2012/06/05 Transit of Venus

This is the first (and also the last) Venus transit experience in my life (I don’t expect that I will still be alive 105 years later).

Transit of Venus Composite Photo
More photos are listed in transit photo gallery

Since most part of transit (1st/2nd contact and mid-transit) would be visible, I decided not to travel unless the weather became an issue.

The forecast did look good on the transit day – scattered mid clouds in the morning and clear sky in the afternoon. It was not the best – it was clear (without even a trace of the cloud) with excellent transparency and seeing for the next few days ; it was not the worst either – it was rainy and windy the day before (very unusual at this time of the year).

At 12PM, scattered passing Cumulus clouds still covered 30-40% of the sky and it did not look to be clear soon. I decided to drove up to the site near the coast (on the west), because the satellite image showed that the sky near the coast was clear so it would unlikely be clouded out during the 1st/2nd contact. The sky got completely cleared up (almost cloudless) at 1:45PM so the decision was not bad. But probably I should have gone to Henry Coe (on the east), where the sky became mostly clear at 3PM, and remained in very good condition after mid-transit when the clouds moved into the coast. But I did not want to take chance, being clouded out during the 1st/2nd contact would ruin the entire viewing experience.

I set up the telescopes on a pullout on HW35, near the junction with HW92. The pullout was on the mountain ridge overlooking the Pacific Ocean to the west . Usually it is breezy at the coast ridge. It was no different on the transit day (~15m/h), and it did not seem particularly worse than other places since the forecast was breezy for the entire valley.

Viewing Site

My kids and I spent a few minutes to view the sunspot to figure out the 1st contact position. It did not take much time, thanks to the composite photo (sun image + predicted transit path) posted on Spaceweater.com.

My Younger Kid Was Viewing Sunspots Before The Transit
CGEM mount, AT111EDT (white) for imaging, AT72ED (black) for visual with 9mm Nagler T6 EP

At 3h06m, my older kid and I started to look for the venus. My kid observed visually using AT72, and I used Canon T3i on AT111 (liveview). At 3h07m03s, by coincidence, we both noticed a small bump/dent on the edge of sun at the predicted position. The dent got bigger and bigger and soon 1/3 of the venus became visible.

There were two special phenomena we were planning to look for – aureole and black drop.
All I knew about the transit was black drop, until I learned aureola from the article in Sky & Telescope two weeks before the transit.

When the venus was half way entered the sun, my son claimed that he could sense the entire disk of the venus. He had shaper vision but I doubted whether it was just an illusion.

At 3h16m, we noticed a bright, thick, light orange arc (spanning ~45 deg, starting from the left point where Venus and Sun intersected) through AT72. My son also noticed the much smaller, dimmer arc on right side intersection point. At 3h19m, ~3/4 of Venus moved into the sun, the aureole – “ring of limb” – appeared. It was hair thin in the middle and slightly thicker (~2x thicker) near both intersection points. It was light orange too but much fainter than the “arc”, and was easy to miss. My son told me later that the ring was broken at 2-3 places in the middle. I did not notice it and I am wondering if it is “baily bead” of transit.

Around 3h24m00s, right after predicted 2nd contact, my son exclaimed that the black drop had started. Initially it was wider and darker, then gradually became narrower and lighter as Venus was moving away front the edge of the Sun. On 3h2420s, the black drop was gone visually and venus moved completely inside the sun. 2-3s prior to it the black drop because a thin line, so my son was able to tell the black drop was about to finish.

I took a few pictures of black drop. Though not as clear as I hoped due to the wind, it did seem that the black drop was not as prominent as visual observation, probably due to a better optics.

After 2nd contact, the venus crept over the sun. It became so boring that my kids stayed in the car playing the game. I took the picture every 5 minutes.The sky remained clear with average seeing until 6:15m. Then high clouds moved in, the seeing became so poor that sun and venus looked like were swimming in the ocean. I could see the turbulence in 9×50 finderscope, which was barely noticeable in AT72ED during the first half of the transit.

At 7h30m, more high clouds moved in and seeing remained very poor so I decided to give up.

It was a truly unforgettable experience. We felt so lucky that we not only experienced the once-in-a-lifetime event, but also witnessed both rare phenomena.

The biggest lesson I learned was that I should have used the fastest shutter speed to take the transit photos. I used 1/500s for all my photos and most of them show blurred venus due to wind and seeing. It would have been much better if I had used 1/1000s or faster.

