Tuesday, March 29, 2016

Shadow Transit on Jupiter!

Lucky Timing

The evening of March 23rd was almost perfect for observing with my new Stellarvue 130 mm refractor. Clouds cleared and the temperature hovered in the low 60's. A gentle breeze and low humidity prevented dew formation on the telescope. By incredible, miraculous coincidence all my neighbors had turned off their outdoor lights!

The one flaw in an otherwise perfect night was intense light from the full Moon. Only bright stars were visible in the moonlit sky. This wasn't a night for observing faint galaxies, but I was very comfortable viewing some red carbon stars and a few double stars. Once again, the telescope and mount performed well as I slewed from object to object. Eventually, I took a look at Jupiter and discovered a shadow transit in progress! I hadn't seen one of these in many years. This presented a great opportunity for imaging, so I quickly installed my video camera to record the event. The following image was produced by stacking the best 100 frames from a 1,000-frame video.
Three Galilean moons are visible. From top to bottom they are: Io, Ganymede, and Europa. The fourth moon, Callisto, was far outside the field of view in the upper left. The moon Ganymede is casting its shadow on Jupiter. This image was captured at about 10:20 pm EDT. If I had begun imaging sooner at about 9:30 pm, I would have seen Ganymede itself transiting Jupiter.

Now I'm even more excited about getting a color camera for planetary imaging. The image above would be even better in color!

Tuesday, March 22, 2016

New Stellarvue Refractor

First Light For a Lovely Telescope

My new Stellarvue 130 mm f/7 apochromatic telescope arrived recently. I've waited my whole life for an instrument of this quality! As you can see in the first image below, its external appearance is simply beautiful! It's almost too pretty to use with its spotless objective lens glass. Also visible is the fine 80 mm black finder scope mounted parallel to the main telescope.

The telescope itself is fairly heavy. It comes with a massive black storage case. Fortunately, the case has wheels, because I found it impossible to lift the case with the telescope inside.
The first opportunity to use the new telescope came just a few days after its arrival. A bright waxing Moon lit the sky on March 18th. The temperature was fairly mild and there was no wind. I set the Stellarvue on my Paramount MX mount during twilight and anticipated my first views through this exquisite refractor.
My non-permanent mount is aligned fairly well to the celestial pole. I have marked location circles for the tripod legs. The mount's altitude and azimuth have been set during the solar observing I've done over the past several years. I synchronized the mount on the star Rigel in Orion. When I slewed the telescope to other stars in Orion, the stars were not exactly centered in the eyepiece, but they were easily visible within about 10 arc minutes of center. It's amazing how well the mount pointed with only single star synchronization. 

Once I was satisfied with the mount's pointing accuracy, I began to enjoy the views. The first thing I noticed was absolutely perfect pinpoint star images. Stars appeared much more condensed and sharp than views I've experienced in Schmidt-Cassegrain telescopes in the past. I'm looking forward to observing lots of gorgeous double stars in the future. Then I moved to Jupiter. The image was crisp and clear. At first I saw three Jovian moons arrayed on one side of the planet. But suddenly I realized there were four moons visible! What I initially perceived to be one moon was actually two moons very, very close together! This is where the quality of the new telescope became evident. I could distinguish these two distant tiny dots of light with a clearly perceptible dark space between them! Next, I moved to the Moon and enjoyed super sharp views of craters and shadows near the terminator.

After playing around with different eyepieces and Barlow lenses, I eventually tried some imaging with my ZWO ASI174 video camera and a 5X Barlow lens. The next picture shows Jupiter with three of its four Galilean moons. The pair of moons nearest to Jupiter had moved slightly further apart since I initially saw them closer together in the eyepiece. Too bad I didn't center the view better to capture all four moons. I might try planetary imaging with a color camera in the future.
The Moon was also an obvious target for imaging. The next image is a 6-panel mosaic near the terminator. I'm really pleased with the detail here.
Soon clouds began to cover the sky. My personal star party ended.

The new telescope will be excellent! I'm enthusiastic about looking at the night sky again. It's been a long time since I wandered around from one celestial object to another just for fun and curiosity. During my academic career it seemed I was always hurrying to measure variable stars while fighting exhaustion. Now I can relax and enjoy the views through a dream telescope.

Friday, March 11, 2016

Bland Sun

Farewell February!

More than two months passed since my December solar observing session. During this time the Sun presented a mostly bland countenance. Lack of dramatic features continued on February 28th, but observing conditions were so nice I decided to capture some images anyway. It was 64 degrees with mild wind gusts from time to time. Seeing was mediocre. I got a late start at 2:47 pm. Only one modest sunspot, a pair of small filaments, and two nice prominences were visible.

The first image below shows the Sun's eastern side with one significant prominence near the top and a small emerging sunspot near the upper right edge. The image is a cropped 15-panel mosaic made with a 5X Barlow lens.
Notice the bright area in the lower right corner of the previous image. This was caused by my own carelessness in obtaining a flat field. A flat field image is supposed to record camera response to a uniform light source. My flat field image was taken too close to the solar limb. Limb darkening caused a brightness gradient across the flat field image. This brightness gradient was then incorporated into every image subsequently processed with the faulty flat field. I can't believe I did this when I know better! Next time I'll be sure to get my flat field close to the center of the Sun.

Some of the unfortunate brightness gradient can be seen in the following 3-panel mosaic showing modest sunspot 2506 with two filaments beneath it. The detail in this image is fairly good in spite of the mediocre seeing.
There were two nice prominences. This one was on the eastern limb.
Another prominence was on the western limb.
Finally, there was a small emerging sunspot with magnetic arches. This was visible near the upper right edge in the first image above.
I hope the Sun perks up in the next few months. Otherwise, 2016 will be a dull year for solar action.

Friday, March 4, 2016

Great Trails - Part 2

Wonderful Canadian Hikes

In the previous post I fought gloomy February blues by remembering warm days and excellent hiking trails from our 2007 trip to the Canadian Rockies. Now it's early March and still chilly. So I'm going to keep digging up good memories with three more Canadian summer hikes.

We stayed in Jasper for a few days and explored the surrounding area. Our first hiking trail, near Lake Patricia, was often lined with beautiful birch trees. (At least they looked like birch trees to my non-expert eyes.)
The hiking trail began next to Lake Patricia and proceeded into pleasant forest.
This soft trail through silvery trees would have been a great running trail if it wasn't also swarming with mosquitoes!
The beginning of our next hike to Stanley Glacier passed through unsightly remnants of a forest fire. Although the initial portion of the trail was not particularly scenic, trees eventually thinned, and the view opened to reveal our final destination.
At the far point of the hike we reached a scenic valley where a glacier descended in the upper left and a sunlit waterfall glistened on the cliff in the center.

Ahead, mountains seemed to block the way.
We encountered a friendly marmot who allowed us to approach closely.
Our last hike near Jasper was in the Valley of Five Lakes. Here is the beginning of the trail.
Soon we walked through birch and pine forests.
The trail then passed a series of small colorful lakes.
 The following magnificent scene came near the end of the hike.
Winter drags on now still, but I feel better after looking at these pictures.

People say I'm crazy doing what I'm doing
Well they give me all kinds of warnings to save me from ruin
When I say that I'm o.k. well they look at me kind of strange
Surely you're not happy now you no longer play the game

People say I'm lazy dreaming my life away
Well they give me all kinds of advice designed to enlighten me
When I tell them that I'm doing fine watching shadows on the wall
Don't you miss the big time boy you're no longer on the ball

I'm just sitting here watching the wheels go round and round
I really love to watch them roll
No longer riding on the merry-go-round
I just had to let it go

John Lennon