2012-05-28

Transit of Venus (2012)


Hello again :D

    WARNING    Before reading the article, please be warned that looking at  the Sun without appropriate precautions (using solar filters, viewers, etc...) may & will cause partial or complete damage to your sight. Please take appropriate measures in advance &/or participate in a local astronomy group that takes precautions on your behalf by letting you view the transit through its equipment. You have been warned!!!

    A rare event that comes in pairs every 120 years, more or less, occurred on June 8, 2004. This rare event is going to occur in a couple of days as the second of the 2004/2012 pair which will not repeat until the year 2117. In other words, this rare celestial happening is the last one to occur in our lives; no one might be able to witness it again, unless science offers a way to extend the human life span.
This special event is the Transit of Venus (i.e; transit of the planet Venus in front -from our viewpoint- of the Sun). The two events are separated by about 8 years. This is characteristic of such a phenomenon which occurs twice every 120 years, as I've mentioned above. That is, it occurs in pairs (e.g; 2004/2012). The next pair will start in the year 2117.

Transit of Venus 2004; astroZ (http://flic.kr/p/ac4z8C)



This year's transit will occur on June 6, 2012 (or June 5 for the Western hemisphere)! Most importantly is that the transit is viewable from almost any region of the globe. Note that transit times for international cities [1] & for the USA [2] are different.

For Beirut city, the transit's contact times (BT*) are:

First contact   Second contact   Sun rise  Third contact   Fourth contact
~0100 hrs             ~0118 hrs         ~0530 hrs       ~0732 hrs            ~0749 hrs
   (not visible)         (not visible)                                                  (transit ends)

First contact @ 0100 hrs (not visible)

Transit @ Sunrise @ 0530 hrs

Third Contact @ 0732 hrs

What usually attracts people & scientists for such an event is the first couple of minutes from 1st contact & 2nd contact (which also applies to the 3rd & 4th contact) when a black drop effect occurs [3].

To observe the transit, you have several options outlined below, but in either case you will need one very important item, a filter. There are specialized solar filters for observing.
  • Telescope:
    • Do NOT use a solar filter that came with a cheap telescope (throw this away), specially those that are installed on/in the eyepiece!!! The filter should be on the main lens/mirror of the telescope. Make sure that the filter is not scratched or punctured before use by raising it against a lamp & checking if there any scratch or holes in it. If your telescope's aperture is large (>3 inch), cover the aperture with an opaque cover (e.g; carton) & leave just a small opening (~1.5 inch) to cover with a filter. This way you use less filter (& save money) & also protect both your telescope's optics & most importantly, your eye which cannot be replaced.
    • Projection: You could build a carton box or even a Sun funnel [4]. By projecting the transit more people will be able to safely view the transit. Moreover, the Sun funnel can also be used for viewing Sunspots on other days until the next far away transit!
  • Binoculars: Similarly to a telescope, you need to cover the binoculars lens's with filters. Make sure though to filter both lenses or cover the other non-filtered one. Do not leave any lens uncovered.
  • SDO: If my information are correct, the Solar Dynamics Observatory -SDO will be watching the Sun & hence the transit will be imaged by SDO. As such, those who cannot directly observe the transit, it might be worth following SDO's live image on my website or SOHO [5],
  • Online [6].

 

  Imaging the Transit


    You might be interested in preparing yourself for this rare event & imaging it. All you need is a camera, a tripod, & most importantly a filter for the cam. Without a filter, the Sun's rays are able to ruin you're cam's sensor. You ask which filter? Well, there are specialized astroimaging filters, but it is possible to use a piece of "unused" X-ray sheet (i.e; those sheets used when you do an X-ray scan not used for any scan; that is, it should be new -uniformly dark; check them for any scratch or holes before using them). Note: Do NOT use these for directly observing the Sun!!!
Attach the filter (& make sure it is tightly attached) to your cam's external lens & you're ready to go. Now it is up to you to decide whether you want to take wide-field image (i.e; scenic -with surrounding background) or narrow images (zoomed in). The latter can be done either with the cam's own zoom or by attached the cam to the telescope (note that in the latter case, the filter must be attached to the front of the telescope instead of the cam, as outlined in the previous section).

On a personal level, this will me my first Venus transit to observe & maybe image. I couldn't observe the 2004 instance for certain reasons and so I am happy that I will be able to observe it at least once in my life time. I therefore urge you all too, to observe this rare event which you might not hear about or witness in your life again. Also note that the most attractive to image are the black drop [3] at the beginning & end of the transit and when is Venus near sunspots!
If you're meaning on imaging the event, I also refer you to link [7], & like to ask my collaborator astroZ, to add any ideas he's got for us about imaging this particular transit, specially that he had already imaged the 2004 transit! There also exists a dedicated project for the transit [8] on which you will find more detailed info & more ways to observe the transit & participate as a Citizen Scientist!!!.

Finally, I'll leave you with the following video & suggest you also read page [9] from a fellow AAVSOer who also seems to go by the nickname "astrobob", and two other pages on how to setup your telescope [10] & bino [11] for the transit!



Update (2012-06-05): Two major observing events are available in Lebanon,
  • Beirut
    • Organized by Science & World Magazine and the Beirut Award International Festival
    • Location: Zaituna Bay parking lot, Beirut Water Front (after the Phoenicia Hotel)
    • Time: 0530 ~ 0800
    • Fee: free
    • Original invitation text:
      أنتم مدعوون لمراقبة عبور كوكب الزهرة أمام قرص الشمس في صباح الأربعاء المقبل 6 حزيران من الساعة 5:30 (الفجر) الى الساعة 8:00 .سنكون مع التلسكوبات والمناظير المجهزة بفلاتر شمسية في موقف السيارات لزيتونة باي Zaitunay Bay ، نراقب العبور مع من يحب أن يشرفنا بحضوره ( الدعوة عامة )..الحدث منقول على شبكات التلفزة اللبنانية والعربية والعالمية لذا سيكون بامكان المهتمين متابعته أيضا من منازلهم.هذا العبور للزهرة لن يتكرر الا في العام 2117 أي بعد حوالي 105 سنوات من اليوم

  • Ouyoun El Simane (or beyond)
    • gsfc
    • Organized by the Lebanese Astronomy Group -LAG
    • Location: Ouyoun El Simane
    • Time:
      • Departure: 02:30 (from Ain El Mreisseh)
      • Arrival to site: 04:00
      • Return: 07:30
    • Fee: $10 (bus fare)
    • Original event details: https://www.facebook.com/events/434257609925348/ (follow this page for any changes)

If you are not able to join a local event, I suggest the following links for live coverage from the Virtual Telescope, Ceccano (FR) Italy [13],  the summit of Mauna Kea, Hawaii [14], and from the Australian Astronomical Observatory [15].

Thanks for reading :)
clear skies
and Happy Transit!

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