Olav Kolbu

NASA makes a new Image Of The Day available every day in their gallery, 
complete with a fairly detailed description of what you see. This plugin 
grabs a thumbnail of the current image along with an extract of the 
accompanying description, and makes it available as a WordPress sidebar 
widget. Clicking on the thumbnail will take you to the NASA Gallery where 
you can view the full sized image and read the rest of the text. No 
local storage is used, the image and text is fetched on every view.
A friendly user let me know that the Image Of The Day is also 
available as an RSS feed. That greatly simplified this plugin and 
should make it impervious to cosmetic changes at NASA. In 
addition to this, the image width is now customizable. The height 
is calculated per image so that it stays proportional when scaled 
(down) to width.
<a href="https://downloads.wordpress.org/plugin/nasa-image-of-the-day.zip" rel="nofollow ugc">Download now!</a>
<a href="http://www.kolbu.com/2008/03/28/nasa-image-of-the-day-plugin/" rel="nofollow ugc">Support</a>

NASA Image Of The Day

Adds a sidebar widget to display the current image from the NASA Image Of The Day Gallery. Now using RSS.

DaWoody

The Astronomy Picture Of the Day plugin fetches data from the NASA open API and specifically data from Astronomy Picture Of the Day (APOD). The data can then be presented within posts/pages through the use of short-codes added to the editor in text-mode. The data is fetched through javascript AJAX calls, and stored within the browser as a cookie for caching purposes. 
Currently the plugin uses the public <code>DEMO_KEY</code> for requests towards the open API, and as mentioned then stores the data as cookies for the next 24 hours, this to lessen the request load on the API and also possibly help the wordpress user to a smoother experience.
How to use: 
After activating the plugin, go to your post/page, go to editor mode, and then either add <code>[astronomy-picture-of-the-day]</code> or <code>[astronomy-picture-of-the-day-hd]</code> to generate a html block consisting of a container div, with a title, the apod image and its explanation. 
All elements receive css classes so they can be styled independently by the WordPress developer. 
Within the admin interface the specific <code>css</code> classes that gets added are mentioned.

Astronomy Picture Of the Day

A plugin that fetches data from NASA's open API regarding the Astronomy Picture Of the Day to be used within posts/pages

NASA Image Of The Day vs Astronomy Picture Of the Day