Viewing in Extreme Conditions-- Cold and High Altitude

[Ben the Ignorant]

2 hours ago, Hayduke27 said:

 It really takes some patience to get your eyes adjusted and then to look so hard into the square trying to tease out the stars that flash into your averted vision but disappear when you try to look straight back at them.

This applies to the eyepiece view, too, of course. After a week of daily practice (if weather and schedule allow), your perception will start to improve, pretty fast at the beginning, then slower and slower. When your sensitivity maxes out you might feel the need for a larger scope. Looking hard for planetary features goes the same, one week of daily practice - a quarter hour each time is enough to get the process going - starts a period of improvement.

Regular observing makes the eye sharper and sharper till you feel the need for a better resolving scope, either a larger reflector, or an apo with at least five inches of aperture. Not saying it will happen exactly like that for you but it's a pretty typical path.

[Ben the Ignorant]

2 hours ago, Hayduke27 said:

I just looked on my Sky Safari app, and it looks like one of the dimmest stars that I could make out for sure and counted in the square is magnitude 6.0. 

This means your nighttime conditions qualify as very good countryside skies, and at least 3,000 stars are accessible to your naked eyes. A telescope improves the count exponentially; magnitude 6 is traditionnally the limit for "very good" skies, but given your altitude and distance from large cities, I'm pretty sure the count will improve with practice.

[Hayduke27]

On 10/22/2017 at 10:43, Luna-tic said:

Your body may be acclimated to 8000 feet, but even so, your night vision will suffer some. Central vision essentially disappears, regardless of altitude (night blind spot). Peripheral vision deteriorates rapidly as the angle off center increases. Pilots are recommended to use supplemental oxygen above 5000 feet for night flying . It's much worse if you are a smoker.

The upside is, you're looking through less atmosphere, so most likely, whatever the decrease in your night visual acuity is most likely offset by the improved "seeing". More than the cold, the altitude is what will improve the viewing. Cold air is more dense than warmer air, but in your area the humidity will be less, so less water vapor to cloud the view. I only wish I had your atmosphere here in the Southeast US, as well as your darker skies.

I was thinking about all of this talk about oxygen today, and I had a thought.  If a person were to take a telescope up to a much higher altitude (I could get mine to upwards of 12,000ft near my home), if you used supplemental oxygen would that allow your eyes to retain their seeing ability while at the same time getting all the benefits of high altitude viewing?

[Luna-tic]

Supplemental oxygen would certainly help you tolerate the higher altitude, either by cannula or mask, but you'd need a way of monitoring your arterial oxygen saturation to see if you were getting enough, or wasting your supply with too much flow. There are small monitors available (called pulse oximeters), lots of private pilots keep them on their planes for use when they are at altitude in an unpressurized cabin They fit on a finger and use light to "read" oxyhemoglobin levels through the skin.

Up to your home level, there is usually little risk, but above 8000 feet, the risk for unacclimated people for AMS (acute mountain sickness) or "altitude sickness" increases, and its onset can be insidious. You should try to maintain your normal oxygen saturation; in healthy, non-smoking adults, this is between 92-99% saturated. As your saturation decreases below 90%, the likelihood of AMS increases. First symptoms are usually headache. Avoid any strenuous exercise, do any exertional tasks gradually (such as climbing or hiking). As you gain in altitude, the percentage of oxygen in the air remains the same; it's just at a lower pressure, and the lungs operate by absorption over a pressure gradient; the lower the atmospheric pressure, the less oxygen gets absorbed. Increasing the percentage of available oxygen by using either bottled oxygen, or an oxygen "generator" helps offset this.

The two highest risks associated with high altitude are pulmonary edema, or cerebral edema. 

[Hayduke27]

@Luna-tic Thanks for the very well informed response!  I am certainly no stranger to altitude sickness, as I often have visitors from lower elevations and I have seen people get sick on many occasions.  It has been anything from hiking to drinking alcohol that has really done people in.  We typically tell newcomers to take it easy and drink lots of water the first couple of days they are here.

Anyway, your answer was incredibly informational.  One last question: if a person were to get all of the equipment together to take a telescope and supplemental oxygen up to an elevation of approximately 12,000 ft, would the improvement in viewing be worth all the effort?  It seems like once you reach about 8,000 ft you are out of the most dense air anyway. Perhaps the difference between 8,000ft and 12,000ft is negligible in terms of viewing quality.

[Luna-tic]

1 hour ago, Hayduke27 said:

@Luna-tic Anyway, your answer was incredibly informational.  One last question: if a person were to get all of the equipment together to take a telescope and supplemental oxygen up to an elevation of approximately 12,000 ft, would the improvement in viewing be worth all the effort?  It seems like once you reach about 8,000 ft you are out of the most dense air anyway. Perhaps the difference between 8,000ft and 12,000ft is negligible in terms of viewing quality.

The only time I've ever been at 12,000 feet was in an airplane, LOL. I have experienced 35,000 feet unpressurized, in an altitude chamber during USAF training, which is where I learned most of what I know about surviving at altitude. I was a Flight Nurse for 8 years, long ago.

Personally, if I were living at 8000 feet and had a good viewing spot there, no way would I waste the time to pack up and climb 4000 feet higher. I can't say whether the seeing would be worth the trip or not; I'd just like to have  seeing as good as you have now, "down here" at 870 feet MSL. My goal is to make it to 6600 feet, which is as high as I can get around here (Mount Mitchell, NC). It's only 1-1/2 hours away, there are a couple of overlooks there where some of our club members go from time to time.

[Hayduke27]

5 minutes ago, Luna-tic said:

Personally, if I were living at 8000 feet and had a good viewing spot there, no way would I waste the time to pack up and climb 4000 feet higher. I can't say whether the seeing would be worth the trip or not; I'd just like to have  seeing as good as you have now, "down here" at 870 feet MSL. My goal is to make it to 6600 feet, which is as high as I can get around here (Mount Mitchell, NC). It's only 1-1/2 hours away, there are a couple of overlooks there where some of our club members go from time to time.

I could drive about 60 minutes to a good high altitude spot, but I tend to agree with you in that the viewing here is so excellent with dark skies, cold dry air, and altitude that it doesn't leave me wanting for much.  I just had to follow that train of thought through to its conclusion, as it was very interesting.  Thanks for indulging me!  

If you ever come out toward Colorado hit me up, I'd be happy to show you my spots!  Otherwise, I hope you make it up to Mt. Mitchell.  That sounds like a good destination for a star vacation!