Sedna – faraway dwarf planet


Sedna is a dwarf planet with a diameter of about 1000 km. Its very elongated orbit takes it to a distance of 11 billion km from the Sun when at its closest to 145 billion km when at its furthest from the Sun. This makes it the most distant solar system body except for long-period comets. It is so far away that it takes 12,000 years to complete its orbit.

Taking a photo of Sedna is an unusual feat and I’m very proud of it because its light is so dim. On this photo, its luminosity is only magnitude 20.9, really at the limit of my instruments which are nevertheless very efficient. At that time, it was 13 billion km from us, or 3 times the distance from Neptune, the farthest planet from us.

Technical details:

Telescope: Celestron Edge HD14 and 0.7x focal reducer
Mount: Paramount MX+
Camera: ZWO ASI 1600
Filter ZWO luminance 1.25″
Exposure: 3 x 10 minutes
Place: Backyard observatory in Sainte-Sophie, Qc
Date: 24 september 2017