Gravitation Lense
With the top left menu you can select from a list of images. With the mouse you can position a gravitation lense in form of a black hole. With the sliding widgets you can additionally adjust various parameters:
- mass of the black hole (in sun masses ("Sonnenmassen"))
- distance ds (in Mpc) of the object image
- distance dl of the black hole in percent of the object distance
- scale of the object image (width ("Breite") and height ("Höhe") in arc seconds)
If you change one or more parameters without changing the position of the black hole, you have to click on re-calculate ("Neu berechnen"). For speeding up the calculation it is recommended to use a web browser that supports at least Java 1.3.
Project "Computer Applications in Astronomy"
The project "Computer Applications in Astronomy" took place in Winter Semester
2000/2001 at Hamburg Observatory. The
instructor was Thomas Berghöfer; it was a first-time project that was
initiated by the observatory.
Our goal was to simulate the effect of a gravitational lense. Taken an arbitrary night sky
photograph as a basis, the lense should be placed between the stars and the observer so
that the observed image is manipulated. As a programming language Java should be taken,
and the program should be run from any web browser as a Java applet. We used
VisualAge as a software development
environment.
The result is the Gravitation Lense Applet "GRALE" (GRAvitationLEnser),
which you also find on the
GRALE site
in the Astrolab of
Hamburg Observatory. The source code
is also available. The class diagram
is also provided.