Lightening my Coulter 8"

I've been using my 8" F/4.5 scope more, because I just haven't been having the energy to pull my 13" out.

The 8" weighs in at around 40 lbs. I wish it was lighter. I shifted the bearings a couple of months ago so it wouldn't need a counterweight at the bottom of the tube.

And today I finally cut out big triangular holes in the sides of the rocker box.

I sketched out a template in Inkscape, and printed it out in three pieces (it didn't fit on an 8.5x11 sheet), glued them together, and transferred the locations to the wood with a punch.  I used a 2.5" hole saw for the corners of the triangle, and joined them up with a jigsaw cut. It was my first time using my fancy (reconditioned) Bosch 1590 jigsaw. I was pretty pleased. I used a Bosch T234X blade. It cut the tough OSB very nicely, and pretty smoothly (though the hole saw smoked a lot and there was a lot of tearout). The dust blower wasn't strong enough to keep the cut line clear, which was unfortunate (since I was wearing a dust mask, I couldn't blow dust away). Then I painted the exposed wood (with an approximately 1:1:1 mix of acrylic black paint, Titebond II and water). The cut out portions weighed in at a total of about two pounds. Not a big difference, but I find that at around 40 lbs, every pound makes a difference.

Aurora

Alas, I can't report whether aurora was visible as far south as here since I was sick and not observing last night. Here are some gorgeous photos from Norway, though.

Jupiter

Had a look at Jupiter in my 13" during the Live Oak school star party. The south equatorial belt that was missing last year is back--somehow I had forgotten about the disappearance and hence didn't really notice that it had reappeared.

I was surprised to see a very dark spot a little bit east of center on the north equatorial belt at JD 2455856.5754. It looked a little fuzzier than a moon shadow, and possibly slightly elliptical. It moved in the same direction as Jupiter was rotating. Experimenting with my collection of gel filters showed that the spot got much harder to see through a magenta filter. Vivid pink, red and orange also decreased contrast. Green may have enhanced contrast slightly. I hypothesize that the spot was dark red in color.

I also saw the Great "Red" Spot--in the words of a colleague, it looked like an empty area.

Both the dark spot and the Great Red Spot looked very good in my colleague's 8" F/6 with a binoviewer.

Update: I looked on Cloudy Nights. The dark spot is nicely seen here. I am pleased to note that I got the color and shape right with my filter swapping technique: it's definitely dark red and oval in the photo. These spots are apparently known as "barges". More information and links here.

The moon, visually

For various reasons, I haven't been doing that much observing for the past half year or so. But I've been out twice this week looking at the moon with my 8" Coulter. I can't really do deep space viewing given the lights that have cropped up in a nearby grassy area, but the moon is all the better for it. I've been observing in and not far from Mare Serenitatis: Posidonius and Cassini were particularly striking, as was Ryma Hyginus together with its central crater. I am finally getting good use of my 5mm ortho eyepiece--it's really nice for the moon, giving a sharp 160X image.

Fixing the SkyMaster 15x70 binocular tripod adapter

Here is my Instructable.

Moon with webcam

While working on an Instructable for how to take pictures through a microscope, I was using a webcam (with lens removed) to take some pictures of the moon, shooting small video sequences and stacking them with Avi Stack.  Conditions were imperfect, but it was fun.

Avi Stack generates photos like these from wobbly video like this:

Micrometeorite candidates

The kids and I took apart a defective hard drive yesterday, and I used one of the magnets (in a plastic bag, which I then inverted) to fish for micrometeorites in the soil near a downspout.  I found a few plausible candidates, as well as a bunch of surprisingly pretty microscopic ferrous dust.

Here is a particularly pretty area.  The pointer is pointing to a round micrometeorite candidate.  It's stuck to some probably earth-origin stuff--the hard drive magnet magnetized all the samples, so they stick together.  There is also a pretty piece of glass or crystal closer to the top edge.

I ended up preparing a slide with four candidates (one a bit dubious) mounted under a glass coverslip.  It's hard to grab pieces as they are very tiny--though big enough to see naked eye as a tiny dot--and stuck magnetically to other things.  In particular, I lost the round one in the first photo, as it just shot away when I tried to grab it with a toothpick (which looked like a big blunt log under the microscope).  Here's one that didn't get away.  It's about 60% of the size of the ball in the first picture.  You can't tell in the photo, but if you shine the light on this, it's very metallic--a nice silvery object.

