Location, Location, Location - for the Mercury Transit

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Bsimon
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Joined: Sat Sep 09, 2017 10:14 am

Location, Location, Location - for the Mercury Transit

Post by Bsimon » Tue Oct 15, 2019 9:04 pm

In a little less than 4 weeks we will have an early morning opportunity to follow the progression of the silhouette of Mercury as it glides across the face of the Sun. That day is Monday, November 11th and the transit begins shortly after sunrise. So technically those in the New Orleans area will be able to view the transit (with proper filtration) from beginning to end. As the transit begins within minutes of sunrise it is critical that you have a low horizon in the direction of sunrise to do this.

Using "Heavens Above" and my location, the Sun will be rising at an azimuth position of between 109 degrees and 110 degrees ( a bit south of due east). While I have a back yard with reasonably low horizons to the east, south and west, my horizons are not low enough to view the Sun until it is about 8 degrees up. Additionally from that vantage in my yard, the view to the north and Polaris is blocked by the house, so polar alignment should I want to track the transit equatoriially would be difficult, pretty much trial and error and likely resulting in unacceptable error. The quest then is to identify another location that has a low horizon in the direction of sunrise and a direct line of site to Polaris so at least a fairly decent polar alignment can be done.

I am sure with a little bit of effort most of us will be able to find such a location close to home. For me an excellent location is the levee just 5 homes down the street from me. This levee is the western bank of the Orleans Avenue Canal which borders on General Haig Street. It is the eastern side of East Lakeshore and on the east side of the canal is Lake Vista. From a good location on top of the levee I can see down to an elevation of 2 degrees so even if I don't quite catch the very beginning of the transit, I will see it very early. This location has a long run of good spots so others are welcome to join me here. Given good weather I will probably arrive by 5:45 am so that I can do a polar alignment so that I can easily follow the transit without having to constantly nudge the telescope along. (To see the transit well I believe that a magnification of close to 100 x, if not a bit more, is necessary.) At 100 x the Sun and Mercury will glide across a field of view fairly rapidly, so a driven mount is, at least for me, mandatory.

Below are some images of my view looking across the Orleans Canal. I also include an image of the device I use to calculate altitude. The azimuth calculation came from both two compasses and the compass reading on my cell phone.

Note - the next Mercury transit will take place on November 13th 2032 and will be centered on Africa, Europe and parts of Asia. None of it will be visible from the United States.

The last transit of Venus occured in June, 2012 and was visible from New Orleans. Venus transits take place in pairs separated by 8 years to be followed by a very long gap of over 100 years. The next pair of transits take place in the years 2117 and 2125 so very, very few people alive to day will see either of those. So for a transit in your lifetime, it is "Now or Never".

Barry Simon
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Bsimon
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Re: Location, Location, Location - for the Mercury Transit

Post by Bsimon » Wed Oct 16, 2019 10:12 am

Pictures of the Venus transit on June 5th, 2012. These pictures were taken at the Gretna Observatory. We had a lot of high level clouds and were only able to just catch the end of the transit right before sunset. Note the low elevation by looking at the angle of the tube assembly of the telescope. For the previous one in 2004, Al Diket and I traveled to Lookout Mountain south of Chattanooga and we were skunked by cloudy skies.

For the Mercury transit the image of Mercury will be approximately 1/4th the size of the Venus image in relation to the Sun as it is roughly half the diameter of Venus and twice the distance from us as Venus is.

Barry Simon
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Jstamm
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Joined: Sat Nov 04, 2017 1:37 pm

Re: Location, Location, Location - for the Mercury Transit

Post by Jstamm » Thu Oct 17, 2019 5:58 pm

Since November 11 is a semi-holiday, Veterans Day, any way this can be turned into outreach?

During the last Venus transit near the Kenner boat launch, many came and enjoyed the view. None went blind! None sued the PAS. 😁

Seriously, it was gratifying to meet so many people who were very interested in a little Astronomy!

John Stamm..

Bjohnson
Posts: 99
Joined: Sat Sep 09, 2017 10:17 am
Location: Kenner, LA

Re: Location, Location, Location - for the Mercury Transit

Post by Bjohnson » Sun Oct 20, 2019 9:37 pm

We have had quite a bit of interest in making this an outreach event. I am unfortunately working that day.
Anyone willing to take the ball on this and plan time and location?

Kenner Boat launch, New Orleans Lakefront, Mnadevielle lakefront. Lots of ideas.
We have about 20 days to get it together. Lets see what can be done!
Bill Johnson
PAS President, 2018-2019

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