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Some Photos from Almost Heaven Star Party

18 Tuesday Aug 2015

Posted by gfbrandenburg in Uncategorized

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A wonderful astronomical weekend near Spruce Knob WV, at the Almost Heaven Star Party.

The fields at The Mountain Institute where it’s held remind me of the farm I grew up on, near Clarksburg MD, and the farm I lived in with Susan Greenthal Hurd in East Ryegate VT about 44 years ago.

The altitude here in WV does mimic the climate in VT. I have never gotten bitten here at TMI or AHSP or anywhere else I’ve hiked or canoed in West Virginia by any ticks or chiggers – which bedeviled me and my siblings 50-60 years ago in Clarksburg MD and continue to bite me at the Hopewell Observatory in Northern VA near Haymarket.

I brought my 12.5″ truss-tube dob, which you can see in one picture. I had just re-made the secondary cage and spider and secondary adjustment mechanism. I had to perform emergency surgery to cut off the truss tubes by exactly one inch so that all of the eypieces would actually come to a focus.

Part of the road up to TMI and AHSP

Part of the road up to TMI and AHSP

Baling hay in fields right next to TMI / AHSP

Baling hay in fields right next to TMI / AHSP

Learning how to use a sextant; if you know the exact time, you can use this to calculate your location to within 100 meters or so.

Learning how to use a sextant; if you know the exact time, you can use this to calculate your location to within 100 meters or so.

Beautiful but slightly threatening clouds the first night ended up dissipating. We had three beautiful nights of observing!

Beautiful but slightly threatening clouds the first night ended up dissipating. We had three beautiful nights of observing!

Me and my 12.5" truss-tube dob that I built,

Me and my 12.5″ truss-tube dob that I built,

This is the Durbin Rocket railroad - a small and slow coal-burning locomotive designed to carry heavy loads of lumber. If you sit behind the engine, you WILL be coated with coal dust and cinders.

This is the Durbin Rocket railroad – a small and slow coal-burning locomotive designed to carry heavy loads of lumber. If you sit behind the engine, you WILL be coated with coal dust and cinders.

A friend's minimalist, ultra-light dobsonian telescope, either 18 or 20 inch diameter. Note the lack of mirror box!

A friend’s minimalist, ultra-light dobsonian telescope, either 18 or 20 inch diameter. Note the lack of mirror box! It also tracks and has both Argo Navis and a go-to capability.

One of the many excellent talks. In this one, Jan Wisniewski (Vish - NYEV-ski) is showing how to make an IR on-axis autoguider.

One of the many excellent talks. In this one, Jan Wisniewski (Vish – NYEV-ski) is showing how to make an IR on-axis autoguider.

Here I demonstrate how light and insubstantial are the famous Seneca Rocks that I passed on the way back from the star party.

Here I demonstrate how light and insubstantial are the famous Seneca Rocks that I passed on the way back from the star party.

Great Long Weekend of Observing Near Spruce Knob, WVa at 11th Almost Heaven Star Party

18 Tuesday Aug 2015

Posted by gfbrandenburg in astronomy, Telescope Making

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AHSP, astronomy, ATM, dobsonian, star party

I put all of my tickets (over 30!) into the raffle for a 100-degree-apparent-field-of-view eyepiece at AHSP but didn’t win it. I probably should have put a few tickets in some other raffles. They had a whole lot of different stuff being raffled off. The eyepiece I wanted was donated by Hands On Optics. At AHSP they give you ten tickets as part of your registration, and then you can buy more of them. Elizabeth Warner and her husband left the morning of the raffle (Sunday) and gave me theirs, which was very nice of them.

At Stellafane, they used to have just ONE humongous item in the raffle, like a full set of really expensive eyepieces from Al Nagler. So it used to be in fact all-or-nothing. Don’t know if it was like that this year?
I discovered that the things I really needed were:
* an inexpensive laser collimator so I can get collimated in a minute or two all by myself, accurately, instead of fumbling around for an hour and needing an assistant… (now on order)
* an inexpensive electronic timer controller for my Canon TSi so it doesn’t need any cables to a computer (also now on order)
* a way to get rid of dew. The last night was fantastic except for the dew, which even defeated the chemical hand warmer packets that I wrapped around my finder and Telrad. I bet it got to the secondary as well. I will study up on the physics of heat production by resistors or heating wire wrapped around those and devise something.
BTW, I had to use a borrowed hack saw and masking tape to cut each of my truss tubes by exactly an inch on the second day so that I could come to a focus with all my eyepieces. I used some local rocks to deburr the cuts.
They had some great presentations on astrophotography, including how to do it simply and effectively. I was much encouraged.

