Aurora in the Distance (APOD 19 Nov 2007)

[iampete]

There is an object about 7 o'clock from the sun in the picture that's not described in the caption.

It looks like a comet, but with the tail pointing sunward, which makes no sense.

What is the object?

Thanks.

[craterchains]

I would hazard a guess, that it is the moon we are seeing, not the sun.

http://antwrp.gsfc.nasa.gov/apod/ap071119.html

Norval

[BMAONE23]

It is an overexposed Moon that is brightest in the image. I was wondering about the green spike myself.

[iampete]

Aaargh.

I just hate it when photographs are "massaged", e.g., over-under exposed, false color, etc., and not specifically identified as such.

I suggest that would be a good policy for all APOD pix --- Always identify the type of "massaging" done to the pictures, not necessary all the gory details, but the general description thereof.

[DerekSmith]

Aaargh.

I just hate it when photographs are "massaged", e.g., over-under exposed, false color, etc., and not specifically identified as such.

I suggest that would be a good policy for all APOD pix --- Always identify the type of "massaging" done to the pictures, not necessary all the gory details, but the general description thereof.

Hi Pete,

You might have gained a clue that it was a night shot from all those stars which would have been obliterated by skyshine in a daytime photo .

As for your pet hates, this image only had a 30 sec exposure and was not over exposed for the content it was intending to record and the clip clearly states that the shot is recording aspects that the human eye is not able to see.

But this still leaves your question -- what is the comet like object, particularly intriguing because it is the same green colour as the aurora.

Could this be a vapour trail illuminated by the aurora?

DerekSmith

[smitty]

It has all the earmarks of being a real comet. If we had additional information about the image (date, etc.) it might be possible to figure it out. It does strike me as odd that the person who wrote the blurb about the photo didn't think to say something about it.

[saholz]

I'm fairly sure this is a real comet. The green coloration would be expected given the color of the aurora, which is in the foreground.

I agree it's very odd that no mention of this is made in the explanation.

[orin stepanek]

My thoughts are that it is a comet. A neat picture though; however I think it would be neater if the moon were cropped out.
Orin

[bystander]

From Lance McVay's website http://sacredartichoke.com/coppermine/d ... m=8&pos=14 the photo was added to his collection on October 4, 2007. I don't know if this is when the photo was taken or not. Were there any visible comets in the scope of the picture on this date?

[zbvhs]

I would venture to guess that the comet-shaped thing is the Moon's shadow stretching off into the distance and illuminated by the same faint aurora shown to the left in the picture.

[nedkelly]

I doubt it is a comet - it is way to big and (relatively) easy to see and would generate a ton of press. And to have the "tail" line up exactly with the moon is too much coincidence. The moonshadow postulation might work Given an apparently full moon (my guess) the sun is relatively somewhat behind the photographer and a shadow might tail out like that. But I do not understand how this "shadow" would show up brighter. Why???

[Axel]

If you click on the link to Lance McVay's site in the APOD page, and then click on "Night Photography", you will find in the (terrific!) gallery two pictures of the same scene, both dated 4 October 2007. One of them is the one we have all just seen; the other is slightly darker and presumably was taken slightly earlier. In the darker picture (IMG_2288.jpg) the comet-like shape is pointing slightly to the left of the where it is pointing in the APOD image. If we assume, judging from the Moon's altitude (roughly estimated) that the shots were made in Alaska around 0530 AKDT on 4th October with the camera directed approximately 70 degrees east of south, then the mystery object is indeed behaving like a comet.

Now you comet hunters will have to do the rest. I'm just an astrologer.

[Indigo_Sunrise]

Now, I'll hazard a guess that it's another aurora that was caught in the image, and it just so happens to bear an uncanny resemblance to a comet. As others have postulated, if it were an actual comet, we'd have heard/read about it on the many other space/astronomy websites that are out there.
And btw, wrt the two different images on the image-taker's website, auroras do change and seem to shift, as well, so it's not automatically a comet.


But I'm definitely not a professional astronomer, so feel free to discount my non-too-educated guess.....

[Axel]

Now, I'll hazard a guess that it's another aurora that was caught in the image, and it just so happens to bear an uncanny resemblance to a comet. As others have postulated, if it were an actual comet, we'd have heard/read about it on the many other space/astronomy websites that are out there.
And btw, wrt the two different images on the image-taker's website, auroras do change and seem to shift, as well, so it's not automatically a comet.

What I meant in my remark above is that, as sunrise approached, the Sun under the horizon was moving south and west. If we assume the mystery object's tail was pointed away from the Sun, as with an actual comet, then the change from the earlier to the later image exactly follows the behaviour of a comet. Aurora do not just change their orientations; they also undergo dramatic changes in shape. But this object remains identical to itself in the two pictures, except for orientation.

One possibility is that the photos were not taken on the stated date. They might have been taken years before. But in Alaska early on the morning of 4 October 2007, the Moon was just past its last quarter; this is consistent with its culminating sometime in the wee hours before sunrise. I did some rough calculations and came up with the above estimate for time and camera position. If it was comet Hale-Bopp a few years ago, that estimate would be of no use whatsoever.

