Eclipses and Transits – Page 5

Partial Solar Eclipse Reminder

Annular Eclipse — Jan 15th, 2010 annular solar eclipse, photo by Dan Birchall

A reminder that this afternoon we will have the opportunity to see a partial solar eclipse. For viewers further south, in Australia and across the South Pacific, this will be an annular eclipse. For viewers here in the Hawaiian islands this will be a deep partial solar eclipse, with well over 40% of the Sun obscured by the Moon. This is enough to produce a noticeable drop in the Sun’s brightness at mid-day.

Please exercise caution when viewing the Sun! Use appropriate eye protection or indirect observing techniques to project an image of the Sun. The link at the start of this paragraph leads to a great discussion on viewing the Sun safely. As always the single best source on the web (or anywhere) for eclipse and transit information is Fred Espenak’s eclipse website at NASA. Stop by whenever you have a question on upcoming events as well as viewing and photography tips.

During a deep partial such as this one check out the shadows under nearby vegetation. Small gaps in leaves can act like pinhole cameras projecting small crescent images of the Sun.

Location	Begins	Maximum	Ends	Altitude	Azimuth	Magnitude
Honolulu	14:23	15:48	17:01	43	275	44
Hilo	14:31	15:56	17:05	61	270	47

Partial Solar Eclipse

May 9th will see a solar eclipse sweep across the Pacific. For viewers in Australia and the southern Pacific Ocean, this will be an annular eclipse, not a total eclipse. With the Moon near apogee and further from the Earth, its apparent size will not be quite enough to cover the entire disk of the Sun, resulting in a ring of light surrounding the silhouette of the Moon.

For viewers here in the Hawaiian islands this will be a deep partial solar eclipse, with well over 40% of the Sun obscured by the Moon. This is enough to produce a noticeable drop in the Sun’s brightness at mid-day.

Location	Begins	Maximum	Ends	Altitude	Azimuth	Magnitude
Honolulu	14:23	15:48	17:01	43	275	44
Hilo	14:31	15:56	17:05	61	270	47

Postcard from the Universe – Venus Transit

Transit is over, an exhausting and exhilarating day! I am headed to bed, but still totally jazzed with the experience. Keeping the webcast going for seven hours was a huge effort. Given the comments from our viewers it was worth it. I will have to more fully write up the experience for a later post.

The best visual for the day was the few minutes just before second contact… A beautiful, razor thin arc of light coming through the Venusian atmosphere, connecting the two horns of the occluded Sun. It was delicate and sublime, one of the most memorable sights I have ever seen through a telescope. With the excellent seeing of Mauna Kea, and the wonderful optics of my TV-76 telescope, the sight was clear and steady. I have yet to find a photograph that captures what I saw through the eyepiece.

I will post a quickly processed version of one of the frames from the second camera…

Venus Transit Second Contact — Transit of Venus 2012, second contact at 12:27pm

Transit of Venus is Today

The gear is tested, packed and ready. All of the arrangements have been made. It is time for the 2012 Transit of Venus!

We will be webcasting the transit live from the Keck telescopes at the summit of Mauna Kea. Tune in for images of the transit, and a lot of information about the transit. Larry O’Hanlon and I will be talking about the transit, the science, the history, and just generally enjoying the experience. You are invited to join us. Expect the broadcast to start about 11:45HST, or about 25 minutes before first contact.

Want to see for yourself? There are multiple locations around the island where you will find solar telescopes and volunteer guides to answer your questions about this event. Not on the Big Island? Check you local paper or look up your local astronomy club to find public events. Science museums, colleges, astronomy clubs and other astronomy organizations are organizing public events wherever the transit can be seen.