I ended up perfecting a method for extracting them.  First, I use the toothpick to sweep the area around it clean, looking in the microscope most of the time.  It's confusing, since the miscroscope reverses the view, but eventually the brain gets used to it.  Then I wet the toothpick with acetone.  The micrometeorite candidate sticks to the toothpick.  I then transfer it to a clean piece of glass.  Because the acetone evaporates so quickly, it's easy to just wipe the toothpick on the glass and the micrometeorite drops off.  I lost two promising samples--especially that nice big round one in the first photo--before I got the above two.

From what I've read, rounded things that look like they were partly melted are good candidates.  Here is a less rounded item that ended up on the slide of the four that I saved.  I don't know how it got there, as I only intentionally transferred three to it, if memory saves.  Maybe it accidentally got carried there.  It looks too rough-edged to be a micrometeorite.  However, I've also read that they can avoid atmospheric melting by being small, so maybe rough-edged things count as candidates, too.  It, too, has a nice shine to it, though the photo doesn't show it.

If you try to view this with bright-field microscopy, of course you just get black silhouettes.  What I did is I taped a bright LED flashlight to the microscope, pointing at the sample, and then I took timed exposures, holding the camera to the eyepiece (sometimes with some sort of adapter to keep the camera in place).  For the second two photos, I found a way of adding more light.  I took the microscope outdoors, and then reflected sunlight onto the slide with a mirror (actually, a hard drive platter--they make lovely mirrors).

The photos were taken with point and shoot cameras hand-held to microscope eyepieces, with some loose-fitting adapters to make it easier. The first photo was with a Sony P100 through the 10X Huygens eyepiece that the microscope came with. The second and third photos were with a Canon G7 through a Rini 30mm telescope eyepiece, using my home-made telescope-to-microscope eyepiece adapter.

Update: I wish I knew how to better identify micrometeorites. The very round one may not be one--see this article.

Paper craft sundial

Here are instructions for a paper craft sundial I built last night.  The hard part was doing the trigonometry for getting the gnomon to be at the right angle after folding--I hadn't done much trigonometry for a while, especially in regard to laying out a three dimensional object (the gnomon is wider at bottom than at the top).  With the script complete, construction takes about fifteen minutes.

Fix for balance issue on 70mm F/4.3 refractor

My son's 70mm F/4.3 refractor had too easy movement, and couldn't balance with a 32mm Plossl eyepiece (it balanced fine with a light Kellner).  We added a tension adjuster on one side.

The second photo shows the right altitude bearing.  The nut is superglued in place.  If it ever comes unglued, I'll glue something on top of it to keep it in place, or replace it with a threaded insert, or think of something else.  The nut actually was a locknut, but I cut out a lot of the locking plastic, so its locking action is very mild.

And the last photo shows the inside of the mount.  The black ring is a superglued fiberglass washer.  On the other side, under the knob (you can kind of see it in the first photo) there is a superglued washer made from milkjug plastic (rough side facing the wood) so the knob doesn't come undone.

Sundial completed

It's done now, and I made an Instructable with detailed instructions.

Now, can I persuade my kids' school to have it painted somewhere?

Working on sundial

I'm planning to draw a large analemmatic sundial with the kids, with chalk on the driveway. But that's not as much fun as writing a perl script to generate a pdf file with all of the dimensions. The beta version of the script is now running here. Source is also available, of course.
Update: Just executed it in sidewalk chalk. That's the best I can do in terms of permanence, since we rent our house from the University.

Another telescope instructable

And another one of my telescope instructables has been put on the home page of Instructables. This is my 8" F/4 travel scope.

Observing on the Gulf Islands

In July, I visited one of the Gulf Islands in British Columbia, where my parents have a sea-side cottage. I brought my airline-portable 8" F/4 scope. The usual curiosity from airport security about the eight pound wooden box in my backpack, but no problems (I just need to allot an extra five minutes).

From my parents' front porch, I looked at and showed them M13, M27, M31/32, M51, M57, NGC 457, the Double Cluster and Albireo. The views were excellent. M27 had a very nice brighter squarish middle, with wings sticking out. I think that's tied for my nicest view of M27 (I've had a good view of it through my 13", too). When looking at M31, I couldn't see M110, perhaps because the M31 area was (a) low in the sky, and (b) that was the direction of Vancouver. NGC 457 (Owl/E.T./Airplane) always pleases people. We also saw a meteor and several satellites.

