This shot is going around like a trail of fire hey? So popular. It appeals to a lot of people and generates controversy as it should but in the end I reckon a lot of nay-sayers will end up with their nose in it. Dennis proof should do it.
You had that pilot on the mobile phone, didn't you? "Come a bit left...a bit more...now steady.........slow down a little."
Great to see the interest in your image. Hilarious to read the uninformed commentary! Well done to take a photo of the equipment in situ with Moon visible and image on camera pre-view screen - a good tip for others.
Here we go Chris. I have just updated the stick diagram and added a few notes to explain a few important details, such that the Moon was high in the East, with the Sun at 3 degrees in the West, hence the airplane is illuminated by the setting Sun.
I have also attached a screen copy of the XLS spreadsheet so that the calculations and assumptions can be independently assessed for errors.
Ok Dennis, just out of interest, how far left or right of the plane's course could Chris have been before the aircraft wouldn't have been reasonably centred in the pic? I wonder how many metres it would have to be?
Fantastic pic, and congrats on APOD too Chris - heck, you've become truely famous since I last visited this thread
Now that Rob,is a excellent question,I have been thinking about this quite a bit.May be Dennis and ChrisM and others might like to have a graph or similar to let us know.
Thanks all for the comments,input and support,I have been rather busy with many emails lately and have not had time to 'crunch the numbers'.
Just a hunch,on Robs question- I reckon about 600 metres either side.for the full 'Planar" eclipse.If I was at the local saw mill about 3 kms with gear set up ,I feel it would have been a "graze".
Finally,we start to see the image in Australian Newspapers today in QLD
"Courier-Mail" page 7,and a good little write up,no mention of the "L" word.
Any others around the country-let us know.
re-the "famous" bit-well its almost a little embarsing,I just applied my skills in a tradesman like manner on my observations which I had aquired over time.
Did my calculations and did the job.Those last few seconds though-no amount of dry runs could prepare for that!but it all went as I had planed.
Looking forward to my next missions! (if this cloud ever goes)
Ok Dennis, just out of interest, how far left or right of the plane's course could Chris have been before the aircraft wouldn't have been reasonably centred in the pic? I wonder how many metres it would have to be?
Quote:
Originally Posted by hotspur
Now that Rob,is a excellent question,I have been thinking about this quite a bit. May be Dennis and ChrisM and others might like to have a graph or similar to let us know.
Cheers Chris
Okay, I’ve approached this in 2 ways and either, or both, may be incorrect so you maths geniuses out there please let me know what you think!
Simplistic analysis from image in Photoshop CS5:
Measured distance from fuselage to “top” of Moon = 470 pixels.
Measured distance from fuselage to “bottom” of Moon = 520 pixels.
At a scale of 23.44 pixels/metre, then the airplane would skim the “top” and “bottom” of the Moon some 21 metres and 23 metres from Chris’ observatory respectively, taking into account the ground angle of 73° 46’.
Parallax calculations:
Using Parallax per the attached diagram, the answer comes out at ± 30 metres.
I don’t know what you all think, but these values seem surprisingly small?
Cheers
Dennis
PS – I have ignored the altitude of Chris’ observatory and the angle of attack of the Airplane to the Moon’s equator of approx -27°, plus other stuff I probably haven’t even thought of!
EDIT #1: Added a screen capture of updated spreadsheet with the calculations for the width of the ground track that straddles Chris’ observatory – a measly ± 30 metres!!!
EDIT #2: Updated diagram added with improved text quality and typo corrections.
Last edited by Dennis; 08-10-2010 at 06:55 PM.
Reason: Screen copy of XLS spreadsheet attached
Another approach is to use the existing data and calculations on the spreadsheet.
The Tangent of half the angle subtended by the Moon’s disc (30.3/2 arcmins) = 0.00440698 x 6719 metres (LOS Distance) which gives a value of 29.61 metres which closely matches the Parallax method.
That is, Chris would only have to move ± 30 metres in the appropriate direction for the airplane to skim the limb of the Moon.
I'm actually not too surprised at that. It just goes to show how hard it would be to plan to reproduce this at another site.
I suspect the planes are on a relatively tight course by VOR or GPS and thus their course (for that Flight number) relatively reproducible. That coupled with Chris' observations over the year + phase of the moon allowed it, but heck I don't think we'll see too many other planned shots like it anytime soon!
Closer to the terminal area at destination the aircraft are probably more likely to get air traffic control course adjustments making this sort of thing very difficult near an airport, but also the aircraft would be too low and appear too fast.
The manager from Bombardier sent a email today-the whole factory has viewed your diagrams and spread sheets,they enjoy looking at them very much too!.
The last one you posted-that's a very small window there,Are there any other maths people here that want to go over Dennis's numbers?
If that last diagram is correct-and Dennis has done two methods and arrived at a similar/same result.It really is amazing!
While all of this has been a hoot,a bit of fun,and a wonderful feeling to have my image around the world.
Unfortunately,there is a down side,a lot of people are now sending very nasty.attacking emails-as it appears they cannot prove the image to be fake.So now it appears if they cannot prove it fake-attack is the option for them.Going by some of the emails,it also appears some are astro=photographers,who are very PO and annoyed with me and my image.
I am really shocked about this,such ashame,that such people would send nasty emails and put down another astronomer.
I do hope that people can accept the image for what it is and move on.