Astronomical Games: January 2000

The Bradley Firstar

GOTO—with a twist

Computers are useless—they can only give you answers.

—Pablo Picasso

IT WAS the dark of the moon, early in October I think. It was still light out, so I left Opus, my 5-inch SCT, out to cool down and settled down with the latest issue of Sky and Telescope. They had just begun to run the Celestron Nexstar ads, and it gave me a funny sense of pride to think what the C5+ had engendered (though of course I had nothing at all to do with the development of any of this!).

The whole GOTO debate rekindled itself in my head at that moment. Is it better for amateurs to have GOTO? Is it better for beginning amateurs to have GOTO? Will it stunt their learning, or will it rather give them a chance to get excited about a hobby in which struggling just to find the objects can be the biggest hurdle? It's difficult to imagine a more polarizing topic in amateur astronomy—at least, not one that doesn't involve brand loyalty.

I've said before, and I'll say it again, that there is no harm in leaving the matter ambiguous. So much energy is wasted by trying to convince others we are right about GOTO. Why? What ill could come out of just leaving the disagreement where it is? I happen to think that GOTO will not be the ruination of the hobby, but it's a moot point—the real answer will come in 10 or more years, I imagine.

I looked at my watch. Still only 4:30. I had time to take a short little nap before beginning a long night of observing. I didn't want sleepiness to cut the program short, although I must admit, I can't remember a night where that ever defeated my eagerness…

I was awakened by an excited murmur, the sounds of people clamoring to look at something new. I opened my eyes. Damn, it was now deep into twilight. How in the world had I managed to sleep that long without anyone coming over to wake me up? And what was everyone making all that noise at? I had no idea.

I walked over. "What's all this?" I asked.

Rich, a long-time member and the one who got me involved in the club, turned around to look at me. "Hi, Brian. How are you?"

"Fine. What's all this?" I repeated, gesturing into the midst of the crowd.

Rich grinned. "I'm fine too, thanks for asking. Mike Bradley's a new member, and he brought out something spiffy. It's some kind of a GOTO telescope."

"The Nexstar 5? I've heard of that."

"No, it's the Firstar." That must have been Mike. "People, please, it's just a prototype, I need a little space, the wires have to breathe." There was a nervous chuckle. "Let me say this once, so you all can hear."

Gradually the murmur quieted down.

"So, this is the Firstar. Yes, it's a play on Celestron's new GOTO scope. I heard about what the new scope does, and I'm sure it's a fine piece of work, but I wanted something that I could use to really teach beginners about astronomy, really hands on. Like a CD-ROM, but actually seeing the stars, you know what I mean?

"What's the major gripe of beginners without GOTO? They can't find anything! The GOTO solves that problem for them, but the long-time amateurs complain that GOTO makes it too easy, and the beginners lose out on a real knowledge of the sky. Besides, if the batteries run out, they're lost if they don't have a spare set in the glove compartment."

There was a general rumble of agreement.

"I thought to myself, why not create a GOTO that teaches you how to star-hop? That way, as you get accustomed to the sky, you learn to use its GOTO less and less. It would be like training wheels for your telescope. With some GOTO scopes already controllable by computer, it was also something that could be done without breaking into the motor controls directly, although I think you'd want to do that eventually, if only for form factor.

"This is the result," Mike said, pointing proudly to his scope. Actually, it seemed like an electronics experiment gone completely haywire. Somewhere, hidden in there, was a 4-inch scope. It was amazing that it could actually see any of the sky. Maybe the equipment served double duty as control and dew cap.

Mike continued: "Like many GOTO scopes, it aligns the scope for you and tracks the stars. I don't have field rotation fixed yet, but my thinking is that this is a beginner's scope in principle, and beginners don't worry about field rotation." Field rotation is a problem for astrophotographers, caused by scopes on mounts that aren't polar aligned, or are imperfectly aligned. Even when a central object is tracked perfectly, the rest of the field rotates around it, because of the scope's constantly changing orientation with respect to the celestial axis. It's a complex problem, but one that happens very slowly throughout the night and only causes headaches for long-exposure photographs.

"I'd show you how to do the alignment, but I thought it might be more impressive to let one of you do it yourself." Instantly a sea of hands went up, mine included. "Err…wow. OK, you with the brown jacket." All the hands went down amidst a collective groan of disappointment. There was an awkward pause before I looked down at what I was wearing and realized he was speaking to me.

"Have a seat." I looked up at Mike, who looked blankly back at me. It occurred to me that the scope was actually talking to me. OK, that's not so crazy; voice chips are pretty sophisticated. "What's your name?"

This time when I looked up at Mike, he pointed helpfully at the microphone. "Brian," I said, carefully enunciating.

"Nice to meet you…Brian." There was a noticeable pause before it repeated my name back at me, and it obviously was using my inflections, played through the filter of its own "voice," but it was still neat. But so far, nothing astronomical. Time to get down to business. "I'm going to polar align myself now. Please stand clear of my wires."

