Thanks, wstrohm, nanoukmetal, Dave_McB, for being so responsive. I've decided to replay the game, tho I'm quite sure I threw the steam pressure switch next to the Gate room.
I found Heimdall's post for the 1.02 patch, but it's for Windows, and I'm on a Mac G5 which I'm using for Riven and, I hope, for the rest of the Myst series (I've played each of them once before) as well as some new games that I can find that are similar to Myst--would love some advice on that possibility! My main computer is a MacBook Pro for work and play.
I couldn't find a 1.01 patch that was accessible, and didn't try to activate the 1.02 Windows patch. I'm hoping that they were incorporated into the single Riven disc.
BUT, the real mystery is, how can the glass "cover" under the hatch be shattered when I haven't been able to lower the telescope? I will try to find some isopropyl alcohol for cleaning the disc, but I don't see how that can clear up the mystery of the already shattered glass.That is truly puzzling.