Category: Eclipses and Transits

Blocking the light

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
Mercury transiting the face of the Sun, 6 Nov 2006
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

 
The table at the right gives the transit geocentric UT and offset HST times. As our line of sight is shifted slightly from Hawaii there is a slight offset in the timing from our vantage point.

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.

Total Lunar Eclipse Reminder

Total Lunar Eclipse 14Apr2014
The total lunar eclipse on Apr 14, 2014, Canon 6D on 90mm f/12 APO
Early tomorrow morning a total lunar eclipse will be visible across the Pacific. Sky watchers in Hawaiʻi will be able to observe this event from beginning to end.

Penumbral Eclipse Begins  11:01 HST   09:01 UT
Partial Eclipse Begins   00:15 HST   10:15 UT
Total Eclipse Begins   01:57 HST   11:57 UT
Greatest Eclipse   02:01 HST   12:01 UT
Total Eclipse Ends   02:02 HST   12:02 UT
Partial Eclipse Ends   03:44 HST   13:44 UT
Penumbral Eclipse Ends   04:58 HST   14:58 UT

Timing for the 4Apr2015 total lunar eclipse

Total Lunar Eclipse

Early on the morning of April 4th a total lunar eclipse will be visible across the Pacific. Sky watchers in Hawaiʻi will be able to observe this event from beginning to end.

Total Lunar Eclipse 14Apr2014
The total lunar eclipse on Apr 14, 2014, Canon 6D on 90mm f/12 APO
This eclipse is just barely total with an umbral magnitude of 1.0008. The northern edge of the Moon will be barely inside the umbra and probably much brighter than the south hemisphere. The eclipse is also quite short, with a total phase lasting only four minutes. Compare this to the next total eclipse of 2015 where totality lasts over an hour.

Maximum totality will occur at 12:02UT or about 02:02HST. First contact will occur at 11:01HST on the evening of the 3rd, with umbral first contact a little after midnight at 00:15HST. It is this umbral contact that will be the first obvious effect of the eclipse to a visual observer, a notable notch out of the Moon.

Observing a total lunar eclipse requires no special equipment, simply the desire to look up. The most useful piece of equipment will be a reclining chair or some other method of staying comfortable while watching the sky. A pair of binoculars or small telescope can provide beautiful views of the Moon during an eclipse. Photography is somewhat more challenging, but not that difficult. Focal lengths of around 1000mm will fill the field of most DSLR cameras allowing photos like that shown here.

Penumbral Eclipse Begins  11:01 HST   09:01 UT
Partial Eclipse Begins   00:15 HST   10:15 UT
Total Eclipse Begins   01:57 HST   11:57 UT
Greatest Eclipse   02:01 HST   12:01 UT
Total Eclipse Ends   02:02 HST   12:02 UT
Partial Eclipse Ends   03:44 HST   13:44 UT
Penumbral Eclipse Ends   04:58 HST   14:58 UT

Timing for the 4Apr2015 total lunar eclipse
The entire eclipse will be visible during the night, quite convenient for amateur and casual sky-watchers.

Total Lunar Eclipse 7 Oct 2014

A total lunar eclipse will occur on the next full Moon, Oct 8th. The eclipse will be visible across much of the western hemisphere, including the west coast of North America and across the Pacific. This is an excellent eclipse for observers here in Hawai’i, the entire eclipse will be visible from start to end.

Lunar Eclipse 28Aug2007
Total lunar eclipse, photo is a 8sec exposure with a Canon 20Da on a 90mm f/12 APO
Some references note that this eclipse will occur on the 8th, and so it will for much of the world. For Hawai’i this will start late on the 7th when considering the time zone correction.

The Moon will be thoroughly submerged in the umbra, the darkest part of the Earth’s shadow, with an umbral magnitude of 1.16. The Moon will not pass directly through the umbra, but rather through the northern section, thus the north pole of the Moon will remain somewhat brighter, even at maximum. The eclipse occurs at the Moon’s descending node in southern Pisces, two days after perigee (October 06 at 09:41 UT). This means that the Moon will appear 5.3% larger than it did during the April 15 eclipse (32.7 vs. 31.3 arc-minutes).

Observing a total lunar eclipse requires no special equipment, simply the desire to look up. The most useful piece of equipment will be a reclining chair or some other method of staying comfortable while watching the sky. A pair of binoculars or small telescope can provide beautiful views of the Moon during an eclipse. Photography is somewhat more challenging, but not that difficult. Focal lengths of around 1000mm will fill the field of most DSLR cameras allowing photos like that shown here.

