It appears that a recent Java patch causes problems launching the IAS Viewer client and other Java-based software launched via Java Web Start. The update changed the location of the Java Web Start application so that the system opens the downloaded JNLP file as a text file, most likely with something called Dashcode. One of our system administrators found a solution on an Apple support discussion archive. You should only have to do this once to fix the problem:

1. Find any *.jnlp file in the Finder. These may be on your Desktop, or in a download folder, depending on how your web browser is configured.
2. Highlight the file by clicking on it, then select ‘Get Info’ from the File menu.
3. In the Open with: section, click on the popup menu and select ‘Other…’.
4. In the file chooser window that pops up, under Devices, pick the hard disk icon that corresponds to the name of your system hard disk (probably has the same name as your computer).
5. From there, select the System folder, then Library, then CoreServices, and scroll down to find the Java Web Start application, select it and click the ‘Add’ button. (Note, the location of Java Web Start application may differ on your system.)
6. Back in the Get Info window, click the button that says change all to apply this change to all of your JNLP files, then close the Get Info window.

When something tries to open a .jnlp file now, it should be properly handled by Java Web Start, launching the corresponding application.

Thanks to one of our twitter followers, @doug_ellison, for pointing out that many of you are having this problem!

Please note, we offer this for informative purposes, and you should make changes at your own discretion.

Our masterful web master creates these wallpapers for each of our weekly captioned releases (these are the images we release each week with some commentary written by the science team). He picks out an interesting area from each image and produces custom cutouts in different sizes. We provide these extra files because we think the images are so beautiful, everyone should have them on their desktop. Because they’re all done by hand, though, we unfortunately don’t have the resources to make these special products for every single image. For example, most of the 1,642 images we released in our big December PDS release don’t have wallpapers. However, you can make your own, and here’s how!

I make my own wallpapers all the time, so I can see the images that I planned. You can make your own, too – it’s really easy. They’re basically just screenshots, zoomed in on a part of the image at high resolution. If you’ve never done that before, here are instructions for one way to do it.

Let’s say you’re enamored with this image of Phlegra Montes (PSP_009308_2295), which was part of our PDS release, but it doesn’t have any wallpapers. There are a few ways to do this. The one we recommend (and the one I personally use) is the IAS Viewer. We’ve talked about this tool quite a few times on this blog, but here’s a short step-by-step in case you’re new to this tool:

1. On the image page, click on JP2 QUICKLOOK (IAS Viewer), and a menu will drop down showing the available products.
2. Click on the product you want.
   • Personally, I like color, but that’s only in the middle of the observation. If you want to see the entire field of view, get the grayscale, which includes all of our red-filter CCDs. Map-projected products will have the image oriented so that North is up – I prefer this because then the shadows appear to my eyes to be in the “right” direction. In this example, I chose IRB color (map projected)
3. You’ll get a popup window asking you to verify the certificate – click Trust.
4. The IAS Viewer will open. Make this as big as you can fit on your screen. Make the image that opened as big as you can fit, too.
5. Zoom (magnifying glass with plus) and pan (scroll bars, hand tool, or Overview map at top left) until you like the view. Don’t forget to re-stretch!
   • The resolution is shown in the bottom of the viewer – 1×8 means it’s eight times reduced, 2x means it’s zoomed in to twice the full resolution, etc.
   • Make sure you zoom in to full-resolution (1×1) at least once, because it’s awesome!



6. Save the view to a JPG file (disk button). It might look something like the one to the right.
7. (optional) Open the JPG file in another application, such as Photoshop or GraphicConverter to do additional stretching or processing. For example, you might want to tweak the color or contrast to your particular taste.
8. Use that file as your wallpaper or screensaver, or both!

Caution: Doing this may lead you to spend WAY too much time looking at beautiful HiRISE images and making wallpaper! You’ll find that you can make many, many unique full-resolution wallpapers out of a single HiRISE image!

Thanks to the webmaster for help in writing this, as well as for all the outstanding wallpapers he’s already produced!

One important feature enhancement is that the auto-stretch preference is now “sticky.” You can disable auto-stretch once and for all, as indicated in the screenshots below.

With this change, you can load our images and see them in the original stretch, while still having the ability to re-stretch within higher-resolution areas.

We use the IAS Viewer ourselves in most cases. A prerequisite is having Java installed already on your computer; I’m pretty sure that both Microsoft Vista and Apple’s OS X do that by default, and most older versions of those operating systems do too. You can check by going to java.com and clicking on the “Do I Have Java?” link.

I have tested the IAS Viewer on a 2001-era computer (an iMac DV) with a low-speed wireless connection. Surprisingly, it worked about as good as on our work machines (dual or quad-core Macs with gigs of memory and ultra-fast Ethernet connections to nearby servers). With much older PC’s or via dial-up it may not be usable, I expect. But the bottom line is, you do not need to have the latest and greatest in computing technology to fill your screen with a steady source of high-res HiRISE pixels.

Early in the mission, our partners at NASA Ames put together a site using a Flash applet called Zoomify. They still maintain this site; however, it takes time and effort for them to keep up with our releases. Zoomify uses “tile pyramids”, or multiple copies of image data at each zoom resolution. So not only must the data be transferred, it must then be rendered into many tiles, occupying slightly more space than the original data. For that reason, they convert to JPEG, which eliminates some of the highest resolution information. Still, it may be faster because the lower resolutions are pre-rendered and the highest resolution has been decreased. Flash, like the IAS Viewer, is supported on Windows, Mac, and (x86 flavors of) Linux.

Because it is closed-source software, we can’t make improvements to the IAS Viewer. Or, if we did, we could not redistribute them under the terms of our license agreement. But here are some features I would like to see it have someday:

• Press page-up (etc) for navigating one screenful at a time
• The ability to open a URL to a particular region at a particular resolution
• The ability to copy the URL for the view you are looking at
• Voice interface (like the zoom scene in Blade Runner)!

The middle two items would, I think, eliminate the need to email multi-megabyte screenshots around for the purposes of scientific discussion.

DRA performs what image processing folks call a “stretch.” A stretch takes some range of pixel values from the file and maps it onto a new range for the screen. To take an example, consider an image that appears over-exposed: much of the information is in the upper range of pixel values and you will have trouble distinquishing any detail. If the over-exposed pixels are not completely saturated (i.e. they don’t all have the maximum value) then a stretch that reduces brightness can reveal this otherwise hidden detail.

HiRISE has a very high signal-to-noise ratio, and our targeting specialists do a very good job choosing camera settings (which they do individually for each and every image) so completely saturated pixels are very rare.

But this also means that a stretch that works well over the entire image (a global stretch) may not be the best, the optimal stretch, for any one sub-image area that you are viewing. This is where the Auto DRA function in IAS becomes critical.

The button (shown below) is located on the right-hand side of the toolbar. A single click will do a stretch based only on the pixels you are viewing. This can bring out detail in shadow–amazingly, there is enough ambient light scattering around in the thin atmosphere to illuminate those scenes (and HiRISE is sensitive enough to pick enough of it up). It can also bring out detail in bright areas of over-exposure. For the color images in particular this can make things look a whole lot better.

Another factor plays a part in this. By default, the IAS viewer performs a global DRA when the image is loaded. As seen in the screenshot below, there are areas in our image that can skew the stretch. The large red rectangle is an area where the red CCDs start imaging before the blue-green. The IRB images often will have a cyan region where one of the IR CCDs was too noisy. We have elected to keep these areas in our images.

When in a sub-area, hit the Auto DRA button and the image should be drastically improved, as you can see in this final screenshot.

DRA early and often!