Download of Specview 2.17.6 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The following version: 2.1 is the most frequently downloaded one by the program users. The application is included in Developer Tools.
This free software for Mac OS X is a product of Space Telescope Science Institute. The default filename for the application's installer is spv_macos_2_17_6.dmg. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
Specview is a Java interactive 1-D spectral visualization and analysis application. The program is reading all spectral formats generated by the Hubble Space Telescope (HST) instruments in FITS format. Specview can save its state to files, thus complex plots can be built and saved to file for posterior recovery.
You may want to check out more Mac applications, such as JBuddy Bot Builder, HexDecBin or Objective Basic, which might be similar to Specview.