WWT Tips and Tricks

apparent retrograde motion 'video game' visualization

Rob Fatland — Fri, 05 Dec 2008 20:44:04 GMT

Just to share another small discovery: From the education game plan in astronomy it is a standard bullet to say "'planet' means 'wanderer' cause the planets wander around the sky" and this often leads to remarks about apparent retrograde motion. That is, apparently changing direction and then changing back messes with the notion of orbit so it is nice to see what is wrapped up in the appearance.

What I did

I focused on earth in solar system mode and set the planet size to "Large" so I could easily see Mars. I sat back to about two moon orbits from earth with the sun at my back. I also cranked the time rate under View to x1000000 so it takes about 31 seconds for an earth year. The video game aspect (after hitting play and waiting for mars to enter the fov) is to just ride the view controls (arrow keys) to keep mars in sight. Sure enough once per year you get some retrograde against the background stars, a more direct experience than looking at the ecliptic from above and inferring apparent retrograde, the usual way I've seen it done. This also works well with Venus although Mercury is a little tougher because of the necessary inflation of the sun putting Mercury on the solar disc for much of its orbit.

Since orbit lines tend to guide the eye they can be a bit distracting; I played around with them both on and off and it's probably a matter of taste.

backing into antipodes, solar system mode

Rob Fatland — Wed, 03 Dec 2008 00:21:07 GMT

Hey there; new to the forum, howdy howdy howdy.

I'm wondering if there is an easier way to do this, although it's fun as-is:

In solar system mode I see the stars beyond and would like to go poke around 'out there' but I can only back away from Sol. I found the Lng/Lat coordinates at lower right very useful since I can

(a) line up the solar system on where I'd like to go (say the Pleiades) like a gunsight

(b) calculate the antipodal coordinates, navigate to them

A couple more checks:

Is Aldeberan really not part of the Hyades? Aw, see now that's sweet! (I thought it was further out but I was wrong.)

What does Praesepe look like? No luck here, too bad, must be too far out to make the db.

Backing out through Orion it also occurs to me that there should be a point where the constellation appears mirror reversed, more or less, from our view albeit with changes in relative brightness in constituent stars. That kinda works but you lose the effect as stuff fades back into the galactic disk.

All in all very nice, even if there's no way of flipping perspective to do it the easy way... reminds me of “I wonder if I shall fall right through the earth! How funny it'll seem to come out among the people that walk with their heads downward! The Antipathies, I think”

Faster loading of images

Xplorer — Sun, 10 Aug 2008 11:14:16 GMT

A cool viewing trick for slower computers.

When images have been stored in the cache they can be quickly accessed for faster viewing at a later time or when off-line.

Assuming that the image file has not been purged (deleted), go to a location that you have already viewed before, zoom all the way into the picture and press Manage Data Cache (MDC) under the settings tab. On pressing MDC it displays image file size which is stored on the computer, but the additional good thing that also happens is that it quickly pulls up the images for what you were viewing. If you do not have minimum requirements for this brilliant application WWT then this tip is ideal for you.

Happy faster viewing

an easy way to fill your cache

Ethan Zoller — Sun, 11 May 2008 04:34:17 GMT

Here's a handy trick, especially for computers with lower-speed connections: Open a collection (Hubble, Spitzer, etc.) and then play it as a slide show (Explore.Play collection as slide show).

This will fill your cache with the images for each of those items, and give you the surrounding stellar background as well. Subsequent visits to any of those objects will be much faster.

You can do a similar thing with tours with Guided Tours.Auto Repeat.

Enjoy!

How to setup a central cache store on LAN

Gaross — Fri, 16 May 2008 07:15:46 GMT

Hi! This is an awesome program!

I manage a school's network and was wondering if it was possible to setup a central cache on a fileserver so each computer in the school doesn't have to use up more bandwidth then it needs to. It also means that the cache will grow quite quickly as more and more people using it, plus each new person gets a better and better experience as the central cache grows.

If anything is not already in cache, the client computer downloads the data but then deposits it in the central cache.

I've got a spare 750Gb sitting here ready to fill with data! I just need to know if it's possible and how to set it up.

Cheers, Damon

sharing what you've found

Ethan Zoller — Sun, 11 May 2008 05:33:51 GMT

When you find something espcially beautiful in the sky and you want to share it with somebody else, you can right-click on its image in the context bar and choose Copy Shortcut. You can also do the same thing from the Finder (Explore.Show Finder) from the Research button. then you can paste it into an email, a blog post, or pretty much anything else.

For example, check out the almost-creepy filaments of the Crab Nebula, the galactic pair M81 and M82 (visible with a pair of binoculars!), or the rich set of images for the also binocular-baggable Lagoon Nebula.

Viewing your own panoramas in WWT

dinos — Sun, 18 May 2008 11:15:52 GMT

Among the not-exactly-documented features of WWT is the ability to load your own images to view as panoramas.

For an example, consider the Summit Panorama from the NASA/JPL Mars Exploration Rover Spirit.

Click on the image (or right click and 'Save Target As') to get a 4096 x 2048 jpeg (600k), or click here for a 8192 x 4096 version (2Mb).

Now, using the "Look At" menu in the bottom left of WWT, choose Panoramas->Browse

This pops up a dialog box where you can enter the file you want to upload. Try the 4096 x 2048 version before you try the 8192 x 4096 version. (And yes, you can also load image formats other than jpeg.)

This should, after a few seconds, display the image in the WWT display window. There will be distortion at the 'poles' since we are using equirectangular projection instead of WWT's usual TOAST projection.

This post also applies to equirectangular all-sky maps in equirectangular format.

best perf on laptops

Ethan Zoller — Mon, 12 May 2008 22:42:49 GMT

If you find that WWT doesn't run as fast as you'd expect on your laptop, you may be artificially capped on processor power. if you're on Vista, try running the "High Performance" power plan -- you can just click on the battery icon in your system tray to have a look. (sorry, I don't remember the language on XP.)

I usually run my laptop in Power Saver mode, because my laptop (a Toshiba R400) is happy running Vista's Aero theme and a whole gaggle of other concurrent apps, even at those reduced CPU speeds. But WWT's animations for zoom and pan require a fair bit of headroom.

if this helps you, you may want to change the Processor Power Management setting (in advanced power settings) to run faster when your system requires it.