APOD: Antarctic Analemma (2015 Sep 23)

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Expand view Topic review: APOD: Antarctic Analemma (2015 Sep 23)

Re: APOD: Antarctic Analemma (2015 Sep 23)

by BMAONE23 » Fri Oct 09, 2015 3:09 am

Guest wrote:
Indigo_Sunrise wrote:
BMAONE23 wrote:What causes the Red Fire patches to the left of the Analemma?
It looks like LMC and SMC or Red Aurorae but ???

I thought they looked like sprites! 8-)
Sorry to disappoint you both, they are neither the aurora nor Mangellan's Clouds (both of which become invisible even in faint sunlight)! What you see here is some internal reflection of sunlight by the solar filter, on the camera CCD. Again, it wasn't the best camera to shoot with, but since my DSLR fell victim to the extreme conditions of Antarctica, it was the only choice!
The YouTube vid you posted clearly shows the red areas as reflections on different days

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Guest » Thu Oct 08, 2015 3:43 pm

Indigo_Sunrise wrote:
BMAONE23 wrote:What causes the Red Fire patches to the left of the Analemma?
It looks like LMC and SMC or Red Aurorae but ???

I thought they looked like sprites! 8-)
Sorry to disappoint you both, they are neither the aurora nor Mangellan's Clouds (both of which become invisible even in faint sunlight)! What you see here is some internal reflection of sunlight by the solar filter, on the camera CCD. Again, it wasn't the best camera to shoot with, but since my DSLR fell victim to the extreme conditions of Antarctica, it was the only choice!

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Adrianos Golemis » Thu Oct 08, 2015 3:40 pm

BMAONE23 wrote:
dennisma wrote:These shadows look all wrong. It looks like the sun farther right and behind the camera not right in front.
The shadows are in deed pointing to the left of the image indicating that the sun is off to the right at the time the image was taken. This is likely because the sun Was off to the right at the time the final background image was taken.
The reason for this is that the 23 sun images that have been combined to form the analemma were taken when the Sun was pointing at the camera lens, Probably through a filter so as not to over bake the CCD. The 24th image was taken with the Sun out of the field of view and without the filter so that the background could be exposed without an overexposed sun within the field of view.
Precisely! That's exactly the reason; the background picture was made at a different time of the day than the filtered the solar exposures and they were all put together at the end. The reason for shooting the background at a different time of day is, mainly, the solar reflection you would have in the photo which might also set the natural colors off a bit.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Adrianos Golemis » Thu Oct 08, 2015 3:34 pm

geckzilla wrote:I think it would be easier for most people to understand the image if they saw all the images (or at least a selection of them) that were combined to create the final composite.
Maybe this can help! https://youtu.be/-p1OTqlx7hU .

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Adrianos Golemis » Thu Oct 08, 2015 3:29 pm

neufer wrote:
Mikado wrote:
Why is the Sun different sizes? Sep 30 being the smallest.
All of the solar images are overexposed and larger than the sun's actual size.

The smaller suns are probably partially obscured by haze/cloud and thus closer to actual size.
Exactly, September 30 was a particularly cloudy day and thus the solar disc appears smaller. For the rest of the exposures, they were all made with a limited-capability compact digital camera (as my primary DSLR was fried in the cold!), hence the overexposure that could not be corrected at the time of shooting.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Adrianos Golemis » Thu Oct 08, 2015 3:25 pm

Nitpicker wrote:Interesting. I guess that the "4 pm" is based on UT+8.
Indeed, 16:00 local time, that is UTC+8 for Concordia Station, without daylight saving (obviously)!

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Adrianos Golemis » Thu Oct 08, 2015 3:23 pm

HellCat wrote:So why does there seem to be some asymmetry here? Did the camera stand wobble because of global warming?
The asymmetry is because you cannot keep the camera at a steady location outside for the entire year (as you would usually do to shoot a year-long analemma). Since temperature goes down to -80 degrees Celsius, you can only retrieve the camera after each shot and take extra care to place it at exactly the same position next time. However, even the tiniest slip in this, coupled with the wind that is blowing at times when you shoot are responsible for the wobbling that you notice.

