(20 000) Varuna TNO

2013 02 14
Trans-Neptunian object Varuna with minor planet number 20000 was the target of this observing night.
It was discovered in 2000 by the Spacewatch survey were it got the designation 2000 wr106. The orbital period is 281 years.

Since the object is very far way it's apparent movement across the sky is to small to be recorded in a few hours, I decided to make two consecutive observations in order to captures it's displacement and confirm it is indeed a TNO Trans-neptunian object - stars don't show this type of movement in this time scale.

The observation was made with a 12inch (30cm) diameter Shmit-Cassegrain Telescope, Clear-filter in a serie of 12 300sec exposures. The animated gif show's a two image blink revealing Varuna's position on the 14th and 15th Feb.

Varuna's position over a one day period.

One way to check and be sure we are looking at a solar system body is to compare our image with an image from the Sloan Digital Sky Survey. These body's don't stay in the same place like stars do, so this way we confirm our object it's a travelling oneand not a star.

On the right DSS2 image of the same field without the trans-neptunian object.

With Astrometrica software I decided to evaluate the error of Varuna's predicted position. It was spot on where it should be, also confirmed the magnitude, hoe faint it was. There is a small difference mainly because this observation was unfiltered.

Astrometrica screenshot identifying the mag 20 object.

Out of curiosity I decided to see how much it travelled in 24hours, used a tool to measure the distance and it reported almost an arc minute, 0,98'. This image is an overlap of two images.

Varuna's jouney in one day orbiting the Sun