BLACKSBURG, Va.--Netscape, Mosaic, Yahoo!, SIP.
Sky Image Processor (SIP) is "one of the first full-fledged astronomical Java programs" and, like Netscape, Mosaic and Yahoo!, it "has come from the classroom," according to Sky and Telescope, the premiere magazine for amateur astronomers, in its November 1999 issue.
John Simonetti, associate professor of physics at Virginia Tech, created SIP so his students could display, process and analyze astronomical images anywhere they have access to a computer--in a laboratory or even in their dorm rooms. Anyone knowing the web address http://www.phys.vt.edu/~jhs/SIP can access Simonetti's Java "applet" from the Internet.
"Most students have experience running a browser program," Simonetti said.
"They can run SIP in their browser without installing another program." Also, any updates to the SIP program are added to the web page and received by the students automatically when they access the SIP web page.
Simonetti made the program simple because he wanted students in astronomy laboratories or observational astrophysics classes to be able "do the kind of work that real astronomers do" without having to grapple with the complexities of professional astronomical image-processing programs. Since the program is available over the web, students at any institution, not just Virginia Tech, can use it.
SIP has many characteristics that are of help to students. Not only can students combine images, much like laying one picture over another, but they can easily understand how to use SIP to analyze images (for example, when taking statistics within an image). SIP handles digital images. "A digital image is just an array of numbers," Simonetti said. "Any simple arithmetic you can perform with two numbers can be performed with two overlying images in SIP--addition, subtraction, multiplication and division." SIP can even enhance fine details in images using simple image arithmetic. In addition, students can save their work, something many Internet programs do not allow, according to Sky and Telescope.
SIP was created with computer security issues in mind. "SIP can access images from the Internet or from your own hard drive," said Stuart J. Goldman in Sky and Telescope. "To blindly allow a downloadable program access to your hard drive is foolhardy," Goldman wrote. "To ensure its integrity, SIP is a 'signed' applet, meaning that the author has certified it and provided an electronic signature of approval."
For one thing, the Java programming language makes SIP more secure than a random program downloaded from the Internet, Simonetti said. Also, Simonetti's digital signature assures the person accessing the program that it has not been tampered with by someone else because tampering would destroy the signature much as opening an envelope breaks the seal, Simonetti said.
Another form of security assurance occurs when the program asks the users if they would like to read or write an image on their own disk. It will present them with a dialog box alerting them to the action that the program will attempt. The same is true if they want to download an image from a site other than the SIP website. If the user wishes to prevent SIP from performing any of these procedures, it's as simple as clicking on the appropriate choice in the dialog box.
Simonetti received initial funding to develop the program from Virginia Tech's Center for Excellence in Undergraduate Teaching and has continued to expand and improve the program.
Simonetti received his doctorate in Astronomy and Space Sciences from Cornell University in 1985. He was a Jansky Fellow at the National Radio Astronomy Observatory from 1985 to 1987. Since then he has been at Virginia Tech. He teaches Introductory Physics, Introductory Astronomy, Introductory Astrophysics and Observational Astrophysics courses.
During the past few years, Simonetti's research has focused on producing a large-scale digital imaging survey of the H-alpha emission from the interstellar medium of our Galaxy, with results bearing on our understanding of interstellar structures (e.g., superbubbles) and on searches for anisotropy in the cosmic microwave background radiation.
Materials provided by Virginia Tech. Note: Content may be edited for style and length.
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