Location Name	External Sun Ingress Alt h m s °	Internal Sun Ingress Alt h m s °	Greatest Sun Transit Alt h m s °	Internal Sun Egress Alt h m s °	External Sun Egress Alt h m s °
Anchorage, AK	14:06:30 51	14:24:04 51	17:26:53 38	20:30:46 16	20:48:32 14
Honolulu, HI	12:10:07 85	12:27:46 89	15:26:20 49	18:26:38 9	18:44:38 5
Kona, HI	12:10:09 86	12:27:48 87	15:26:16 47	18:26:33 7	18:44:33 3
Los Angeles, CA	15:06:26 58	15:24:02 55	18:25:33 18	— –	— –
Phoenix, AZ	15:06:03 54	15:23:40 50	18:25:32 13	— –	— –
Portland, OR	15:06:05 57	15:23:40 54	18:25:53 23	— –	— –
San Francisco, CA	15:06:29 61	15:24:04 57	18:25:39 22	— –	— –
Seattle, WA	15:05:58 56	15:23:32 53	18:25:57 23	— –	— –

All times local. The data is taken from Fred Espenak’s NASA Eclipse Website. I extracted the cities that are of most interest to my Hawaiian readers. For the full list of US cities you can go here.

Venus Transit Reminder

This is your last chance this lifetime to witness a Venus transit! On June 5th the Earth, Venus and the Sun will line up correctly so that earthbound observers will see Venus cross the disk of the Sun.

Mercury Transit — Mercury transiting the face of the Sun, 6 Nov 2006

Venus transits are relatively rare events, that occur in pairs¹, with the paired events separated by eight years. Each pair is separated from the next pair in a predictable pattern, alternating 105.5 or 120.5 year gaps. The first transit of the current pair was in June 2004, with the 2012 event completing the pair. The next pair of events will begin in December 2117. Given the century long separation between events Venus transits have only occurred seven times since the invention of the telescope (1631, 1639, 1761, 1769, 1874, 1882 and 2004)².

To witness this event you only need to be on the daylight side of our planet when it occurs. The 2012 event favors the Pacific, Australia, Japan and eastern Asia.

For Hawai’i the event will begin at about 12:10pm with the Sun high in the sky, mid-point will be about 3:26pm and will end about 6:44pm, just before sunset. These times are only approximate, exact times will depend on the observer’s location and can vary by several minutes across the islands.

As always the single best source on the web (or anywhere) for eclipse and transit information is Fred Espenak’s eclipse website at NASA. Stop by whenever you have a question on upcoming events as well as viewing and photography tips.

Keck Observatory will be making an extra effort for this transit as Mauna Kea is perfectly positioned to observe the event. We will be webcasting the transit from a small telescope located at the summit. The webcast can be seen on your computer, or come over to our headquaters in Waimea to see the webcast and a live view in a solar telescope if the weather cooperates. there will be extra staff on hand to answer your questions.

Stay tuned to DarkerView for further details as the transit draws near.

1) Transit of Venus, Wikipedia Article, retrieved 8 Feb 2009

2) 2004 and 2012 Transits of Venus, Fred Espenak, NASA/GSFC, NASA Eclipse Website, retrieved 8 Feb 2009

Safe Transit Viewing

You have heard it before, but it really is true! Looking at the Sun for longer than a few brief moments with an unprotected eye can lead to permanent damage. Looking at the Sun with any sort of optical deceive that has not been properly filtered can lead to instantaneous eye damage.

Discussed below are the only safe methods I am aware of to view the Sun. There are some dodgy methods out there. Take chance with your irreplaceable eyesight? I think not. Be careful and do it right if you want a look.

For the unaided eye there are a couple options to view the Sun safely…

Solar Viewing Glasses Proper solar viewing filters are made from a thin plastic film, usually mylar, coated with metal to properly filter the Sun’s light for viewing with the unaided eye. These are widely available and quite cheap. Local astronomy organizations have been giving them away in preparation for the transit. Do not attempt to use these viewers in conjunction with binoculars or small telescopes, they do not provide sufficient filtering for optics!
Welding Glass Filters used for viewing welding offer much the same protection as solar filters. A shade 13 or darker welding filter can provide good protection for the unaided eye. Again, do not use a welding filter with any sort of optical device such as binoculars, they are not designed for such use and may not block enough light.

