The Story of John Dobson
John Dobson, famous the Dobsonian telescope style, had an enormous impact on amateur telescopes. His
story is worth a read (with a photo of a classic Dobsonian scope from
another site):
Dobson isn't a household name, nor is he one of those people you could describe "in a nutshell." He has been compared to Isaac Newton. Brett Campbell, in an article for the Wall Street Journal, called him "one of history's great popularizers of science."
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In 1956, Dobson built his first telescope, a two-inch 'scope made from scavanged parts. With it he could see the rings of Saturn, so he made another bigger one. Peering through it at the moon, he thought everyone should have the chance to see what he was seeing. Because Dobson was a monk and had no money, he had to make his telescopes with scraps and things that were given to him - old portholes and scrap wood, for example. He learned to grind his own lenses and make his own mirrors. His heavenly obsession, however, got him in trouble with his monastery, and eventually, in 1967, he was asked to leave.
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All the great big telescopes now on the planet are called Dobsonians," he said, although that's because the mount that is used on virtually every telescope today is a version of the mount that he invented. In 1978, Dobson was invited to speak at the Vedanta Society of Southern California. He now teaches a "Conceptual Cosmology" class each year there and has written several books on the subject. He has matched his peerings into deep space with deep thoughts about the nature of the universe, some of which turn astrophysics on its head. According to him, the question we should be asking is "Why do we have a universe at all?"
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Optics-shaped building #2
As a follow-up to the recent post on
giant binoculars, here's a building
planned for China in the shape of a "giant square telescope." This seems like a bit of a stretch. Click through for various Chinese buildings in development.
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The 990-foot China World Trade Center, in Beijing, will be the centerpiece of Beijing’s developing business district. The glass-and-steel tower very gradually steps back as it rises, looking a bit like a giant square telescope. Its facade is layered with a series of faceted vertical glass-and-metal fins, creating a texture that the firm says will look somewhat like a waterfall.
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Distinct homemade telescope
Here's a
story on a telescope constructed with surplus parts from Ebay:
This is a telescope constructed from the combination of a Russian "Tourist-FL" eyepiece which accepts M42 (a.k.a. Pentax/Universal) manual screw mount lenses a 2x teleconverter and a Russian Lytkarino 3M-5CA 8/500(f/8 500mm)Maksutov Catadioptric Lens.. I constructed it for less than $100 using surplus and parts obtained over eBay.
The resulting telescope has an 111x magnification with "right side up" imaging, without the teleconverter the magnification is 55x. The telescope is nearly free of abberations.
Given the extreme magnification it is necessary to mount a "red-dot" paintball gunsight on top to aim it.
I'm curious about the image quality for only $100 in costs.
Hard storage case: Info and vendors
Here's a topic near and dear to many of my hobbies: hard waterproof storage cases. This
article discusses the topic in the context of boating, but the considerations apply to many other situations. Don't miss the vendor list at the end:
Hard case, soft case, which to choose for that next raft, canoe, or kayak trip? Each has a place in the entourage, but a hard case is about serious protection and organization. Sometimes it's overkill and sometimes it just won't fit in the boat. When to use one, what type to use and why, are the questions we'll give consideration to here.
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20 Years of Digital Imaging
A
fascinating article in a professional imaging magazine describes many of the advances in imaging of the last 20 years. Digital cameras are the most relevant to this blog, but lots of this stuff is great! Click through for about 20 more photos.
Stargazing and the Solstice
No, not
THAT Solstice! Here's a
roundup of things to see in the sky this June:
The first day of summer is called the summer solstice, and although we don’t use standing stones and priests (the priests were replaced by astronomers) any more to foretell its arrival we still use the sun.
Our planet is tilted 23 1/2 degrees to a point in space called the North Celestial Pole. It is this tilt that is responsible for the seasons since at one point of Earth’s orbit the northern hemisphere is facing towards the sun and on the opposite side of its orbit it’s facing away.
When we view the rising sun at this time from Connecticut, we see our star rising further to the north as we approach the summer solstice. Since the sun rises further to the north, it is higher in the sky. This results in more direct rays, which gives us longer daylight hours and warmer temperatures.
Astronomically, summer begins when the sun’s vertical ray strikes 23 1/2 degrees north of the equator. This imaginary line of latitude is called the Tropic of Cancer.
If you were at this location during the summer solstice, the sun would be directly overhead at noon.