2012/06/04 Partial Lunar Eclipse

Composite of 8 photos taken between 2:45AM ~ 4:30AM, shows the progress of the eclipse.

The forecast did not look promising, the clouds would move in at 3AM, right in time to ruin the eclipse. Henry Coe State Park, my usual viewing place for special astronomical event, would have better sky. But since it was partial eclipse and the transit of venus was coming on the next day, I decided to view it from my home only.

I woke up at 2AM, the sky was crystal clear without even a trace of cloud, everything was bathed in the moonlight. It seemed that the it would remain in this condition forever, however the satellite image showed that the clouds were on their way.

Regardless I grabbed my AT72ED refractor and CG3 mount, with T3i camera. I set them up on the sidewalk outside my house, where the moon would be visible throughout the eclipse thought the gap between the trees.

I focused the camera and started taking photos at 2:40AM. The shadow of earth was already visible at 2:50AM, long before the eclipse began.

02h49m13, 1/320s @ ISO100

Taken at 02h49m13, about 10 min before the 1st contact. The penumbra of earth shadow was already visible.

The first high clouds showed up at 3PM, coincided with the first contact. The thin clouds did not interfere eclipse viewing until 3:20AM, when broken mid/low clouds started rolling in. The moon was still visible through the clouds, but I could only take some good photos when moon appeared in the opening in the clouds from time to time.

03h00m03s, 1/320s @ISO100
First Contact

The first contact, taken at 03h00m03s, part of moon had already been covered by earth shadow.

At 3:40AM, I noticed earthshine of the eclipsed moon by naked eyes when the sky was clear. I was a little bit surprised because usually earthshine is visible when moon is less than 5 days old, and this was the first time I saw it during eclipse (partial and total).

03h40m05s,  0.2s @ ISO100

Taken at 03h40m05s. The earth shadow was visible in the photo and it resembled what I saw with my naked eyes. You may also notice the transition area between umbra (almost full dark) and  penumbra (full bright).

03h41m53s, 1.0s @ ISO100

Taken at 03h41m53s, the rusty red color was visible in the earth shadow.

The sky condition continued to degrade. At 4:00AM the moon barely appeared behind the clouds; at 4:30AM, a low cloud bank moved in from the west and it completely blocked the moon, so I wrapped up my equipments and returned home.

04h03m48s
Greatest Eclipse

Greatest eclipse, taken at 04h03m48s.

The time of each contact:

Partial Eclipse Begins: 02:59:53 PDT
Greatest Eclipse: 04:03:13 PDT
Partial Eclipse Ends: 05:06:30 PDT

Location: Sunnyvale, CA
Equipment:
– AT72ED
– CG3 mount with RA motor
– Canon T3i

2012/05/20 Annular Eclipse

2012/05/20 Annular Solar Eclipse Composite

This is my first annular eclipse experience. Though the annular would not be as stunning as the total, I decided to set out another eclipse expedition (my first was 2009 total eclipse in China), as the next annular opportunity will probably be 20 years later.

About a month prior to the eclipse, I did some search on possible sites along the center line. Some people preferred the beauty of baily’s bead, but I would stay on the center line to enjoy the perfect “ring of fire”.

This was the first time I used Google Earth. In addition to Street View, Google Earth could also show the Sun’s position in the sky at any given time. Both were used to determine whether the western horizon would be clear from trees, buildings or mountains during entire eclipse.

I selected about 6 sites, from Redding, CA to the Fallon, NV, through Nixon (Pyramid Lake area), hoping to get at least one or two sites which would be clear on the eclipse day. My most favorite site was Shasta Dam where I had visited less than a year ago. It was easy to access, and had a nice lawn near the visitor center where the telescope could be set up. But the weather did not corporate, the forecast showed that the high cloud of a cold front would move in N. CA on Sun afternoon, possibly ruined the eclipse viewing.

So my choice would be somewhere in NV. I arrived at Cason City, NV on Sat night with my kids. On Sun morning, I checked local weather forecast, NOAA Reno favored Reno, Pyramid Lake and Central West NV area. I was not too sure about Reno, because it was too close to Sierra Nevada so the weather could change any time. Further more both SkippySky and CSC indicated that the region north of Pyramid Lake, and south of Fallon would have some clouds. I decided to drive to Fallon to stay away from the mountain ridges, meantime I would still have time to drive around (either to the Nixon on the N, or to HW121@HW50 on the S) based on the local weather. On my way to Fallon, there were some annoying high clouds to the North (presumably over Pyramid Lake), so I headed directly  to Grimes Point, which was a few miles southwest of Stillwater Reservoir which was on the center line.

