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Dennis
21-10-2006, 06:36 AM
Hello,

I've just started jotting down some notes on the upcoming transit of Mercury on 9th November, 2006. I thought I would post them here and add to them if I, or other contributors, think of more stuff later.

Pre-planning issues:
Have a clear idea of what you want to achieve otherwise you will be in a flap, like I was, during the June 2004 transit of Venus, which found me running around like a headless chuck, not knowing which camera to use on what ‘scope, and when in the sequence.

Full solar disc views with Mercury a small black dot making its journey across the face of the Sun.
Close up of Mercury at the 4 critical points of 1st & 2nd contacts, ingress and 3rd & 4th contacts, egress.
Animation of the transit across the face of the Sun.
Close ups of Mercury adjacent any sunspots.


Dry runs:
Before the day of the transit, complete at least one dry run with the exact equipment and configurations you will be using for the transit.

Establish optimal exposures for each phase of the transit.
Make sure you have all the power cords, camera cables, camera adapters, focusing aids, etc.


Imaging issues:
Which camera are you going to use?

Meade LPI
Philips ToUcam
DSLR

Practice with it at least once before the transit, even if it means taking images of a blank solar disc.
Determine the best exposures for the Sun; 3 degrees above the horizon and as it gradually climbs to 68 degrees.

Environmental issues:

Shield the notebook computer from bright daylight. I use my observing hutch which has a curtain so the inside in reasonably dark.
Sun protection for you. Hat and sun screen.
Comfortable, lightweight clothing to protect you from the Sun, without overheating.


Set up issues:
Focusing can be tricky unless there is a sunspot to pre-focus on.
Work out the orientation and predicted path in advance, so your ‘scope is pointing to the correct segment of the solar limb. Or, if using GoTo, you can work this out by doing a GoTo on Mercury; although remember that it will only be a degree or two above the horizon.

How good will it be?
The relative sizes are based on data taken from Starry Night Pro V6. Mercury will be 10.0 arc seconds in diameter on November 9, as compared to the Sun’s diameter of 32 arc minutes, a ratio of 1 to 192. By comparison, Venus’ diameter during the transit of June 8, 2004 was 58 arc seconds, a ratio of 1 to 33.
I have posted a scale image of the relative sizes of Venus and Mercury against the solar disc, just so no one is disappointed on the day with how small Mercury will appear compared to Venus in June 2004.

Cheers

Dennis

Astroman
21-10-2006, 06:40 AM
Thanks Dennis thats a great help, now if only I can get some Solar FIlm :)

[1ponders]
21-10-2006, 07:14 AM
Top stuff, thanks for that Dennis. Wise words. Now if I an just convince my boss I need to have the whole week off prior to practice :D

Sausageman
21-10-2006, 08:55 AM
Thanks Dennis,
I assume, (not having checked the transit time yet) that it will be at sunrise?
I was going to take my scope to work that day and let people see it also.
The Venus transit was a failure due to clouds all day.

Mike.

Dennis
21-10-2006, 09:54 AM
Hi Mike

Good to hear from you. The transit starts around 5:12am I think, with sunrise around 4:52am. (NOTE: Times are for Brisbane which does not operate daylight saving).

Venus - yeah, I spent the morning driving west to find a gap in the cloud and finally, some 70kms from home, I found a public lookout and a clear patch of sky so I set up and managed to grab a few images. Good luck for the 9th!

Cheers

Dennis

Edit: Added the NOTE re Brisbane time.

ving
21-10-2006, 10:09 AM
when does it finish?

acropolite
21-10-2006, 10:18 AM
I've made this thread sticky, if in your practice sessions you could post your OTA/filter (Incl size) details, tracking and maximum useable magnification, exposure details etc it would help those of us unlikely to get practice sessions in.

Ving, according to the info published in (page 61 Nov/Dec 2006) AS&T this month, the transit starts at 6:12:08 Daylight saving time in Sydney and ends at 11:10:23.

Herr Ponders advises that there is visible, at the time of this post, a small sunspot of approximately the same size as Mercury during the transit.

iceman
21-10-2006, 10:22 AM
Excellent information Dennis, I'd like to include it in an article if you could "word it up" for me and send it via email?

Thanks!

Anything else you want to add to it, feel welcome :)

Dennis
21-10-2006, 10:47 AM
At 4th contact. :whistle: :whistle:


....which will be around 10:00am I think. (Brisbane time which is non daylight saving)

Cheers

Dennis

[1ponders]
21-10-2006, 10:50 AM
You mean ving you don't check the Event Calendar for these little details. Tsk Tsk ..... What sort of serious party/holiday/"any excuse for a nosh up" librarian to you take yourself for.

:lol:

[1ponders]
21-10-2006, 11:14 AM
Does anyone have a link for long range weather forecasts? It might be interesting to track the upcoming weather situation as well.

Astroman
21-10-2006, 11:20 AM
Predicting cloud or the amount of cloud cover that far out is like trying to shoot a target the size of an ant, 5 million, billion km away. Almost impossible. Going by current trend though, best chances of seeing it will be further inland away from the coast. Having said that unless there are storms about then it wont matter where you are, you will get rained out :P I will predict a 60-75% chance of clear skies somewhere near a capital city. Hope this helps :D

Also check out www.weatherzone.com.au and www.bom.gov.au for latest forecasts around the place.

[1ponders]
21-10-2006, 11:29 AM
:lol: you're probably right there Andrew ;)

janoskiss
21-10-2006, 12:00 PM
I just want a good visual setup for public viewing.
I'm planning to have my Mak out but I'd also like to have a projection screen set up. Dennis, looking at your diagram, the planet will probably be too small for pinhole projection to show it properly. Can anyone suggest what might be a quick and easy projection setup?

Dennis
21-10-2006, 01:13 PM
I guess for public viewing, if possible, it would be highly desirable to keep people away from the ‘scope. If the ‘scope can track, then having a webcam with the image displayed on a notebook computer seems a good way to go.

You could isolate the ‘scope and only have people come by the notebook display, inside a cardboard box on a sturdy camping table?

Batteries, equipment, leads, etc. could be routed and stored under the sturdy camping table whilst people could view just from the front direction?

The cardboard box could be deepened to ensure the notebook display is reasonably dark and you could operate the ‘scope via the hand paddle near the notebook?

This way, no one gets to look through the ‘scope, or even touch the ‘scope, leaving you to focus on operating the computer and keeping the image centred?

Cheers

Dennis

ving
21-10-2006, 03:39 PM
a lazy one? :rolleyes:

lol, well i will be up for it then :P