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36

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 ...


31

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 ...


27

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 ...


16

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 ...


15

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

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.


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 ...


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 ...


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 ...


4

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


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

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

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

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 ...


2

This is for the same reason that you don't see any stars on moonwalk pictures or videos; the reflected sunlight from Earth (or in my example, the moon) is so much brighter that it washes out the faint starlight.


2

Because the scale, in terms of how much of the sky the picture covers, almost never matters. The scale/pixel does matter because it tells you if / how much you can believe the details in the image or if they are likely to be artifacts of the AO system or the image analysis.


2

Another very simple answer is to use a google image search with astronomy +"public domain" as the search term. This will give you a wide range of images.


2

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 ...


2

Fundamentally yes, practically yes as well. All physical optical surfaces will add some scatter, 'there is no such thing as a perfect optical surface'. Even flat mirrors are not really flat. In practical terms it also depends on what you are doing, but yes generally adding additional surfaces into the optical path will lead to degradation of any 'image'. ...



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