Viewing Site

While waiting for the eclipse, we took a short (~1/2 mile) hike to the ancient Indian petroglyph site. The site was relatively small and most petroglyph have been weathered, but it was interesting to see it as a side trip.

Indian Petroglyph

My kids at Hidden Cave

The scattered clouds to the West and South started to develop at 2PM, hanging over the mountains. I paid my attention particularly to the South, because both CrippySky and CSC forecasted mid clouds, though CrippySky was a little bit optimistic. For the next two hours (actually till the end of eclipse), all the clouds were confined over the mountains but developed quite a bit, esp the one to the south, which merged to a big bank and covered the entire mountain ridge there.

Fallon’s weather was not always promising. I had been checking the satellite image for about a week poor to the eclipse day, and noticed that the clouds developed in the afternoon over the maintains to the east, and moved either further to the east (great), or to the west (bad) and covered Fallon and Reno, depending on the wind.

The weather on the eclipse was proved to be perfect for such expedition. The sky was crystal clear, and the high clouds near horizon did not interfere the eclipse except for last 10 minutes. The seeing was great, details of the sun spot and brighten area near the limb were easily visible.

To my surprise, there were only about 20 people showed up in the parking lot, one with a short tube refractor telescope and camera, 2 or 3 of them with tripod and camera, rest with eclipse glasses, I was wondering how it would be different for them to view the eclipse here than at their home. Almost all the people seemed to be impressed by my setup.

My Kid and My Setup
CGEM mount, AT111EDT (white) for imaging, AT72ED (black) for visual with 24mm Panoptic EP

It was hot and breezy when the eclipse started. But as the eclipse progressed (~30 mins), the wind subsidized and the temperature became cooler, and the conditions remained comfortable until the end of the eclipse. However I had a hard time to view the laptop screen due to sun light, next time I would need to bring something to block the sunlight.

As time went by, the moon crept over the sun, and the crescent sun looked more like a moon. You would not notice moon’s moving at all at first, but as the 2nd contact approached, the crescent sun seemed to look different every second. Finally the moon completely moved inside the sun and the fire of ring was hanging in the western sky – a beautiful scene that one would never forget. It was so beautiful that everyone seemed very excited. The annular eclipse lasted about 5min, after which people started trickling away.

Maximum Eclipse
More photos are listed in annular eclipse photo gallery

When the moon finally moved out, it was almost 19h40m. The sun was low in the western sky and blocked partially by the clouds over the mountains.

On 8:15pm, the final part of the expedition began – 5-hour drive back to the home. It was a tough drive, after 3-hours tireless observation under the schoching sun.

Overall the expedition was a great success, after a month planning and preparation.

The most difficult part of the eclipse planning has always been how to beat (not really) the weather .It is always a tough decision when the forecast is not perfect. I use the following information available to make the final decision:
– Aviation forecast: most accurate but only for 24-hours, and should always be checked first if there is an airport nearby
– CSC and SkippySky: it is hard to tell which one is more accurate, so I check both to see if they agree with each other
– Satellite image
– NOAA

2011/12/10 Total Lunar Eclipse

I drove up to Henry Coe state park for its excellent western horizon despite of the poor weather forecast. The mid and high clouds rolled in and covered most of the sky before midnight. At 3:30AM, about an hour before the first contact, the high clouds finally broke up. I setup my telescopes quickly – AT111EDT for imaging and AT72 for visual. Weather remained favorable throughout the eclipse, scattered high clouds came and went, only blocked the moon from time to time.
This composite combines 12 photos taken between the first contact and greatest eclipse.

This composite shows the change of the brightness and color of the Moon, prior to and throughout the totality.

This 11-pane composite shows the shape of the Moon while approaching the 2nd contact.

 

04h12m57s, 1/400s @ ISO200
Full moon

04h36m47s, 1/400s @ ISO200
~10 min before the 1st contact, the shadow of the Earth was already visible

05h15m59s, 1/320s @ ISO200
the Moon was covered by half

05h29m01s, 1/125s @ ISO200
Tycho was about to be covered

05h52m27s, 1s @ ISO200
the Moon was visible in Earth shadow

06h01m34s, 1/8s @ ISO200
Crescent Moon

06h01m58s, 5s @ ISO200
Colorful Moon

In this 5s exposure, in addition to the usual red/orange color of the lunar eclipse, if you look closer you will also notice pinkish and blueish color (turquoise) near the shadow of the Earth.

