Making a green laser pointer a little safer

I made my green laser pointer, which I use for showing things in the sky to friends, family and the public, a little bit safer by adding an IR block filter. Here are the instructions.

Comet Pannstars C/2011 L4

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.

The Seventh Sister

I am embarrassed that I had been telling people at public star parties that it's not known why we can only see six stars in the Pleiades naked eye, whereas the ancients talked of Seven Sisters. But it was just a matter of looking harder, from a suburb town, and then I saw the seventh.

PerApp -- input method adjustment

My PerApp Android app which lets you have different settings (volume boost, CPU speed, screen timeout, etc.) for different apps has been updated to allow you to set different input methods for different apps on rooted devices. I'm posting this here, as some of you may be using my red Gingerbread keyboard with astronomy apps. If your device is rooted, you can now use PerApp to make that keyboard automatically come up for your astronomy apps.

LunarMap 1.20 released

I've released LunarMap 1.20 Lite/HD for Android.  Both versions got optimizations which could improve scrolling smoothness a fair amount (it's still not perfect).  The free Lite version also got a big change.  Previously, only a few maps were available, and only of the front of the moon.  Also, after 8X zoom it would just blow up the 8X map, pixelating more and more as you zoomed more.  Now, the Lite version has access to all of the same maps as the HD version, but if you exceed 8X zoom, it watermarks the screen with a big ugly "LITE".  But since it has the same maps, you now know exactly what you're missing with the HD version.

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.

GalacticNight 1.06

My night-mode (and other re-coloring) app for Galaxy S2/S3/Note now officially supports the Note 2 as of version 1.06. Source code is here.

Not much astronomy lately...

Since baby was born in October, I haven't had much chance for astronomy, except for coordinating a school star party, and showing Jupiter to kids visiting us at home. And it's been cold, but it seems warmer now.

Galactic Night released

I've released Galactic Night, my night mode app for rooted Samsung Galaxy S2, S3 and Note.

Progress on Samsung night mode

I have test code that works on my rooted S2 with GB and according to testers previous versions have worked partially (the night mode got disabled by power off/on) on an S3 with ICS and an S2 with ICS.  Anybody who wants to try it can get it from here. It definitely needs root.

Samsung red mode

I am working on a better red night mode for rooted Samsung phones. The usual way to do red mode for rooted Android devices is to use ChainFire3D. However, ChainFire3D does red mode simply by dropping the green and blue components, and as psonice once pointed out to me, that's not the best way. After all, then, green and blue stuff on the screen is invisible.

The right way to do it is to combine the color components, using an RGB to grayscale conversion, and then use the red component.

I just managed to do it on my rooted Android 2.3 Epic 4G Touch using Samsung's MDNIE profiles (see screenshot) and some simple shell scripts. But I don't know if this will work on other Samsung phones, though I assume all Galaxy S2 family phones will work with my method.

A good rule of thumb is that a version of this hack should work on all rooted Samsung phones that have the Dynamic/Standard/Movie color mode switcher under Settings | Display | Screen mode.

If you want to help me with this project and have a rooted Samsung phone, there are some things you can do:

1. (Easy, and you can do it even if your phone isn't rooted.) Go to Settings | Display | Screen mode and see if you have Dynamic/Standard/Movie switch. Tell me (either by email or by commenting) which phone and OS version you have, whether it has the switch, and whether it has these three or some other modes there.
2. (A little more advanced and needs root.) Email me your /system/etc/mdnie_tune_movie_mode and /system/etc/mdnie_tune_ui_standard_mode files , also telling me which phone and OS version you have.

You can email me at arpruss at gmail dot com, with subject line "red".

The resulting switcher will be free and open source.

LunarMap HD USGS Geologic Map

I've added the 1971 USGS Geologic Map to LunarMap HD for Android (available in Google Play and Amazon Appstore (which will take a couple of days to update)).

Notice in the screenshot how the labels hard-printed on the map get combined with the yellow labels added by LunarMap, without any duplication of labels.

Transit of Venus

Here are some photos over the first 45 minutes or so. They are in sequence, but not evenly spaced in time.

This is from my 8" F/4.5 scope, stopped down to about 3", with photo taken hand-held with my Canon G7 camera off the projection funnel.

Here is the last photo in a larger size.  The sunspots were very nicely visible in the funnel (I counted about 15), and I could even see two without a telescope in the #14 welder's glass.  The photo doesn't do justice to the sunspots, especially the nice bright area that was just barely visible at the bottom of the disc.

Eclipse

Here in central Texas, the sun set before the eclipse hit maximum.  But we had some lovely views of the moon gobbling up sunspots as the sun was setting over the lake.  Photos are taken by a Canon G7 camera, using a solar funnel for projection.  The scope is an 8" F/4.5.  For the first photo it was stopped down to about 3".  The second photo I think used the full aperture.

And for reference, here's the sun in the afternoon, before the eclipse:

More sunspots

I still don't quite have the hang of photographing the projected solar image on my funnel--it's still sharper naked-eye--but the photos are improving. When the clouds aren't in the way.

Sun funnel done

To get the size of sun funnel I wanted, I had to join two different funnels.  But it works!

More sunspots

I was handholding the projection screen material in front of my scope for a 4-5" image.  Wow!  Today's sunspots were really impressive.

I noticed that they were very much in pairs.  Apparently sunspots come in pairs with opposite magnetic polarity.

Sunspots today

A kind soul sent me a 25mm Kellner eyepiece for solar projection purposes for the cost of shipping.  A nice thing about this eyepiece is that the field stop extends quite far from the lens, and will dissipate any sunlight if the sun goes to the edge of the field.

I played with it today to see how far away from the eyepiece I'd need to get to have a 4" image in my 8" F/4.5 (stopped down to two 3" apertures).  Answer: ~26cm.  When I projected the sun on a piece of cardstock, at that size, I was blown away by the richness of the structure of the sunspots today.  And the sun was quite low, as it was shortly before sunset.  Here's today's LMSAL photo.  I saw the two larger groups but somehow missed the smaller group that's down from center.

It's time to build a sun funnel as soon as my projection material comes.

Venus

Afocal, Coulter 8" F/4.5, TMB/BO Planetary 6mm eyepiece, with my son's Sony P100 camera.

Hard drive platter as flat mirror

Some time ago, I disassembled some old hard drives with the kids (including one that was donated to the cause by my employer's IT services), and extracted magnets (fun, as long as you're careful) and platters.  The platters gave me the impression of high quality first-surface mirrors, and I've been looking for a use for them.  I've put one into my so far not very successful solar projector project as a heliostat.

I was just playing with looking at stars reflected in this platter through my 15x70 binoculars, with only one eye.  There was some unidirectional glare from Venus, but stars looked pinpoint.  I was only hand-holding the binoculars, so the test isn't great.  And it would have been better if the central hole was blacked out.  This isn't a very demanding test, higher magnification would be much better, but it's a promising start.

Mars

I've never done very well with Mars, and my best views--never that good--have been with an aperture mask.  With full aperture, I just get a red and white blob of chromatic aberration.

I had a 75mm single-hole aperture mask that I was planning to use in my 8" F/4.5 Coulter for solar projection, but tonight I added another hole to it.  Both holes miss the two-vane spider.  The views of Mars with the aperture mask and a 5mm ortho are great--best I've had.  Two dark areas (one was probably Mare Acidalium) and a bit of polar cap.  I don't know if they're better with two holes than with one--there may be better contrast with one--but they are a bit brighter with two, and I love the easy focusing (with the mask, you see double and you focus by merging the images).