I was really
having some fun last night. Two nights ago I took 4 photos each with
2min exposures spaced by a 3 min separation period. If you look at the photo you will see that I did take a picture of the planet Pluto at 3
Billion miles away, even though among all of the stars Pluto only has
Am I sure
that I have the right dot? Yes, and that was what the excitement was
all about. I have discovered some new sophisticated astrometric measuring
tools within my growing suite of astronomy software. I was intentionally
taking multiple photos to use a blinking comparator. The idea was… with
autoguiding, the stars do not move but the planets do move, so that I could
pick out Pluto by using a Blinking Comparator. I later read, however,
that while this technique works great for finding minor planets and asteroids,
each picture needs about 45min of separation. So mine were too close
and showed no movement for Pluto.
So I used
an alternative method last night. Each photograph carries a great deal
of information in the header of the .FIT file which is produced by the CCD
camera. This not only includes the exact date, time, exposure information
but it also includes the camera’s celestial coordinates (Right Ascension and
Declination) and much more. I have software which produces a virtual
image of the sky for any time and date (past or future). This virtual
image of the sky is zoom-able to almost any distance that is necessary for
measurements. The really cool trick that the software was able to do
is to overlay the actual photograph (given the date, time and coordinates)
onto the virtual sky and exactly fit the two images. It takes about
a 6 star match to call it a successful overlay, I had 403 matches. So
for sure my photo was in the exact right place on the virtual (and fully known)
night sky. Once this matching was complete I had 403 known star locations
on my photograph,. Also the cursor position
now revealed precise celestial coordinates as I moved my mouse over the photograph.
By looking at the exact position of Pluto on the virtual sky at the moment
of the photo I could see the expected RA and DEC coordinates of Pluto. By
moving the mouse over the photo and reading the coordinates within the photo
I located Pluto. I was then able to double-check and verify it by verifying
the coordinates of the neighboring star images. As a final (third) confirmation
I was also able to verify the expected and actual magnitude of brightness
for both the neighboring stars as well as for Pluto itself. So without
much doubt, the line in the picture points to Pluto. Pretty
cool?
Now if I
had a few hundred hours to spend under clear skies, maybe I could find some
new Asteroid or Minor Planet which I could name as… “Joanna.”