Comet C/2007 N3 Lulin

The clouds have not been kind to those of use hoping to observe a comet here in Hawai’i. Last night Deb and I were at the Mauna Kea VIS, volunteering with the evening stargazing. I had hoped to get a good look at the comet from a dark site. But the clouds kept me from seeing the comet at all. A few people did get a look when a hole in the clouds allowed a glimpse, but by the time I got to an eyepiece the clouds had again closed over Leo, obscuring the view.

I did get a few hours of decent skies a few nights ago from the driveway in Waikoloa. I took advantage of that time to get twenty four minute exposures with the Canon 20Da and forty exposures with the CCD camera. Unfortunately the streetlights precluded my getting a decent visual view. The camera did a bit better, revealing some interesting structure to the tail.

Processing the image proved to be quite a challenge. The comet is moving very fast against the background stars. Aligning the images on the stars turns the comet into a long blur, likewise aligning the images on the comet creates streaks in place of stars. The answer is to process the image both ways and add the two resulting frames together as layers in Photoshop. This is the first time I had attempted this process and the results are reasonable…

C/2007N3 Lulin
Comet C/2007 N3 Lulin on the morning of 22 Feb 2009

Comet 144P Kushida

I took advantage of a clear evening to do a little more driveway astrophotography. The target was comet 144P Kushida. The comet is nearly at the Zenith in the evening, very conveniently placed with ample time to take more than a few frames.

The setup was fairly typical for me, the Canon 20Da and the TV-76 shooting for over 40 minutes (10 frames at 4 min each). The frames were calibrated and stacked in Images Plus and post proccessed with Photoshop and FITS Liberator. I followed Jerry Lodgriss’ instructions for preserving and enhancing the star colors with pleasing results. I suspect I will be using this technique more in the future and star colors are something that has always frustrated me.

Comet 144P Kushida, 20 x 2min exposures w/180mm lens @ f2.8 and IDAS LP Filter, 15 Feb 2009
Since I have a CCD camera co-boresighted with the TV-76mm refractor I was able to use the CCD to take frames simultaneously. This arrangement is convenient as I can use the CCD for finding and framing the target, the field of view is very similar between the two cameras. I spent time early in the evening to carefully align the CCD to match the view in the refractor. There is also a small 10cm SCT in the setup for use as a autoguider scope, but I have not been using this lately. I suspect I will try some longer exposures of C/2007 N3 Lulin in a few days and will need the guider.

The comet itself was fairly straightforward, a round coma with no real tail, a slight off centered shape to the coma. The cyanogen green comes through nicely, very apparent when processing the color planes separately. It is moving fairly slowly, for the DSLR photo I aligned on the stars and only had slight issues with the comet trailing. For the CCD image I aligned the images on the comet, showing some trailing in the stars.

The CCD frames do not show any sign of a tail or other structure either. This is not surprising as 144P Kushida is usually a fairly dim comet that is bright only due to material from an outburst a couple months ago. It is not a highly active comet with jets, tail and all of the other features that can make comet photography so interesting.

Comet 144P Kushida passing through heavy starfield in Taurus on the evening of 15 Feb 2009, stack of 10 x 4min exposures with a Canon 20Da and TV-76mm

Shoveling Snow

Monday I spent the day on the summit, I often choose Mondays, if I have a choice, as we often have a smaller crew and getting access to the various parts of the telescope is easier. There are fewer people trying to do fewer things at once. Monday turned out to be very good choice indeed, the first clear day at the summit since Christmas. We arrived at the summit to deep blue skies over a landscape of white. Poli’ahu has again blessed the summit of the White Mountain with deep snow.

Snow Day
Looking across at the Keck 1 dome from the top of Keck 2 with Mauna Loa in the background
A small crew does have a disadvantage as well, the chance of being drafted into whatever job needs being done. Not that I was unwilling, the job in this case was clearing snow and ice from the domes. This meant climbing to the top, one place in the facility I had not yet had a chance to go.

So after rigging myself in full safety harness I climbed the dome with the crew. The view from the top is stunning! A full 360 degree view of the summit on a perfectly clear sunny day. The entire summit is blanketed in a beautiful white coat of snow, one of the most dramatic scenes I have ever witnessed. The small Canon G9 camera fit in a breast pocket, small enough not to interfere. I began filling my memory card with many images of the view from the top, reveling in the spectacular vista.

