I've been using Backup on my Mac to back up my home folder. It has been putting these backups on my hard drive. Now I want to put all my backups on my Seagate external drive. Can I safely delete the backups that are on my hard drive since they're taking up 80 GB of space?

Plug the seagate in and it will ask you if you want to use the drive for time machine. Say yes, wait until it does a backup then delete the backups on your hard drive.

When you move the backups, make sure that you can see all the files (there are hidden files in OS X). I think that some of those hidden files are related to time machine.

Here’s a how-to article re: moving your Time Machine disk.

Yea, my suggestion doesn’t move the backups. It just replaces them over time.

I actually used the Backup program for the ones that are currently on my HD. I’m using Time Machine for the first time to do the backup to the Seagate. So I’m not moving any backup files, I’m switching methods of backing up.

As suggested, make sure you do a complete backup before deleting existing archives. Double check the new backups to make sure you’ve got every thing you wanted to backup.

Note the difference between the above Time Machine suggestions and using the Apple Backup program. Time Machine will backup everything by default, and its archives will keep expanding to fill your external drive over time. You can tell Time Machine not to backup certain folders in Preferences. I exclude my System and Applications folders, since I can reinstall those from disks. Time Machine is great to go back and get previous versions of files that you may have discarded or altered.

Backup will perform manual or scheduled backups of specified folders to a variety of media, including your internal drive, CD/DVD, or to the MobileMe cloud. Good move changing from backing up to your internal drive. If (I should say when) that fails, you’d be screwed.

I use a combination of Time Machine for frequent, file-level archives and Retrospect for complete daily backups.

Note that Time Machine will give you bootable backups that you can use to restore your internal, if you don’t exclude System files.