Jan 15 2020

Betelgeuse is Fading

There has been a lot of buzz on the net about the star, Betelgeuse, Alpha Ori… the red supergiant in Orion’s shoulder (or armpit as people might prefer). It is a well known, bright red, supergiant, and it is a well known variable with a long period. Of late, it has been fading rather unusually for its regular patterns of ups and downs in brightness. This fading has everyone charged up…. you see, the star is old, near the end of its life. Stars of this high mass are supposed to supernova… BOOM! The trick is to know when. We have little idea on that, so any changes seen in stars like this make us get realllllly focused. Below is a snap of the latest observations of Betelgeuse’s brightness in V taken from the AAVSO. You can go see this data for yourself at http://www.aavso.org, and entering “Alfa Ori” sans quotes into the “Pick a star” field on the lower right of the page. Select plot light curve after that.

AAVSO V filter light curve of Betelgeuse

Orion with Betelgeuse as it would appear at 9:00pm from mid-northern latitudes tonight (January 15)

Dec 27 2019

The Dome Works!

Not a surprise at all, but we now have a rotating, opening and closing dome! Next steps are to putty in the weather seal along edges, and it will be complete. The interior of the building is getting walls and paint soon. Lighting and network cabling come next followed by the installation of the telescope by end of January! Stay tuned!

A wide angle look at the dome interior with the lower shutter open.

Exterior view with the lower shutter open and the dome rotated to point north.

All three of the observatory’s domes visible for comparison.

Below: Two short movies of the dome shutter being opened. This is a two-part process with the top shutter opened first followed by the lower shutter which tilts out. The top shutter’s lower edge overlaps the bottom shutter thus preventing weather from getting inside.

Dec 21 2019

There is a Roof and a Dome

Progress has been swift on the construction of the new building. Roofers have installed the waterproof roof layer and sealed around the dome’s base structure (framing). The dome has been built in place, and the shutter also installed. Interior work now progresses with the installation of the walls, trim, lights and such. Remember that for any of the images below, just click on them for a larger view.

Prior to pouring the concrete walkway we were expecting both rain then snow and freezing temperatures. Heating pads were placed to prevent frost on the ground before pouring the cement.

One wall has siding in this image, and the dome opening has been covered to protect the interior from rainfall.

All four exterior walls now have been sided, ventilation louvers have been installed, and the roofers are working on the rubberized layer on top the structure and around the dome, base frame.

Inside the control room, the base bearings of the dome have been unpacked for inspection and comprehension! So many parts are in this package, that it is a little mystifying.

The view of the telescope room through the framed wall of the control room. The window casement has been installed along with initial conduit for electrical. network and telescope control lines.

The dome is almost complete in this image taken at 6:30am with the sun rising. The dome’s motion is smooth and has that familiar rumble to it as it rotates in azimuth on its well-aligned and level bearings.

A wide-field image of the dome interior. Note that edges are a little warped in this image due to the camera’s odd stitching of the frames. You can see the top of the pier and the orange power line system for dome operations which make the system effectively wireless. No wires will be dangling down from above to control the dome’s motion.

Roof is complete. Dome is complete. Door has been installed.

Dec 3 2019

2019 Geminid Meteor Shower

One of the best meteor showers of the year is rapidly approaching. Peaking on the night of December 13/14, the Geminids put on a good show with peaks averaging at 120 meteors per hour. Now, with the moon being just past full that night, many of the fainter meteors will be drowned out by moonlight. Don’t be discouraged, though: we still expect to see some 30 meteors per hour. The best time to watch? After midnight, usually around 2:00am is best, but you can start seeing them after 10pm easily enough. Gemini will be high in the sky, and the night time side of Earth will be heading into the meteor stream.

The source of these meteors is from asteroid 3200 Phaethon, named after the son of Helios… Phaeton swings very close to the Sun in its orbit, being one of the Apollo asteroid members. Does it pose a threat to Earth? Not for the next 400 years or so, which is as far as our high-level orbital analysis shows. The asteroid has a 30 year orbit… so maybe in the distant future we might have to worry about this one.

Looking east at about 9pm local time, the constellations Orion and Gemini will be well above the horizon. Alas, the moon will also be in Gemini and just past full phase. Rather than looking at the moon-lit Gemini, look straight up and all around in the sky for the Geminid meteors.

Nov 17 2019

The Structure Takes Shape

This has been an exciting couple of weeks. As we have seen our first frost of the season (no snow just yet!), we have been putting up the frame and the structure of the building. Click on images for full size.

The corners of the building have been placed and the first wall frame goes up.

Work on the wall frames continues. Soon after this they will be sheathed with plywood.

The four walls are up, and the roof’s lower layers have been installed. There is also a ring for the dome.

The entrance to the observatory. Note the walls inside have yet to receive their plywood, and the floor needs to have concrete poured.

A view of the dome base framework from the rooftop. Imagine a large telescope on the pier with a 16′ dome surrounding it. The roof has a slight pitch to allow water and snow to run off to the north.

Another view from the roof. Where is that dome? Here it is! It’s the bundle of materials on the pallet. Some assembly is required. The black mats are covering what will be the walkway to the building.

Nov 10 2019

Now That is a Pier!

Construction is well on its way. The pier being poured and the concrete now setting, the various braces have been removed allowing for a clear view of the structure’s foundation.