Well, my hair stood on end at that! Needless to say, I backed up my chair respectfully, and watched as it slewed toward the zenith, then began wandering, seemingly randomly. Mike broke in. "Next to the finder is a videocamera that tracks where the scope is pointed. It knows what time it is and where it is from GPS signals, so it can figure out what's in the sky, and what patterns to look for." Holy cow, this could make learning the sky totally unnecessary. But wasn't that what Mike wanted to avoid?

"OK, I'm done." That was the Firstar again. "Let me show you a few sights in the sky tonight. Please stand clear of the front of the scope." Slowly, cautiously, an ordinary pointer began extending out like one of those automatic car stereo antennas. The Firstar slewed slightly, and pointed to the northwest. "That's Cygnus, the Swan, and it's also called the Northern Cross. The brightest star at the top right is called Deneb, and at the opposite end of the cross is Albireo, which is a lovely double star with blue and yellow components, the Michigan colors."

I looked over at Mike. "I'm a Wolverine, what can I say?" he said back, grinning slyly.

"Do you want to take a look at Albireo, Brian?"

"Uh, sure…Yes," I finally said, remembering to say it clearly.

"Take a look through the eyepiece." I found that, amazingly enough, and stuck my eye up to it. What I saw was two blobs, one yellow, one blue, classic bad focus. I resisted the urge to reach up to the focus knob—I wanted to hear what the Firstar would say, and besides, I was deathly afraid I'd adjust the stabilizing gelernter device and blow the whole thing to smithereens.

"It's probably out of focus, but hopefully it's close. Try adjusting the focusing knobs, which are the big knobs on either side of the eyepiece. Turn it in both directions to find the best focus." I was strangely relieved that there was at least one thing we still had to learn how to do for ourselves. The rack-and-pinion focuser was buttery smooth and solid with no play. The Firstar might be some technological nightmare, but it was a well-built nightmare.

Mike cut in again. "The Firstar knows that once you've focused for one astronomical object, you're done focusing—barring thermal and equipment changes, of course. It has a database of objects that I've determined are the easiest for beginners to calibrate the focus on. If the moon's up, it'll use that, but of course we're all up here tonight because the moon isn't."

I nodded and returned to the eyepiece. Albireo is a lovely star and there's an equally lovely story behind its name. It's originally from the Arabic, "Al Minhar al Dajajah," which means "hen's beak." (The other end of Cygnus, Deneb, derives its name from "Al Dhanab al Dajajah," which means "hen's tail.") But this was mistranslated; a Latin scholar mistakenly thought the Arabic meant "from the iris," which in Latin is written ab ireo. Later, since Arabic names so predominantly begin with the "Al-" prefix, an "l" was inserted almost out of habit, resulting in "Albireo." [1]

Lovely as the pair is, however, there's only so much time that you can spend on it. I didn't want to keep the crowd waiting, so I looked at it for about a minute before sitting back from the eyepiece. I was so used to the Firstar anticipating my moves already that I was surprised not to hear it respond.

"The Firstar doesn't want to rush you," Mike explained. "It'll let you observe a single object for as long as you like. So you have to let it know you're done before it'll go on."

"And how do I do that?"

Mike whispered something into my ear, and I smiled. "Thank you," I spoke into the microphone.

"Ready to go on?" the Firstar asked, just to make sure, I assumed.


"Deneb," it said without further ado, "is just one of three bright stars in an arrangement called the Summer Triangle. The other two are Altair, in Aquila the Eagle, over here"—it slewed to a stop with the pointer pointing right at Altair—"and Vega, in Lyra the Lyre, over here"—slew slew—"the brightest of the three.

"Lyra is also the home of one of the sky's best deep sky objects, the Ring Nebula, also known as M57. It's a planetary nebula, which happens when a sun-like star dies and blows off its outer layers in a puff of smoke.

"Here's how to find it. Off of Vega is a parallelogram of stars—a kind of elongated diamond." The Firstar went through a series of short slews to outline the famous asterism. "There's the end that's nearest to Vega, and the end that's further away. The Ring Nebula is just about halfway in between the two further stars. Now look through the eyepiece."

I did so. The wide field granted by the low-power eyepiece allowed me to see both beta and gamma Lyrae, just barely, in the same field of view. "Those two bright stars at the top and bottom of the field of view are the two further stars in that parallelogram. M57 is basically in the middle, but it's ever so little closer to the bottom one. It's a fuzzy little circle. I'll center it for you, and see if you can figure out where it is before I'm done." I had to grin at that. I kept my eye at the eyepiece and watched as the Firstar microslewed to center the planetary. Dead on! The GOTO performance of this scope is legendary, I thought to myself.

"If you'd like to see it at higher power, try switching eyepieces. Be sure to check the set screw before and after changing the eyepiece." Mike handed me a higher-power orthoscopic, which had a little band of plastic around the collar. "Don't worry, I made it parfocal with the other," he said. I inserted the shorter ocular and sure enough, I didn't need to refocus. M57 was now a broader smoke ring, set against the darker sky afforded by the higher magnification. It was nothing like what I'd seen in high-quality, large-aperture Newtonians—the Firstar was still just a 4-inch glass—but it was still very impressive and reminded me of the way it looks in my own 5-inch scope.