Penumbral Eclipse Begins  22:15:33 HST   08:15:33 UT
Partial Eclipse Begins   23:14:48 HST   09:14:48 UT
Total Eclipse Begins   00:25:10 HST   10:25:10 UT
Greatest Eclipse   00:54:36 HST   10:54:36 UT
Total Eclipse Ends   01:24:00 HST   11:24:00 UT
Partial Eclipse Ends   02:34:21 HST   12:34:21 UT
Penumbral Eclipse Ends   03:33:43 HST   13:33:43 UT

Timing for the 7Oct2013 total lunar eclipse
The entire eclipse will be visible during the night, quite convenient for amateur and casual sky-watchers. This is an excellent eclipse to publicize and use for outreach purposes.

The final eclipse of 2014 will be a partial solar eclipse visible in late October across North America.

Total Lunar Eclipse 14 April 2014

A total lunar eclipse will occur on the next full Moon, April 14th. The eclipse will be visible across much of the western hemisphere, including the west coast of North America and across the Pacific. This is an excellent eclipse for observers here in Hawai’i, the entire eclipse will be visible from start to end.

Lunar Eclipse 28Aug2007
Total lunar eclipse, photo is a 8sec exposure with a Canon 20Da on a 90mm f/12 APO
Some references note that this eclipse will occur on the 15th, and so it will for much of the world. For Hawai’i this will occur late on the 14th when considering the time zone correction.

The Moon will be thoroughly submerged in the umbra, the darkest part of the Earth’s shadow, with an umbral magnitude of 1.29. The Moon will not pass directly through the umbra, but rather through the northern section, thus the north pole of the Moon will remain somewhat brighter, even at maximum.

Observing a total lunar eclipse requires no special equipment, simply the desire to look up. The most useful piece of equipment will be a reclining chair or some other method of staying comfortable while watching the sky. A pair of binoculars or small telescope can provide beautiful views of the Moon during an eclipse. Photography is somewhat more challenging, but not that difficult. Focal lengths of around 1000mm will fill the field of most DSLR cameras allowing photos like that shown here.

Penumbral Eclipse Begins  18:53:37 HST   04:53:37 UT
Partial Eclipse Begins   19:58:19 HST   05:58:19 UT
Total Eclipse Begins   21:06:47 HST   07:06:47 UT
Greatest Eclipse   21:45:40 HST   07:45:40 UT
Total Eclipse Ends   22:24:35 HST   08:24:35 UT
Partial Eclipse Ends   23:33:04 HST   09:33:04 UT
Penumbral Eclipse Ends   00:37:37 HST   10:37:37 UT

Timing for the 14Apr2013 total lunar eclipse
In Hawai’i the eclipse will begin not long after moonrise. The entire eclipse will be visible during the evening hours, quite convenient for amateur and casual sky-watchers. This is an excellent eclipse to publicize and use for outreach purposes.

The next total lunar eclipse in October will also be visible across the Pacific region. It will occur somewhat later in the night and be slightly brighter, only 1.16 umbral magnitude. With two good lunar eclipses 2014 is a treat for sky watchers across the western hemisphere. An annular eclipse is visible later in April in Australia and the South Indian Ocean, a partial solar eclipse is visible in late October across North America.

Naked Eye 100 Challenge

Amateur astronomers love lists… The Messier observing list, the Hershel 400, the Hershel II, and on. Some lists can be complete on a night or two, some lists may take years, or even a lifetime to accomplish. Amateur astronomy is not the only avocation to use lists like this. Birders attempt to see all of the birds known to occur in their home country. Aircraft spotters love to see each model of aircraft in the air. Divers keep lists of species seen underwater.

Rainbow Wheel
A rainbow and cloud shadows produce a rainbow wheel
Lists like these are not only fun, but allow the list chaser to sample the wonders our universe has to offer. The challenge of finding and observing each of the items is worthwhile. Each object is a lesson into the science, hunting each object allows skills to be practiced.

Most of the astronomy observing lists require a small telescope to accomplish, or at least a pair of binoculars. One list is a bit different, it does not require any optical aid at all… The Naked Eye 100.

Continue reading “Naked Eye 100 Challenge”

Partial Solar Eclipse from Hawai’i

We were all ready to view to eclipse from Keck HQ in Waimea. The gear was ready to go, our astronomers setup to answer questions, the public invited…

It rained.

Not to be deterred I grabbed my little telescope and headed for the Sun. The satellite showed a reasonable possibility of clear skies in Kawaihae. As I rolled into the parking lot at Pu’u Kohala Heiau National Historic Site I found the hole in the clouds needed for eclipse photography.

I was not the first there, I met another gentleman setup with a 70mm Meade ETX, we chatted as I set up beside him. I found out later that a couple of the gals from CFHT were setup at Spencer Beach just below the heiau. For clear skies this was about the only reliable place on the island other than the summit.

I quickly setup my little TV-76mm and got the images I was looking for at maximum. We only got to 47% here on the big island, but still worth the effort to see.

Partial Solar Eclipse
A partial solar eclipse from Kawaihae, 9 May 2013