Charon (NOT Pluto) with a huge crater that may have bashed it out of round

14 Tuesday Jul 2015

Posted by gfbrandenburg in astronomy, astrophysics

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Tags

astronomy, comet, crater, impact, minor planet, New Horizons, planet, pluto, solar system

Here’s a very recent (7-12-2015) picture of Pluto Charon that shows a bright circular feature near 1 o’clock with a long white streak heading down and to the right for a very long way – possibly even as much as half the diameter of the entire planet. If you look near the top of the image, you can see that it’s partly in shadow, and the low angle of the light from the Sun exaggerates vertical elevation changes much as they do here on earth just after dawn and before sunset. So we can see that the upper portion of the surface of Charon Pluto appears to be very irregular and not precisely spherical.

pluto w large crater

Which should be no huge surprise, given how small Charon Pluto really is (only 1200 2300 km across, or about 750 1400 miles, which is much smaller than our own Moon (Luna or Selene), in fact less than the distance from my town (Washington DC) to Miami. In this image the ‘top’ of the planet looks almost like a somewhat-rounded 7-sided heptagon rather than a sphere.

It appears to me that the object (asteroid or comet or whatever) which smacked Charon Pluto and formed that large crater came not along a radius, but at some other angle — I’d have to do some experiments to see whether the object came, so to speak, from somewhere off to our right and from our back as we view the image, or from the exact opposite direction, from above and in front of us, perhaps a bit to our left. I just don’t know if the debris from such an impact would fly back in the direction from which the impactor came, or whether it would continue going forward in the direction of the impactor. It’s fun to do experiments with sandboxes and lofting various projectiles, but you never know how well your set up will match reality. Sand and water at room temperature probably don’t act the same way as the surface of Pluto (various types of frozen ices, at its insanely cold temperatures), being hit by something that vaporizes and melts solid rocks by the tremendous force of impact!

I got the image from here. And thought this was a picture of Pluto. But it’s not.

Felling Some Trees at Hopewell Observatory So We Can View Polaris Again

20 Monday Apr 2015

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Yesterday, we felled a large red oak tree that was blocking our view of Polaris from the outside pier. (If you can’t see the North Star then it becomes very, very difficult to align your telescope for imaging.) Since the observatory was built in the 1970s and 1980s a lot of trees have grown a lot taller, and we’ve had to cut or trim several of them. This one apparently sprouted in 1940, by my count. Fortunately, one of our members heats his house with wood, and burned about 7 cords last winter. This tree is not even one cord.

The very first picture was taken just as the tree began toppling. I have a video of the tree falling and crashing, but WordPress doesn’t allow movies.

003

Timber!!!

008 007 006 005

Where I disagree with Francis S Collins

25 Wednesday Mar 2015

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Collins is a scientific big shot (head of the Human Genome Project) and is famous for also being very religious.

I’m not. I am in awe of the incredible wonders of this planet, not to mention the wonders of the universe. I am awed even watching my 20-month-old granddaughter learn new skills and new words, but I have no idea what CAUSED all those wonders to come into being.

In the copy of Mationsl Geographic that I just opened, Collins is quoted thusly:

“At the most fundament level, it’s a miracle that there’s a universe at all.”

I agree! 

He continues:

“It’s a miracle that it [the universe] has order, fine-tuning that allows the possibility of complexity, and laws that follow precise mathematical formulas.”

Perhaps miracle isn’t the word I would use, but it is indeed amazing that the universe has those properties. Why is it that neutrons and electrons have the properties that the do, and hydrogen and oxygen and all the rest behave the way they do? I have no idea. Physicists and chemists and biologists can describe those properties, and explain why more complex phenomena occur as a result of the fundamental properties, but we have no frigging idea what caused the Big Bang or why atoms and subatomic particles behave the way they do. Its a mystery that I think we will never discover. But Collins continues:

“Contemplating this, an open-minded observer is almost forced to conclude that there must be a ‘mind’ behind all this.”

Here I disagree. I haveno idea what caused the universe to occur starting 14.7 billion years ago, but for a “mind” of some sort to be In charge of setting the values of all those physical constants raises even more questions. And provides even fewer explanations. For example, one might ask: ok, where did this “mind” come from? Why did it set the mass of a neutrino at such and such? Can this “mind” change its mind if it gets bored? If yes, what happens? If not, why not?

He concludes that “to me that qualifies as amiracle, a profound truth that lies outside of scientific explanation.”

Here I might agree. I doubt we will ever discover a cause for the Big Bang or why the various physical properties of the universe are what they are and are uniform in all places and for all time. (Or why dark energy may be an exception)

It does not force me to conclude there is a “mind@ controlling all that. No particular evidence would leave me to conclude that the human sky deities and inventions called Zeus, Legba, Thor, Cronis, Allah, Atman, or YHVH are responsible for any of those mysteries.

A good night at the DC NCA CCCC telescope-making workshop

25 Wednesday Mar 2015

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Two major accomplishments tonight:

1. David C finally Aluminized his mirror in our vacuum chamber. Long story with mishaps that included pyrolized Sharpie marks on a previous quick and dirty aluminizationsfor attempt, and a Varian high-vacuum gauge that got stuck for a while. But he was persistent and diligent and forgiving as well.

