Moore's Law for Telescopes

Moore's law for computers says that every 18 months, the number of parts on a computer chip doubles. And this has been going on for a long time. Keep in mind that it doesn't take many doubles before something very small is very large. If you put a penny on one square of a chess board, 2 on the next square, the last square in the row has 128 pennies, and the row has $2.55 in total. It takes $184,467,440,737,095,516.15 to fill the whole chess board.

A couple years ago, i computed the Moore's Law for telescopes. For end points, i used the 1609 1.5 cm Galileo telescope, and the 1992 10 meter Keck telescope (first light with all the segments). Telescopes increased in diameter by a factor of 666x and doubled in size only about 8.58 times over 383 years, giving a telescope diameter doubling period of about 44.6 years. Has the pace increased lately?

Of course, diameter gives resolving power, whereas area gives light collecting. And interferometry should be taken into account for resolving power. The Kecks have 100 meter separation, and the light collecting area of a 14 meter scope. Interferometry started there in 2001, giving a very quick jump for 'diameter'. Size matters, but what size matters to you?

I can hardly wait for space based interferometers at optic wavelengths. In space, you can pretty much always take a longer exposure. And, you could have kilometers or megameters of separation. With radio, VLBI has achieved something like 10-15 microarcseconds resolving power, and with patience determined proper motion for M33. What could you do with a 2 AU optical interferometer? Parallax for any star in the Milky Way? Parallax to M31?

Mars, Bigger than the Moon

It's that time of year again. It's August 27th. And the email from 2003 has been modified and recycled again. Each time, it gets less factual. I didn't get a copy this year. But you can get the gist of it here.

In 2003, the claim was... in a 75x telescope, Mars appears the size of the Full Moon (naked eye). That wasn't a hoax. It was handy. Can you see the "Dog on the Moon" or other shapes in the maria? That's about the level of detail you might have expected on Mars in 2003 in a back yard scope.

Back then, i did the math. The Moon had about 71 times the apparent size of Mars. The Moon is so bright, you think it's bigger. It's not so big. It's about 30 arc minutes across. Your eye can resolve about 3 arc minutes. So the Moon is only something like 10 pixels across. That is, it's a little tiny icon image. Can you see any craters on the Moon, naked eye? I tried to do some image manipulation to give you an idea what a 10x10 pixel Mars looks like. But it's very small on your screen. So instead, i then took that small image and made it bigger. In my opinion, Mars looks better at 100x through a scope.

Now is the time to mention that though Mars won't be at opposition in late August this year, it will be at opposition in January 2010. It's not that long from now. And, it won't appear as large as in 2003. So you'll need maybe 120x instead of 70x to get the icon resolution. But a well collimated ten inch scope will easily support over 240x. Your local astronomy club has several scopes this size or larger. And, they'd be happy to show you Mars in January for free at one of their monthly star parties. Dress warm!

Jupiter's scar

It took several minutes to convince myself that i was seeing the new spot last night, in my 10" at 240x. I tried a trick i'd heard. Since Jupiter is so low (24 degrees at 11 last night), the idea was to use an oxygen 3 filter. The idea is that, being narrowband, there'd be no chromatic aberration from the atmosphere. However, IMO, i saw more detail without it. The main problem seemed to be that the O3 filter tossed away too much light. And, the atmosphere had as it's worst feature, turbulence. So it was mostly comparing an out of focus dim green Jupiter to a brighter out of focus Jupiter. For that matter, it was at least five minutes to convince myself that i'd set the focus as good as it was going to get.

I did not see the GRS or GRS Jr. But i did see quite a huge structure in the Northern band. This was darker, but matched the big parallelogram in the first image. (North is down).

So, if Harry Potter 6 weren't in theaters right now, would we be calling this new feature on Jupiter a scar? I dunno. There's not much resemblance.

Check out the APOD entries.

Super Secret Project

It's hard to believe, but i'm involved in producing a monthly half hour TV show. OK, it's aired on local cable, in the probably ignored "public access" slot. But, we've produced four episodes. Back in May, i called this the "super secret project". Not because we're trying to keep it under wraps. But more because we've been so busy producing the show, that we've hardly had time to promote it. Well, now we have a web site.

