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45 votes

Why do stars appear as circles, not points?

Whenever light passes a boundary, it diffracts, or bends, due to the wavelike property of light interacting with that boundary. An aperture in an optical system, typically circular or circle-like, is ...
scottbb's user avatar
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44 votes
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What are the reasons for not taking super long exposures (hours) in astrophotography?

@Michael Clark and @Itai have provided good answers. A few more thoughts from the perspective of the enthusiastic amateur: Tracking technology isn't perfect and sometimes its better to work within ...
MartinV's user avatar
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35 votes
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What makes the difference on partially and fully visible moon?

What makes the difference on partially and fully visible moon? In a word: shadows. I cannot understand why the IQ is extremely diminished when doing the same with an almost fully visible moon. ...
scottbb's user avatar
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35 votes
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How to capture more stars?

1) To capture more stars, go somewhere where there is less light pollution. If you can't see the north star, you aren't going to get much. I can't see the north star from my front yard, so attempting ...
Mattman944's user avatar
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34 votes
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Which planet looks the biggest through a camera? Which planet is the easiest to take a picture?

Because the distance from Earth to each of the other planets varies due to orbital mechanics, the size of each planet as seen from Earth can vary significantly. Which planet is the largest and the ...
Michael C's user avatar
  • 175k
32 votes

Multiple copies of the same exposure, but randomizing the noise?

To achieve what you're thinking of you would have to know what the noise was. If you knew what the noise was then you could just remove that to get clean images.
James Snell's user avatar
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27 votes
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Why is the North America Nebula so hard to see on this astrophoto?

Your exposures are very different. Ignore the quantity of images that you captured for a moment... and just compare the the single exposure settings (for reasons I'll describe in a moment). Top: 13 ...
Tim Campbell's user avatar
  • 3,967
23 votes

Which planet looks the biggest through a camera? Which planet is the easiest to take a picture?

Normally Jupiter is easily the largest seen from Earth, but depending on orbits, it could sometimes be Venus (next time in September, and then next in 2020). This site will answer about details ...
WayneF's user avatar
  • 12.9k
23 votes

Why are the star trails in Richard Angle's photos of a SpaceX launch and landing so non-uniform?

They are not uniform but they all show the same bright-dim-bright pattern. One explanation is that this is a composite picture of several exposures and that the middle exposure(s) was/were dimmed a ...
xenoid's user avatar
  • 21.6k
20 votes
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What kind of filter do I need for safe sun photography?

You need more than an ND filter and a polarizer. You need a solar filter specifically designed for imaging the sun. The danger to your eyes and camera are very real if you are pointing the unprotected ...
Michael C's user avatar
  • 175k
20 votes
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Photo of sprites in a clear dark sky, is this possible?

Shots I've done of the Magellanic Clouds required an 8 second shutter speed at f/3.5, ISO 3200. It is conceivable that he could have captured these events since he was trying to photograph Lyrid ...
qrk's user avatar
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20 votes

How can I make the milky way more apparent in my photos?

Using the Curves tool in your favorite image editor:
xenoid's user avatar
  • 21.6k
19 votes

What are the reasons for not taking super long exposures (hours) in astrophotography?

It is firstly because we can now. Bulb photography can indeed shoot exposures of minutes to several hours, depending on the camera. Using a film camera, astrophotography is done with very long ...
Itai's user avatar
  • 103k
19 votes

What are the reasons for not taking super long exposures (hours) in astrophotography?

The main advantage of stacking is to average out the randomized Poisson distribution "shot noise" that can be a problem in low light images such as astrophotography. Another advantage for stacking ...
Michael C's user avatar
  • 175k
19 votes

Multiple copies of the same exposure, but randomizing the noise?

Image stacking works to reduce noise because the noise is random — or at least, ideally so — while the stars are (famously) constant. That means that (once you've corrected for rotation) the stars ...
mattdm's user avatar
  • 143k
19 votes

How to capture more stars?

Shoot when there is no moon in the sky. e.g. Near the "New Moon" or "Last Quarter Moon" if shooting after sunset. Get away from urban light pollution. I've generated a simulated field of view (...
Tim Campbell's user avatar
  • 3,967
19 votes
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New Pi camera - any good for Astrophotography?

I have tested RPi HQ Cam for astrophotography over last month and it works quite well. First, sample images: Canon FD 200/2.8 lens, 42 minutes exposure time (not a high quality glass, and not long ...
j-z's user avatar
  • 344
19 votes

Why do I need a telescope for astrophotography?

In principle, there's no difference between a camera lens and a refractor telescope. While focal distance is related with the magnification of the image, in astronomy, resolution is related to ...
vsis's user avatar
  • 1,251
19 votes

What causes the fake colors of stars on these pictures?

I can tell 3 common reasons for weird/fake colors in astrophotography: Chromatic aberration makes some starts appear white in the center, but their borders blue or red, depending what of those two ...
vsis's user avatar
  • 1,251
17 votes
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Does the EXIF data "DateTimeOriginal" get recorded at the start or end of the exposure?

The EXIF standard describes the DateTimeOriginal tag simply as "the date and time when the original image data was generated." It gives no guidance about what ...
Blrfl's user avatar
  • 5,592
15 votes
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How can I achieve more clarity in my photos of the moon?

Some possible reasons, arranged in the likely order of influence, for the lack of clarity in the example photo: 1) The optical limits of your lens. The EF 100-300mm f/4.5-5.6 was released as a budget ...
Michael C's user avatar
  • 175k
15 votes

How can I make the milky way more apparent in my photos?

Amateur astronomer here. Most images of the Milky Way we see around are the results of multiple exposures combined in Photoshop or another image-editing software. However, it is indeed possible to get ...
Pierre Paquette's user avatar
14 votes
Accepted

What is the best way to focus when doing night photography or astrophotography?

For focusing on stars, I suggest using a Bahtinov mask, which uses purposely-created diffraction spikes to determine correct focus. Bahtinov mask by Justin Dolske, from Flickr. CC BY-SA-2.0 This ...
scottbb's user avatar
  • 33.1k
14 votes

Why do I need a telescope for astrophotography?

@vsis already said this, but I'm going to be more explicit: It's all about the brightness. Most astronomical objects worth looking at are dim. The more light your optical system "gathers," ...
Solomon Slow's user avatar
13 votes

Does the EXIF data "DateTimeOriginal" get recorded at the start or end of the exposure?

Experimentally (on my EOS 70D), this is the beginning of the exposure, and not the end. But: this seems truncated to the second it depends how accurate is the time of the camera (before doing this ...
xenoid's user avatar
  • 21.6k
12 votes
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What are the features needed in a DSLR for astrophotography?

I already have a Nikon D5200 and I I tried so much to get a clear view of the sky and it didn't work so much. The camera you have is a fine one to start with. You should spend some time working on ...
Caleb's user avatar
  • 31.7k
12 votes
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How to take photos in burst mode, without vibration?

In theory, live view mode should ensure the mirror doesn't flip, if you don't use quick mode autofocus. In practice, though, your camera is a very cheap one, that has probably an integrated shutter/...
juhist's user avatar
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12 votes
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How does one actually *use* a dark frame?

Straight away I should mention that lunar photography is different that astrophotography of deep-sky objects. The types of frames you are describing (calibration frames) are extremely helpful for ...
Tim Campbell's user avatar
  • 3,967
11 votes

What caused some of the bright, diffuse areas of sky in some of the Apollo images from the moon?

It looks like lens flare. It is an internal reflection inside the lens. It is caused by off axis light allowed to fall on the front surface if the lens from outside the field of view. For an example ...
Michael C's user avatar
  • 175k

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