A Daytime Comet?

The rumor is running around the various astronomy sites and listservers that Comet C/2011 W3 Lovejoy might be daytime visible. Will it be? That is a very qualified maybe.

C2006/P1 McNaught
C2006/P1 McNaught photographed five degrees from the Sun, stack of three images
This sun-grazer comet was discovered just a few days ago, on November 27th, by Australian amateur astronomer Terry Lovejoy. The comet is a member of the Kreutz comet family, and like other members of the family it will approach the Sun quite closely, about 548,000 miles (882,000 km) from the Sun. Of course those distances are solar centric distances. Taking the radius of the Sun into account means that the comet will be a mere 115,000 miles (186,000 km) above the photosphere, hot indeed!

It becomes a valid question to ask if comet Lovejoy will even survive perihelion transit.

Passing that close to the Sun will mean that the volatile elements of the comet will be streaming off the comet at a fantastic rate, enough to dramatically brighten the comet. Below you will find the ephemeris for perihelion on Dec 16th (Dec 15th HST) from the Minor Planet Center. As you can note, the predicted magnitude is -8! This is bright enough to be seen in broad daylight. Thus the possibility of a daytime comet.

The catch is that the comet will be quite close to the Sun. Within 2° as the Sun and comet rise on the morning of the 15th here in Hawai’i. For observers in the islands the best chance to look is on the morning of the 15th, as perihelion will occur in the afternoon as the comet passed behind the Sun from our point of view.

Will it be visible? Maybe. It depends on the accuracy of the magnitude estimates, which are uncertain to say the least. It could be substantially dimmer, or even substantially brighter than forecast under such conditions. The proximity to the Sun also complicates the issue. It is worth a look, seeing a daytime comet is highly unusual.

If you do look please take a few simple precautions… Do NOT use any sort of optical aid this close to the Sun, the risk of permanent eye damage is too great. If it is bright enough the comet should be a naked eye object. It will greatly help to position yourself to put the Sun just behind some obstruction. A building, a streetlight, anything to block the Sun’s glare and aid in picking out the comet. On the morning of the 15th the comet will rise 2° behind the Sun, thus 2° lower in the sky.

Give it a try!

Green Flash

It was a beautiful evening as I drove home from work. The clear air allowing appreciation of all five volcanoes that loom over South Kohala. Indeed, the horizon was completely clear, the island of Kahoʻolwe visible over 60 miles away.

As I drove I noted the Sun beginning to settle into the distant horizon. At the wheel I couldn’t look long enough to be certain, but I thought I saw an Etruscan vase effect as the solar disk made first contact with the horizon. Curiosity peaked, I pulled over to properly watch the end of sunset. A pleasant surprise rewarded my view, a decent green flash was apparent as the last glimmer vanished.

Better yet, the camera caught the effect as well. Of the dozens of sunsets I have stopped and watched, this was the best green flash seen yet from such a high elevation. Still, it was modest compared to a couple flashes I have seen from sea level. I can only wonder how good this evening’s flash was as seen from the shoreline, 2,000 feet below.

Green Flash
A modest green flash as seen from the Mamalahoa Highway outside Waimea, 1 Dec 2011

Postcard from the Summit – Colorful Commute

As winter descends on Mauna Kea, commuting to and from the summit had become… interesting. Fog, snow and ice being regular features of the drive. Winter weather has also brought fantastic cloud formations, all the more interesting as you drive into them. The later dawn and earlier sunset means that our usual arrival and departure times are filled with dramatic light. All elements become part of a spectacular show.

Colorful Commute
Shane, a Mauna Kea Ranger, heading down the mountain into a rainbow

Diving Black Friday

Black Friday, a phrase that brings to mind stores jammed with shoppers seeking the first Christmas sales. Not my idea of fun and something to be completely avoided if at all possible. Better to spend the day where credit cards do not work… Possibly under water?

The plan was to return to O’oma and the dive sites near the popular Pine Trees surfing breaks. The area is very good diving, with many sites and entries to choose from along a half mile of coastline, From OTEC to Kaloko. The area is popular with the dive boats as well, we were dropping into the water mere yards from the moorings used by the Honokohau diving operations. As we prepared for the dive we watched as the boats did as well, we just did it without paying $150 per person. The only disadvantage? We had to walk across 50 yards of pahoehoe lava to get to the lava, not a problem with the very gentle swell of the day. Entry was quite easy with a sheltered shallows available just in from the popular Suck ’em Up cave and dive site.