Astronomy For Everyone

The first episode has Don interviewing me, and we're talking about astronomy with zero equipment. Naked eye astronomy is best for meteor showers (The Perseid Meteor shower peaks on August 12th - coming fast), constellations, navigation, the Milky Way, and just a few galaxies, clusters, nebulae, and double stars. Did you know that you can see everything that amateur astronomers can see for free? Almost every club has monthly public star parties and observatory open houses. There are seven clubs in the Metro Detroit area. That's a boat load of opportunity. We tried hard to make the show interesting, and only let a half dozen factual errors slip by (see the transcript).

The second episode covers binoculars. Ken brought, like, a dozen pair. It was show and tell. His smallest pair, 2.5x - have a 28 degree field of view. That's big enough for some constellations. And his largest pair are 25x100. That's really a pair of 4 inch telescopes, with excellent alignment. Holy Cow!

Thanks to Greg Ozimek for the observatory photo.

The third episode, on the air now, features an interview with four Ford Amateur Astronomy Club members who helped in a project to restore a local high school observatory. It's very hot. While observatories often go into disuse when the guy who knew something about it retires or leaves, this shouldn't happen again. The Ford club will continue to stay involved. With 150 members, there will always be a really good chance that maybe ten of them will be on hand to work with students and the public. So, it's not just a first rate new observatory. It's a plan.

Our forth episode, for September, focuses on Jupiter. It features an interview with Sandra, our local Jupiter (and other things) expert.

We're working on October. Probably something about telescopes.

We're also working to expand our coverage. We've been picking up a new local cable company about once a month. It's an easy sell. It's free content. It's pretty good. It's local. Did i mention it's free? But many municipalities require that a resident "sponsor" the show. So, i've been handing out DVD's like candy to anyone who says they might look into how this might happen for their town.

In Astronomy News

Without naming names or places, but we have an "In the news" segment at the club. And recently, one of the guys pointed out that between the 1st and the 6th of July, there were 30 distinct astronomy news stories. He then proceeded to read snippets from about 15 of them.

I have infinite patience. But this read like a dictionary. And it was, in my opinion, for two reasons. First, there were so many stories. But second, the way all these stories were written (and therefore read) has a fundamental flaw.

Let me back up just a bit. Here's how most astronomy (and probably by extension - science stories in general) are written. The first step is to pick up a science journal - like Science, Nature, Physical Review, etc. Skim until you find something that strikes you. Write up a summary in laymen's terms. Read it back and it sounds great.

However, the audience doesn't have your background. The recent Jupiter impact brings the 1994 SL9 strikes to mind. Incredibly exciting. But that was 15 years ago. Anyone under 25 won't remember them. I mean, at 25, you were 10. Short of guys bouncing around on the Moon, at 10, you're just not going to remember it.

What these stories need is context. If it's the Jupiter impact, you've got to mention SL9. Maybe a little digging will bring up the estimates of how often these things happen. Does it mean that Jupiter protects Earth from such impacts? Or does it mean that we should kick our planetary defence program into high gear or risk going the way of the dinosaurs? Without context, IMO, it's just a dictionary entry. Without context, it's not a story. Without a story, it's soon forgotten.

IMO, the best "In The News" segment anywhere is Megan's segment in "The Jodcast". It's all about context. Of course, having a sexy voice helps.

Free Astronomy software for observation planning

I'm giving a talk tomorrow at the Ford Club. It's just a short one. What software is available for free? All the software i use is available for free. But i start with my browser. I'm sure you have one. I use firefox (free) on Linux (free).

It's good to know when it's dark. So i go to heavens-above, look up the Sun, and discover that it's 11:30 pm to 3:40 am. Short nights.

I often start out my planning by going to Alice's site. I listen to her Astronomy A Go Go podcast. She's got a very, very sexy voice, and i could listen to it for hours. Which is a good thing because her monthly show is an hour long. Anyway, she's a bit behind this month. Still, she has a chart of meteor showers. Right now is the June Bootids meteor shower, fairly bright. June 22 - July 2. Worth a look, right? If i can get out to dark skies.

