jskycat 3.0 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The program is categorized as Developer Tools. According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. This free Mac app was originally created by Allan Brighton.
From the developer:
jskycat is a desktop app that allows you to use the JSky package. The JSky project aims to build a collection of reusable Java components for use in astronomy. It contains java classes for displaying astronomical images, searching astronomical catalogs and plotting catalog symbols on images.
You may want to check out more software for Mac, such as ChIDE, flex sdk 3 or MahJong Farmers, which might be similar to jskycat.