Shoveling Snow
Mike Dahler clearing snow from the edge of the Keck 2 shutter
Not that it was all sightseeing, there was work to do, shoveling snow and chipping ice from the areas where it could interfere with operation of the telescope. Ice and snow coated the upper sections of the dome. Several inches of ice needed to be hammered free of the steelwork and drifts of snow, up to two meters (six feet) deep were packed into any corner and along the side of the shutter. Blocks of ice and shovelfuls of snow flew, crashing to the ground 30m (100ft) below. A crew worked each side of both domes for several hours to complete the task, made all that more difficult by the extreme altitude.

In the thin air there is only so much you can do before you are short of breath. Put down the shovel for a few moments and take a few more pictures. I have material from which to assemble a full panorama as well as dozens of individual images.

After much of the snow and ice had been cleared by hand there was one more step to accomplish. Clear the large drift of snow from the back of the shutter by using the shutter itself as a snowplow. This drift is many tons of snow, over 2m (6ft) thick at the top and about 12m (40ft) wide. When it came down it becomes an artificial avalanche, with huge blocks of snow falling to the ground far below.

Avalanche from Andrew Cooper on Vimeo.

Lunar Halo

Damon alerted us to a nice display of a lunar halo currently gracing the skies over the Big Island. A nice example of a common 22° halo that can occur any time there is a thin layer if high cirrus. The 22° angle from the Moon is a result of refracting moonlight through ice crystals. These high altitude crystals act as little prisms, catching and deflecting the light at specific angles. The halo is actually very large, extending from 22° to 50° away from the Moon, but is brightest at the inner edge.

Lunar Halo
A 22° lunar halo produced by ice crystals high in the atmosphere over Hawai’i on 8 Dec 2008
Halos like this are really quite common, but always seem to catch the attention of those who do not regularly watch the sky. There are many fantastic sights that occur regularly around us, all we have to do is keep an eye to the sky. It has taken centuries to learn how these effects are created though the play of light and water, even now there are some that are poorly explained. It is fascinating to learn what can occur and how it works.

There is a great website, Atmospheric Optics, that has examples and explanations for the many beautiful effects that the play of light can create in the atmosphere. Sun dogs, rainbows, parhelic arcs, glories, specters and more.

This halo is fairly broad and ill defined, probably because the ice crystals are randomly arranged. The halo could be sharper if the crystals were all at the same orientation to us, something that can occur if the winds are right. I attempted a shot of this one, the first time I had attempted to photograph a lunar halo. Not the greatest photo, this was pressing the camera to it’s limit. Even so the image starts to show effects invisible to the human eye, including a hint of color at the inner edge of the halo.

A Phone Call

Monday morning comes with a round of meetings. The entire department sitting down to plan activities for the week. In about ten minutes I need to set up for a technical presentation, my Power Point file on the thumb drive beside a pad of paper. It is just past the opening niceties that my cell phone rings, an abrupt interruption that stops all conversation around the table. It takes a few seconds to fumble the phone out of the belt pouch, stabbing the button on the side to silence the cheerful and yet unwelcome tune.

Looking at the number on the little screen I take a deep breath, reading no further than the area code before all thoughts of the meeting fade. This is the morning my father is in surgery, a heart bypass operation. It is not his first, the family went through this same event many years ago, but he is older, a worry is there, coloring all emotions. The last times I have seen my father he has seemed to tire a little more easily, looked a little older. Unable to join my mother and I in a swim out to the reef, turning around part way out to sit on the beach instead. Opting not to travel to the summit and the thin air of 13,600ft for a tour of the telescope where I work.

Fred Cooper
Fredrick Cooper kayaking in Warm Springs Bay, Baranof Island, Alaska
We are planning another vacation to Alaska this coming summer. A trip that will bring together close family who are normally spread across half a continent and more. Twenty two days on a rented boat out of Juneau, fishing, cruising and watching bears, glaciers and whales. But most importantly spending time with my family, something I all too seldom do. Chasing dreams and working at the observatory in Hawai’i has a price, years spent far from family.

