1997 Oct 18

It was a nice quiet night. Michelle Stone and I arrived about 5pm. Robin Casady arrived just after sunset and Jay Freeman showed up a while later.

We set up in Coulter Row for a change. I like it there because the wind isn't so bad. But there was no wind anyway. In fact, it was quite warm all night -- Mark Taylor would have been wearing shorts and a T-shirt :-) With only the four of us there was plenty of room even though Michelle had two scopes (Pronto, Obsession). I had two scopes, too: Pronto piggybacked on my Meade LX200. Robin had his nice little 6" Intes Mak. Jay made us promise not to say what he brought; but it was interesting and he promised a full report.

The fog came in below (so much so that Robin feared that it would be a white-out as he was driving up) but as usual it was only "pretty dark", especially to the west and southwest. Michelle was complaining that it was too bad the Moon would come up at 9pm and spoil it all, but with my new binoviewer, I was looking forward to it! If the Moon is going to blow away the deep sky stuff 1/2 the time, why not look at it? After all there is more detail visible on the Moon with any of our scopes than there is on any other object in the Universe with HST!

The first event for the evening was a transit of Io. Just after it entered It was very prominent for a while. I attribute the ease of seeing it to the fact that it was against the dark limb of Jupiter at that point. It became invisible later. I *think* I may have also seen it when it was just past the meridian (just past the GRS). Later we saw a nice shadow transit.

We had a few visitors, too. One young woman was doing her best to imitate Sandra's enthusiasm with great "ooh"s and "ahhh"s on all the goodies we quickly pointed out with Michelle's big Dob. Too bad we didn't see any shooters, then her mettle would have really been tested! :-) Later on a couple other folks showed up looking for the TAC star party they had read about on the Web. I guess we were it :-) I think they had a good time but I think they were a little disappointed that there were only 4 scopes. I couldn't help recalling the big thread we had here about the SJAA's star parties :-( Oh well, at least there was someone there and they did find us.

At 2:23 PM -0700 10/19/97, Robin Casady wrote:

... We watched the Aldebaran occultation. As the occultaion approached I had the GM8 on Lunar rate and Aldebaran seemed to be approaching the Moon. I switched to siderial and watched the Moon swallow Aldebaran. A fun sight. I just missed its reappearance by microseconds. I was slewing up the limb and asked Bill if he knew where it would emerge. He said "There" (when it appeared) just as I slewed into it.

I watched an Aldebaran occulatation earlier this year with my Pronto. As I recall we had a discussion afterwards about how long it takes for the star to disappear. I seem to recall someone calculated it should take 25 milliseconds. So this time I was primed to think about that issue. It was a little strange. My scope was showing several "diffraction rings" (refractor types would say "ugly spikey crud" :) around Aldebaran giving it an apparent diameter of several arcseconds. As it approached the Moon, the "rings" were gobbled up on one side for about one second before the actual disappearance. But the rings on the other side were not diminshed in brightness. Then BAM! it was gone in no perceptable time. It might have taken 25ms but I don't think I could measure that without some more equipment.

I was a little late getting ready to watch the reappearance. And I wasn't quite sure where it would be. So I was using my Pronto at only about 40x to give myself a very wide field. Just as I was settling in to wait for it to appear I blinked and when I opened my eye again there it was. It appeared literally in the blink of an eye.

But the bottom line is that these things are FUN! Who would have thought such a simple thing would be so cool?! I'm going to have to make an effort to watch more occultations.

With the help of Starry Night, I tracked down seven of Saturn's moons. I missed the eighth "easy" one, Mimas, which is always hugging the bright rings. It was well placed earlier but I didn't get around to looking for it until 10:30 by which time it was to close to see again.

Bill and I played with eyepieces in the binoviewers. We tried a 15mm Panoptic against a 16mm Zeiss Abbe Ortho.

We had one in each half of the binoviewer as I had suggested earlier this week. It works pretty well, actually. The only difficulty is getting both eyepieces focused simultaneously but that turns out to be not too hard (at least in the cases we tried) by simply sliding one of them up slightly in the holder. The great advantage is that you can switch from on to the other in just a second making repeated detailed comparisons much easier. Of course, all the extra glass may be causing some problems....