Kind regards,

the photographer.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Nitpicker » Tue Sep 29, 2015 12:26 am

phoenix900 wrote:Suggest this and all similar posts be written not as the SUN MOVING, but the EARTH moving.
I find that to be a relatively ignorant suggestion. :P

Re: APOD: Antarctic Analemma (2015 Sep 23)

by phoenix900 » Mon Sep 28, 2015 8:18 pm

Suggest this and all similar posts be written not as the SUN MOVING, but the EARTH moving.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Joe Stieber » Thu Sep 24, 2015 2:55 am

Mikado wrote:Why is the Sun different sizes? Sep 30 being the smallest.
The relatively small disc on September 30th in the picture looks like it's due to considerably less exposure, and therefore shows less distortion than most of the other solar images, which look enlarged due to flaring from overexposure. The position of the September 30th sun also looks a little out of place, as do a few of the other dates, so the analemma loop is a bit lumpy.

Otherwise, the earth's orbit is an ellipse, not a circle, so the distance from the earth to the sun varies, and consequently, the apparent diameter of the sun varies. The earth is at aphelion (farthest from the sun) in early July; that's when the sun appears it's smallest as viewed from earth. Conversely, the earth is at perihelion (closest to the sun) in early January; that's when the sun appears it's largest diameter as viewed from earth.

More here: https://en.wikipedia.org/wiki/Earth's_orbit

Re: APOD: Antarctic Analemma (2015 Sep 23)

by neufer » Thu Sep 24, 2015 2:13 am

Mikado wrote:
Why is the Sun different sizes? Sep 30 being the smallest.
All of the solar images are overexposed and larger than the sun's actual size.

The smaller suns are probably partially obscured by haze/cloud and thus closer to actual size.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Mikado » Thu Sep 24, 2015 1:47 am

Why is the Sun different sizes? Sep 30 being the smallest.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by geckzilla » Wed Sep 23, 2015 9:40 pm

I think it would be easier for most people to understand the image if they saw all the images (or at least a selection of them) that were combined to create the final composite.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by saturno2 » Wed Sep 23, 2015 9:40 pm

Interesting

Re: APOD: Antarctic Analemma (2015 Sep 23)

by BMAONE23 » Wed Sep 23, 2015 9:33 pm

dennisma wrote:These shadows look all wrong. It looks like the sun farther right and behind the camera not right in front.
The shadows are in deed pointing to the left of the image indicating that the sun is off to the right at the time the image was taken. This is likely because the sun Was off to the right at the time the final background image was taken.
The reason for this is that the 23 sun images that have been combined to form the analemma were taken when the Sun was pointing at the camera lens, Probably through a filter so as not to over bake the CCD. The 24th image was taken with the Sun out of the field of view and without the filter so that the background could be exposed without an overexposed sun within the field of view.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by BMAONE23 » Wed Sep 23, 2015 9:24 pm

Ron-Astro Pharmacist wrote:I don't suppose that's the most southern set of McArches is it? Leave it to a "Ronald" to notice them. Keeping the fries hot all the way home is tough enough here.
Ronald.jpg
C'est tout ce que j'aime.
Just keeping the fries all the way home can be tough

Re: APOD: Antarctic Analemma (2015 Sep 23)

by dennisma » Wed Sep 23, 2015 8:55 pm

These shadows look all wrong. It looks like the sun farther right and behind the camera not right in front.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by ta152h0 » Wed Sep 23, 2015 8:13 pm

what a coincidence. Just this morning, about a couple hours ago on NPR, they had a scientist, operating a microwave telescope, describe the visual of the sun rising slowly over the horizon in Antartica and without the moon, it is getting lighter and lighter everyday

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Ron-Astro Pharmacist » Wed Sep 23, 2015 7:23 pm

I don't suppose that's the most southern set of McArches is it? Leave it to a "Ronald" to notice them. Keeping the fries hot all the way home is tough enough here.
Ronald.jpg
Ronald.jpg (24.23 KiB) Viewed 4929 times
C'est tout ce que j'aime.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Indigo_Sunrise » Wed Sep 23, 2015 5:17 pm

BMAONE23 wrote:What causes the Red Fire patches to the left of the Analemma?
It looks like LMC and SMC or Red Aurorae but ???

I thought they looked like sprites! 8-)

Re: APOD: Antarctic Analemma (2015 Sep 23)

by BMAONE23 » Wed Sep 23, 2015 5:13 pm

What causes the Red Fire patches to the left of the Analemma?
It looks like LMC and SMC or Red Aurorae but ???