Once my parents went in, I went after the North American Nebula (NGC 7000). I have never had much luck with it. I saw it in my 68mm refractor with an O-III filter in a past year from the same location, but it was a very faint fuzzy with no structure. This time, still with an O-III filter, it was better due to better aperture: the edges were defined, and I could pan around it with the approximately two degree view of the Rini 30mm in the scope. (I should consider putting in a 2" focuser and using an even wider eyepiece in it.) I kind of got an impression of a shape reminiscent of North America, too.

I had heard that one can see the North American Nebula naked-eye with a filter if the sky is dark, and so I stared at the sky through the O-III filter. And I think I did in fact see it. I think I could also see M13 naked-eye with averted vision (no filter of course). It was almost directly overhead, so that helped no doubt.

The next time we went to a peak in the middle of the island, where I did an unofficial star party. We had almost thirty people show up, unofficially invited by email. We started with Saturn at around 10:15 pm. The rings were sharply defined, though I was using a low magnification due to the scope being fast and there being wind. (I also discarded the light shield due to wind.) I thought that it would be dark by 10:15 pm, but I didn't reckon with northern summer. It was closer to 11 pm before it was nice and dark. However, the party went very well. I showed the same objects as I had shown my parents, plus the Lagoon and Swan nebulae.

I always like it when deep sky objects are naked-eye visible. Overall, on the island, I naked-eye bagged North American (if O-III is allowed for naked-eye; but a filter only blocks light!), M8, M13, M31 and the Double Cluster. Only North American and M13 were particularly special to see naked-eye. M8 is naked-eye from my home, and M31 and Double Cluster are naked-eye from my regular observing location. I think sometimes I can see M31 naked-eye from home, too, but it's hard with the streetlights to the north.

My smaller Dobsonian instructable

Looks like my smaller Dobsonian telescope instructable has been featured as an editor's choice and is on the front page of Instructables. Yay!

Instructables space contest

Instructables is running a space-related stuff contest with nice prizes. I posted photos of four of the projects I described in this blog, and I encourage any readers to post their own projects.

How fat am I?

Suppose I think of myself as shaped like a four-dimensional spacetime worm. We draw diagrams of such things for students—a wide line moving up the board. It is amusing to note that such diagrams are not at all to scale. In a natural unit system, the speed of light will be taken to be c=1. For instance, one might measure time in seconds and distance in in light-seconds. A light second is 299792458 meters long. An average human earthly lifespan is of the order of magnitude of 10⁹ seconds. My largest spatial dimension is about two meters, i.e., about 10⁻⁸ light-seconds. That means that my earthly temporal dimension is of the order of magnitude 10¹⁷ times longer than my largest spatial dimension. This means that I thought of as a spacetime worm, I am an exceedingly thin worm. If this worm were rotated, projected and scaled so as to be a meter long and maximally thick, a hydrogen atom would be ten million times thicker than the worm.

Moreover, this worm is quite straight. The main variation in its shape seems to be a cork-screw shape induced by the earth's orbit around the sun. But the diameter of the spiral is about a thousand light-seconds, which is a millionth of its length.

So a scale drawing of me in my earthly career as a space-time worm would have me be 10¹⁷ times thinner than I am long, and despite a subtle cork-screw, straight to within about one part per million.

Progress on AstroObserver for Android

I've been learning OpenGL ES 1.0. Here's what I'm getting as a full-sky star map. It looks a brighter and better on my device than on this laptop, though--different gamma settings, I suppose.

I'm modeling the light flux pretty precisely: in other words, I scale the star by a factor proportional to 2.512^(-mag/2) (the 1/2 is there because the light flux is proportional to the square of the radius of a two-dimensional image).

If anybody wants to try the demo (which just shows a rotating sky at maximum speed), it's here.

More Android dark adaptation goodies

And here is an Android app, which requires a rooted device, to give better control over screen brightness, allowing almost continuous adjustment to very, very close to zero, at least on my device.  This will be useless to you if you don't have a rooted device.

Red keyboard for Android devices

I've been working on a red-themed keyboard based on the Gingerbread keyboard.  Should be nice for night use.  Here is a copy.

The screenshot is in Google Sky Map.

Night mode for Android devices

While astronomy apps tend to have a built-in nightmode, I was very pleased to come across ChainFire3D for Android which, among other things, has a global night mode that works on all apps. The red is a bit too bright, I think (maybe someone should email the developer about it), but otherwise I think it's great.

It needs a rooted device.

p.s. I'm still working away on AstroObserver. It's going more slowly than I'm used to, partly because I've been sick. I'm basing it on AstroTools, but I'm redoing a lot.