In his LX200 we could see no difference in discernible detail. I had tried this same comparison at home in either the Takahashi or Intes (can't remember) and there was a distinct difference in the amount of detail I could see on both the Moon and Jupiter. Interesting that this didn't show up in the LX200. Bill suggested that if it had been the Tak, he could understand that the quality difference in the scopes would account for the different results.

The Panoptic had a significantly wider view and the image was bluish. The image through the Zeiss was greenish. Since we all know that the Moon is made of green cheese, I conclude that the Zeiss has the truer color. :-) The contrast was very similar in both, but they were looking through all of the glass in the binoviewer.

Both Robin and I couldn't see much difference in contrast or detail between the two. Michelle concluded that the Panoptic was her favorite because of the wider FOV. I tend to agree, but as far as I'm concerned the jury is still out. I want to try this again when some of our planetary/lunar experts are around and we have better seeing. Perhaps we just didn't have the proper conditions for the Zeiss Abbe Orthos to show their stuff.

Robin and I also compared his AP Maxbright diagonal to my Lumicon mirror diagonal with my LX200. No differences seen thru the eyepiece but the AP diagonal sure looks nicer on the outside :-)

Ah, but the AP/Zeiss/Baader binoviewer! What a wonderful device. How could I have gone so long without one. It has literally opened my eyes to a whole new way of seeing. Try reading the rest of this paragraph with one eye shut and you'll see what i mean. Eyepatches, hoods, careful training to ignore the "other" eye, etc are all fine but they're techniques for ameliorating a bad situation. A binoviewer goes to the heart of the matter. And succeeds.

My first target was Jupiter. At first I had my usual difficulty fusing the images. But strangely after a little while it became trivially easy. I think there is a training effect here. The seeing wasn't great but even so there was more detail visible in the SEB than I can ever remember seeing. It is just SO MUCH easier with both eyes. We watched the GRS transit. I could even see the large white ovals east to the GRS. Though I couldn't really see them as separate entities, it was easy to tell that there was some sort of non-uniformity to them. Not much else was to be seen on Jupiter this particular night.

So I switched to some of the easy deep sky objects before the Moon came up. They were a little disappointing, actually. The image with the binoviewer is MUCH dimmer than with the usual setup. On the planets and the Moon there is plenty of light to throw away but even on the really bright things like M13, it really matters. You still get the relaxed, psuedo-3D effect but seeing details becomes more difficult. Of course, this was not unexpected. (It didn't help any, either, that I was going back and forth between my 12" with the binoviewer and Michelle's 18" which is so much brighter to begin with.) My preliminary conclusion is that the binoviewer is pretty much a solar system viewer. But I'm looking forward to trying it on a really dark night.

I won't repeat my ravings about Luna in the binoviewer. You simply have to see for yourself. Suffice it to say that I now have something to see EVERY night of the month and that my copy of Rukl's is going to get a lot of use :-)

But all is not quite yet for the best in this best of all possible worlds. Robin reported earlier that he saw a considerable amount of scattered light near the lunar limb with his binoviewer. I can now verify that. In fact, it is a very bright and very obnixious flare, so much so that it even obscures some detail on the lunar disk itself. The problem apparently arises due to a shiny metal part in the binoviewer's diagonal. Robin has installed, at Roland Christen's (President of Astro-Physics) direction, an additional aperture stop in the diagonal that pretty much fixes the problem. We switched back and forth various combinations of our equipment to verify this. (We didn't think, however, to try the binoviewer with an ordinary diagonal. I don't see why that wouldn't work. I'll try it tonight and see.) I'm also looking forward to seeing Rich's unit again to see if it has the same problem.

I am quite annoyed at Astro-Physics over this. They should know better. I think I'll write to Roland and see what he is willing to do to rectify the situation. I suppose I could do what Robin did, but I really don't like the idea of disassembing such an expensive piece of equipment. I like even less having paid over a kilobuck for something that turns out to be flawed in such a silly way that it can be fixed with two little pieces of black paper.

Bill Arnett; last updated: 1997 Oct 19