A much better view of the event can be seen if modest magnification is used. Do keep in mind that any soft of binoculars or telescope also concentrates much more light that the eye alone. Remember those childhood “experiments” involving a magnifying glass and ants? The best options here are the use of solar filters designed to be used on a telescope, or indirect means such as image projection.

Solar Filter — A solar filter mounted on a refracting telescope

Solar Filters for Telescopes Filters specifically designed for telescopes consist of either a plastic film, or a sheet of glass, coated with a thin layer of metal to block the Sun’s light. These filters pass about 1/1000 of one percent of the light. More importantly, they block the harmful infrared and ultraviolet light that could so easily cause damage. The filters can be purchased in many sizes as appropriate for various models of telescopes, costing between one hundred and several hundred dollars.
Image Projection One of the simplest methods of displaying a solar image is projection. A white screen placed a foot or two behind a telescope will produce a very nice image of the Sun that can be safely viewed by a number of people simultaneously.
Keep in mind that the beam of light out of the eyepiece is quite intense, potentially hot enough to burn a careless finger placed near the exit from the telescope.

The method works best with small optical systems, binoculars or the smallest of telescopes. You do not need big optics to project a very nice solar image.

You do not have any optics? Use the simplest optical arrangement of all, the pinhole camera!

If you do not have a safe means of viewing the transit and do want a look, you can go to one of the many public events being organized. Here on the Big Island there are quite a few options, one should be close to you.

Viewing the Transit of Venus on Hawaii

There is only one more chance in our lifetimes to see a Transit of Venus. If you are curious about this event, where do you go to see it?

Hawai’i is well placed to see the entire event. The transit starts just after noon, with the sun high in the sky. As the transit ends just before sunset, a clear western horizon will be required to witness final contact. For the true astronomical diehards, the summit of Mauna Kea will be the destination. With a clear view, above the clouds, the entire event will be visible.

For those folks who just want a nice view of the event, and do not necessarily need to watch for the entire seven hours, there are a number of easier options. To accommodate the public, there will be solar telescopes setup and manned by volunteers at a number of locations around the island…

Mauna Kea Visitor Information Station (MKVIS) A portion of the VIS parking lot will be converted into a viewing station. Telescopes with solar filters will be available. A NASA-sponsored live web cast of the Transit will be displayed inside the VIS and in the presentation room. Parking space at the VIS is limited. If parking fills, vehicles will be held below the VIS until parking becomes available. You may want to consider some of the other sites listed below.
ʻImiloa Astronomy Center of Hawaii, Hilo ʻImiloa will display the NASA webcast of the Transit. Leading up to the day of Transit, ʻImiloa will also be running a special planetarium show titled “When Venus Transits the Sun.”
W. M. Keck Headquarters, Waimea Livestream from the summit at headquarters in Waimea. Headquarters will be open until 6 p.m. Solar telescopes will be available. Free solar cards for viewing the Transit directly will be provided, while supplies last.
Canada France Hawaii Telescope (CFHT), Waimea Solar telescopes and a sunspotter will be available for the public. A raffle for a copy of “Hokuloa: The 1874 Transit of Venus Expedition to Hawaii” by Michael Chauvin will also be held.
Puʻu Koholā Heiau National Historic Site, Kawaihae From Noon till 4:30pm. Special glasses will be available, and a live webcast from the summit of Mauna Kea in the Visitor Center theater. As well, park rangers will give special presentations about the historical significance of this event throughout the day.
Natural Energy Lab in Kailua-Kona Mahalo to the Natural Energy Lab for sponsoring this event!
Keaʻau In the lot across from the Fire Station, Mahalo to W. H. Shipman Ltd for sponsoring this event!

Preparing for the Venus Transit

Time to start preparing the gear for Venus Transit! This means dismantling the astrophotography rig in the garage and reconfiguring for solar work. Taking the the AT6RC telescope off and remounting the 90mm APO. The APO has just the right focal length to produce a nicely sized solar image on an APC-C sized sensor, such as the sensor in the Canon 60D.

