Strange Quarks

I’ve had a Seestar S50 since mid-August 2024. The S50 is a small refracting (f/5 apochromatic triplet) telescope with a focal length of 250mm, an aperture of 50mm, and a ZWO-based imaging system that can be controlled with an iOS or Android app.

Images can be taken, enhanced and accessed via the app but the FITS (Flexible Image Transport System, commonly used in astronomy) files can also be downloaded via USB cable for further processing on a computer. This includes photometry, to determine the brightness of targets such as variable stars or asteroids.

So far I’ve taken images of the Triffid nebula, planetary nebulae such as the Dumbbell and Helix nebulae, globular star clusters, the yet-to-erupt recurrent nova T Corona Borealis, a nova in Scorpius (V1725 Sco), a short period (79 minutes) pulsating variable (SX Phe), Luna during the daytime (just because), the Sun, and Pluto from my suburban backyard in South Australia.

I wanted to take two images a few days apart to show Pluto’s movement against the background stars. These images were taken on September 3 and 7:

Note that the images are “decorated” by information and cross hairs because this is a view of the field from the software Tycho Tracker that I use (primarily for variable star photometry).

Here is an animated GIF created from these two images to make the change in location of Pluto on the two dates more obvious. Focus your attention just to the upper right and lower left not far from the centre of the image.

Here are some undecorated images with arrows pointing at Pluto, on Sep 3 and Sep 7 (around 20 minutes of total exposure each, via multiple stacked 10 second exposures):

Pluto takes 248 years to orbit around the Sun at an average distance of almost 6 billion km.

How far did Pluto travel along its orbit between September 3 and 7?

At an average speed of 17,096 km/hour, over the 3.96 days between the images I took, Pluto travelled approximately 1,625,000 km. We could arrive at a better result with some trigonometry.

I also measured Pluto’s magnitude on September 7 at 14.64 +/- 0.05, very close to the catalogue value:

The image comparator below provides another way to reveal the location of Pluto on September 3 (upper right of red cross hairs) and September 7 (lower left of cross hairs), by moving the vertical line left or right.

Below are SkySafari Pro screenshots for comparison in case you want to check Pluto’s position for yourself on the dates and times in question.

Finally, compare the images from the S50 to those Clyde Tombaugh had to work with in 1930 when he discovered Pluto using a mechanical blink comparator!

Being able to see the movement of Pluto is something I’ve wanted to do for myself since Martin George showed me Pluto through the eyepiece of a 14 inch aperture reflecting telescope in Tasmania about 30 years ago.

This entry was posted on September 20, 2024 at 12:23 am and is filed under Astronomy. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.