She's got a link to Skymaps, so i download the current PDF. The first page has the map. It's got a calendar of events. The calendar has events like "on the 25th, the Moon will be next to the Beehive Cluster". I can find the Beehive without the Moon. And i'm pretty sure that i don't want to see the Beehive washed out by the Moon. But this may be really handy for beginners. Anyway, i ignore the calendar. I'd be more interested to find out that Venus is next to Mars (in the morning). So it might be a cool way to spot Mars. And Jupiter is next to Neptune. That might be a really easy way to find Neptune. The interesting thing is page two of the SkyMap. It has easy, medium and hard objects lists for the month - starting with Naked Eye. Just stars this month. Binocular objects are generally findable in my ten inch scope from my highly light polluted driveway. Telescope objects, not including galaxies, are also visible. I mostly look for things i haven't seen.

There are two good comets pages. Skyhound isn't up to date. The header says June, but the data says May. I move on. This other page is pretty cool. And it looks like a 8th magnitude comet is in Pegasus. I bring that up in kstars, a free planetarium program. Really, "sudo apt-get install kstars" is the easy way to get it for Linux. Stars down to 16th magnitude. Pegasus is visible most of the night. And kstars knows where this C/2006 W3 Christensen is, so i can print a field finder chart.

The Tools menu of kstars has a "What's Up Tonight" feature. The evening planet is Saturn. It sets around midnight. The morning planets are everything else. Mercury is pretty tough for me, as i don't have much of an Eastern horizon. But i saw Venus at 4:30 in the morning, and it was so bright i knew it was Venus without my glasses.

I switch to Comets, and look up Christensen. It transits at 4:30 am. That's only a bit after astronomical night ends. Maybe 3:40 is a better time to look.

The Asteroids list isn't very handy. Ceres is good. It's near Saturn in Leo. But if you look up Pallas, it turns out that it sets before it gets very dark. And Vesta is hopeless.

The kstars tools->Jupiters' Moons gives a chart. Usually i want to know which moon is which at some specific time. So, i set kstar's time, and zoom into Jupiter. Unfortunately, this doesn't work for Saturn. But Stellarium does this just fine. I don't generally use Stellarium, with all it's eye candy, to do planning. But this feature makes me fire it up. Stellarium has the feature that is works on Linux, Windows and Mac. And, did i mention, it has eye candy?

Back to kstars. Sometimes, i just set the time, and look at the Zenith. Boom. There's Hercules. M13 and M92 are always worth a look. But the whole line from Polaris to the southern horizon is worth thinking about. Ophiuchus is near there, and that's where Pluto is. So i look for Pluto. It transits at 12:30 am, at 30 degrees up. Not bad!

Or, i point kstars East, and see what's rising.

When i've totally failed to do any planning, sometimes i let my telescope's computer suggest things. It's got 12 objects per month. And nearby months are OK. Or i just ask it for clusters in some constellation that's high in the sky. Or maybe double stars. But now we're not talking free. Unless you think "Free with a $700 telescope" is free.

What's the difference between a comet and a planet?

I've mentioned that i lurk on Yahoo! Answers (a complete waste of time), and answer questions from time to time. Here's an example where i attempted to not answer the question, while staying on topic, mostly. I should point out that other answers included the IAU's three points of the definition of a planet.

Planets are those things that got a really crappy definition by the IAU a couple years back. One feature of this definition is that they have to be massive enough to collapse into a rough sphere (hydrostatic equilibrium - if it's rotating, it can be fat at the equator).

Comets have no official definition. Nor do asteroids. So both could be either. As it turns out, there are objects classified as asteroids that clearly had a tail at one time. Indeed, one of the annual meteor showers has particles that clearly come from an object that we currently call an asteroid. These particles are thought to come from the objects out-gassing, which would have formed a tail.

To make the definition matters worse, asteroids are officially cataloged as "minor planets". Two of the minor planets, 1 Ceres, and 134340 Pluto, also have the classification of "Dwarf Planets". Clearly, not all asteroids are Dwarf Planets, but at least some Dwarf Planets are asteroids. So one could argue (and i'm doing that now) that comets are closely related to planets.

Comet Lulin - still visible in April 2009However, comets are generally described as objects that do out gassing, sometimes have tails, and so on. They're not generally described as "spherical", and indeed, the ones whose cores have been imaged look something like lumpy potatoes. But planets can and do have tails. Planets with atmospheres have some bits of their atmosphere blown into space by the solar wind, etc. For some of the hot Jupiters found around other stars, this super heated atmosphere is blown out into space as a very visible tail. I don't expect an object with Jupiter+ mass to be called a comet, but i do expect the IAU to completely mess up the definition of comet when they get around to it.

