research question

[swan_tower]

This may possibly take the cake for Most Arcane Research Question I've Ever Asked Because Of Writing.

Is anybody out there familiar enough with Terrestrial Dynamic Time to tell me what if any conversions I need to make for a timestamp from 1547? As in, was 12:54 TD roughly noonish back then? The Wikipedia article on Terrestrial Time leaves me entirely unclear as to how closely that timestamp matches normal person time.


Edited to add: astroaztec has been kind enough to verify my math for me. It turns out the difference is truly negligible, so I needn't worry.

Comments

[sapphohestia.livejournal.com]

Ask a librarian!!!
http://www.libraries.iub.edu/index.php?pageId=43

You can even chat with them in real time. :)

[swan-tower.livejournal.com]

I'm sorry to tell you this, but the response I got from the chat line boiled down to "gee, um, we don't know, this isn't really the kind of thing we do."

To be fair, they offered to take my e-mail address and get back to me later, after they'd done some searching -- but I was a little disappointed.

[sapphohestia.livejournal.com]

Boo on them! Bad librarians!

[novalis.livejournal.com]

I guess you probably have some sort of astronomical event at some time TDT, and you want to know if TDT (a modified UTC) matched earth-rotation time in 1547. I found a page saying that the difference over 600 years between UTC and T1 (pure atomic time) is about a half hour, and would have been less in the past than for the future. So, in other words, yes, if you belive that page.

[swan-tower.livejournal.com]

What I was able to dig up on the NASA page seems to indicate that the difference between TDT and UTC back then was in the vicinity of a hundred and sixty seconds. Which I think jibes with what you found.

I don't need precision, either; I just need to know whether it's morning or afternoon or what.

[astroaztec.livejournal.com]

there is no TDT now (it's TT), and there was no TT then, so the question deserves serious refinement prior to receiving an answer.
write me and I'll discuss it off lj.

[astroaztec.livejournal.com]

Are you aware, by the way, of Duncan Steele's theory that Elizabeth was part of a conspiracy to establish a colony in Virginia with the intention of wrestling control of the calendar back away from the Pope and into the hands of England? He details this in Marking Time (http://www.amazon.com/Marking-Time-Invent-Perfect-Calendar/dp/0471404217).

[swan-tower.livejournal.com]

Interesting! (That page is also a great example of when Amazon reviews can be useful; I appreciated the commentary from the guy who pointed out factual errors. Much like with the Dee book I recently read skimmed, it's good to know when to be wary of somebody's work. It sounds like there's a lot of great stuff in the book, but also some flaws.)

(And, as so often happens with me, my parenthetical aside has ended up being the longest part of the comment. It happens.)