Suppose you have a photograph of a small part of the sky, and you want to see it in WWT and share it with friends. Here’s how you can do so.

We assume that the image (and, if you wish, a thumbnail) is already internet-accessible.

All you need to do is use the url below, with a few parameters. This is from information provided by Jonathan Fay, the architect/developer of WWT.

Base URL:

http://www.worldwidetelescope.org/wwtweb/ShowImage.aspx?

URL Parameters:

You require the following parameters. All strings are URL encoded – spaces replaced by %20 or +, etc.

name = {string: URL encoded, user friendly, but relatively unique name }
ra = {double: right ascension of image center (or tangent point) from plate solution}
x = {double: pixel position corresponding to the ra above}
dec = {double: declination of the image center {or tangent point) from plate solution}
y = {double: pixel position corresponding to the dec above}
scale = {double: arc seconds per pixel from plate solution}
rotation = {double: rotation east of north}
imageurl = {string: URL encoded link to original image at the scale and size of the image described in the rest of the URL}

While the following parameters are optional:

thumb = {string: URL encoded href to thumbnail image (Should be 96x45)
credits = {string: Text for credits }
creditsUrl = {string: URL encoded link to credit information or image page }
reverseparity = {Bool: True or False (default to false) for image flip } .

PS: reverseparity=true is implemented in a not-yet-released version of WWT. So if you have a flipped image, flip it first for now.

When you are testing, the following parameters could be useful:

goto = {Bool: True or False (default to false) True: Slew and Zoom on Image only, False: Show Image Thumbnail in Open Collections, user must click thumbnail to Slew and Zoom and can save image to collections}
debug = { Bool: True or False (default to false) shows the WTML instead of launching it }

For an example of something really cool that you can do with this, have a gander at Christopher Stumm’s post on the astrometry flickr group. Any image uploaded to that group gets solved by the astrometry.net solver. Chris added a feature whereby the format above is used to display these solved images in WWT. So members of that group can see their images in WWT (and use them in tours) right now. Nifty, eh?

Let’s use this from scratch, say with today’s APOD image of the Horsehead Nebula.

The results of sending this through astrometry.net to get a solved image are here.  The key part of the page is this, as well as the knowledge that the original image was 900 x 600 pixels.

And if you click on the url below, you’ll get to the image on WWT.

This method works for small and medium sized images. For large images – over 2048 x 2048 pixels, say -  you will want to tile that and use a WTML file for it.

There are other interesting things you can do with this. The image you place doesn’t have to be a picture of the sky. For instance, here’s a constellation image – the crown for the Corona Borealis - from the Hevelius collection digitized and put online by the U.S. Naval Observatory and the Space Telescope Science Institute. With some adjustment (making the non-transparent areas white instead of black), this can be placed online and viewed in WWT by clicking on the link below.

http://www.worldwidetelescope.org/wwtweb/ShowImage.aspx?name=Crown
&ra=236&dec=28.894&x=250&y=217&scale=60&rotation=180
&imageurl=http://research.microsoft.com/~dinos/wwtimages/coronawhitesmaller.png
&thumb=http://research.microsoft.com/~dinos/wwtimages/coronatn.jpg

The result looks like this (with crossfade)

Its placement could be improved… but since this is a demo, we’ll leave that as an exercise for the reader.

Did we mention that one can use these in tours?