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Week of 28 May 2001

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Monday, 28 May 2001

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Memorial Day here in the U.S., the day set aside to remember those who sacrificed to keep us free.

I'm going to take part of the day off, although I do want to finish Chapter 12, DVD Drives, and get it off to my editor. I should have that chapter as well as Chapter 13, Hard Disk Interfaces, up on the Subscribers page tomorrow.

Very strange articles in the paper this morning. California can expect to average 20 hours/week of rolling blackouts throughout the summer. President Bush is headed there for a visit. Apparently, many Californians blame him for the problems they've caused themselves. Let's see. They don't have enough electrical power, so they want Bush to cap the wholesale price of electricity, thereby guaranteeing that they have even less electrical power. Duh. I've always said universal suffrage was a huge mistake.

Then there's the article about the Catholic Archbishop getting married. That's odd enough, but what's truly strange is that he was married by Sun Myung Moon to a woman that Moon chose for him. Apparently, even Princes of the Roman Catholic church sometimes join cults. A Moonie Archbishop. The mind boggles.

Barbara made a mistake last night. She's decided not to allow Malcolm to be growly/snarly any more. Every time he gets that way, she plans to get in his face, growling back at him. Duncan was lying in the hall just outside my office, minding his own business. Malcolm went into confrontational mode, and approached Duncan, head down, growling, and fangs showing. Barbara went over to separate them, got down on the floor and started showing her fangs at Malcolm. Just then, Duncan and Malcolm got into a furball, with Barbara in the middle of it. She got chomped in the chest, we're not sure by which dog. Fortunately, it didn't break the skin, but she has a 2" (5 cm) diameter bruise where one of them got her. When I asked Barbara if I could post a picture, she said "I don't think so, Tim." There are more details on Barbara's page (probably more than you want to know...)

At any rate, Barbara dragged Malcolm down the stairs and tossed him into his crate, which is still set up in the basement. We left him there for an hour or so, and he calmed down. As usual, Malcolm came off the loser, having been chomped in the face. Duncan really doesn't like to fight, and will do anything to avoid it, but if a fight erupts, he wins. Malcolm is a very nice dog. He's the most affectionate dog I've ever had. But he and Duncan really don't like each other. We'll persevere until we get past this problem, but it sure would have been better not to have it in the first place.

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Tuesday, 29 May 2001

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Yesterday I finished updating two chapters--Chapter 12, DVD Drives and Chapter 13, Hard Disk Interfaces--and sent them off to my editor. They're available for download on the Subscribers Page now. DVD Drives is a 150 KB Word 2000 document and Hard Disk Interfaces is a 1,937 KB Word 2000 Document. If you care to read and comment on them, I'd love to hear what you have to say. There are links on the subscribers' page that you can click to provide feedback in the Subscribers Only forum on the HardwareGuys.com messageboard. I'm working now on Chapter 14, Hard Disk Drives. That one should be up in the next few days.

If you're not a subscriber and want to become one, click here.

I ordered some telescope eyepieces yesterday. Mars will be at it's closest approach in 13 years this summer, and we wanted a high-power eyepiece or two to use for observing it. Even at its closest approach, Mars is a tiny object, so we want to use as much power as the seeing will allow. In theory, the maximum usable magnification is between 50X and 60X per inch of aperture, which would amount to 500X to 600X with our scope. Anything more than that gives empty magnification--a larger, dimmer image without additional detail. In practice, the telescope itself is seldom the bottleneck. The atmosphere itself seldom allows much more than 300X--perhaps 400X on a very good night--regardless of the size of the scope. And on most nights 200X to 250X is the limit.

Our scope has a 1250 mm focal length. Magnification is determined by dividing the focal length of the scope by the focal length of the eyepiece, so for 250X we need a 5 mm eyepiece. There are two problems with such short focal length eyepieces. First, the true field of view is very narrow, which means when using an undriven scope like our Dobsonian objects drift quickly out of the field of view. Second, most short focal length eyepieces have next to no eye relief, which means you have to mash your eye right down on the eye lens. In addition to being uncomfortable and tending to get eyelashes and oil on the lens, that also means it's very easy to touch the eyepiece, which can bump the object right out of the field of view.

So, what I was looking for was a short focal length eyepiece with a reasonable apparent field of view and decent eye relief. That's no problem at all if one is willing to buy high-end eyepieces like Tele Vue Radians. Those are wonderful eyepieces in nearly every respect. They have a 60 degree apparent field of view. They have 20 mm of eye relief, which is actually more than I prefer. But they cost $228 each, and I wanted more than one focal length. There are similar competing eyepieces from other makers, including the Vixen Lanthanum Wide and the Pentax XL series, but they're all priced similarly.

So I decided to check around some more. I came across a line of eyepieces made by Siebert Optics here in North Carolina. Harry Siebert uses military surplus optics to produce a very inexpensive line of eyepieces that have most of the features I wanted, including low price. The good thing about military surplus lenses is that not only are they cheap but they're of superb quality. The military doesn't screw around when it comes to specifying level of polish, coatings, etc. If you're buying lenses for say a tank sight, you don't risk a tank and crew to save a couple bucks on lenses. Harry also uses relatively simple designs with few lens elements, which contributes to bright, high-contrast images. He sells a lot of his eyepieces on e-Bay, so I checked the buyer evaluations. There were something like 637 total responses from 500+ unique responders. Of those responses, Harry got zero negative evaluations, one neutral evaluation, and all the rest positive evaluations. He also has a 30-day return policy, so the risk of ordering from him is nil. I decided to order the following eyepieces:

  • 4.9 mm ($70)
  • 7.0 mm ($45)
  • 12.5 mm ($40)
  • 21.0 mm ($40) 

All have 7 mm of eye relief and 65 degree apparent field of view, except the 21 mm, which has an 80 degree AFOV. The eye relief is a bit tighter than I'd prefer, but it's usable, and getting longer eye relief requires paying much more for a premium eyepiece. The 4.9 mm provides about 255X natively, or 510X with a 2X Barlow, which is probably a bit much. The 7 mm provides 179X/358X, the 12.5 mm 100X/200X, and the 21 mm 60X/120X. It'll be interesting to see how good the images look. From all accounts, they should be excellent.

