Today Mercury will be at maximum eastern elongation, as high in the evening sky as it will appear for this current apparition. After today the planet will slide back into the sunset, passing through inferior conjunction on May 30th and reappearing in the dawn during the first weeks of June.
Category: Astronomy
Exploring the cosmos
Full Moon
A Peek into CFHT
What do we really spend our days doing on the mountain? Usually pretty mundane stuff, just fixing stuff and making improvements to the gear. A little peek into one of those improvements over at CFHT, a fiber run to allow the 8 meter Gemini telescope to feed a spectrograph next door at CFHT. Something not so mundane, rather fun actually…
Canada France Hawaii Telescope Graces Fiber Link with Gemini Telescope from CFHT on Vimeo.
The Dark Matter Conspiracy
W. M. Keck Observatory press release…
An international team of astronomers, led by Michele Cappellari from the University of Oxford, has used data gathered by the W. M. Keck Observatory in Hawaii to analyze the motions of stars in the outer parts of elliptical galaxies, in the first such survey to capture large numbers of these galaxies. The team discovered surprising gravitational similarities between spiral and elliptical galaxies, implying the influence of hidden forces. The study will be published in The Astrophysical Journal Letters.
“The DEIMOS spectrograph was crucial for this discovery since it can take in data from an entire giant galaxy all at once, while at the same time sampling the speeds of its stars at a hundred separate locations with exquisite accuracy,” said Aaron Romanowsky, of San Jose State University.
One of the most important scientific discoveries of the 20th century was that the spectacular spiral galaxies, such as our own Milky Way, rotate much faster than expected, powered by an extra gravitational force of invisible “dark matter” as it is now called. Since this discovery 40 years ago, we have learned that this mysterious substance, which is probably an exotic elementary particle, makes up about 85 percent of the mass in the Universe, leaving only 15 percent to be the ordinary stuff encountered in our everyday lives. Dark matter is central to our understanding of how galaxies form and evolve – and is ultimately one of the reasons for the existence of life on Earth – yet we know almost nothing about it.
“The surprising finding of our study was that elliptical galaxies maintain a remarkably constant circular speed out to large distances from their centers, in the same way that spiral galaxies are already known to do,” said Cappellari. “This means that in these very different types of galaxies, stars and dark matter conspire to redistribute themselves to produce this effect, with stars dominating in the inner regions of the galaxies, and a gradual shift in the outer regions to dark matter dominance.”
Spiral galaxies only constitute less than half of the stellar mass in the Universe, which is dominated by elliptical and lenticular galaxies, and which have puffier configurations of stars and lack the flat disks of gas that spirals have. In these galaxies, it has been very difficult technically to measure their masses and to find out how much dark matter they have, and how this is distributed – until now.
Because the elliptical galaxies have different shapes and formation histories than spiral galaxies, the newly discovered conspiracy is even more profound and will lead experts in dark matter and galaxy formation to think carefully about what has happened in the “dark sector” of the universe.
“This question is particularly timely in this period when physicists at CERN are about to restart the Large Hadron Collider to try to directly detect the same elusive dark matter particle, which makes galaxies rotate fast, if it really exists!,” said Professor Jean Brodie, principal investigator of the SLUGGS survey.
Perspectives on the Future of Mauna Kea
Here is the video of last Friday’s presentation, Perspectives on the Future of Mauna Kea. Well worth the watch for anyone interesting in the issue. My thanks to Doug Simons for representing the observatories!
If there is any complaint about the camera work… My fault.
Bringing out the Worst
An impassioned argument is one thing. I realize that tempers can flare and some people may say things that they might otherwise not say. But strong emotion can also reveal the truth behind the facade that we all maintain. What is revealed under stress can be our finest or our worst.
My thanks to Ian Lind for covering this on his blog as well as posting the response from the Mauna Kea Hui. Sorry, this sort of behavior must be called out and condemned by those on both sides of the discussion.
Perspectives on the Future of Mauna Kea
A lot of emotion and bandwidth has been swirling around our mountain this past month. It has been unfortunate that two otherwise positive forces have collided atop one summit. Last night the local community had a chance to listen to various perspectives in a more personal and reasoned forum. The Honokaʻa Peoples Theater, located on the slopes of Mauna Kea is the perfect place for this to happen. An evening of face to face discussion.