Oct 31 2019

The Pier is Poured

Yesterday the concrete for the telescope’s pier was poured. What an exciting moment in this telescope’s history. The contractors used a very large Sonotube held rigidly in place with a temporary framework of wood and cables. Internally there is quite the framework of rebar to help reinforce the pier’s strength. A few conduits were also placed inside for electrical and data lines which will drive the telescope. Images (click on them to enlarge):

A view of the building’s site with the framework around the Sonotube for the pier.

A closeup of the pier near the completion of the pour.

A wide field view of the site.

Oct 24 2019

0.7m Telescope Observatory Construction Begins

This will likely be a series of posts involving some very exciting news here at the observatory: We are adding a new observatory building complete with dome and telescope! Very much exciting times! The new structure will be 16’25’ in dimension with a 16′ diameter dome on the south side. The interior will be divided into two sections: the telescope/equipment room and the control room. A wall with large glass window will separate the two so that people can work with low-level red lighting while keeping the telescope and its sensitive instrumentation in the dark and away from the heat of humans which can cause disturbing air currents.

Artists Impression of the 0.7m Telescope Dome.

The telescope is a PlaneWave 0.70m diameter modified Dall-Kirkham optical system with two ports. One port will hold a CCD imager with filter wheel. The other will attach to a fiber-fed echelle spectrograph. It is difficult to imagine the scale of such an instrument. The telescope alone weighs over 1500 pounds! For a comparison here I am standing besides the same model of instrument at a recent American Astronomical Society meeting.

Ground breaking started a couple of weeks ago. Concrete pouring started today for the pier footing and the footing for the building’s foundation. This will help give a sense of scale the final structure.

The boundaries of the structure have been posted here with wooden stakes. The ground is being prepped to dig for the base level foundation.

The gravel base for the concrete has been laid here. Looking closely you can see the inset region in the gravel where the pier for the telescope will rest.

The initial concrete pour which took place today. The central region is the base for the telescope pier. The surrounding is the base for the building’s foundation.

Aug 1 2019

The Perseid Meteor Shower has Arrived

The Annual Perseid Meteor Shower

Each August, the Earth passes through a stream of comet debris from Comet 109P/Swift-Tuttle. The comet will not be back our way until 2126… so… I wouldn’t wait up for that one. Along the orbital path, the comet has left behind small bits and pieces, most no bigger than a grain of sand. These run into our planet’s atmosphere and burn up due to friction. The result of this friction-filled reentry is a meteor, a rapid streak of light through the sky. This shower usually gives us about 60 meteors per hour at peak, and many fireballs: bright meteors that can even be bright enough to cast a shadow. How to see it?

Pick a clear night closest to the peak, which is on August 11th/12th/13th.
Go to a dark sky site: avoid lights and cities. The darker, the better.
Bring something comfortable to lie down on: sleeping bags are good.
Bring food, drink, and bug spray if needed for your location.
Spend the night time hours looking up at the sky! No optics required other than your eyeballs.
Avoid lights! No cell phones. No flashlights. Your eyes take between 30-60 minutes to become dark adapted, and you lose that dark adaptation instantly if you see a light. Avoid lights!
The shower appears to come from a spot in the sky in the constellation Perseus. This rises just before midnight, so best observing will be after that, into the morning hours.
Have fun!

Jan 2 2019

Then and Now: Astrophotography on the Simple Side?

I spent some time this morning with PixInsight on a stack of M-42 images. This is the result. PixInsight is an impressive, though oddly challenging, piece of software. The interface still eludes me at times. The results are splendid, however.

This image was taken through a Nikon D-810a at f/4, 200mm, tracked on an iOptron mount in gusty winds. This piece is the result of three major processes:

All images were aligned using stellar centroids.
The images were then stacked… this is an image integration of 100 seconds worth of exposures.
PixInsight was then used to do a Dynamic Background Extraction to essentially perform a flat field thus removing the lens’ vignetting. I still can’t get over this process: no flat fields required… though I bet real flats would result in a better overall image.

The camera does its own internal bias and dark subtraction. The image was then brought into PhotoShop for adjustment to levels and cropping.

Now… compare that colorful image with the monochrome one: that was taken way back in 1986 on Tri-X Pan film pushed to about 1000 ASA by boiling it in nitrogen. The image is a 20 minute exposure through a Celestron C-8 at f/10, manually guided with an illuminated reticle eyepiece. I developed this in my bathroom using duct tape and towels to block all external light from entering.

What a difference! New technology brings better sensitivity and a whole new world of imaging…. but we knew this. I’ve been playing with CCDs since the early 1990s. No surprises. The real surprise? Cost! All this tech adds up in cost. I am not really sure that it saved me a whole lot of time to make the new image with the new tech… perhaps if both images were color? Then, yes, the new tech has saved me time. Simple? M’eh. It’s about the same level of technical detail. It ends up being about one’s knowledge base: software or film developing? You choose. Certainly some of my best images were taken with film. Which do you prefer? It’s totally up to you. Like vinyl records, film is making a comeback, but hasn’t made its way to the realm of astrophotography again. I am pretty sure that CCDs and CMOS sensors are here to stay for astro-art imaging.

PixInsight sounds interesting: check out their site here.
iOptron? Check out their site here.

ExeterAstro

Astronomy at Phillips Exeter Academy

Category astronomy