2. Rich K appears to have finished parabolizing his 10″ f/7 mirror, which he had started about 20 years ago under the guidance of my predecessor, Jerry Schnall. If my Foucault knife-edge measurements are correct then it’s 1/15 lambda which is great.

Here is a treasury of talks by Neal DeGrasse Tyson

16 Monday Feb 2015

Posted by gfbrandenburg in astronomy, astrophysics

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Neal DeGrasse Tyson

Here’s the link: 

or use this:

http://www.sciencedump.com/content/storytelling-science-neil-degrasse-tyson

And here is a screen shot of what part of the page looks like:

neal d tyson science talks

Adventures in Making a Glass Surface Optically Flat

13 Friday Feb 2015

Posted by gfbrandenburg in flat, monochromatic, optical flat, Telescope Making

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ATM, CCCC, flat, interference testing, mercury vapor, monochromatic, optical flat

I’ve been trying to make an optical flat for some time now. It’s not easy, even if you are starting with a piece of ‘float’ glass – modern 3/4″ thick window sheet glass that is manufactured by floating a layer of molten glass on a bath of molten tin.

The test apparatus consists of a supposedly-flat 12-inch diameter and a monochromatic light box, and my own gradually-increasing understanding of what the interference lines actually mean. Essentially, they are like contour lines on a topographic map, but the trick is to figure out which sections represent valleys and which ones represent hills. It’s taken help from other amateur telescope makers (particularly Philip P) and sections of Malacara’s book on Optical Testing and http://www.lapping.com .

It’s pretty amazing how we can measure stuff that is soooooo small!

Here are some photos in chronological order of my working on them. I would paste some videos but WordPress won’t allow them and I don’t feel like uploading them to YouTube. BTW: I am not done!!!

022

006

008

009

That’s me looking skeptically at my cell phone, pretending to look skeptically at the glass.010

001

Up until this point I was trying to make the flat more perfect by using a hard Gugolz lap of full size (6 inches in diameter), much as we do with parabolizing concave mirrors. I don’t think I made a whole lot of progress. Then I read some of the papers that Philip P sent me, and re-read the Malacara, and decided to think of the contour lines in terms of measures of height, and decided to use a two-inch-diameter lap only on the parts that appeared to be “high”. I marked the back of those regions with a Sharpie permanent marker (which comes off easily with isopropyl alcohol when needed) so I could see where to work and could see if what I did made any difference.flats i guess 001The places that I marked with the letter H were High spots, kind of like you see on a weather map that is plotting isobars (lines connecting places with the same barometric pressure). The lower right-hand corner was one of those places, as was the smudged region at about 9 o’clock.

BTW I got the green color by using ordinary fluorescent lamps and two carefully-selected theatrical lighting gels to filter out all the light with wavelengths either longer than or shorter than the green Mercury vapor line of 5461 Angstroms.

By the way: I’ve discovered that the 12-inch-diameter optical flat that is underneath my 6 inch test flat isn’t as flat as I thought. Boo.

Will work on this some more this afternoon.

D’oh and Duh! 12 Inches in a Foot! My previous tables were all wrong!

09 Friday Jan 2015

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Oh, jeez, what an idiot I am. I overlooked the amazingly obvious fact that the focal lengths in my table were in INCHES. I somehow thought they were in FEET, but they weren’t.

As they say about scientific investigation in general, the easiest person to fool is yourself. I see that I did a pretty good job of doing just that. Thanks to those who pointed out my error, for example Mel Bartels. I guess that’s the great thing about these interwefts: you can get immediate feedback and have other, wiser souls point out your stupid mistakes in a matter of hours or minutes.

Here’s how the table should go:

corrected min distances for star testAs you can see, the distances are still pretty long,  but not nearly as long as I claimed. For our fairly-standard 8-inch (20-cm) f/5 mirrors, the distance we would need for a good star test would be 73 feet (22 meters). We still can’t fit that inside the CCCC building in one straight line. However, I guess that if we get some good first-surface flat mirrors, we could arrange for 73 feet/22 meters if we reflect the pinhole light a few times. I also bet we won’t need that lens to reduce the size of the pinhole, which you can see here.

A 12.5″ f/6 mirror will need 119 feet, or about 3 times the width of the CCCC game room. My 16″ f/5 will need a distance of 287 feet or 87 meters. That’s a long way; 7 times the distance across our largest room! I guess we’ll need a bunch of decent small flats from Surplus Shed, as well as precision tip-tilt devices to line all those mirrors up properly.

Introducing another telescope making blog

09 Friday Jan 2015

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David Collins has a nice blog where he’s been documenting his telescope making projects. His first scope, a 6″, is named the Riccioli, and his second, a 12″, is named the Schall von Bell. Beautiful workmanship and good optical practices as well. If you are interested in finding out why they have those names, you will need to read his blog.

The link for his blog is here.

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