Monday, October 12, 2015
Tuesday, May 5, 2015
I've released Color Changer for rooted Android 4.4 and higher devices, which remaps screen colors in all apps. There is a Free and a Pro version, but the Free version includes the red screen mode for night-vision preservation, so you don't need to buy the Pro version (unless you want some of the other modes--the Free version includes a trial of all the Pro features--or want to support my development efforts).
(There is currently no way to do this without root. Sorry!)
Even if you are going to purchase the Pro version, please try the Free version first to ensure compatibility.
Saturday, April 19, 2014
I initially made AstroSurvey to work with SkySafari. If you view a region of the sky in SkySafari and then launch AstroSurvey for SkySafari, it will show that region in AstroSurvey. You can also go the other way: browse the sky in AstroSurvey and then view the region in SkySafari (Menu, SkySafari View), though this feature may still be buggy (I've had it corrupt my SkySafari star brightness preferences in testing).
AstroSurvey is also designed to interface with other astronomy apps by supporting what I am calling the AstroShare API, which is an extension of the SkEye ACTION_VIEW API, with an extra "Size" field (Double, in radians) for the size of the field of view. So you can choose "AstroShare" in AstroSurvey and view the current field of view in any supporting astronomy app (right now SkEye is the only released one), and any supporting astronomy app can launch AstroSurvey. The next release of the Open Star Map port of Google Sky Map supports AstroShare as well.
AstroSurvey is basically a wrapper around the Android WebView which gets pointed to Aladin Lite (and imposes some patches for touch-screen devices). That's why the UI is not quite what you'd expect. I may eventually impose more patches and make a more Androidy UI.
Monday, March 31, 2014
Over the weekend, I made myself a simple hand-powered Haig barndoor mount with the standard 1 RPM dimensions (11.43" distance of bolt from hinges, 20 per inch thread). Not wanting to deal with hardware complication, I planned to do tangent correction in software (i.e., I made a simple Android app that shows where to turn the circle). But I noticed that when I put in all the parameters, the amount of tangent correction from my app was strangely small.
It turned out that a chance modification I made to the Haig design reduced tangent error quite a bit.
To save a few cents, instead of using an acorn nut on threaded rod, I used a carriage bolt's rounded head to bear on the upper surface of the mount. (Of course I filed and sanded the head for smoothness, by chucking the bolt into a drill press.) The cost of this modification was nil, and the amount of work was a few minutes of filing and sanding.
It turns out that the wide rounded head of the carriage bolt corrects tangent error quite a bit. Assuming that the threaded insert for the bolt is slightly countersunk (I didn't actually do this, but optimum performance would then be achieved) so that at minimum extension we get zero angle in the mount, tangent error after 10 minutes of operation is about one second of arc, versus seven seconds of arc for the standard mount.
And here's the mount.
Thursday, October 24, 2013
Anyway, I now have a faster development laptop, so I was able to fix the problem. The problem was that the Kindle HD reports having a compass but doesn't.
Anyway, here's the app.
Open Star Map is basically the open-sourced code from the Google Sky Map, with some modifications to make it run a little better on Kindle Fires.
Sunday, October 6, 2013
Friday, July 12, 2013
Wednesday, July 10, 2013
Here is what I did with Lyra.
Step 1 is to rotate the image, e.g., in Gimp or Photoshop, until the trails are all horizontal.
Thursday, July 4, 2013
Wednesday, July 3, 2013
Monday, July 1, 2013
Monday, April 1, 2013
Monday, March 11, 2013
I took the kids out, and went with a friend and his kids, to see Comet Pannstars C/2011 L4, at my usual 10-miles-out-of-town observing site. Well, not quite the usual one, but a little ways from it where we had views almost down to the horizon to the west. It was hard to find in the bright sunset sky, but eventually the sky got a bit dark enough to see the Pleiades, and then I could just go straight down from them with binoculars (while the Pleiades were much higher than the comet, the azimuth was within about a degree). And there it was. Lovely tail streaking away from the sun. Looked great in my 15x70s, and pretty good in my 8". Naked-eye, I could see a fuzzy dot, and maybe a hint of a tail.
We also had a nice view of the Orion Nebula, the Double Cluster, and that big open cluster in Canis Major, and some naked-eye cluster which resolved in my 7x35 binoculars I didn't get around to identifying. But then it was time to get the kids home to bed.
Saturday, February 9, 2013
Monday, January 28, 2013
If you preferred the way the old Lite version worked, the last such version is available here, at least temporarily.
LunarMap also works great under Bluestacks on a Windows 7 laptop.