It appears that finding a large object causes astronomers in general to become stupid. We got poorly defined minor planets soon after Ceres was discovered and studied for 50 years. We then got poorly defined planets when Eris was discovered. Stupidity like this can only come from large committees. Group intelligence seems to go down as you add more people. So even a group of PhD astronomers, when taken by the thousand, are incredibly stupid. So imagine Congress, where a PhD isn't required. IMO, the IAU should be disbanded, and replaced by a peer review system. Peer review, at the very least, is fairly fast, and has been shown to work. It also has self checking for those cases where it doesn't.

Find Polaris

This is extremely unusual. I was listening to an episode of the 365 Days of Astronomy podcast. I happen to finish listening to the March 16th episode just as i was getting home, at night, and it was clear out. It's so seldom clear out.

The episode is entitled Using the Sun to Find the North Star. It talks about how you can go out during the day at solar noon, and where i live in the Northern Hemisphere, your shadow will point North. So if you mark where that is during the day, you'll be able to find the Polaris, the North Star, at night.

Up until that moment, i'd been thinking that i know how to find Polaris, and certainly wasn't going to figure out when solar noon is at my western edge of a time zone, and daylight savings, and all that (though now that i think of it, my planetarium program will tell me exactly when that is), wait till that point in time on a clear day (it's nearly never clear), and put a landmark somewhere along my shadow.

But as my driveway is my primary observing spot, and as i was there, it couldn't hurt to see what sort of landmark i could use. It was only a few seconds, and i could say, "there are the pointer stars of the bowl of the Big Dipper, so that is Polaris". Could my basketball hoop be used? As it turns out, when the basketball backboard just blocks out the street lamp, the post holding the basketball hoop points straight up at Polaris. I don't need a landmark, i have one. And, as that's where the street lamp is blocked, this patch of grass is where the scope should go, at least when there's no snow.

I've been doing it sub-optimally all this time.

Hey. It's clear. Time to get out the scope!

Where can you name a star for free?

This is more from my adventures on Yahoo! Answers. As i've said, a complete waste of time. Here's my answer:

Polaris with Polaris BHere's a trick that i've used to good effect. I picked a really, really bright star that happens to be nearly due north. I watched it a bit, and it doesn't move much, all night. Most of the other stars seem to circle it.

I named it "Polaris". I didn't go to a web site and buy the star name. I didn't even write it down. It just thought it was a good name for the star. You know, cause it's right there by the pole.

When i looked it up in a planetarium program, to my astonishment, they used the very same name for the star! It's official.

So, as a follow up, i was looking at Leo. There's this one really, really bright star. And i thought, "Hey, that's the King star of Leo." And lions are the kings of the beasts. And, i'd read Harry Potter. So i called it "Regulus". It's a great name for a great star. And guess what? That's what my planetarium calls it. That's two, and completely free!

Spotting alien Earths on the cheap

Every now and then, there's a news article where they talk about something that might be interesting for astronomy. There was the meta materials article where they talked about achieving, in the lab, a substance with a negative index of refraction. The work was done in microwaves, which are a good deal longer than visible light. So, although a visible light version would be much, much harder to do, there wasn't anything in physics that suggested it was impossible. And the interesting thing is that such optics might be able to produce images with a resolution limit ten times smaller than the diffraction limit we normally get. Even if it were incredibly expensive, it would make a 3 meter space telescope act like a 30 meter space telescope. But though it's been years since this announcement, i've not heard anything more about it.

So here's another idea. Read this article. I'm not going to repeat the article here. The idea is to sort of combine lucky imaging with adaptive optics. Take lots of images, but treat the pixels independently, to improve the wavefront of the distorted light. You're still using today's massive compute power to make the final image work. And, the article says to expect real results in months.

I've done estimating before. Take the original reasonable estimate, double it, then change the units up one. So if they say 5 years, then it's doubled to 10, and instead of years, you have decades. But if the estimate is 2 months, double it to 4 months, then change months to years - 4 years. This estimating technique is scary on how accurate it is. And though 4 years sounds like a long time, it's not. This is very exciting.