Olivier and Camera
Olivier Martin with his camera rig on the reef at O’oma
We again had a large crew… Mark, Patti, Dennis, Sky, Olivier, Pete and his two off island friends.. Isaac and Jeff. Mark and Patti took advantage of the holiday camping at O’oma to camp out on the beach for a couple nights. While parts of the beach were crowded with campers, the popular spots were those adjacent to the surf breaks. Much of the remaining shoreline was quiet, where you could have a nice stretch of sand to yourself. Not that the peace was totally uninterrupted… The rest of our crew invaded their peaceful campsite, for a time turning it into a diving base camp, with vehicles, wetsuits and tanks everywhere. But then, they did invite us.

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An Evening with a New Telescope

The Astro-Tech 6″ RC is a wonderful little telescope… A true Ritchey–Chrétien design, at a size well matched to DSLR astrophotography. It was get one now or never, these were the last of the production run, and now they are gone.

Best of all, Astronomics was letting them go at a fire sale price… Less than $300 each!! It may have taken months on a waiting list, but I finally received one. Then it took another two months of waiting for some necessary accessories to make it work! No problem with the wait, I was patient… mostly.

With the final parts, the extension tubes, in hand. I determined to spend part of my four day Thanksgiving weekend getting the new ‘scope into service.

The Orion Nebula
NGC1976 or M42, the Great Orion Nebula, sum of 113 frames at 35x5min, 38x1min, 20x20sec, and 20x5sec. Taken with the Canon 20Da and a AT6RC telescope.
It took hours to rearrange the setup, un-bolting and re-bolting telescopes to and from the plates of aluminum that hold everything. Carefully aligning each of the four items in the setup… Main telescope, guide telescope, the finder CCD camera and a Telrad. Finding the best focus, recollimating the 6″RC, re-balancing the mount, fixing a computer power supply issue, rearranging and tying up all the myriad of cables, etc. etc… Astrophotgraphy really is the art of endless details. Finally, late into the evening, I took the first test image.

A few images later and things were not looking all that bad, maybe even functional. Better yet, my venerable ST-4 autoguider seemed to be tracking well. Maybe take a real picture? What to shoot? Something easy… M42 was rising over the garage… Why not? Just a test for the new setup, a fair chance something will go horribly wrong.

AT6RC atop an iOptron ZEQ25 mount
Result? Not too bad. This is despite many shortcomings… I forgot to take raw images, thus I had to process from the JPEG’s. I didn’t get any decent calibration frames. There seems to be substantial flexure between the guide ‘scope and the imaging ‘scope, but it is slow and does not effect individual frames. Actually the registration drift over the hours helped me process out the hot pixels and other image artifacts by creating an effective dithering. I did lose a few frames to vibration, the mounting could be stiffer, and I must be careful to walk softly on the concrete slab of the driveway during exposures.

But still, not bad for a first real attempt.

The stars look nice across the frame, showing that the collimation is decent, always an issue with the RC design. I suspect the optical quality of the telescope is quite acceptable. The brighter star images are a bit “fat” but that is due more to the mediocre seeing over Waikoloa. After all of these years shooting with a refractor, I had forgotten how pleasing diffraction spikes can be. Better yet, with the scope positioned for north up on the tube, the spikes are neatly at 45° to the cardinal directions. I am looking forward to some more imaging sessions with a new telescope.

Postcard from the Universe – Moon and Venus

Last night the Moon and Venus were a mere 2.5° apart. I tried to look for the pair after sunset, but all I was able to see was a dim glow in the clouds. My friend Maureen was luckier, she was able to catch the pair through a gap in the clouds while the same clouds were lit up by the sunset. I am just a little jealous…

Luna & Venus
A thin crescent Moon and Venus in the sunset, photo by Maureen Salmi, used with permission

WHAC Visits Gemini and CFHT

There are few opportunities to visit most of the telescopes on Mauna Kea. Only two of the thirteen telescopes maintain any sort of regular public access. Keck opens a viewing gallery during business hours on weekdays and to the MKVIS weekend tours. Subaru provides interior tours, but only with advance reservations. Visiting inside any of the other telescopes is normally not open to the general public, but can be arranged with some work.

Thanks to the work of a few individuals the West Hawai’i Astronomy Club arranged tours of both Gemini and CFHT. Marc Baril was kind enough to arrange the CFHT tour, setting up staff and transportation for the visit. This included a pair of CFHT 4WD vehicles taking folks from Waimea to the summit. Many thanks are owed to Joy Pollard who set up the Gemini portion of the tour. Weekend tours are not normally arranged, but Joy managed to put together the needed staff to allow us to visit the telescope on a Saturday. The result was a couple great tours of these facilities.

Arriving at CFHT
Arriving at a very foggy summit to visit Gemini and CFHT
This marks the second recent summit tour available to members of the West Hawai’i Astronomy Club. Last year we toured the W.M. Keck Observatory. This year CFHT and Gemini allowed us to view a pair of telescope that have helped keep Mauna Kea at the forefront of astronomy for decades.

