Subject: Aladin review

OK so I am a Java junkie.  I wanted to see what other people did with Java and catalogs.


The applet started fine and even had a "getting started" text area displayed to get you going.

First you have to load an image.  You click load and get a target resolver that knows several different sources.  I used the Aladin and got a list of POSS plates to display.

I got the image as a JPEG and it still knows the coordinates...pretty cool.

The problem now was that the image covered up the getting started help.   I went to the help button and you get context sensitive help displayed for all the tools...pretty cool.  And clicking faq got me a nice faq in a separate browser window...

So I wanted to display a clicking the Load button does nothing.  Litterally...not cool.  After a while it did bring the window to the front though.  I then selected from the list of Vizier catalogs the 2mass point source catalog.  The sources are marked on the image.  You can then mouse over each one and get its identification.  It tells you to click on it to get more info.  When I did I found my browser window was covering up the information pane, but when you click or drag a box around a set of objects their catalog info is displayed in a table (when you mouse over the number it tells you what that number is...kind of confusing until you get used to it).  Cool.

Each object has a link that will dipslay its full Vizier page of information in another window.  Cool.

So then I wanted to export the catalog entries I have higlighted.  Say all the 2mass point sources in the central 30" of M82.  Only through lots of random clicking did I find that the PAD button is a history of all the things I have displayed or highlighted as sort of a log.  You can clear the log and copy and paste out of it, but there is no way to get just a list of the boxes you have highlighted.  So I read the help on info and figured out that you have to first open the pad, clear the entries, close it, and then highlight what you want marked, then hit pad, highlight all the entries and do a control-c (maybe a copy under CDE???) to copy this to the clipboard, and then you can paste the info into another window (I need to try this on a Sun as Xwindows and Java clipboards don't play well together).

The info in this has no labels as to what the numbers are.  They are in the same order as in the info window, but you have to label them yourself.  An export feature for the info would be a great feature (but this is an applet so...there are problems doing that).

I then added HST pointings as an overlay.  I now had red + for 2mas and blue + for the HST pointings.  To reduce the clutter I turned the display of the 2mass off by clicking on its key in the right hand column.  Clicking on a pointing got me the VIZIER info again...but on the far left hand column was what looked to be the first three characters of each pointings datasetname that was hyperlinked (they ran out of room in the window).  Clicking it gets the information for this dataset in a web page.  You can even get to the preview image from MAST of the data from here (this was a WFP2 pointing)...but no way to request the data from here (cut and paste...)

Question here as an aside...should MAST talk to the Vizier folks about linking to the data request pages form their catalog pages (e.g. a hyperlink from to the request page with the dataset already in the list?).

So then I wanted to put my own image in to do identification...and found in the FAQ that there is a stand alone version of this tool (where you can get around the java applet security).  So I downloaded it and (after fixing the .bat file) ran it.

So I got a WFPC2 image.  It loaded the first extension.  I then tried to do some overlays and got a bunch of null pointer exceptions (no overlays ever loaded).

Overall a cool tool to do catalog browsing and even find HST data.  Unfortunately it looks to currently be best supported on the web as an applet as the application wasn't all that hot.  Also it was clear that the Vizier catalog service looks to be a fairly good source of information and could be a good source for MAST/StarView to link into to get catalog info.  The ability to do layers was a good thing you can blink layers to find sources that overlap in two catalogs.  Import and exporting of data left a lot to be desired, as you cant do it as an applet and it doesnt connect to the external sources as an application.

Overall I give it a 90.  Good beat and easy to dance to.


Niall Gaffney
StarView developer          STScI/ESS           410-516-8771