I had to tear myself away and repeat "Thank you" to the Firstar. At every moment it seemed less silly to be talking to the scope. I let the scope direct me to a number of popular deep-sky objects. According to Mike, the Firstar knows when it's looking below a local horizon, and tells you so when it encounters a problem. Many people were eager to look, so after M57, we all had a gander. It was really neat; the electronics were actually teaching quite a few people how to starhop to new objects!

Mike said, "It's just a prototype, so it's best suited for just one person. I think the programming should be reasonably straightforward to handle a moderate classroom size—say, about 15 or 20 people. Beyond that I think the benefit goes down for the amount of effort I have to put into it."

"That reminds me, Mike, I've been meaning to ask, how much would one of these go for, if you were to sell it?"

"I'm afraid that without much volume, it'll be quite expensive, probably in the high four digits at best. I'm thinking about ways to bring that down, but it's almost inherent in the design. I'm not using cheap optics, either." Indeed he wasn't. We'd all been awed by the intelligent GOTO, but the 4-inch refractor he used was a custom job. He claimed it had tested at about 1/8-wave on an interferometer at 550 nm. Not the best, but pretty close.

"Does it do anything else amazing?" I asked.

Mike laughed. "Depends on what you consider amazing. Here's the latest feature, supernovae." This promised to be interesting; I've not seen many remnants and was half expecting the Firstar to enhance the image electronically. "I haven't made it user-friendly yet, though. Firstar, Mike here." He followed that with a stream of half-intelligible GOTO-speak. The Firstar seemed almost to nod in response, and slewed to an unremarkable patch of sky. I looked up at where the pointer was directed. I couldn't think of anything special in that direction, but then again I don't know the sky as well as many.

"Have a look," Mike said, directing me to the seat.

I did. I adjusted the focus ever so minutely, but all I could see was an array of stars on a dark background. "I don't see anything."

"Just wait!"

"What am I wai—" Without warning, the field of view of the scope grew brighter than daylight. I instintively shut my eyes and backed off from the scope. When the afterimage faded I looked up in the night sky and everyone was oohing and ahhing at an intensely bright new star, the first supernova in the Milky Way in almost four centuries.

"OK, the jig is up, Mike—what the hell is going on here?!"

You've already guessed what the hell was going on, of course. I woke up and it was still bright out—not from any new supernova, unfortunately, but just the sun, our sun. I stood up and stretched. There was no Firstar. No Mike Bradley, no intelligent GOTO teaching beginners how to starhop. Richard had asked me to come out, but he was only looking at me bemusedly as he finished setting up his Ranger. A few yards away a pair of amateurs was huddled around a loudly whirring LX200.

I set about assembling my scope for the night's run, still shaking my head at the vividness of it all. A scope that could GOTO and give you a running commentary. One that could align itself and figure out when it was lost. One that would probably let you take over the reins gradually, as you gained confidence. It wasn't so farfetched—certainly less farfetched than most of my dreams and even some of my real life, you can count on it. You should write it up, I told myself. And maybe, if you point ol' Opus up there, you might see something new…

[1] Does this sound too farfetched? Because it is, sort of. Since I wrote this, I've read that this story, although widely believed, isn't plausible upon closer examination. First of all, the Latin word for iris (not a very common word in Latin) is just iris, and in order to get ireo for "from the iris," the Latin word in question should be ireus, or possibly ireum, but not iris.

Instead, according to the German linguist Paul Kunitzsch, the path to ireus, and then ab ireo, was a bit more involved. As he and Tim Smart write in their Short Guide to Modern Star Names and Their Derivations, Ptolemy called Cygnus Ornis (whence we get our word "ornithology"), which the Arabic translators of Ptolemy's Almagest merely transliterated as urnis. Later, when a Latin scholar came to translate the Arabic Almagest into Latin, he didn't recognize any Greek word akin to urnis, and he transliterated the Arabic form as eirisim.

In an attempt to interpret this unknown form, one later Latin commentator proposed that it was derived from the Latin name of a medieval herb, called ireus. The way he wrote this was "eirisim … ab ireo," meaning that the constellation name was eirisim, from (ab) the herb name ireus (ireo is the proper form of ireus after a proposition like ab, much as in English we would write "from me," rather than "from I").

In one of the Latin manuscripts of the Almagest, this commentary appeared after the Latin name of the constellation, Cygnus. The first star listed after the constellation name, as it happens, is beta Cygni, and it seemed to some observers in Renaissance times that the ab ireo comment applied to that star, rather than the constellation as a whole. Since this name was "evidently" Arabic, and therefore "obviously" missing an 'l' after the 'a', the name "Albireo" was attached to the star.

Copyright (c) 2000 Brian Tung