The moon in Minetest

I was at a conference over the weekend, and I also had some spare time at the airport, on the plane and in the hotel, so I entertained myself by finishing off a lunar mod for Minetest (a free Minecraft-like game, which works a lot better than Minecraft on old hardware) that uses real-world data from NASA's LRO spacecraft to generate lunar textures. To make this more Minetest-y, I flatten the moon out into two pancakes, and then I exaggerate the terrain by a factor of five (which is adjustable). And I added some sky background textures from SpaceEngine. (The Enterprise isn't a part of this mod, but is generated with the render.py script for RaspberryJamMod).

SkySafari out in Android Market

SkySafari is now up on Android Market.  I've been one of the beta testers.

Here's my five-star Market review:
This is easily and by far the best astronomy software for Android devices.  I think it's better than Stellarium for the desktop.  Superb coverage of the solar system (planets, minor planets and comets) and deep sky objects.  Good information on various objects.    It's great to have outlines of wide deep sky objects.    The Pro version adds tons of stars.  From my experience with Palm apps, for serious star-hopping and identifying of faint objects with a decently sized telescope (I have a 13"), one really should benefit from having the greater depth of coverage that the Pro version provides over the Plus version.    Hint 1: If you have a somewhat slower device, you can greatly improve smoothness by setting the Horizon to Transparent with Line and turning off Milky Way textures.  Hint 2; While the built-in night mode works well, it doesn't affect the on-screen keyboard keyboard or any soft keys on screen if your device have them.  For rooted devices, you can install ChainFire3D and use its night mode, and for unrooted devices, you might try my own free "GB keyboard with optional night mode".

Various things

It's been cloudy and rainy for a couple of days.

I'll be building a 70mm F/4.3 refractor with my five-year-old son.  Lens and diagonal have arrived ($33, from Sheldon Faworski).  We have a mailing tube of just about the right size.  I ordered some screws and nuts from Amazon to attach the lens to the tube.  I am working on a simplified PTFE-on-PTFE Crayford variant for the focuser, made out of one piece of wood, plus some hardware.  I'll post details once it's done.

I've spent some of the weekend playing with using a Wii remote with an IR pen.  This might be nice for operating Stellarium at public star parties.

Galaxies and a comet

Last night I went out to my local darker sky site (yellow skies, not nearly, but still much better than in the city; and it's only 24 minutes away from home) with my 13" F/4.5 Coulter split-tube. And it was really quite delightful. But I was surprised by how late it gets dark. Sunset was about 8:30 pm, but at 9:00 pm it was very bright, and it was only around 9:20 that it got decently dark. I looked at Venus, Saturn and Mars first, since it doesn't need to be dark for them, and aligned AstroInfo to my setting "circles" (the azimuth circle is actually a square). Not much detail.

Most of my session was deep sky stuff.

Nebulae: Just M97. At one point I thought I saw a hint of the eyes (it is the "Owl Nebula"). But it really was a very faint blur.

Open clusters: Just M44. The sky in that direction was still bright, so it wasn't particularly spectacular. It was rather pretty in a delicate sort of way in my 70mm finder, and it was nice to pan with my SuperView 30mm in the main telescope.

Globular clusters: M3 and M13. I thought M13 wouldn't be so great because it was still fairly low, but it was quite nice, and indeed nicer than M3. Both resolved well with a 13mm Hyperion.

Galaxies (my main focus this time): Whirlpool (M51) looked decent. I could see a connection between the main galaxy and the smaller one being eaten, and I could see portions of the spiral, though it looked more like a concentric ring. I couldn't see the black eye in the Black Eye Galaxy (M64) very well. I think I once saw it, but faintly. I guess the seeing wasn't as good as last time I looked at M64. And the Leo Triplet looked delightful as always. Then I went around browsing for fainter NGC galaxies. First, 3593 (mag 11) and 3559 (12.8) in the vicinity of the Leo Triplet. Then on to the Coma Cluster. I've looked at that before, but without much luck. This time, I didn't have all that much luck either--I picked out a bunch of faint fuzzies, but some needed averted vision: 4944 (12.9), 4874 (11.9), 4884 (11.5), 4898 (13.6 -- yay! this is the dimmest galaxy I have ever seen), 4895 (13.2). Then I moved closer to Virgo, because I was looking for comet. I moved the scope around where the comet was supposed to be and picked up a faint fuzzy. But I was afraid it might be something else, so I compared with the chart to see what galaxies were in the vicinity, and while I was at it, I picked up the 5427 (11.4) and 5426 (12.1) pair. I then moved on to the comet (below), and ended my observing session with Centaurus A which was pretty low (I should have caught it an hour earlier) and all I could see was a bit of fuzzy with a lane.

The comet: 81P/Wild. My Palm TX downloads AstroInfo-compatible positions for brighter asteroids and comets every night (using a script that grabs data from Harvard's ephemeris service). Unfortunately, AstroInfo doesn't do orbital movement, so the positions are really only valid for one time in the evening, but unless the object is pretty close to earth, they'll get one pretty close. Anyway, 81P/Wild was in Virgo, at magnitude 11, so well within the range of what my scope could do, and it did show up as an elongated blur. Nothing particularly impressive, but fun to see--only my third or so comet so far.

On the less happy side, I found two bugs in AstroInfo. After I added a fourth alignment object, the computations went haywire. And I couldn't tap on the screen to select a minor planet--instead I got an object far, far way. I'll have to try to duplicate these at home and fix. But I shouldn't get distracted from my nature of modality book.

I have the entire Tycho-2 star catalog on my PDA. But it's still not enough--there are way more stars in the field of view than in the catalog. (Occasionally, too, the catalog misses something really bright, even in the mag 11.5 range. It's amazing just how bright an 11.5 magnitude star looks when one's been hunting for magnitude 13 galaxies.) But I shouldn't complain. The catalog was deep enough to help me find all the objects I was hoping to find.

(When I was a kid, and early in my amateur astronomy hobby, I found the night sky spooky. But now I feel relaxed and at home in the starry dark, with a telescope and (electronic) charts. There is a pleasant familiarity (though I still don't know the constellations by name very well; I often just see the shape on the chart and think of them as "the one that has such-and-such a squiggle"). I wonder if the feeling of at-homeness in the universe isn't some evidence that the universe is created for humans. On the other hand, we are made for heavenly life and exiles here. So maybe the feeling is pernicious. But the "here" where we are exiles, maybe that is not a spatial here. Perhaps the new earth and the new heavens will include--as in the last Narnia book--all the best features of the present earth and the present heavens.)

Waco area cloud cover predictor

Using NOAA weather maps, some time ago I made a little online Waco area cloud cover predictor, which is now hosted on a better server than before. It shows data for about a week ahead of time (unlike the otherwise superior clear sky clock), every couple of hours, and it shows a mini map of the area. The numbers are percentage cloud covers. My experience is that small numbers are overestimated--about 20% on the map equals to the sky looking clear.

Custom moon map service relocated

I've relocated the custom moon map service to http://pruss.mobi/cgi-bin/moon.pl.  This may only be a temporary fix.

Need hosting for my custom moon map service

It being hot weather, and the air conditioning being in operation, I want to take a long hard look at always-on heat emitters, like our home server. Currently, besides doing some file serving that we can do, and some work-related stuff that I can move to my office server, it serves up custom moon maps--you choose the features you want, and it makes the map. Bandwidth requirements are low as I only have one user about every second day. My current server is a 2ghz P4 with 512mb RAM, so nothing fancy is called for. Just apache+modperl (with Perlmagick). If anybody is interested in volunteering some server CPU time and bandwidth, email me.