[Axel]

It has struck my slow mind that the APOD picture is labelled IMG_2287.jpg in McVay's gallery, whereas the darker picture is labelled IMG_2288.jpg. While it isn't 100 percent certain, chances are the lighter picture was taken before the darker one, in which case both would have been after sunset - and the Moon would definitely not be there on 4 October 2007. Whatever... McVay's photography is stunning.

[Chris Peterson]

One possibility is that the photos were not taken on the stated date. They might have been taken years before. But in Alaska early on the morning of 4 October 2007, the Moon was just past its last quarter; this is consistent with its culminating sometime in the wee hours before sunrise.

Note that the EXIF header is intact in the photos. There's no good reason to doubt that they were taken on October 4, 2007.

The fixed orientation of the artifact with respect to a saturating light source in the three images where it is seen strongly suggests nothing more than lens flare.

It certainly isn't a comet. The color is wrong, the shape is wrong, and there have been no comets in recent years that looked like this.

[Lance McVay]

Thank you all for the kind comments.

The object near the moon is, as far as I know, nothing more than lens flare. I was using a 12mm lens at full aperture, and in my experience, pointed at a bright light source, this lens will definitely flare.

The photo was taken early in the morning of October 4th, 2007. I'm not sure if I had changed the camera's setting for daylight savings or not, so it was either taken around 4 or 5 am.

The moon was just a crescent, and there was no visible aurora that night, just a faint light that outlines the mountains from the sky, which is sometimes hard to tell if it is a faint aurora or just the moon illuminating the Juneau Icefield behind these peaks. I was exposing for the foreground icebergs with the hope that I would get some subvisual aurora. The photo has had some slight adjustment to levels in Photoshop, but no more than I do to any other photo. There is certainly no false coloring or other trickery involved.

It is a 30 second exposure at ISO 3200 taken with a Canon 20D. I generally take a high ISO photo at a short shutter speed to check for framing before taking longer photos at lower ISOs. Photo IMG_2288.jpg on this page: http://sacredartichoke.com/coppermine/d ... m=8&pos=16

was a longer, two and a half minute exposure at ISO 200.

Again, thanks for the kind words. I've been overwhelmed with the response I've gotten today from this photo.

Lance McVay
lancemcvay@gmail.com
http://sacredartichoke.com

[Andy Wade]

Again, thanks for the kind words. I've been overwhelmed with the response I've gotten today from this photo.

Lance McVay
lancemcvay@gmail.com
http://sacredartichoke.com

Well in that case Lance, I'll add mine too. It is a great picture. It looks really cold!
Many thanks from a mere stargazer in Yorkshire, England, who has never seen an aurora in his life.
Actually I did want to ask, what is the red glow at the base of the mountains just to the right of centre?

[podkayn]

Since the moon is overexposed, could the streak just be an artifact of the camera? Obviously, it's cold (the lake is iced over) and ice crystals could form on the lens cover and reflect light in a way which would automatically be oriented toward the light source (the moon). I know that I've often seen a movie camera record streaks when it is panned past the sun. Could this be such a streak? I'll believe this until someone proves me wrong.

[craterchains]

Looks up, , , "sighs".

Some people just can't read.

Edited to add, , , , , ,

Looks down, yep, you were right, Thanks for being a vet, they are good people most of the time. Congrats on making it to retirement also.

[iampete]

. . .
Actually I did want to ask, what is the red glow at the base of the mountains just to the right of centre?

I assume it's some inhabited area. I have seen long exp nighttime pix which show distant towns/villages as "glows" somewhat similar to that, although the one in this picture is much redder than I recall seeing previously.

[podkayn]

I apologize! I thought I'd gotten to the end of the string; obviously, I didn't notice that there was another page. At least I was right.

[Lance McVay]

Actually I did want to ask, what is the red glow at the base of the mountains just to the right of centre?

That's glow from the Forest Service Mendenhall Glacier Visitor's Center. Their lights do seem to have quite a red glow about them. In this photo, those lights are providing the foreground light on the brush and the icebergs.

[Carl Horn]

G'day, As a rank amateur who likes to look at NASA's "pretty pictures", I must ask if the object at 7pm to the Sun is a comet, and if it might be Comet Holmes? Cheers, Carl

[DerekSmith]

Thank you all for the kind comments.

The object near the moon is, as far as I know, nothing more than lens flare. I was using a 12mm lens at full aperture, and in my experience, pointed at a bright light source, this lens will definitely flare.
snip....
Lance McVay
lancemcvay@gmail.com
http://sacredartichoke.com

Hi Lance,

I have a real problem with your conclusion as to the nature of the 'object' as being lens flare.

Undoubtedly, that lens open as it is on F4 is flaring quite badly from the moonlight, you can see the huge flare halo and its numerous flare spikes radiating out from the moons light source. But they are all WHITE - as they should be for a white source. However, this single spike is green and almost identical in hue and intensity to the aurora. If it were to be flare, then it would have had to have been auroral flare, but the auroral light source is far too diffuse to cause such an event.

I do not think this can be explained away as lens flare, and as its orientation is different in a subsequent shot, yet it is still present, indicates that it is real, but as yet unidentified.

Derek