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49

The error is probably in this statement if it is 13 billion light years away wouldn't it take 26 billion light years to take those pictures? I think you are imagining that cameras send out light to the objects, and when this light comes back records the light as an image. Not really. Cameras merely record the light they see from that area. So if that ...


37

You can see Jupiter in the night sky with your naked eyes due to its reflected sunlight (although I believe that in July and August of 2014 Jupiter is very close to the Sun in the sky and is visible only for a little while near twilight). You can take a picture of Jupiter in the sky with any old camera. If you want a high-quality picture, your camera needs ...


35

[…] if it is 13 billion light years away wouldn't it take 26 billion light years to take those pictures? Only if you were using a flash. With a flash, you'd trigger the flash here, 13 billion years later the flash light would have traveled all the way there and illuminate the distant galaxy, and yet another 13 billion years later it would have traveled ...


32

This was just going to be a comment, but it got too long. Technically the picture is a fake. It's actually a composite image of what we would see with our eyes (visible light) blended with light seen in 3 different filters (see this NASA article on the different filters on-board Cassini, the probe that took the images). The image below is taken from the ...


28

Not quite like in the photo above, which shows more than what the naked eye can see, but yes, absolutely! Our galaxy (well, the chunk of it visible from these parts) is a naked-eye object. The fact that your question even exists shows how much time is now spent by people under light-polluted skies. It will not be visible from the city, however. You need to ...


17

The light that shines on Jupiter is of course the Sun's. It is indeed fainter than on Earth, by a factor of about 25, but that is still plenty. Using appropriate cameras, and long enough exposures, one can photograph much fainter targets. You can also note that there is a moon transiting in that picture, and its shadow is clearly visible. This should help ...


16

Any NASA image is in the public domain, although it's common practice to provide attribution back to NASA. (I often see people trying to make copyright claims on images that I know are NASA provided images) I believe that other images provided by US government funded observatories are also public domain, but you occassionally get a PI institution trying to ...


15

Part of why you don't see colors in astronomical objects through a telescope is that your eye isn't sensitive to colors when what you are looking at is faint. Your eyes have two types of photoreceptors: rods and cones. Cones detect color, but rods are more sensitive. So, when seeing something faint, you mostly use your rods, and you don't get much color. Try ...


9

If you prefer to make visual observation only, while some procedures are almost the same, the criteria for a telescope gets easier and the price is lower than with astrophotography. The light gathering of the telescope becomes one of the most important criteria and a dobsonian telescope could be a good choice for that, specially one with at least 6 inches of ...


8

You are correct: Jupiter is rather dim photography-wise. We can't use flash photography, as Jupiter is way too big for that to make any sense (even from a probe), so all the light in this image is indeed from the Sun, or from photo enhancement applied to the image after it was recorded (in which case it's still originally from the Sun). There are ways to ...


6

There are a couple of main sources of intrinsic error (that is, not associated with counting photons from your source) which CCD's have. The first is as you have already mentioned called read noise. Here is a reasonable definition of read noise (taken from Romanishin's free pdf on Photometry): After an integration (exposure), the CCD must be read out to ...


6

The reason is that the exposure on the camera is set so that the main subject of the image is properly exposed, ie not too dim and not too bright. Because the typical objects being photographed are quite bright, the image detector (camera) will not get enough light from the stars for them to show up.


5

Dithering is as much an art as a science and depends on many factors including, but not limited to: The type of object being observed (point source, small extended object, large extended object) Telescope parameters (The field of view of the telescope relative to the size of the object, optical quality, size and type of abberations, etc) The quality of the ...


5

I got my answer from my colleagues :) And I guess you were trying to say the same. Taking a photo does not require sending some photons and waiting for them to reflect back from object. Taking a photo is basically getting the photons that are thrown by the object. In my case photons thrown from the objects 13 billion years ago.


5

First, a light year is just a unit of distance, and not a unit of time. It is 9 460 538 400 000 000 metres. It's widely used as a measure of distance in astronomy as the numbers come out more reasonable, and very conveniently, light travels at 1 light year per year. You can take a photo of an exploding star 13 billion light years away in exactly the same ...


4

There are plenty of pictures from the ISS in which you can see stars.


4

TLDR: Cheap optics - the image gets worse with each new element added, pretty quickly. High end optics - the image may get better, may stay pretty much the same, or may get worse; if it does get worse, it's by such a small amount that you can usually ignore it. This assumes a scope that is in good shape, otherwise all bets are off. Now the long version: A ...


4

Since you say you're a programmer, I see where criterion #1 comes from. But telescopes are not computers, you can't upgrade the CPU today, the RAM tomorrow, and so on. A scope is defined largely by its aperture (the diameter of the objective lens or mirror). That puts a major cap on pretty much everything else, performance-wise. Aperture is like an old ...


3

For solar physics, the false colors were used to quickly identify the filter that was used, and possibly even the instrument itself. So, for instance, SOHO/EIT, there are three filters, each one typically shown with a color that are ordered by spectrum (eg, the 'green' false color image has a spectral sensitivity between the 'yellow' and 'blue' images. ...


3

A scale of distance would not make sense as a photograph often shows objects at vastly different distances from the observer and thus the distance of two objects on the photograph does not translate directly into a distance in real space. Or in other words: a map of an area on earth is mostly a projection of a 2D area onto a 2D map while a astronomical ...


3

As one more option, all the pictures on Wikimedia Commons are freely licensed or in the public domain. In particular, you're free to distribute, modify and/or even sell them, although you may be required to credit the author(s) and possibly to release any derivative works under the same license. They have plenty of high-quality astronomy pictures, both ...


3

No, due to the Redshift the light of stars further away will be shifted more and more towards the infrared (and beyond), becoming invisible to the eye.


3

It's because of the short Dynamic range of the camera. The human eye has a very large dynamic range which allows it to see at the same time, lights of low exposure and lights of high exposure. The same problem exists when you try to capture a photo against the sun light. Either the sky is completely white and the object is correclty lightened, or the sky is ...


3

NASA still images; audio files; video; and computer files used in the rendition of 3-dimensional models, such as texture maps and polygon data in any format, generally are not copyrighted. You may use NASA imagery, video, audio, and data files used for the rendition of 3-dimensional models for educational or informational purposes, including photo ...



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