I would highly suggest NOT using Joel Delta software as I have found it glitchy and difficult to use.
In order to download the Delta software you must first open an account on the Joel Delta page. You will need the following information to do so:
Spectrometer Info:
Brand: Joel
Type: Eclipse
Field: 400
Workstation: Intel PC
Operating System: Windows
Version: 764 bit
Once you have requested an account they will email you if/when your request is approved. You can then sign in to your account and download a version of Delta. I downloaded version 4.3.3; however, you should be able to download any subset of version 4 or 5.