Andrew

The Moon and Venus

The nice evening planetary alignment continues tonight. This evening will feature a nice pairing of Venus and the Moon. It will be hard to miss the bright pair only 8° apart. Venus will be shining brilliantly at about -4.2 magnitude next to a 10% illuminated Moon. Jupiter can be seen 16° above the pair. Mercury is visible just above the sunset. The Moon and Venus will be even closer tomorrow night, only 5° apart.

Postcard from the Universe – The Moon and Mercury

A very thin Moon could be seen last night. Only 1.1 days old the Moon was only 1.6% illuminated, a thin crescent indeed. A few degrees away was Mercury. I did get a couple photos with a telephoto lens before the clouds moved in and obscured the view…

Violet Haze, A 90mm f/13 Apochromat

I had wanted a high quality APO refractor for some time. Mostly for photographic use. Opportunity presented itself when Roger Ceragioli offered me a 90mm telescope he had finished the year before and was willing to sell. Working for the Steward Mirror Lab, Roger normally grinds very large optics, things like secondaries for six to eight meter telescopes. But as a hobby he makes somewhat smaller telescopes. This particular lens set had won him a merit award at RTMC in 2002. I had previously seen this telescope and after some negotiation we settled on a price.

The lens triplet is exquisite, providing absolutely perfect airy disks at high power. The photo below shows an example of the out of focus image of Antares taken with the telescope. Pulling out my copy of Suiter’s Star Testing Astronomical Telescopes shows nearly identical images for the ideal diffraction pattern. No wonder the ‘scope won a RTMC merit award.

Photographically it has proven to be almost perfectly free of color, corrected across the spectrum. There do not seem to be any detectable UV or IR halos around bright stars. This is partly a result of good design, and aided by the long focal length of f/13. No field flattener is required, with pinpoint stars across the focal plane.

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The Moon and Mercury

This evening a thin crescent Moon will join Mercury in the sunset. The pair will be separated by just under 6°, at about the same elevation and 15° above the horizon at sunset. The Moon will be extremely thin, only 1.7% illuminated, while Mercury is shining at -1.2 magnitude.

A Backyard Telescope Pier

Complete Pier — The completed pier with a telescope atop

Have you ever wanted to have a place to set up your scope easily in the backyard? with instant polar alignment? no tripod legs in the way? Even for someone with little handyman experience a pier is an easy weekend project that can be completed for around $60. Add the cost of a wedge for your scope, about $125-$400 new, less used, and you have a usable pier. A few bags of concrete, a little rebar and a sonotube will do the job. I know, we ATM’s usually use sonotube for telescope tubes, but this is what it is really meant to do, cast concrete.

A pier is also the first step in a real backyard observatory, build the pier first, then a building around it. The process shown here works for any pier and can be scaled as needed for larger scopes. The pier shown in the photos is intended to hold an eight inch SCT.

The plans and photos shown here have been used for several piers here in the Tucson area and have been refined with the experience. Feel free to improve on what is here, and if your idea works well send photos!

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Dispatch from the Summit – Chaining Up

By all accounts it was bad.

I was scheduled to go up, but ended up not joining the summit crews today. Just as well, they did not make the summit. The crew made it partway up, to about 12,000ft., into snow and freezing rain. Not a lot of snow, but a lot of slick ice, altogether much worse.

I talked to a few guys and the descriptions ranged from nasty to miserable. Pete remarked that his hair and pants were slowly icing up in the freezing rain. Kirk recalls parking the pickup to put on the chains, when getting out Michaela noted the vehicle was still moving, sliding sideways on the ice.

The road is closed to all vehicles! This is quite unusual, normally it is closed to the public when bad weather dictates, but remains open to observatory vehicles. Our trucks are some of the few vehicles on the island equipped with bad weather kits that include chains and other useful gear for dealing with ice and snow. Watching island boys with no winter weather experience trying to drive on ice can be rather entertaining.

I am scheduled for tomorrow as well. I will read the early morning reports from the rangers and decide if it worth my time. No point in going up just to spend the day sitting at Hale Pohaku. I may as well get something productive done at headquarters. Thus I pass along a photo from fellow Keck engineer Ean James…

Chaining Up — The Keck crew chaining up on the summit road, image credit: Ean James

A GPS Observing Clock

For years, when observing, I found myself wanting a clock on my observing table when recording observations. I have used either a wrist watch or a cell phone, but looking at these was uncomfortable as these modern devices use bright backlit LCD displays, not a nice night-vision friendly red. The cell phone also has the additional problem of using up its battery quite quickly when out of range of a digital cell tower at some remote observing site. I needed a simple desk clock for my observing setup.

Accuracy was also a question, accurate time is always important when observing. Asteroid occultations, lunar and solar eclipses, iridium flares, twilight, jovian moon transits, the list of things where accurate time is useful is long in astronomy.

The Specs

Of course being a electrical engineer makes designing and building a clock a fairly trivial exercise. But why stop there? Why not build in a few extra features…

Use red 7-segment LED’s and build in some type of selectable dimming mechanism.
Why bother setting the clock each time you set it up? Make the clock self setting and very accurate.
Since the clock is accurate add a serial port to allow the clock to supply accurate time to a laptop when taking astrophotos.

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New Moon

Young Moon — A very young moon over Waikoloa, this is only 26 hours after new, visible to the unaided eye as a sliver in the fading glow of sunset

New Moon will occur today at 12:35HST.

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Dealing With the Old Darker View

How do I fold all of the legacy parts of Darker View into the new format?

Not easily.

Slowly, I hope to move all of the legacy information in the old darker view site onto the WordPress platform. The first goal is to deal with the old static HTML pages that existed beside the blog. These pages have an ancient heritage, at least by web standards. They are fragments of the website I began almost twenty years ago, the old WhitethornHouse.com. Much of this was ported into the blog when the website was converted in 2007. At one point the whole thing was seamless, the blog integrated with static HTML pages, integrated with a batch of PHP scripts to dynamically create the observing database.

Right now the thing is just a mess.

The goal is to achieve the same seamless appearance. First to import all of the old static pages into WordPress as either posts or pages within the WordPress database. This requires some method of redirecting the old pages to the new locations when a 404 error occurs. To this end I have borrowed and modified a custom PHP script to automate the 404 page. With this I can map any deleted pages to the new location.

I hope.

Actually, it seems to work reasonably well. With this I can begin the process of deleting the old material as it is imported into the new format, without abandoning all of the old links to my site that exist across the net.

Expect problems. Expect dead links that will eventually get corrected as the material posts to the new site. Expect to see old articles posted as new on the new site, that material I deem worth preserving. This will be a long process as I slowly, page by page, move the material across and get the links re-mapped.

Bear with me. Thanks!

Improved Rocker Box Pads

A small design detail in a dobsonian telescope is a method to restrain the mirror box in the center of the rocker box, to keep it from sliding side-to-side in the elevation bearings.

A common solution is to use a couple carpet pads to provide a lateral support that keeps the wood from rubbing. The pads do not add any friction that would keep the scope from tracking smoothly at high power. These pads are available in most hardware stores in both sheet form as well as pre-cut circles, usually one inch in diameter.

I have had trouble with these pads in Deep Violet. They do not stay put! Sometimes when inserting the heavy mirror box into the rocker I would catch a pad and simply shear it away from the wood. I ended up using a larger pad and using small wood screws to secure it instead of the adhesive.

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