Categorizing summer APODs (split from Blatant Bias thread)

[Ann]

This discussion made me want to take a crack at describing what pictures are typically posted here at APOD. So let's look at this summer's APODs, from June 1, 2013, to September 6, 2013.

To come up with any sort of description I have to put the pictures in categories. The first category would be extremely close to home, namely, pictures showing humans doing fairly normal human things. The APOD that fits this description most perfectly might be Happy People Dancing on Planet Earth, but that picture - or rather, that video - is not from 2013.

I found one such "human" APOD from this summer, namely, Earth Waves at Saturn from August 24.

The next "closest to home" motif would probably be scenes or aspects of Earthly daylight landscapes or the Earth's daylight sky. An interesting example from this year is from September 01, Fire on Earth. Quite a few pictures show clouds in the Earth's atmosphere, such as this, this, this, this and this one.

Very many APODs show Earthly landscape and the night sky. Some of the many examples are this, this, this, this, this, this, this and this. The "landscape and night sky picture" appears to be one of the most common motifs among the APODs.

A special kind of night sky is the aurora night sky, which is featured here, here and here.

This summer's Perseids got quite a lot of attention, for example here, here, here and here.

There are several pictures of the Moon, including this, this, this and this one.

Pictures of the Sun are popular, and can be seen here, here, here, here and here.

There are many other solar system pictures, for example this, this, this, this, this, this, this, this, this, this, this, this and this.

A special kind of solar system picture is the comet picture. I think I only saw two here, namely this and this one.

There were also a few "human equipment in the nearby solar system" images. One example is this one, another one is this one.

I'm getting a bit tired now, so I'm giving up for now. I may come back tomorrow.

Ann

[owlice]

Ann, I'm unclear as to what point you are trying to make in your post. APOD shows a lot of different things, and some of the images shown relate to what is currently observable in the sky, which I think your post shows very nicely! I'm not sure what that has to do with Fred's perceived bias, though. (I'm a little tired, might need coffee, and hope you will forgive my request for clarification!)

[Ann]

Well, owlice, I'm going to try - if I can find the energy - to categorize most of the APODs posted this summer. My purpose is to see what kind of pictures are commonly chosen to be APODs and what pictures are not selected to often. As you can see, I haven't moved far beyond the solar system yet.

Ann

[owlice]

Well, owlice, I'm going to try - if I can find the energy - to categorize most of the APODs posted this summer. My purpose is to see what kind of pictures are commonly chosen to be APODs and what pictures are not selected to often. As you can see, I haven't moved far beyond the solar system yet.

Ann

There's a seasonal bias, so categorizing summer images may not say much about the other seasons.

[owlice]

Well, owlice, I'm going to try - if I can find the energy - to categorize most of the APODs posted this summer. My purpose is to see what kind of pictures are commonly chosen to be APODs and what pictures are not selected to often. As you can see, I haven't moved far beyond the solar system yet.

Ann

There's a seasonal bias, so categorizing summer images may not say much about the other seasons.

But please don't take this to mean I'm discouraging you! I'm not; I think a table of what kind of images are presented over time might be useful. I'm not sure how, but I think it likely the data could revealing something interesting.

[Ann]

I'm going to try to categorize the deep-sky images now. Unfortunately I'm not going to look at their "quality", partly because I'm not qualified to do so. I am going to note if the pictures are RGB, narrow-band, two-filter images or "other".

Here, then, are my categories (and obviously there is going to be a "seasonal" or "topical" slant):

Open clusters
Globular clusters
Individual stars and starscapes
Exoplanets
Bright nebulae
Dark nebulae
Planetary nebulae
Ongoing novae
Ongoing supernovae
Supernova remnants
Black holes
Galaxies
Cosmology

I am going to further subdivide the bright nebulae into very well-known and bright objects (Orion, Lagoon, Trifid, North America, Carina, Tarantula) and those slightly well-known and less often photographed. (Obviously there is going to be a seasonal bias here.)

I am going to subdivide the galaxies into Local Group galaxies, other nearby galaxies (~10 million light-years), well-known Messier galaxies, and other galaxies.

Let's start. The only open clusters I could find are few open clusters in this Sagittarius starscape and an open cluster seen in the background of this image. Admittedly there are other open clusters that can be seen in this summer's APODs, but these clusters are overshadowed by the nebulae they produce.

There is a closeup of a globular cluster here. It is an RGB image.

I found two individual star images here: this and this. But perhaps this video should also be included.

I couldn't find an exoplanet image, possibly because Kepler has recently broken down.

There are many bright nebula images here. I'm going to start with the best-known bright nebulae in RGB: this, this, this and this.

These are slightly less well-known bright nebulae in RGB: this (which also qualifies as a dark nebula image and this one. The latter might possibly have been included among the well-known nebulae.

These are some bright nebula in narrow-band: this, this, this, this, this and this.


I'm going to categorize this image as a dark nebula, although that is a bit arbitrary.

I could find four planetary nebulae here, all of them in more or less mapped colors: this, this,
this and this.

This summer there has been an ongoing Milky Way nova, and there are "true" color pictures here and here.

There was an ongoing supernova in M74 this summer, but the supernova did not become an APOD. There was a non-supernova picture of galaxy M74 itself, however.

There was a picture of a supernova remnant here.

Black holes were shown here, here and here.

There were a number of galaxy pictures. I'm going to start with the Local Group galaxies in RGB: this and this.

Local Group galaxies in non-RGB are here and here.

An RGB image of a very nearby galaxy that does not belong to the Local Group is here.

RGB images of very well-known and much-photographed Messier galaxies are here (RGB + Ha) and here. Perhaps M74 also counts, although it isn't strictly an RGB image, and although I have linked to that picture already.

RGB images of less well known and less often photographed galaxies are here, here, here - it is not strictly an RGB image, but it will do and here - it looks mostly like an RGB image.

Non-RGB galaxy images are here and here.

A cosmology image is here.


Well, I think I'm done. Obviously a three-month period can't be representative of APOD as a site. Nevertheless, what do the rest of you think of the pictures that were chosen for APODs this summer - the motifs, the quality of the pictures? I'll leave that up to the rest of you.

Ann