2012/06/05 Transit of Venus Photo Gallery

This post includes some photos taken during the transit, click here to see the details of the transit viewing event.

My Kids

My kids in front of the telescopes, taken at 14h17m, before the transit began.

Composite Transit of Venus Ingress Photo
ISO100, 1/500s

This composite photo contains 15 cropped photos  (100% zoom, un-processed) taken between the 1st and 2nd contact.

The first 5 photos show detailed progress of 1st contact. The Venus is already visible in the 1st picture (a tiny dent on edge of the Sun), which was taken just 16s after predicted time. The 2nd picture was taken 3s after I had noticed the Venus visually using liveview of T3i camera.  In the picture taken at 15h23m29s and 15h23m50s, blackdrop effect is clearly visible.

The Venus in most of these photos is blurry due to wind and seeing.

15h15m00s, ISO100, 1/500s
Mid Ingress

This photo was take at 15h15m00s, when Venus was about half way through the ingress.

16h50m00s, ISO100, 1/500s
Venus Transit

This photo was taken at 16h50m00s and it was the sharpest photos for the transit.

Transit of Venus Composite Photo
ISO100, 1/500s

Stack of 9 photos (100% zoom, un-processed) taken at: 15h20m00s, 15h49m00s, 16h19m59s, 16h50m00s, 17h20m00s, 17h50m00s, 18h20m00s, 18h50m00s, 19h19m59s. Note: The it is rotated 90 deg counter clockwise after stack.


Sunset at 20h13m, when transit was still in progress.


This was the setup I used for the transit (except for the camera which was being used to take this picture):

– Celestron CGEM
– AT111 EDT (white), F/7, full aperture Baader AstroSolar visual filter
– AT72ED (black), F/6, 2″ diagonal, 9mm Nagler T6 EP.

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.

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
– AT72ED
– CG3 mount with RA motor
– Canon T3i