Observing with Street Lights

Observing with Street Lights
Dark sky sites not always necessary to see the Milky Way (This image was taken ouside of a B&B in Julian, CA)

Thursday, October 29, 2015

Finally caught the plane in the moon and trying some photo interpretation to determine height and range

Greetings from Palmia Observatory

Well, you probably all have tried looking for the man in the moon, but have you tried looking for the plane in the moon?  I myself don't recall actually seeing the man in the moon, but have been unsuccessfully trying, until now, to get an image of the plane in the moon.

The opportunity for this image came up last night.  Resident astronomer Peggy was off baby sitting great nephew Jackson, so I attended one of the 50th anniversary presentations for the founding of the UCI campus.  The speaker was Nobel laureate Mario Molina, who as a young post doc at UCI working with Professor Rowland, decided an interesting chemistry topic would be
what reactions occurred with the chlorofluorocarbons in the atmosphere.  Neither of them were atmospheric scientists but their curiosity kept them going and their study, which resulted in the Nobel prize, showed the effect on the ozone layer.  Molina recounted how the vested interests at the time, similar to now with global climate change, fought to discredit them, but the science was right, as it is now.  The cooling of the stratosphere and the warming of the troposphere is a  smoking gun and fingerprint for the effects of greenhouse gases.

So, after returning home and it was my turn to take Astronomer Assistant Danny out for his walk to ensure no unauthorized personnel had entered the observatory grounds.  While returning, I noticed that the nearly full noon was just in the right location to be in the normal flight path of planes climbing out of Santa Ana or more likely LAX.  I've been trying to capture this image for about 6 months now, so I quickly ran back inside and grabbed my camera.  I tried to focus on the moon, adjust the exposure and keep track of when the plane would fly directly in front of the plane.

Wow, as many of you readers know, the trials and tribulations of trying any new astronomical observation can be tricky and present a learning experience for the amateur.  Sure, enough, my push on the shutter button came at the wrong time and I missed the shot.  Then, fortunately, I could just make out another plane coming over and while I waited for its navigation lights to cross the moon, the bad luck struck again and my camera battery, already flashing red, quit and I again missed the shot.

But, I assumed there still might be other planes going overhead, so I returned to get a fresh battery and at the same time changed from a 60 mm lens to a 300 mm telephoto and grabbed the camera tripod.  Now, all set up and focused on the moon, I waited patiently for the next plane if there was to be one.  At the same time, I had to continually jiggle the camera controls so it wouldn't time out and cause me to miss the shot just at the wrong time.  Anyway, an airplane came by, but it just missed the moon.  Another plane came by in about 5 minutes, this time right at the moon, but I snapped the shutter cable release just a bit late and missed the shot.  Darn.  Luckily, another plane was just behind and I followed the navigation lights and just clicked the shutter at the right time.

Hooray!  Success!  See the image below.



Plane discovered in Moon.  Photo from Palmia Observatory
Finally found plane in Moon


Well, this success bring up an opportunity to do a little astrophysics and photo interpretation.  How high is the plane flying as determined from this image?  Should we make this a homework assignment for you budding amateurs?  Ok, ok, I'll tell you what I attempted to do.
 First, I assumed the plane was a dual engine 737, of unknown configuration, but with average wingspan of say 120 feet.  The plane image wingspan covers about 1/3 of the moon diameter.  So, since the moon extends an angular size of about 1/2 degree, the plane extends about 1/6 of a degree.  Now we can use the tangent of this angle and the assumed wingspan of 120 feet to calculate the slant range to plane and get an estimate of 41,250 feet.  My calculation of the moon's altitude was about 33 degrees at the time and was changing about 3 degrees every 15 minutes.  But using the 33 degree elevation we can then use the sine of 33 degrees to convert the slant range into the elevation of the airplane, which I calculate to be 22,460 feet.

What do you think?  Does this make sense?  Should we take other things into account too?  Also, my guess is that the plane was still climbing to a higher cruise altitude.

This image will probably be the last until next week because I will be tied up with the American Physical Society far west meeting this weekend.  Just think two glorious days with physicists jabbering on about their favorite physics stuff.  It should be great, especially for us physicist wannabes.  Anyway, you too can show up at the meeting at Cal State Long Beach and get your fill of physics stuff.  Besides this Saturday is not going to have good astronomical seeing, what with the ghost, goblins and witches flying all about.

Happy Halloween and until next time

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