06h15m30s , 5s @ ISO200
Red Moon

The eclipse coincided with Geminids which peaked on 12~13th. Since the moon conveniently located near the radiant, my kid and I were awarded with about a dozen of meteors.

The sky started to brighten at 2nd contact. The moon became fainter and fainter, as the sky brightened and the moon set in the clouds/haze .At the greatest eclipse the moon became so faint that it was difficult to spot. At 6:40AM, last sight of the moon disappeared over the silicon valley.

My kid and telescopes

Partial Eclipse Begins: 4:45:42 PST
Total Eclipse Begins: 6:06:16 PST
Greatest Eclipse: 6:31:49 PST
Total Eclipse Ends: 6:57:24 PST
Partial Eclipse Ends: 8:17:58 PST

Location: Henry Coe state park, Morgan Hill, CA
Equipment:
– CGEM
– AT111EDT + AT72ED
– Canon XS

2010 Geminids

Geminids is one of the most reliable meteor showers, with peak rate of more than 100 meteors/hour. Since its peak occurs on Dec 13-14th, cold weather across the world makes it less famous than its counterpart – Perseids.

THe weather forecast called for overcast/rain on Dec 13th night. Despite of being foggy for 3 days in the valley, I decided to go to Henry Coe State Park on Dec 12th night, hoping to get clear sky up there before the storm rolled in.

On the way up to the park, fog became so dense that I could not even see the road sometime. But the fog finally cleared up when we were approaching to the parking lot, and the sky was clear!!!

My kid and I arrived at the parking lot just before 10PM and Gemini was already high in the sky. The first quarter moon did not set until 11:30PM, but it had very little interference on the observation as it was low on the west (behind me). The fog covered the entire valley and it was the darkest sky the one could ever get near the bay area once the moon set.

I voice recorded meteor activities using my cellphone, between 10PM Dec 12th and 3:15AM Dec 13th 2010, except for the period between 23:30PM ~ 00h20AM as I was watching Geminids with my son. The activity of Geminids during this period was at the same level as the rest of observation. The high clouds rolled in at 3:30AM, though it was still observable I decided to head back home. Within 240 minutes, I recorded 344 meteors – 53 SPOs and 291 PERs, and my kids saw at least 60 meteors in less than an hour. It made this another very pleasant trip.
Almost all Geminids observed were of white color, with no train left behind. They were largely moderate bright (2~4m) and traveled at medium to fast speed. There were a few bright, yellow Geminids which produced train. No fireball was observed.

2010 Perseids

Perseids is one of the most reliable meteor showers, with peak rate of more than 100 meteors/hour. It peaks on Aug 12-13th, warm weather across the world makes it more famous than its counterpart – Geminids. This year, the peak occurs 2 days after the new moon so it will not be interfered by the moon.

I decided to go to Henry Coe State Park to avoid being fogged out. The parking lot was almost full when my kid and I arrived around 10pm, but most people left before 2AM,only then Perseids became really active.

This was the first time we went to dark site for meteor showers, I was a little bit worried because I was not sure whether it would disappoint my kid.

I voice recorded meteor activities using my cellphone, between 12AM and 4h50m (PDT) 08/13/2010, except for the period between 02h05m ~ 03h40m as I was watching Perseids with my son. As far as I could tell, the rate remained at least the same during this period, or might have been increasing steadily as the radiation point was rising. Within 190 minutes, I recorded 205 meteors – 27 SPOs and 198 PERs, and my kids saw at least 50 meteors in about an hour. It made this a very pleasant trip.

There were mainly three types of Perseids:
1.Green & Blue Colored: Some appeared as yellow first, then turned to green & blue. Most were bright (>2m) and left trains behind. Literally they were the only Perseids observed before “yellow colored” appeared. They mostly appeared in the area near or reasonably close to the radiation point, and rarely in the area near the horizon.
2. Yellow/Yellowish-white Colored: Most were bright (> 2m) and left trains behind. They dominated Perseids after Auriga had risen above the horizon. They were mostly observed near or towards the horizon (which means that they appeared lower in the sky, and farther away from radiation point than “green & blue colored”).
3. White Color: Most were faint (<3m) and moved swiftly, seeming that they were moving on the surface of water. They were visible throughout the night.