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Zuben L. Genubi » Wed Sep 23, 2015 5:07 pm

Over Bering: prepositional phrase. What Vitus, aka Ivan, sailed over trying to get to get to Alaska.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by neufer » Wed Sep 23, 2015 4:20 pm

Zuben L. Genubi wrote:
I hope we are "barring atmospheric effects" not "baring" them. I'm not sure I could handle seeing totally naked atmospheric effects! Whichever the case, we will be "bearing" them either way. Doubtless Vitus Bering, aka "Ivan", the Danish explorer, would have appreciated this polar view of long summer days, during which in 1925 he discovered the straits bearing his name, and after which he reported straight back to Peter the Great. Got it straight?
OVERBEARING, a., Haughty and dogmatical; disposed or tending to repress or subdue by insolence or effrontery.

Re: APOD: Antarctic Analemma (2015 Sep 23)

by Zuben L. Genubi » Wed Sep 23, 2015 3:22 pm

I hope we are "barring atmospheric effects" not "baring" them. I'm not sure I could handle seeing totally naked atmospheric effects! Whichever the case, we will be "bearing" them either way. Doubtless Vitus Bering, aka "Ivan", the Danish explorer, would have appreciated this polar view of long summer days, during which in 1925 he discovered the straits bearing his name, and after which he reported straight back to Peter the Great. Got it straight?

Ignorance is Blizz

by neufer » Wed Sep 23, 2015 2:51 pm

Rdlm wrote:
JohnCarswell wrote:
Why did they build a fence in Antartica? ...keep the penguins out?
I think it's used as handrails in order to avoid being lost during storm when you can't even see your noze. Being lost there means Death! :|
http://www.antarctica.gov.au/living-and-working/stations/mawson/this-week-at-mawson/2012/this-week-at-mawson-11-may-2012/2 wrote:

  • To each his sufferings: all are men,
    Condemn'd alike to groan—
    The tender for another's pain,
    Th' unfeeling for his own.
    Yet, ah! why should they know their fate,
    Since sorrow never comes too late,
    And happiness too swiftly flies?
    Thought would destroy their Paradise.
    No more;—where ignorance is bliss,
    'Tis folly to be wise.
    - Thomas Gray
---------------------------------------------------
Blizz lines
This week at Mawson: 11 May 2012

<<Blizz lines or blizzard lines are ropes connecting one building to another, which we use when we are walking around the station or in the field in blizzards. What is a blizzard (blizz)? A blizzard must satisfy 4 factors. The wind must be equal to or greater than 34 knots, the temperature must be below zero, the visibility must be less than 100m and all these factors must last for at least one hour. So a blizzard is a gale force wind with blowing snow reducing visibility. In these situations and remember it could be dark, we walk from one building to another, holding onto a blizz line.

Malcolm is the blizz line monitor and he has spent many hours over the last week installing new sections, improving others, digging steps over and down blizz tails (bank of snow deposited downwind from any obstruction as a building, large boulder etc) and generally maintaining and improving all the lines. The most used blizz line is the section from the EVS (Emergency Vehicle Shelter) to the Trades Workshop. Seven people use this line several times every day. An accident occurred on this line where it crosses a blizz tail, so after speaking to all the users of the line a plan of action was developed. As it was not sensible to totally remove the blizz tail after every blizzard, Malcolm and Ian set to realigning the entire blizz line, transferring the rope so that it is always on the right hand side as one walks south from the Workshop to the EVS. This involved removing many obstructions and installing 2 additional drums full of rocks into the line. This realignment then allowed us to tension the rope as it crosses the blizz tail. We also aligned the rope with a series of steps up the blizz tail, improving the safety for the users. It will be interesting to assess the improvements during our next blizzard.

In addition to the blizz lines, when we walk in a blizzard we also have a Field Travel Conditions Advice Sheet, which is known colloquially in Antarctica as “Traffic Lights” as it has 4 categories of Field Travel (Normal, Caution, Danger and Stop) each with its own colour code (green, yellow, red and black). Since our arrival, 3 blizzards have been recorded in the red category for travel. In these conditions we only travel outside when it is necessary and in addition to the blizz lines we travel in pairs when possible, carry a radio and tell others where we are going and then ring them when we arrive at our destination. We also dress appropriately for the conditions wearing warm and windproof clothes, goggles, gloves and most importantly balaclavas and wristlets.>>

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