The format was simple, a presentation by Hāwane Rios, explaining her perspective on growing up in the traditions of Mauna Kea. This was followed by a presentation by Doug Simons, executive director of the Canada-France-Hawaii Telescope. After a 15 minute intermission there was another hour of panel discussion with questions provided by the audience. What started at 6pm went on until well after nine, with personal conversations that kept the theater a buzz until well after 11pm.
Unfortunately one of the featured speakers Lanakila Mangauli was unable to attend, having flown to Oahu for a hasty meeting with OHA and state officials. He was not completely absent, a Skype connection projected on the theater screen allowed him to give a short presentation at the start. After having watched video of his tirade (Yes, I will call it that!) at the TMT groundbreaking ceremony, I had been given a somewhat less than flattering opinion of him. The person who addressed the audience this night was much more impressive, giving an intelligent and reasoned argument to his cause. I wish he had been able to address the audience in person.
Doug Simons also related his personal connection to the mountain, having spent the last 30 years working, hunting and raising his family here in Waimea and on Mauna Kea. Starting with the great discoveries that have been accomplished by the telescopes atop Mauna Kea, Doug did an admirable job of covering the importance of the research done at the telescopes and why these great instruments belong to all of mankind.
I spent the evening listening and operating a production video camera we had brought over from Keck. CFHT, Subaru and Keck staff operated a battery of audio/visual gear, live casting the event on YouTube, recording video for later editing and managing a Skype connection for Lanakila. I expect we should have good videos up shortly, they are definitely worth watching by anyone interested in the issues surrounding our mountain. The presentation by Hāwane should be worth watching just to hear her sing. I will put the links here as soon as they become available.
Update… Check out the video here.
Transit of Mercury May 9, 2016
On May 9th, 2016 Mercury will transit the Sun. While transits of Mercury are not rare, they are not all that common either. The last transit was almost a decade ago in November of 2006. On average there are fourteen transits of Mercury each century or one every seven years. If you wish to observe one the situation is much better than transits of Venus which occur in pairs over a century apart.
This particular transit will favor observers in Europe and North America where the entire transit will be visible. Unfortunately for observers in the islands only the final three hours of the transit will be visible having begun well before local dawn. Sunrise will occur around 05:48 for the island of Hawaiʻi, with the transit ending at 08:42 in the morning.
| Mercury Transit May 9th, 2016
|
||||
|---|---|---|---|---|
| UT (geo) | HST | HST (offset) | ||
| First Contact | 11:12 | 01:12 | –:–:– | |
| Second Contact | 11:15 | 01:15 | –:–:– | |
| Greatest | 14:57 | 04:57 | –:–:– | |
| Third Contact | 18:39 | 08:39 | 08:39:58 | |
| Fourth Contact | 18:42 | 08:42 | 08:43:10 | |
| Source: NASA Eclipse website | ||||
First contact is simply the first moment that the disk of Mercury begins to impinge on the disk of the Sun. Second contact will be the moment when Mercury is entirely in front of the Sun. Third and fourth contacts are a reverse of first and second with fourth contact as the end of the event.
Observing a planetary transit of the Sun requires proper eye protection. If you can not look safely, do not look! The Sun can cause permanent eye damage if viewed without proper protection. As Mercury is quite small some magnification will be useful in observing this event, a telescope of binoculars with a solar filter. A pinhole camera can be made out of things lying around in your kitchen that provides a very good image. Read my Guide to Safe Solar Viewing for a lot more information on viewing the Sun safely.
The next transit of Mercury will occur November 11, 2019 at 15:20UT (mid-transit). This next transit also favors Europe and eastern North America where the entire transit will be visible.
Mercury Appears in the Evening Sky
The planet Mercury is starting an evening apparition. The planet should become visible this week just above the fading glow of the setting Sun as a magnitude -1 object. The planet is moving about 1° further from the Sun and higher in the sunset each day, reaching a maximum elongation of 21° on May 6th.
A Pop, a Puff of Smoke, and an Ominous Red Glow… Not Good
When powering up a nearly three decade old computer for the first time I should really have a video camera running…
The loud pop, and the stream of smoke issuing from the side vents was bad enough. It was the ominous orange glow seen for just a couple seconds from the same vent that really sent me the message…
Not good.
Without this machine it will be very difficult to program the old PLC the dome runs on. I do have a replacement for that PLC controller running in my office, but I face the challenge of verifying the design, I would like to run the old software in the test setup to compare it to the new. I would also like to have a backup in case something goes wrong during the transition, a way of putting the old PLC back into the system and programming it.
Continue reading “A Pop, a Puff of Smoke, and an Ominous Red Glow… Not Good”