location, location, location

chuchurokit · Oct 3, 2004

Just wondering... What makes a bigger difference what part of the sky you are seeing, latitude, or longitude? If i had to guess it would be lat. But I’m not sure Any experience?

nevers · Oct 3, 2004

When observing the sky, ones longitude would make no difference at all.

newtonian · Oct 3, 2004

Longitude effects the time the sun sets - i.e. the time zone. So you can view the night sky at a different time if you lived in India than if you lived in the United States, for example. Normally, this would not make much difference. It does make a difference for short term events, such as: Specific meteors or meteor strikes. Solar ecclipses. Supernovae observations. Violent solar prominences, and therefore the northern lights (assuming your latitude is far enough north), i.e. specific peak activity. Magnetar emissions. Etc.

nevers · Oct 3, 2004

Oh yeah...except for those things Newtonian mentioned! <img src="/images/icons/smile.gif" />

Saiph · Oct 4, 2004

Newtonian's right. Outside of those he mentioned (i.e. anything not related to the sun, very short-term astrnomical phenomena or directly related to earth's orbital path) longitude means diddly. You latitude makes all the difference. Since everybody see's the same sky (you rotate through it all in 24hrs) what matters is what's blocked by the earth. If you're at the poles, 50% of the night sky is blocked. Of course, the other 50% is always up (though the sun may outshine it all...). If you're at the equator, you can see it all. Except good portions near the poles are to low for any meaningful observation. And it's only up for 12hrs. And then you've got the inbetweeners. Like nebraska. We can see anything from +50 to +90 declination at all times (never sets, they're circumpolar). However, we can't ever see anything from -50 to -90 declination (never rises, to close to the other pole). ANd from 50 to -50, things are basically up for 12 hours. And we see the same stars New York, Europe, INdia, China, Hawaii, and California see, so longitude doesn't matter. (I excluded latitude effects on those names, it's just what's on the top of my head). <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Oct 4, 2004

Ricimer Saiph - Ricimer being your first name, and Saiph your last: Actually Brad Nevers was right, I simply added a few exceptions. paul Newtonian

newtonian · Oct 4, 2004

churchurokitc- You mean we are not the salt of the earth? I guess the subjects are not that heavy and are digestable. Seriously, elevation matters. The higher you are (in elevation, not spaced out) the more you will see. Also, the darker your location, the more you will see. Also, the lower the humidity- and the colder it is...

Saiph · Oct 4, 2004

The higher you are, the better you can see. As for quantity (i.e. % of the entire sky) elevation means almost nothing. At least, as long as you stick to the ground (even the mountain tops). You've got to go to orbit or higher to notice an appreciable difference in the amount of sky visible. <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

CalliArcale · Oct 5, 2004

However, the sky may *seem* bigger from a mountain top. It's why Montana is called Big Sky Country. <img src="/images/icons/wink.gif" /> But it's an optical illusion -- the sky's just a bit darker (due to altitude) and generally a lot clearer there. <div class="Discussion_UserSignature"> "People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff." -- The Tenth Doctor, "Blink" </div>

bobvanx · Oct 5, 2004

I also noticed a daytime optical illusion, vacationing in Montana, Idaho, Wyoming... The clouds in the daytime all had a similar, puffy cumulus look. But in Montana, they seemed to go on forever, receding into the distance ever and ever more. Traveling around, I realized it was an illusion worthy of Disney: The clouds were fractally larger over Montana, and tapered off in just the right way to make you feel like the scaling was merely distance, not also physical size. So you could see clouds going on forever, and ever. In the neighboring states, the illusion worked the other way. With the smaller clouds closer and the larger ones farther, the sky looked smaller.

chuchurokit · Oct 7, 2004

how does the humidity affect it?

nevers · Oct 7, 2004

Humidity is moisture which adds to more "stuff" in the atmosphere. The more "stuff" in the atmosphere, the dimmer and less crisp the object will look. That is one of the reasons Observatory's are placed high on mountain tops: less stuff to look through. Plus, they look cool sittin' way up there! <img src="/images/icons/smile.gif" />

Saiph · Oct 7, 2004

no, no no. We all know observatories are placed up on mountain tops because we wish to "one up" our physicist friend's "ivory tower". Besides, we've got a wise man complex too. <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> --------------------SaiphMOD@gmail.com -------------------"This is my Timey Wimey Detector. Goes "bing" when there's stuff. It also fries eggs at 30 paces, wether you want it to or not actually. I've learned to stay away from hens: It's not pretty when they blow" -- The Tenth Doctor, "Blink" </div>

newtonian · Oct 8, 2004

Calli - Actually, you CAN see more sky at high elevations. For proof I cite personal experience driving in Alaska towards the moutains (Logan?- coastal range about 19,000 feet elevation) from Anchorage at 55 mph for some 12 hours. First, we could see those mountains all day - incredible visibility of hundreds of miles due to lack of pollution, etc. However, after sunset driving south to the east of this range, it was dark- after twilight. However, we saw an awesome sight: Even those these mountains were east of us and hence would have sunset earlier, they were still bathed in sunlight - and instead of sunlight, we experienced mountain light - in all the awesome hues as it went from white snow-capped light to orange to red. My point being that because of the curvature of earth's crust, those mountains saw a more distant and LOWER horizon. In effect, they saw BELOW our lower elevation horizon! The effect was magnefied by the fact that the western horizon was lower - it was over the ocean for the mountain view - hence sea level. I assume Hawaian observatories also have the ocean as the lower horizon.

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