Pluto the Previous Planet

This little former planet – 4.9 billion kilometres away – has been on my wanted list for a long, long time!

The above highly cropped animation shows the eight-day movement of the very dim dwarf planet Pluto against the starry background of the Milky Way in Sagittarius. Both sets of images were taken in suburbia under similar conditions.

Pluto has a diameter of 2302 km and has five known satellites, the largest being Charon, which has a diameter of 1207 km. Pluto and Charon form a binary dwarf planet, in my humble opinion!

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Acknowledgements
Thanks to Astro-physicist (and MAS guest speaker)
Amanda Bauer (formerly at the AAO),
for inspiring the title of my post
with her humorous and talented rendition of the song:

“Pluto The Previous Planet“.

Please watch it!

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Below are two less cropped images (which also show Pluto if you look carefully), followed by the pair of original images.

Take-1 cropped:

2017-09-09: Pluto Take-1 6 x 1 min, 840 mm, f/7, ISO 2000, 1500 x 1500.

Take-2 cropped:

2017-09-17: Pluto Take-2 – 6 x 1min, 840 mm, f/7, ISO 2000, 1500 x 1500.

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Take 1 full size:

2017-09-09: Pluto Take-1 – 6 x 1 min, 840 mm, f7, ISO 2000, full size. The central star of the three bright star triangle is Albaldha.

Take-2 full size:

2017-09-17: Pluto Take-2 – 6 x 1 min, 840 mm, f/7, ISO 2000. The brightest of the triangle of three brightest stars is Omicron Sagittarii.

Pluto Details:

Visual magnitude: +14.3 (That’s dim! I assume this includes Charon, which is an unsplitable component at +16.7)
Apparent diameter: 0.1 arc-sec. (That’s small!)
Actual diameter: 2302 km.
Distance: 32.88 AU : 4,920,000,000 km : 273.5 light minutes.
Motion over eight days: 82 arc-sec.

Image:

Exposure: 6 x 1 min ISO 2000. (x2)
Dates: 2017-09-09 and 2017-09-17
Location: Leumeah, NSW.
Sky: outer suburban sky, clear.
Processing: Canon DPP, Deep Sky Stacker and GIMP
Image cropping: yes, quite a lot!
Gif creation: imgflip.com

Gear:
Imaging telescope: Skywatcher Esprit 120ED Super APO triplet refractor.
Focal length: 840 mm, focal ratio: f/7.
Imaging camera: Canon EOS 60D.
Guiding telescope: Orion ShortTube 80mm Achromatic doublet.
Focal length: 400 mm, focal ratio: f/5.
Guiding camera: Orion StarShoot camera.
Guiding control software: PHD2.
Telescope mount: SkyWatcher EQ6-R.
Polar aligning: QHYCCD PoleMaster.
Flattener, no filter.

How do I know it is Pluto?

I cannot know for certain! However, I am 99.9% sure because:

1. My mount was aligned accurately and finding required objects.
2. The imaged location is consistent with location maps of Pluto.
3. No other object blinks.
4. The object moved in the predicted direction , towards upper right.

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Image © R.Powell

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EDIT:

MVSchulze

This is a link to a recent interesting story from an experienced amateur astronomer, who attempted to visually observe Pluto in 1964, when it was still classified as a planet.

After reading my post above, he dug out his observation report and rebooted his research in a valiant and honest attempt to verify what he saw was actually Pluto.

A good read!

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