week for a quick view of some of my favorites in the southern sky. The seeing that night was the best I’ve had since we moved here in 2018. Better than anything I experienced in L.A., but not so much so as to be readily quantifiable. Maybe like the difference between an inexpensive eyepiece and an expensive one. (I kind of had that experince the first time I slid a Televue eyepiece into the diagonal of my EVO).  Don’t really know if someone could make comparable images to illustrate the phenomena tho, since they’d have to be at both places (altitudes) at the same time to make the captures. Cheers…

[Napp]

As others have posted it's more complicated than just going to higher elevation.  I am in Florida so my observing sites are not a whole lot higher than sea level.  I went to the Texas Star Party in 2022.  The sky was darker than my darkest site in Florida and the elevation is about 5000 feet.  The deep sky observing was unsurprisingly much better than home in Florida.  Some could be attiributed to a darker sky and some to the higher elevation but some to the much lower humidity.  I definitely felt the thinner air.  I moved slower. 

 

However, if I wanted the best planetary observing I'd likely head to the Florida Keys.  Observing would be inches above sea level but the laminar flow of air above the water means very steady skies are common.  Cranking up magnification with quality optics is easy.  Planetary observing doesn't need dark skies so the light domes are not a bother.  And that far south the planets are higher in the sky.

[ABQJeff]

As stated many times, altitude primarily gets you transparency and darker, drier skies (less light scatter). Seeing doesn’t necessarily track as well with altitude. Some sites are better, some worse. Some of the best planetary spots are in the Florida Keys and the Azores. So to me altitude really buys you awesome DSO viewing.

For me, my dark sky spot (1:45 hours away) is at 7100 feet, Okie Tex Star Party (2.75 hours away) is 4500 feet. Both are loosely rated Bortle 1-2, but my SQM-L meter read a full 0.4-0.5 mag (21.4 vs 21.9) on average darker at my dark sky spot and the background was noticeably clearer and darker when I observed at each location in the same week.

On DJ Lorenz map, I am in orange but I can see pretty much (98%) see everything on my observing lists from my 6040 foot altitude home looking 45 degrees above horizon to the East (into blue and gray wilderness) even though Zenith would be classified “Bortle 6.” I can see the Milky Way naked eye even at my orange Zenith (it is faint, but noticeable). I credit altitude and dry NM air for pretty much extinguishing light pollution skyglow pretty quickly.

I am planning to forego Okie Tex and go to Enchanted Skies (near Pie Town) this year, mainly because of altitude.

Edited by ABQJeff, 20 March 2025 - 12:02 AM.

[AlamoBob]

I once drove to the top of Loveland Pass (Elevation 11,991) - an easy drive west of Denver - to observe the Geminids.  Just breathtaking - figuratively and literally!

[Tony Flanders]

On DJ Lorenz map, I am in orange but I can see pretty much (98%) see everything on my observing lists from my 6040 foot altitude home looking 45 degrees above horizon to the East (into blue and gray wilderness) even though Zenith would be classified “Bortle 6.” I can see the Milky Way naked eye even at my orange Zenith (it is faint, but noticeable). I credit altitude and dry NM air for pretty much extinguishing light pollution skyglow pretty quickly.

The summer Milky Way is readily visible when it's overhead from sites near sea level in Boston's outer suburbs that are shown as dark red in the 2022 atlas. And even the winter Milky Way is readily visible from my astronomy club's observing field, which is shown as orange but very near the border with red. I also had little trouble viewing all the Herschel 400 from my astro club's field. So I don't think you can attribute that to your altitude.

[ABQJeff]

The summer Milky Way is readily visible when it's overhead from sites near sea level in Boston's outer suburbs that are shown as dark red in the 2022 atlas. And even the winter Milky Way is readily visible from my astronomy club's observing field, which is shown as orange but very near the border with red. I also had little trouble viewing all the Herschel 400 from my astro club's field. So I don't think you can attribute that to your altitude.

Ok. Well I will just chalk it up to people not being experienced enough when they say you can’t see many DSOs or the Milky Way from bright locations (Besides H-400, I have done Pensack 500, Roger Clark’s 611 DSO, Illustrated DSO guide 650, Vic Menard 400, etc. lists among many brighter lists).

But I do stand by skies are much clearer and darker at altitude.

[truckerfromaustin]

The higher the altitude, the less atmosphere you will look through. I was in Colorado last year and was hoping to do some stargazing since I was at 10,000 feet above sea level. I started cussing at the clouds until reality slapped me upside my head. I was seeing the Milky Way!

CS