Monday, May 9, 2016

1569d 2016/05/09

1569d 2016/05/09 07:08–14:55  EDT Foxmead observatory 9 28cmsc

Transit of Mercury

As usual, missed first contact by a few seconds, but had a fine view of second contact with 279mm SCT @70x with Kendrick Baader filter. Seeing poor but transparency good. Temperature = +1°C.

No sign of "black drop" at second contact: just a clean crisp tiny black disk against the Sun's limb.

Michael Watson has just posted a nice image of Mercury and the sunspot group near the centre of the disk:
Michael Watson's image

09:00–09:10: Mercury is now well onto the Sun's disk, but the seeing has deteriorated badly, with vast ripples across the face of the Sun. Temperature = +4°C.

10:00–10:10: I can now see the two small sunspots about half way between the large suspot group and Mercury. Temperature = +6°C.

12:55–13:05: I've had a number of visitors drop by to view the transit: Lorna Bolden, Pam and Allen King, Dave Wilkins, and Gord Michener. Plus, of course, my wife Louise and our cat Furr. Mercury has now moved over, closing on the opposite limb of the Sun. Temperature = +9°C.

04:25–14:55: Third contact at 14:37:55, Fourth contact at 14:41:05. Again, no black drop seen. Temperature = +10°C.

Michael Watson's collage of the transit sums it up beautifully:


  1. 25° Celsius here in England. Good view through Coronado PST. Couldn't see any sunspots though. First view from here since the 2003 rehearsal for the 2004 transit of Venus.

    1. There's one sunspot group with a medium sized spot in its centre, close to the centre of the Sun's disk. I find smaller sunspots often don't show up much in my PST, unless there is a flare associated with them.

    2. Ah yes, I see AR 2542 on the BBSO and spaceweather sites, but it has clouded over here :-(

    3. I was totally clouded out for the last Mercury transit, but managed to observe a couple of earlier ones. plus BOTH transits of Venus. At least you saw the beginning of this one...otherwise it's a bit like watching paint dry! It's a beautiful morning here, cool but very clear.

    4. Yes, I was lucky to see the whole of the 2004 Venus transit from here. Some lovely halo effects at the start of the Venus transit in the early morning also.

  2. Great weather in southern Ontario!

  3. The sunspot group is easily visible in white light, but I just know where it is in our Coronado 70 because of the white light view. There is also a very small group near to the limb on the side Mercury entered the Sun by.

  4. I'm glad you're blogging this event Geoff! I'm in an all day shell-scripting session and I'm looking forward to reading your reports.