Naked-eye June planets
Mercury, the innermost planet in the solar system, will make a rare appearance in the west about an hour before sunset.
On June 20, the tiny planet reaches its highest point in the sky (called greatest eastern elongation), and this is the time to look for it. If you do plan to observe Mercury, the sky must be clear, and you will need an unobstructed view of the western sky.
The red planet Mars is still visible in the west just after sunset. The planet will move through the constellation of Cancer this month and on June 15th will be located in the Beehive star cluster (also called M-44).
This event will be quite an interesting sight in binoculars since the Beehive is one of the most beautiful star clusters in the sky. This star cluster is called the “Beehive” since stargazers of long ago compared the dozens of tightly packed visible stars to a swarm of bees flying around a hive.
If you do have binoculars, check it out. It’s easy to find, and worth the effort.
The ringed planet Saturn is also visible in the west, and although it is slowly fading in the sky, it is still a prominent object and a grand sight in a telescope of any size.
Jupiter, the largest planet in the solar system, will be located in the southern sky as soon as the sun sets, and excluding the moon, it will be the brightest object in the night sky.
On June 8, the moon will apparently pass close to Jupiter, and this will be a good time to locate the planet. Venus appears like a dazzling jewel in the eastern predawn sky and is located near the Pleiades star cluster, which is also known as the Seven Sisters.
The two together in the early morning make a wonderful sight when viewed with the naked eye or low-power, wide-angle binoculars.
June lunacy: the Strawberry Moon
Each full moon was given a name depending upon what was taking place at that time on the earth. The full moon in June was called the “Strawberry Moon” by the Algonquin Native Americans since the strawberry harvest took place only during this month.
The June moon was also called the “Rose Moon” by Europeans since June was a month when the roses began to bloom.
First Quarter Moon will take place on June 3 (this Saturday); Full Moon will be on June 11, Last Quarter June 18 and New Moon on June 25.
On June 22, the thin crescent moon will pass near the planet Venus in the early morning sky just before sunrise. This naked eye lunar-planetary alignment should be quite a beautiful sight. Don’t miss it!
Adventures in cheap digiscoping
A
news story outlines one man's story in digiscoping:
You have a camera that takes nice nature photos, but only if the birds are good enough to land directly in front of you.
You have a spotting scope that brings distant birds up close, but the only way to share the image later is to describe it.
I've recently been playing with a way to bring the two together — a bracket that turns my scope into a telephoto lens for a digital point-and-shoot camera.
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I have a Swift Searcher 60 mm scope with 20X and 40X eyepieces. It gives me a nice, close up view of distant animals. A local retailer told me the camera adapter for my Swift was not available, so I went to where those two words are never spoken — the Internet.
There I found the 841-PA Telemaster Telephoto Adapter. It was listed as fitting the Searcher, so with a credit card and a click of the mouse, it was mine.
Now here's the lesson about the value of dealing with a local retailer. The accommodating Web site neglected to tell me that a piece is needed to connect the 841-PA to the Searcher. Swift no longer makes that piece. It's not available.
Undeterred, I continued my quest. While attending the massive paddle sports sale Canoecopia in Madison, I happened upon the Eagle Optics booth and the Radian UNIVERSAL Digital Camera Adapter. For about $50, I entered the world of digiscoping.
The adapter clamps onto the eyepiece of my scope. The camera screws on by the hole normally used for a tripod. Fine-tuning adjustments move the camera up or down, left or right and in or out so it matches up perfectly with the eyehole.
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My digiscope setup did capture nice closeups of a downy woodpecker, northern oriole and indigo bunting.
Next, I spent an early morning in a farm field where sandhill cranes shake off their slumber with a leisurely walk and a light breakfast of grubs and corn stubble. The limitations of digiscoping quickly became even more apparent.
To get a clear shot, you need to focus through the scope, which has a very narrow depth of field, and then clamp on the camera. Sandhill cranes standing nearby become sandhill cranes in the distance by the time you accomplish this.
I did get better at focusing through the blurry, little camera viewing screen, but this setup definitely works best on subjects that don't move around much or for focusing on a spot and waiting for the wildlife to come to it.
My own story isn't much different (I'll do a separate post when I have the time). I bought a cheap 40mm Plossl for my Pentax scope to produce the lowest magnification (it improves the exit pupil and brightness of image). It works. I also got a $35 Orion camera bracket...but can produce better pictures by handholding the camera!
