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Instrument-specific FAQ (VIRCAM) (Phase 2) - Knowledgebase / How to prepare your observations (Phase 2) / Instrument-specific FAQs (Phase 2) - ESO Operations Helpdesk

Instrument-specific FAQ (VIRCAM) (Phase 2)

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Frequently Asked Questions related to VIRCAM

  • I downloaded and installed SADT, but when I start it, I get a java error message. What should I do?

Answer: If the error message has the content shown below, then probably you do not have the correct java version installed on your computer. Please check using "java -version" command on your terminal that you have java version 1.6 or later.

Error message looks like this:

Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad versionnumber in .class file

at java.lang.ClassLoader.defineClass1(Native Method)

at java.lang.ClassLoader.defineClass(





at Method)


at java.lang.ClassLoader.loadClass(

at sun.misc.Launcher$AppClassLoader.loadClass(

at java.lang.ClassLoader.loadClass(

at java.lang.ClassLoader.loadClassInternal(

  • When I try to save the survey area created with the SADT I get an exception error message indicating that the problem is that the numbers are written with a decimal "," instead of ".". I run Mac in French but with numerical option.

Answer: Open System Preferences and then change Language to English. Switching to number format in the "Formats" tab from "," to "." unfortunately does not solve the issue. You'll have to re-start the SADT for the change to take effect.