For a few seconds after the phone is silenced I can do nothing but stare at the number. I need to return this call, but am loath to do so. Sliding out of the conference room I feel my co-workers’s eyes following. Once in the hall I take a breath and attempt to remember the keys needed to redial the last caller. For a moment the sequence escapes me, my mind far beyond the keypad. I hit end to reset the phone and start again.

The phone rings, and continues to ring, I hold my breath as it takes far too long for someone to answer. Finally I hear my mother’s voice, a smooth and normal tone that puts fears to rest even before her words have meaning. The news is good, everything went well, he is in recovery and should be be receiving guests shortly. I return to the meeting, making my apologies, turn on the projector and begin to load the file into the laptop.

There is a boat and a fishing pole waiting in Alaska this summer, I will be there.

The Symmetry of Mountain Shadows

The sunset view from the summit of Mauna Kea is truly spectacular. From the summit you are usually above the clouds, watching the sun sink into a cloud layer thousands of feet below. The colors are intense, the deep blue sky, the red cinder and the gleaming telescope domes. This spectacle draws tourists from across the globe, trekking up the mountain just in time to witness sunset.

The Shadow of Mauna Kea
The shadow of Mauna Kea rising through the haze at sunset with the pink of the Belt of Venus above
One part of this spectacle is the enigmatic shadow that rises through the eastern haze, a beautiful pyramid of darkness that stretches to the distant horizon. A serene and yet awesome sight, the shadow reaches for infinity through the pastel shades of the Belt of Venus above the blue-grey shadow of the Earth itself. The shape is a perfect pyramid, with a symmetry not expected in a natural phenomena.

Oddly enough, it seems that the actual shape of the mountain is not that important in the creation of such a triangular shadow. The shadow will show that beautiful shape regardless of the mountain’s profile. Even a flat topped mountain will have a shadow that converges to a point at the top. This contradicts our experience, where common shadows match the shape of the casting object. We expect a shadow to portray the object.

A mountain shadow is different, the shadow is elongated to a great distance by the scales involved, in this situation the geometry dictates a different result. The secret to the shape of the shadow is that it is driven by the effects of perspective, with the shadow reaching to a vanishing point in the far distance. In 1979 the problem of the mountain shadow shape was mathematically modeled by William Livingston and David Lynch. They showed that regardless of the mountain’s profile a conical shadow would be perceived by a viewer near the summit. The proportions may differ depending on the profile of the mountain, but the conical shape would remain.

In the case of Mauna Kea, the effect is not obvious, the mountain does have a fairly symmetrical shape with steep sides. A viewer might not recognize the fact that the projected shadow does not match the shape of the volcano. An astute observer may notice a discrepancy, Mauna Kea is notably rounded at the summit, yet the shadow possesses a sharp apex.

I was completely unaware of this until it was pointed out to me a few days ago by Dean Ketelsen when I posted the Mauna Kea mountain shadow image. I suspect Dean has had many opportunities to see this phenomena from atop Kitt Peak, a flat topped mountain that casts a conical shadow.

Telescope Maintenance

At the Mauna Kea Visitor Information Station telescopes are available every clear night for the public to enjoy the wonders of the night sky. Every evening a set of telescopes ranging from 102mm to 16 inches is setup in the patio beside the VIS. The gear is used heavily, every night of the year, the wear on the telescopes does exact a toll. The abuse is constant, kids hanging on the eyepiece, volunteer operators who have never used a telescope, rain, fog, blowing cinder dust. Conditions that were never foreseen by the designers and far beyond what most telescopes encounter. Sometimes the condition of the equipment is embarrassing, dirty eyepieces, groaning mounts that refuse to track, much of the gear just looks worn and tired.

Dirty Primary
An 8" telescope mirror covered with a ridiculous amount of dust
It is hard for me to see this, but at least I can do something about it, I do, after all, fix telescopes for a living. It is not unusual for me to spend an evening repairing a telescope and I have made a point of getting some more extensive maintenance accomplished.

