Strange spots on Astronomy Picture of the Day image, what are they?

Can someone explain why this picture of a sunset on Astronomy Picture of the Day website has these odd marks? There are some obvious ... cloudy dots ... or something on the image. Are they photographic artifacts? Are they maybe evidence of photo-tampering? Are they natural?

antwrp.gsfc.nasa.gov...

Not sure if this is the correct forum, if not, I apologize beforehand.

This looks like it was taken with traditional film as opposed to digital. it has some marks on it that look like dust scratches on the film emulsion. As for the spots that you refer to, I think those are water spots on the film that have not been retouched. I really don't think this is anything unusual.

A sloppy job of processing the film indeed and it should have been cleaned up when digitized.

I agree with poster two. Those spots are nothing but water spots.

[edit on 20-3-2008 by kennethmd]

On my monitor, the image appears to be lightly peppered with hot pixels. If that's what these white points are, then this is a digital image. I'd say the smudges are on the outer lens of the camera.

WG3

[edit on 20-3-2008 by waveguide3]

Waveguide, do you see the scratches right at the horizon that seem to lead right to the hot pixels. I seem them too but thought maybe they were caused in the digitization process.

Looks fine to me. Kinda pretty.
I don't see what you see, I guess.

Originally posted by gordstephan
A sloppy job of processing the film indeed and it should have been cleaned up when digitized.

Heh and if they did this then people would jump on the photo saying "what are they hiding"

I dont think there is anything there, except as pointed out already...water spots - just like i get on my laptop screen when it suddenly starts to rain (damn weather controllers!)

Explanation: Today, the Sun crosses the celestial equator heading north at 0548 UT. Known as the equinox, the geocentric astronomical event marks the first day of spring in the northern hemisphere and autumn in the south. Equinox means equal night and with the Sun on the celestial equator, Earth dwellers will experience nearly 12 hours of daylight and 12 hours of darkness. Of course, for those in the north, the days will grow longer with the Sun marching higher in the sky as summer approaches. To celebrate the equinox, consider this colorful view of the setting Sun. Recorded last June from the International Space Station, the Sun's limb still peeks above the distant horizon as seen from Earth orbit. Clouds appear in silhouette as the sunlight is reddened by dust in the dense lower atmosphere. Molecules in the more tenuous upper atmosphere are preferentially scattering blue light.

Source This link leads to the daily update, and may not show the same tomorrow.

My interest was piqued because Astronomy Picture of the Day usually describes any technical photographic inconsistancies in the images shown, and they did not mention these odd dark blobs.

I also found it odd that they are all very similar, if not exactly the same, and they appear in such a pattern. Water drops on the film has been suggested. I suppose that's possible. This image was taken from the ISS, does that affect the possibility of water spots? Would they look ... repeated? All the same size, etc?

As for the scratches, I assume you mean the vertical lines descending from the stars? Could that be scratches? I hadn't even noticed them, I was originally asking about the dark blobs, but now I am interested in the vertical lines also.

The water spots would have from the developing process, not the camera.

As for the lines, they are just scratches in the film, when developing film this is a common issue.

"Straight scratches extending the length of the photo Tram lines. Caused by dirt or grit either on the felt light trap on the film cassette or on the film plate in the camera. Tram lines can also occur if you squeegee or run wet film through your fingers to remove excess water before drying. Wet emulsion is very delicate and even a small piece of dirt or grit will leave a scratch the length of your photo."


*edited to add to my one liner*


[edit on 20-3-2008 by freakyclown]

reply to post by freakyclown


Yes, I assumed the implication was the film development process. I suppose my curiosity is to whether or not the ISS cameras would be film or digital? If digital, there would be no film to process, correct?

reply to post by freakyclown


Sorry, I was responding and apparently you were editing at the same time.

Yes, I see what you mean. If the cameras are film, and not digital, then your explanation makes perfect sense, Thank you. I had simply assumed the images would be digital.

However, I am still surprised that APOD didn't provide an explanation, as they usually do.

Thanks, again!

An intresting question...

looking through the rest of the images spaceflight.nasa.gov... from that flight taken by Expedition 15
I found this image.

spaceflight.nasa.gov...
which when cleaned up a bit reveals they had a nikon F5 which is a 35mm film camera.




[edit on 20-3-2008 by freakyclown]

[edit on 20-3-2008 by freakyclown]

reply to post by freakyclown



Thank you very much! So they had at least one 35mm camera, that would explain alot. Although I am curious now why they would do such a poor job developing the film? It kind of looked to me like someone had touched it all over with a pencil eraser or something and I knew that was not the answer, lol.


Perhaps this is a common thing on NASA film, and I've just never noticed. I will have to do more research (before posting, apparently).


Thanks again for your explanation.

These spots occur in DSLR digital cameras (the ones with detachable lenses). It is due to dust and dirt that gets inside on the cameras sensor when the lenses are changed. I have had it happen to me and it can a pain to clean and also dangerous to the sensitive parts of the camera if done wrong.

Here is an example:



Source - Spots on Digital Images

reply to post by samureyed



Thank you for that perfect example.

So film and digital cameras can both produce the effect, but for different reasons. I have learned something, and that's why I am here. Thanks again!

reply to post by samureyed


This may be odd but what is that under the letter "u" in dust. Doesn't look like a bird or plane.

Finding UFO's in the most common pictures these days.

LOL i saw that too, its just a bird, but strangely on the site they show the before and after photo of it being cleaned of the dust spot...and they have removed the bird too!
(or is it a ufo and government covering it up?)