Why do we not see the Milky Way in all its glory during cross-ocean flights at night?

AIUI, in order to get the true view of the Milky Way in its splendor, one has to be in a very rural and remote region, in true darkness, in order to see it.

What I’m wondering, then, is why during cross-Pacific flights at night time, one does not see it, despite there being no artificial human light in the vicinity. Wouldn’t that be a prime time to see the billions of stars?

Depending on the location and orientation of the aircraft, you could literally be on the wrong side of the aircraft.

I’m pretty sure that once you’re above the cloud layer and in full darkness, the only impediment to seeing any particular deep space object would be which window you have to look out of, plus window reflections of interior lighting. (The cabin of a airliner is never completely dark.)

Seeing lots of stars from land requires there be almost no ambient lighting.

You can increase the number of visible stars if you have a bit of luck and a blanket. You can cover your head and the window to reduce the ambient cabin light. Hopefully you’re not over a wing, because bright blinking lights or reflections from other windows will also make it hard. If you’re really lucky, that might be enough to see a bit of the Milky Way.

That said, the Aurora is often easier to see from an airplane if you’re flying at the right latitudes. You still want it as dark as possible, but it doesn’t require it to be quite as dark.

The same reason that you don’t see the Wilky Way in all its glory while sitting in a house in a rural area and looking out the window, because you have some lights on in the house. Do passenger airlines ever fly in complete darkness? Not subdued cabin lighting, but completely no cabin lights at all, and no running lights on the airplane. They don’t fly dark. A passenger airline could even be brighter inside than sitting in your house way out in nowhere.

It only takes a very little light for it to become light pollution that interferes with your eyes and what is a very faint light from the Milky Way.

Yeah, I was thinking the aircraft windows are tinted, so you would not have an unobstructed view of the sky. Also, the windows are aimed out, not up, so again you are looking out thru a tinted window and across the Earth’s surface thru the atmosphere, so even more filtering. If you were able to look out the roof of the aircraft thru a clear, domed window, you may be able to see more, I would think.

And don’t forget about the Moon. Where is it? Is it up or below the horizon? Even a sliver of moonlight will reflect off the water and is light pollution that interferes with your eyes.

The answer to the question is in the OP, you are never in true darkness while flying on an airplane even over the ocean away from other sources of light.

I’ve shot Milky Way a number of times. Things you need:

  • Lack of clouds - will probably have this in a plane
  • Newish moon - a full moon is very bright & obscures the MW. A waning moon tends to rise during the overnight hours which is when it is otherwise dark enough to see the MW.
  • Right time of year - it isn’t visible in Northern hemisphere from about Nov - late Jan. It begins the year in the eastern sky & moves to the West during the summer.
  • light pollution - as others have stated the cabin is never truly dark. Even if you put your head under a black hood, like old-time photographers, you’d still have the wingtip strobes. By the time you hit even astronomical twilight it’s usually too bright to see it.
  • Need to know correct time of day & direction to look; it’s sometimes only up for an hour or two in a given night.
  • Your eyes need ten to 15 mins to adjust to the low light conditions; you can’t just glance out the window & see it like you do with the moon
  • Even when all of the conditions are right, it’s kind of faint; photos are long exposure; usually in the 10-15 second range. It’s quite obvious when looking at the image I just shot rather than looking up to the sky with my naked eye. There are a few bright stars that you use as your guide on where to aim the camera but I can’t see all of them with just my eye.

There’s too much light in the cabin of an airliner. On night freight flights I used to look at the stars from the flight deck but I had to have all lights off and lean forward shielding other light sources with my hands to get the best view. Also the windscreen is angled back so you can get a much broader view than from a passenger window.

Yeah, to me this seems like one of the biggest impediments. Passenger jet windows are side-facing. I’ve tried to look at the sky from them, and I simply could not direct my gaze more than about 40 degrees above the horizon.

Plus, they’re double windows, and often are not the clearest. Scratches, fogging, specks, &cetera present a challenge in viewing faint objects.

All that plus the light pollution concerns that have already been mentioned.

Given the choice I would take a rural location with clear skies and minimal light pollution over a plane cabin, or flight deck, any night.

One other factor: Your eyes are less light sensitive at higher altitudes. Cabin pressure is generally maintained at 8,000 ft. Night vision can decline by as much as 30% by 10,000 ft.

I hope this isn’t highjacking the thread, but this got me to wondering what someone on a cruise ship or an ocean liner, far away from light pollution, can see at night.

Cruise ships bring their light pollution along with them. Never been on one, but in all the pictures I’ve ever seen, at night they’re lit up like a Christmas tree. They may have a deck set up for star viewing and that probably gets some awesome seeing.

Yes and Yes.

I’ve seen the Milky Way many times at altitude. But it’s really nothing more than a faint band of dim diffuse glow you could almost mistake for a strip of higher clouds if you didn’t know for certain there were no higher clouds.

The many brilliant long-exposure photographs of some wide band of bright light with embedded detail really don’t help IMO. They are fine “artist’s impressions”, but they do a disservice to people who don’t have the opportunity to see it as unaided human eyes really do.

Indeed so.

In the before times (a few months pre-COVID), I was on a cruise ship in the middle of the Tasman Sea, hundreds of miles from land and could certainly see stars but there was no chance I was going to see the Milky Way. The ship was lit up way too much for that, even in the middle of the night. It wasn’t much better viewing than the middle of suburbia.

For me, the poor optical quality of airplane windows is a major factor. A couple layers of thick acrylic plus a hazy plastic sheet is really going to make seeing the Milky Way difficult.

(But for something like the total eclipse of the Moon I saw on one flight, it was plenty clear enough.)