My first effort last year was to clean and repair the small dobsonians used by visitors every night. Two eight inch, a six and a 4.5″ Orion dob are put out for anyone to use, from adults to children. After years of use they were in horrible shape, bearings and focusers were coming apart, collimation gone, moisture dissolving the woodwork, a finder attached with duct tape, the mirrors so covered with dust it is surprising there was much of an image to see. One of the eight inch scopes and the 4.5 inch were in pieces in the warehouse after a fix attempt by another volunteer. It took a few days of work to put all to right. Stealing parts from an older scope, repairing what could be saved, cleaning and pounding out a couple dents. Clean, re-install and re-collimate the optics. Four dobs back in service and in better shape than they had been in quite some time.

Losmandy Teardown
Parts of a Losmandy G-11 telescope mount spread across a table top
The 16″ Meade LX200 should be the flagship of the equipment used at the VIS. But for all too long it refused to work properly, it would not track. A trip back to the manufacturer failed to correct the problem, despite nearly a thousand dollars in shipping fees for factory service the telescope still would not work most of the time. Most volunteers would not use it, having given up in frustration. Surprisingly the issue was obvious, just listening to the scope indicated gears not fully meshed and grinding on one another. An hour’s worth of dismounting the scope, opening the bottom panel and re-seating a motor mount had the telescope back on sky and slewing from target to target. The scope has failed since, but the problem was even simpler, a loose connection found after a half hour of poking around.

Currently, one of the three Losmandy G-11 mounts belonging to the VIS is in my garage, spread across the table in many parts. I spent a few hours yesterday dismantling the mount and cleaning the grease and cinder dust out of the bearings. It is in pretty good shape, a good cleaning, re-seat the worm gears and some new clutch pads and it will be ready for a few more years of service. I need to get some more grease before I can reassemble the mount, but otherwise everything is ready to put back together. Finish this one and there are two more like it in sore need of maintenance.

One thing at a time, of course by the time I get through it all it will be necessary to start over again…

Two Moonrises

I enjoyed moonrise tonight on the way home, and then enjoyed it again. The first was just after leaving Waimea, a golden full Moon rose over a band of clouds, a beautiful sight as I drove home from work. My drive then takes me deep into the shadow of Mauna Kea, the Moon disappearing behind the bulk of the mountain. A second moonrise found me about ten miles further down the road, with that golden orb rising over the summit. Two beautiful moonrises to grace the end of a long day.

Venus was visible in the golden glow of sunset, mercury right below if you knew to look for it. I saw no sign of Saturn which should have been a ways below the other two, it was probably hidden by a band of clouds that occupied the right spot.

Yes, I did say I was driving home from work on a Saturday. One of the guys on the crew is out with a bad back, and I worked a couple more days on the summit to cover. I was performing some procedures I had never done before, optical alignments in preparation for using the interferometer that night. As a result I will have spent five out of seven days on the summit, quite a bit more than my usual two days a week. I get a day off tomorrow, then back at it Monday. Even tomorrow will not be completely a day off, with an interferometer run in progress there will be some work I need to do from home to check the systems and insure they are ready for the night.

Hopefully the phone stays silent through the night.

TMT versus Space Based Alternatives

There is an article on the TMT in yesterdays’s Honolulu Advertiser. While the article shows growing community awareness of the Thirty Meter Telescope project and puts forth some of the basics, it concentrates on some of the political issues. Those are, as typical for Hawai’i, rather fractious, showing the very polarized nature of political discourse in the state.

TMT Rendering
An overhead view of the proposed Thirty Meter Telescope, credit TMT Observatory Corporation
It is the comments that make the most interesting reading. These show the wide range of feelings in the community. There also seems to be a misunderstanding about the roles of large telescopes in general. The last two decades has seen an enormous advance in our understanding of the universe and its history. We now know the age of the universe, we have discovered planets around other stars, we have learned that ordinary matter makes up only a small fraction of the universe. These represent huge leaps in our understanding and these revelations have come, to the greater degree, from ground based astronomy. Many of these discoveries have been made, or greatly assisted, by the telescopes atop Mauna Kea.

One of the themes that popped up in the comments several times was the idea that space telescopes are where to put the money and the belief that ground telescopes were “obsolete’, thus projects like TMT are not needed. This could not be further from the truth. Yes there are advantages to space telescopes with respect to interference from the atmosphere. But space telescopes face several severe and inherent disadvantages.

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