The weather was pretty awful, winter weather closing in on the summit for the last couple weeks. We arrived at the summit to encounter patchy snow, dense fog and a bitter chill. This would not be an opportunity to enjoy the stunning vistas or sunset that the summit of Mauna Kea is renowned for, we could barely see the next telescope, much less the sunset. At least the road was open to the public and our tour could go on.

We convened in the control room of the Gemini telescope. Here our guides, Joy and Sonny, explained the operation of the telescope and how the operators controlled everything through the night. Our tour of Gemini ran a bit longer than the scheduled hour. During that hour we toured the control room, the coating facility, and the telescope itself.

Gemini Control
Members of the West Hawai’i Astronomy Club listen to guide Sonny Stewart explain the operation of Gemini Observatory
In contrast to many of the other telescopes on the mountain, Gemini is an almost new facility, having seen first light in 1999 and begun science operations in 2000. It is a beautiful telescope, the 8.1 meter instrument sits in a spacious dome. As someone who’s experience has been that a productive environment is always bit messy, the clean facility of Gemini seems a bit odd.

A few levels below the main dome floor is the coating facility. This is where the telescope mirror receives a new reflective surface very few years. For a single piece eight meter primary, a vacuum chamber slightly larger is required. The large chamber makes it seem as if there is a flying saucer docked in the lower bay of the telescope building. The many viewing ports and vacuum lines simply adding to the impression.

The members of the West Hawai’i Astronomy Club pause for a group photo at CFHT
After Gemini it was on the CFHT… The contrasts between the telescopes was dramatic. CFHT is a facility that shows the scars and wear of decades of research. There was an eclectic mix of new equipment intermingled with gear that had been running for over thirty years since the telescope began operations in 1979. This is a facility that started recording observations with photographic plates, along the way making the transition to electronic CCD image sensors. The telescope now boasts one of the world’s largest cameras, the 340 megapixel MegaCam.

Again we visited the coating facility, complete with the massive cranes and the vacuum chamber needed to coat mirrors up to three and a half meters in diameter. This facility is also used by the IRTF and UKIRT observatories to coat the primary mirrors for those telescopes. A treat for me was visiting the OHANA interferometer test lab in the coudé room below the telescope. A project I knew a fair amount about, but had never seen.

The tour finally arrived at the telescope itself. The large equatorial design is such a contrast to the alt-azimuth designs of the more modern designs of Gemini, Subaru and Keck. The enormous steel horseshoe and yoke represent a classic design used for large telescopes throughout the 20th century. We wandered about the dome floor, learning about the details of the telescope, the drives, and the instruments. The AO system was scheduled for the night and was mounted to the telescope. While the massive MegaCam prime focus camera was sitting to the side of the telescope.

The hoped for view of sunset from the upper balcony of the CFHT telescope was nothing to write about. Clouds obscuring all but a hint of sunset’s colors. The final treat was instead an opportunity to ride the rotating dome while the telescope slewed. The show highlighted this big machine, a testament to the people who build and operate these telescopes to push the boundaries of human knowledge deep into the universe.

These tours take a fair amount of work to put together, but are very much worth it. I expect we will do another tour in the spring. Perhaps do a couple of the radio telescopes? CSO, JCMT or SMA? Personally I have never had a chance to properly appreciate the sub-millimeter observatories on the summit. CSO is due to be dismantled in a couple years, it would be a good time to visit this groundbreaking facility.

CFHT Interior
The interior of the CFHT facility atop Mauna Kea

Postcard from Hawaii – Too Many Bananas!

A third bunch of bananas in as many weeks! Yeah, just a few too many bananas around here. Did the cooler weather bring them all on at once? Look for bunches of apple bananas in the Kohala break room at work tomorrow!

In the meantime… Banana smoothies! Two bananas, a cup of plain yogurt, a bit of milk to thin out the mixture, a handful of ice cubes, and a couple heaping spoonfuls of my sister-in-laws strawberry jam. Blend and enjoy!

A bunch of apple bananas from the backyard banana patch

Postcard from the Universe – Sunspots

As we approach solar maximum, large sunspot groups have again become a common sight. The last few years have seen an unusually quiet solar minimum, long stretches of time when not a single sunspot appeared. that has certainly changed, the Sun is now dotted with sunspots, with the occasional monster. At it’s peak, AR1339, seen above, was over 100,000km across. That is larger than 15 Earths, side by side. I mean monster!

The photo was taken with the Canon 60D, a 0.8x TeleVue adaptor, a C-11 and a Thousand Oaks full aperture solar filter.

Sunspot group AR1339 as seen on the afternoon of 5Nov2011