Roland Roberts's blog

Supermoon? Well, sort of....

I've had several people ask me whether I went out to look at the full moon on March 19. Uhm, no, I didn't. Why not? After all, it made the local (radio) news as "supermoon" since it was going to be closest it has been in nearly 20 years.

Perihelion Day!

Today is the day when Earth makes its closest approach to the Sun, around 2pm EST (New York time). If you live in the northern hemisphere, you might find it surprising that the Earth is closer to the Sun during winter than during summer, but it is. The difference in distance is "small," astronomically speaking, a bit under 5 million kilometers. Our most distant point from the Sun will happen on July 4th.

See also:

This Month in Physics History: Louie de Broglie

Every month I get the APS News (the dead-tree version, which I can carry on the subway), and the two parts I always read first are the Members in the Media (link is to Oct 2010 issue) and This Month in Physics History. Both of these sections help in putting a personal face on physics, and the history column helps set physics discoveries in the context of their historical setting which reads very differently from the typical text book description. This month is about Louis de Broglie.

ZIP Recovery Tools - Not *Exactly* an Endorsement

I was going to make this just a comment on my previous blog entry, but after spending a couple of hours trying various tools and making notes, the "comment" was getting longer than the original post. So it gets it's own entry.

I've kept poking at various tools to try to recover some of my data. It looks like most of it is
recoverable, at least with the right tool. The going price for zip
repair tools appears to be about $30. I haven't
forked over the money yet, as I'm still going over my options. If they
were under $20, I'd probably have already bought one, and if they were
$10-15 I might have bought a couple to try different things. But my
cheapness has paid off in that there is one free solution I've found
that appears to work well.

Windows XP Ate My Images

In order to save space on my Windows XP laptop, which I use for a lot of my imaging, I used the built-in compression to zip up the entire directory tree from the 2009 Summer Star Party. When all was done, the final archive was nearly 4 GB. Nearly, but not quite. To my horror, today, when I tried to unzip the archive to get at some of the files, I got a dreaded

The Compressed (zipped) Folder is invalid or corrupted.

Life in the Fast Lane?

I don't think I'm actually in the fast lane, but it sort of feels like it. The past month has had me away for two weeks, one with the Cub Scouts in Alpine, NJ and another at the Summer Star Party in Savoy, MA. Between that and being in physical therapy three days each week since the shoulder surgery at the end of April, time is passing too quickly and I can't keep up. Fortunately, most of our bills are in autopay mode, so the only bad thing happening is that too much paperwork is piling up and not being recorded and filed.

Modeling the Moon's Phases

I originally built these models a couple of years ago, but didn't realize it was something "novel" until I got some comments at this past year's NEAF where I had brought them for the children's section. Quite frankly, I think it works well with adults, too, as I've heard some well-educated adults propagating common misconceptions about what causes the phases of the moon. The idea is simple enough. One side of the moon is illuminated by the Sun, the other is not.

Performance of AstroTrac TT320X-AG

It's been a busy year. I bought this at NEAF back in April and have only just now been able to get out and give it a spin. The new feature, of course, is the autoguiding. With the original TT320, the specifications state a periodic error limit of 5 arcseconds per 5 minutes. As it works out, when using my Borg 45ED lens, the pixels in my Canon 350D are about 5 arcseconds wide. What I've seen is that I can, with great care, get exposures up to 4 minutes long, but some of them invariably show trailing and have to be thrown out.

Happy June Solstice Day!

For those of you who missed it, yesterday marked the June solstice, the first day of summer. Of course, my children disagree about the "first day of summer" part since they know the first day of summer doesn't really happen until after school is out and here in New York City, the last day of school is June 28.


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