Pluto at 2018 Opposition

orbital-positions   Thursday July 12th the Dwarf Planet Pluto will be at opposition. All outer planets and other solar system objects that orbit the Sun beyond the orbit of the Earth have opposition. At that orbital position the Earth is between the Sun and the outer solar system object, much like the Sun-Earth-Moon arrangement for a full Moon. At opposition the outer solar system object rises at the local time for sunset and sets at the local time for sunrise – again just like the full Moon.

   Where is Pluto and is Pluto visible to the naked eye? Pluto currently is a few degrees east from the handle of the teapot-shaped asterism for Sagittarius the Archer, and mid-way between Mars and Saturn. Pluto is visible, but with an apparent magnitude of 14.8 Pluto would only be visible with large aperture telescopes and with time-exposure pictures.

Click here to learn more about the New Horizons mission and take part in the mission with some of the interactives created by NASA.

   
   
   
   

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

Mars in Conjunction with Pluto

   Thursday morning before sunrise local time the ‘red planet’ Mars will be about 1-2o from the dwarf planet Pluto. Given the difference in distance and magnitude (Mars -0.26; Pluto 14.29) Mars is easy to see with the unaided eye, while Pluto would require a large telescope or a long time exposure to see.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

Mercury Near Pluto

(posting this ahead of time – on the road back to Quito and no Internet for a couple of days)

   Sunday morning January 29th the innermost planet Mercury will be about 1o from the the former outermost planet and now a Dwarf Planet, Pluto. Mercury with an apparent magnitude of -0.18 far outshines the 14.19 apparent magnitude of Pluto.
These two graphics show the sky as viewed from Quito Ecuador at 0o latitude, and my home latitude of approximately 40o North.

   
   
   

Click here to go to the Qué tal in the Current Skies web site for monthly observing information, or here to return to bobs-spaces.

#PlutoTime

eyes-screen   On July 14th, 2015 the New Horizons spacecraft will fly by successfully flew past the dwarf planet Pluto and its 5 currently known moons. An important part of the mission is the educational outreach – involving the public. So in addition to a new module added to NASA’s Eyes on the Solar System software, called Eyes on Pluto, there is now an online program, Pluto Time, that helps explain how bright it would appear at mid-day on Pluto and how that would compare with Earth.

A Picture or the Inverse Square Law?
   At the Pluto Time web site you enter your location and then are told the next time it will be ‘Pluto bright’ at your location. This seems to be around your local time for dusk or dawn – before sunrise or after sunset. So this picture from Tucson Arizona, facing northwest toward the Catalina Mountains, is as bright as it would be on Pluto during the daytime. Or at least according to the web site.

A Picture or the Inverse Square Law?
On the other hand, the average distance from the Sun for Pluto is about 5,906,376,272 km (3,670,052,066 miles) compared with the Earth’s average distance of 149,668,992 km (93,000,000 miles). Within the confines of the solar system distances like this are often referred to as units of AU or Astronomical Unit. One AU is the Earth to Sun average distance, while Pluto is 39.5 AU. Using the Inverse Square Law we can also determine how much dimmer Pluto is than the Earth, or how much brighter Earth is than Pluto.
inverse square law   The Inverse Square Law measures how much radiation, light in this situation, will decrease as distance from the light source increases. To calculate one simply inverses the distance value (makes it a fraction with 1 as the numerator) and then squares this fraction. For example if the distance were twice as much or were to double (2) then you would write it as its inverse, 1/2, and when squared (1/2)2 you would have 1/4. This would mean that if the distance were to double or be twice as much then the amount of light would decrease by 1/4th. 3 times would equal 1/9th; 4 times would equal 1/16th, and so on.
   What would it be like on Pluto? As of this posting Pluto is approximately 33 AU from the Sun (4,936,729,732 km; 3,067,541,639 miles). So the inverse square of 33/1: (1/33)2 = 0.00092 means that Pluto receives nearly 1100 times less sunlight than the Earth, or that mid-day on Pluto is that many times dimmer than than mid-day on Earth. The Sun in the sky above Pluto may look like this simulated view from the surface of Pluto suggests.

Here’s How to Make NASA’s Pluto Flyby a ‘Teachable Moment‘ for Students:

Caution: Objects viewed with an optical aid are further than they appear.
Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.

The Innie and the Outie

Click on graphic to see it full size.

Click on graphic to see it full size.

   This evening, Saturday 16 November, appearing within the field of view of 7×50 binoculars, the inner planet Venus will be about 6.5 degrees away from the the former outermost planet, Pluto. Now designated as a Dwarf Planet Pluto is at home with a group of at least 4 other dwarf planets with the closest one the former asteroid Ceres. However there are likely hundreds or thousands of similar rocky/icy objects located in the region of the solar system from Neptune’s orbit outward. and beyond that could be classified as a Dwarf Planet.

   Click here to see 10 facts about Dwarf Planets from NASA.

   
   
Caution: Objects viewed with an optical aid are further than they appear.
   Click here to go to the Qué tal in the Current Skies web site for more observing information for this month.