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Topics

 

The Natural Resolution of the Heritage Images

 

Display Tips

 

Format and File Size

 

Downloading Images

 

Monitor Wallpaper

 

Reprinting Images and Copyright Issues

 

Posters and Photographs

The Natural Resolution of the Heritage Images

In the case of Hubble Heritage images, larger files do not necessarily mean more detail. Hubble's digital cameras produce images of fixed size (a maximum dimension of 1600 pixels as in the above image) that are not large by usual graphics standards. Therefore, we recommend copying and printing the "big" JPEG images available from the Heritage site. These are nearly the quality of the originals but will download much faster than a full-size, uncompressed image (see formats below). Although any image can be reproduced at larger reproduction sizes (for example poster size), individual pixels may be visible even in our uncompressed tiff images.An attempt to increase the resolution by increasing the number of pixels beyond the data's original dimensions will degrade the image. So we match the dimensions of the image to the dimensions of the data rather than convert it to sizes standard for monitor wallpaper or posters.

Display Tips

Note that if you are running color intensive applications, your computer will not use a full color table to display the image. Monitor wallpaper, and even the borders of windows steal colors from the available palette. Additionally, if your monitor is 8-bit your image might appear dotted or hatched. Often you can set your applications to compensate for these effects.

Here's an example for ensuring the UNIX XV application displays a reasonable texture and color rendition even on an 8-bit monitor. After loading the tiff or jpeg file into XV, open the XV control panel by clicking on the image with the right mouse button. In the "24/8 Bit" menu select the algorithm "Slow 24->8" and then select "8-bit mode". Then in the "Display" menu select "Perfect Colors" or "Use Own Colormap". A line near the bottom of the XV control panel will state whether or not you now are using all 256 available colors.

Note that you may wish to dim the overhead lights and/or adjust the intensity and contrast settings of your monitor. As an aside, your browser permits you to select your own colors for hyperlinks and select your font size for the text. In the browser's "Edit" menu, explore the "Preferences" control panel to customize your display.

Format and File Size

The information in the smaller format release images, which are roughly 400x500 pixels square, has been compressed so that they download more quickly. Their file size is usually under 120 kilobytes. The big size images, 800x1000 pixels, range from 50 - 400 kilobytes. To check the file size of a specific image, move your cursor on top of the small version. A window will appear with the number of kilobytes of both that image and the big image it links to.

The release images are presented in JPEG format which includes image file compression. This may slightly degrade the image from the original. Note that editing a JPEG and saving it as another JPEG will degrade the image further.

Downloading Images

You can use your browser functions to download these files to your disk. For example, in Netscape, go to the image you want, click the RIGHT mouse key and select "Save Image As...". Your browser should open a window asking for a directory on your computer and what you would like to name the file. Similarly, in Internet Explorer, click the RIGHT mouse button on the image and select "Save Image As...". Also note that the image may already be stored on your disk in the browser cache area, in which case you simply have to move it to another directory in order to save it.

Monitor Wallpaper

Convert downloaded images to monitor wallpaper using a standard graphics package such as GIMP or Adobe Photoshop. Alternatively, your computer software may provide specific applications for making desktop backgrounds. Note that replicating pixels in order to increase the resolution of the Heritage images to fill your monitor area may make them blurry. (See notes about the images natural resolution above.) This is why the Hubble Heritage Project does not provide wallpaper or screensavers. Check our copyright if you wish to use any image for a purpose other than for your own personal use.

Reprinting Images and Copyright

Hubble Heritage images can be reproduced without requests for permission if the credit line is "NASA, ESA, and The Hubble Heritage Team (STScI/AURA)." (Hubble Heritage image credits are listed in each image's description and links to descriptions are on the gallery page.) Please remember to properly credit or acknowledge the credit line in the reproduction of the image. However, if a credit line or a credit note beside the image includes other institutions and individuals, then these individuals must also be contacted for permission. More information on Copyright issues at STScI is available.

Posters and Photographs

Posters and prints are produced by many outside vendors. Doing a net search on "Hubble Poster" will point you to a number of these sources. Among them, the Astronomical Society of the Pacific and Sky Publishing, have been known to sell posters and prints of Hubble images.

For educators: There are some resources specifically designed for education available here at the Education Group at Space Telescope Science Institute and NASA provides educational resources through NASA CORE.

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