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Wednesday, 30 May 2001

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Barbara is gone all day today, off to play golf with her father this morning, then to meet someone half-way between here and Raleigh to pick up a rescue Border Collie, then to Mt. Airy to deliver the BC to its new owners. She did leave some left-over casserole in the refrigerator that I'm supposed to re-heat for dinner. That should be within my culinary skills, just.

More trouble from the teenage punks last night. Barbara had gone back to bed around 10:00. Just after 11:00, as I was sitting reading, I heard a loud crash, as if a picture had fallen off a wall or something. I checked around the house and couldn't find anything. This morning, when Barbara came in with the dogs from First Time Out, she announced that she'd solved the mystery. The punks had tossed a half-full can of beer at our house, which she carried across the street and tossed back into the front yard of one of the punk's houses.

I'm not sure what to do about this problem. I suggested calling the police, but Barbara says they won't be able to do anything. She's probably right. What I'd like to do one evening is amble down to the cul-de-sac where a half dozen or so of them congregate, taking a witness or two along with me. If one of the punks were foolish enough to take a swing at me... A guy is entitled to defend himself, and if that results in six hospitalized punks, oh well.

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Thursday, 31 May 2001

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Thanks to everyone who's suggested using cameras to catch images of the punks in action. I'd actually thought about that, and did a bit of checking. My first thought was to use web cams, but those have two problems. First, the maximum resolution is only 640X480 at best, and I need more than that to make sure I'm capturing enough detail. Second, web cams typically have poor low-light performance. Most of those I looked at, assuming I could find specifications for light sensitivity, require something like 20+ lux, whereas I'd need something that would function in anything from bright daylight down to a fraction of a lux. I may rig up something with a couple of standard analog surveillance cameras with overlapping fields of view, setting them to capture perhaps one frame every five seconds and save it to disk. Or not. Right now, the punks are annoying us, but I'm not sure I want to spend the time needed to deal with them.

Barbara and I are off tomorrow to Doe Run Lodge, a resort up on the Blue Ridge Parkway. We've stayed there two or three times before, but never in one of the cabins, which are usually booked months in advance. Barbara had always wanted to stay in one of the cabins, so she reserved the Log Cabin for us. My brother is coming over from Raleigh to mom/dog sit.

We're taking my Trooper, now known as AstroTruck because it's crammed full of astronomy gear. We'll head up tomorrow and come back late Sunday, so there probably won't be anything up here until next Monday morning. I may have a short post up tomorrow morning, and perhaps a short post Sunday afternoon, but no promises.

I've updated the HardwareGuys.com web site with current picks for Removable Storage and Optical Storage.

More next week.

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Friday, 1 June 2001

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Last night the punks turned over Barbara's yard cart, which was sitting at the curb full of grass clippings and other yard waste. I think when we get back next week we'll call the police and tell them we're being harassed by neighborhood teenagers. Not that there's much they can or will do. Still, it's probably worth getting a complaint on file.

Barbara and I will be packing up this morning for our trip up to Doe Run Lodge on the Blue Ridge Parkway. It looks like the weather will be cloudy and rainy, but that's okay. If we end up stuck in the cabin in the rain with a bunch of books and a log fire, that's okay with us. We'll take the telescope along just in case, but we probably won't have a chance to use it.

We're both looking forward to the Mars opposition, which happens in a couple of weeks. We're going to try to to observe one of Mars' moons. There are two, Deimos and Phobos. They were discovered in 1877 by Asaph Hall. He was using a 26" refractor, which at the time was the largest such instrument in the world. Others had tried before then to locate moons, but had failed. As is usually the case, once something has been discovered, others see it with smaller and smaller instruments. I think the record for the smallest scope that's resolved one of Mars' moons is now 7 inches. So the "easier" moon may, with luck, be just barely visible in our 10 inch scope.

Of the two moons, Phobos is about 26 by 22 kilometers and Deimos only about 15 by 12 kilometers. Although Phobos is much larger and much brighter, it's also much harder to observe. That's because Deimos, smaller and dimmer, is also much farther away from Mars. Mars is so bright--something like magnitude -2.2--that its light swamps that of the tiny moons. Imagine staring at a searchlight from ten miles away, with someone standing two feet from the searchlight holding a lit candle. Resolving Deimos without being swamped by the light from Mars is similar in difficulty to resolving the candle flame without being blinded by the searchlight.

I may build an occulting eyepiece to help. To do that, I'll simply unscrew the barrel from a regular eyepiece and put a thin strip of aluminum foil across the field stop, which'll leave a black bar across the field of view. We can nudge the scope to put Mars behind the black bar, which leaves Deimos visible without the glare of Mars. Of course, we have the advantage of knowing exactly where Deimos is in its orbit, which tells us where to look. Still, it's pretty small and pretty dim.

I'd better get started packing up. Barbara and I went out to dinner and the library yesterday, so I have twenty or so mysteries in my book bag. That should hold me for a couple of days. I'm not taking a computer, though, so there won't be anything up here until late Sunday at the earliest, and probably Monday. My brother is coming over sometime, and we'll be leaving as soon as he gets here.

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Saturday, 2 June 2001

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On vacation.

 

 

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Sunday, 3 June 2001

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On vacation.

 

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