Friday, June 28, 2013

Thomas Harriot's Moon

Between 1609 and 1610, Englishmen Thomas Harriot produced a number of drawings of the Moon, as well as what is probably the first map of its surface as well. The instrument he used was a simple Dutch "trunke", a telescope, of what we generally refer to as "Galilean" in design.
That is, of course, a misnomer; Galileo did not invent this optical design, he refined it. Others proceeeded him, Hans Lippershey in particular, with Sacharias Jansen and Jacob Metius also playing significant roles. 
Yet it was Harriot who aimed a telescope skyward and recorded the results.
It is interesting when we compare his map of the Moon with a modern image.

One of Harriot's Moon maps, Courtesy The Science Museum, Kensington
My image of the full Moon, early morning of the 23rd June, 2013 (the so-called Super Moon)

While not as artistic as Galileo's drawings, it is nevertheless remarkable, and proof of what a small telescope is capable of revealing to the humble viewer.

Wednesday, June 19, 2013

Galileo, Scheiner, Sunspots & Saturn

I decided to work on my Galilean-Scheiner sunspot study by conducting a test of instruments with those old optical layouts. For this, I used my facsimile Galilean and my small Keplerian.

Someone replied not too long ago that looking through a long tube Galilean telescope was akin to looking through a straw. Nothing could be more frustratingly true, but from a projection standpoint, it works much better.

However, the question must be asked, which telescope did Galileo use? The long tube instruments are incapable of projecting a full Sun; they simply have too much magnification. 

Surely, he used a smaller instrument. It was obvious, though, that it could be done, and the result is simply a mirror image.
Christoph Scheiner, however, preferred the Keplerian telescope. The Keplerian design uses plano-convex lenses for both objective and eyepiece. Like the Galilean, it is a simple two element design, but it produces a much better field of view. The tradeoff is that the image is inverted, but for astronomical purposes, this really isn't a problem. Scheiner was an early proponent of this design, and perhaps to be credited for its greater acceptance.

As expected, the images produced by the Keplerian were brighter and much clearer.

In this case, the image needs to be rotated 180°. I've enhanced it somewhat to bring out some of the sunspots.

The final test will be the creation of a Galilean eyepiece for the small Keplerian telescope, and a projection made to see if that approximates the studies performed by Galileo. In the meantime, it is clear that Scheiner does deserve more recognition for his pioneering work.

Wave At Saturn Night!

Tonight is "Wave At Saturn Night". This showed up on my Facebook page yesterday. This is the first time I've seen or heard of it. Nor am I able to find it again. But it seems like such a fun idea. Silly, yes, but fun.
Holidays like this, though, will forever be moving ones; planets fail to appreciate our calendar and seldom tarry long in one place.
Tonight, Saturn is pretty close to zenith at sunset. with a waxing gibbous Moon to its east. The white moonlight should proved strong contrast to Saturn's yellowish hue. 
If you get the chance to, be sure to take a step outside and look for Saturn, that bright yellow star north and west of the Moon.

Addendum - It was Philip Astore, amateur astronomer and professional firefighter, who made the comment about looking through a straw. Anybody who loves astronomy is a friend in my book, but this fellow also has one of the toughest jobs in the world. Stay awesome, Philip.

Monday, June 17, 2013

First First Light - The Anniversary

A few entries back, I wrote about my first first light with my old Tasco 50mm. The date I included was wrong; it was actually the 14th, not the 18th. It was a Sunday night.
Anyway, to commemorate the event, on the night of the 14th, I decided to recreate that moment with my Tasco 50mm, same model I had back then. I used two of its original eyepieces, a 20 and 12.5mm, both Huygens, as well as a new 20mm MA. All three eyepieces are, of course, .965".As with that night, I chose to observe Saturn, as well as the Moon.

What a difference thirty years makes.
The Moon that night was near full. I knew back then from using my binoculars that the Moon isn't much fun to observe near full. For the 32nd anniversary session, it was waxing crescent, and glorious. In 1981, Saturn and Jupiter were near one another. in 2013, Saturn lies just east of Spica.

The sky over Jacksonville the night of the 14th June, 1981.
(Courtesy YourSky at Fourmilab)
The night sky over Jacksonville, 14 June, 2013.
And like then, the sense of wonder I felt, even with such a small instrument, was the same.
I simply love the heavens.

Such a fine little instrument. The tripod isn't original, but everything else is. I seldom use small telescopes with finder scopes, by the way.

Wednesday, June 12, 2013

A Fireball, If Ever So Briefly

Last night, at 9:48 PM, I was exiting the van in the driveway when something caught my attention up in the north-northeastern sky. I turned just in time to catch a fireball. It was easily brighter than Venus. Duration was maybe three seconds, tops.
The problem was that the beautiful live oaks that make this part of Jacksonville so alluring were in the way. Still, this object was so bright it showed through the tree canopy. 
It also led to my first fireball report to the American Meteor Society
I've seen literally hundreds of meteors, dozens of fireballs and a handful of explosive bolides. I have never taken the time to report the more significant events. Even when I worked as an astronomy educator, this little matter went to the wayside. For me, those astronomical objects of true desire for me, the planets, open and globular clusters, stellar associations and such, were far more important than these errant pieces of Solar System jetsam and flotsam. In light of the interest in the possible recurrence of the legendary Gamma Delphinids, however, I decided to, for once, be a responsible observer and report the fireball. 
From my vantage point, this is the path the object took.

As it turns out, I wasn't alone. There were two other possible sightings from two very different locales; Myrtle Beach, South Carolina and Lakeland, Florida. Taken together, with information gleaned from the pending reports at the AMS site, we get the following. 

The green lines represent line of initial sighting, the red the last. Angles are approximated. The yellow path is a potential trajectory that the object may have taken. Unfortunately, to verify that trajectory, exact times for all the sightings would be needed.
Nonetheless, it was a bit thrilling to catch such a wondrous event, albeit briefly. 
You never know when you have just observed a greater event, and when you contribute that information, you are doing, you guessed it, science.
Next time, better notes.

The AMS has compiled a total of five reports, of which mine was one. Here is the final analysis -
Event 1267