First up? just setup the ‘scope in the driveway and take a few photos of the Sun. Just checking the photographic setup, the necessary parts and pieces. Nothing misplaced? Where did I store the solar filter? A nice focus on the camera? Perhaps take some nice photos of the large sunspots that current grace the surface of the Sun while I am set up. I hope we have some nice spots during the transit, they make focusing so much easier!

Next step is to get autoguiding operational, this will be a seven hour event and I really do not want to manually guide for the entire duration. Particularly with a telescope that was setup in the daytime and is not properly polar aligned.

A couple other steps remain in the preparation. Automate the camera to take photos at a regular interval. Insure I can provide a good video feed to the computer sending out the webcast. I do have a few more weeks to accomplish this. I am certain those weeks with speed by surprisingly quickly. Time to get ready!

Venus Transit

To witness this event you only need to be on the daylight side of our planet when it occurs. The 2012 event favors the Pacific, Australia, Japan and eastern Asia.

Stay tuned to DarkerView for further details as the transit draws near.

1) Transit of Venus, Wikipedia Article, retrieved 8 Feb 2009

2) 2004 and 2012 Transits of Venus, Fred Espenak, NASA/GSFC, NASA Eclipse Website, retrieved 8 Feb 2009

Venus Transit on Mauna Kea

A Venus Transit is a truly rare event. Transits occur in pairs eight years apart, with the next pair not occurring for another 120 years. The first event of the current pair occurred in 2004. Thus the next event will happen in June 2012. Considering the century long period between events, this is the last chance to witness a Venus transit during our lifetimes.

The 2012 event will be visible from the west coast of North America to Japan, China, Australia and Central Asia. For those wanting to observe the entire event from start to finish the choices narrow quite a bit. You have the choice of the Central Pacific, Japan, as well as Eastern China and Eastern Australia. This, of course, includes here in the Hawaiian Islands.

Many sky-watchers from North America will see only one choice if they wish to observe the event… the Big Island. The only place easily accessible by air, featuring excellent visitor accommodation, and an observing site that sits above the clouds that could so easily interfere with carefully laid plans. For the serious observer there is one obvious choice… Mauna Kea.

We saw the first signs of this well over a year ago. The tour companies that specialize in astronomy related travel, the folks that feature solar eclipse tours and similar events, began scouting Mauna Kea as a destination. Then the ads appeared, in Sky & Telescope magazine, Astronomy magazine, etc., “See the transit from Mauna Kea!” We had fair warning that this event was not going to pass peacefully.

Visibility chart for the 2012 Venus transit, image credit: Fred Espenak/NASA

Some folks seem to think the crowd will be huge, a thousand people or more. I am not so certain, this does not have the general appeal of a total solar eclipse. The transit is something that will be of interest to amateur astronomers and some interested segments of the public. I personally expect hundreds of people coming to Mauna Kea to view the transit, not thousands.

However many folks do ascend the mountain for this event, we have begun putting plans in place to handle it. Various groups have met to do a bit of planning. Most significantly, those in charge of managing the mountain, The Office of Mauna Kea Management, are putting a few measures in place. As usual, expect to stop at the Mauna Kea Visitor Information Station on the day of the transit. But this day there will be a few differences…

All available MKSS staff will be on duty. All of the Mauna Kea rangers and visitor station staff will be helping make sure assistance is available to visitors when traveling to the high altitude environment of the summit.
Access to the mountain will be controlled for the day, a gate at the VIS allowing access for official vehicles only.
A free shuttle will run from the VIS to the summit. The Mauna Kea tour companies providing the vehicles and drivers.
Solar telescopes and video monitors will be set up at the VIS to allow safe viewing. Staff will be available to answer questions and assists with the equipment.
Several other locations on the island will be setup for viewing the transit with solar telescopes and staff. Expect these to include ‘Imiloa, Keck HQ in Waimea, and some possible other locations.

All of these plans are somewhat preliminary, details may change as the date approaches and final arrangements are made. I will attempt to post what I know here on Darker View.

Myself? I plan to observe the event from the summit. Set up behind Keck with a solar telescope to photograph the transit. We plan to set up a live feed of the transit for use by other sites, and available to viewers across the internet.