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+--- Thread: 1989 JA -Bright Rock Finally Late May (/showthread.php?tid=2507)
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RE: 1989 JA -Bright Rock Finally Late May - Dennis - 2022-05-30
We're back to cloudy nights again so I decided to measure the trail of 1989 JA using Photoshop to compare the result to the SkyTools 4 Information. Here are the results, noting that using PS to measure the 2 sides of the triangle will introduce uncertainty in the Pixel Measurements, affecting the accuracy of the calculations.
SKYTOOLS 4 IMAGING
(7335) 1989 JA
Minor Planet
Apollo class (NEO)
R.A. 11h26m47.8s Dec. -44°41'24" (2000) in Centaurus
Magnitude: 12.00
Orbit Data:
Orbit Period: 2.4 years
Perihelion Distance: 0.9 AU
Aphelion Distance: 2.6 AU
Diameter: 1 - 2 km
Orbital Elements Epoch 2022 May 1.
Current Status:
Earth Distance: 0.03 AU
Sun Distance: 1.0 AU
Total motion: 40.3 "/min PA 237.0°
RA: -47.66 "/min
Dec: -21.97 "/min
PHOTOSHOP MEASUREMENTS
Cropped the image to 1024x1024 Pixels (full resolution).
Selected one of the 30 second trails and measured the 2 sides of the triangle.
Horizontal = 28 Pixels
Vertical = 48 Pixels
Hypotenuse = 56 Pixels.
Therefore, movement along trail = 56 Pixels in 30 seconds.
This gives a rate of 1.87 Pixels/Second.
Image Scale = 0.364 Arcsec/Pixel.
Therefore rate = 0.68 Arcsec/Second, or,
40.8 Arcsec/Minute.
CONCLUSION
So, pretty close to the SkyTools data I think.
Cheers
Dennis
RE: 1989 JA -Bright Rock Finally Late May - PMSchu - 2022-05-30
So, the error is (40.8-40.3)/40.8=0.012 or 1.2%. Not bad when you measured 28 & 48 pixels.
Well done!
Phil S.
RE: 1989 JA -Bright Rock Finally Late May - Dennis - 2022-06-01
Hi Phil
More cloudy nights, so I had a play with grabbing a screen capture in ST4 and overlaying it on a 1600x1600 crop of the image and discovered that I had also grabbed a Galaxy in the field.
Cheers
Dennis
ST4 Screen Capture
1600x1600 Crop of image
RE: 1989 JA -Bright Rock Finally Late May - PMSchu - 2022-06-01
Nice! Too bad you don't get more clear nights
.Phil S.
RE: 1989 JA -Bright Rock Finally Late May - Dennis - 2022-06-02
Thanks Phil, the Bureau of Meteorology just released some figures indicating that this has been our wettest Autumn in the last decade.
However, at least I managed to get some much needed beauty sleep.
Cheers
Dennis
RE: 1989 JA -Bright Rock Finally Late May - PMSchu - 2022-06-02
Yes, it's best to always look on the bright side
. You don't get so frustrated that way. Especially about the weather.If it clears up, you might have a go at 2022 KD2 in Scorpius.
Phil S.