At opposition, Saturn is typically about 793 million miles (1,269 million km) from the Earth, over twice the comparable distance to Jupiter. Saturn is a gas giant, like Jupiter, and most of the planet we see represents its atmosphere. However, it receives much less solar energy at its great distance from the sun and the fact that the planet is smaller than Jupiter means that there is less internal heat to drive the planet’s weather. Atmospheric banding is muted and, to the eye, the planet appears golden with muted pastel color banding.
The magnificent rings are formed by a composite of thousands of ringlets of particles of ice and rock, most ranging in size from dust to sand. The rings, which tend to look white in a telescope, combined with the golden hue of the planet itself create a view that many consider to be the jewel of the solar system. The planet has over 50 verified moons along with a number that are still pending. These make up some of the most interesting satellites in the solar system, including the record for the largest moon of any planet – Titan. Click on Saturn on the [NASA Solar System Exploration] page for more information on this beautiful and fascinating planet.
Saturn is the most distant of the naked eye planets known in antiquity. It is equal in brightness to typical relatively bright stars, but has only ~15% of the brightness of Jupiter or Mars at opposition. When you go to image it you realize how little light is actually available. In smaller telescopes, Saturn is definitely a “dim bulb”, requiring longer, less favorable exposures. Saturn was also very low on the horizon in the 2017 opposition, further reducing its brightness and providing more opportunities for atmospheric distortion. Despite this, a number of passable images were obtained. The tilt of the planet this year shows the rings very close to their optimal exposure. Over an 11 year cycle the tilt of the planet as we see it will begin to decrease until the rings will be viewed edge on and will barely be visible. Given another 11 years beyond that, the rings will be back pretty much as we saw them this year.
My best images of the 2017 apparition were obtained on 25 July 2017, almost six weeks after opposition. Saturn is large enough that, like Jupiter, it is worth attempting to image whenever it is visible in a dark sky.
The 2018 opposition of Saturn will be on 27 June 2018. You should get reasonably good views for two months on either side of the formal opposition. New images will be posted as they are acquired. Like last year, the planet will be low in terms of maximum elevation and the rings will be well-displayed.
This is the first image from this apparition, with Saturn just 24 degrees above the horizon. My expectations were not high, but the image is better than expected!
The Hogsback 2018 Florida Expedition
Jupiter (32, Saturn (25), and Mars (25) all have oppositions this summer – that’s the good news. The bad news is the numbers in parentheses, which represent the highest that each planet will get in terms of degrees above the horizon here in Mason. At 32 degrees, Jupiter may yield some good images, but at ~25 degrees, the situation is not good for Mars and Jupiter. Although I will certainly try to get good pictures at the observatory, the best opportunity for optimum images will be to drive a whole bunch of equipment to the Gulf Coast of Florida. This will yield two immediate benefits:
By moving my observing point south by approximately 13.5 degrees of latitude, all three planets will reach an elevation that is essentially 13.5 degrees higher than would be the case in Michigan, giving a much better chance of having at least a few sessions with less atmospheric disturbance!
The site we will be using is an excellent “dark sky” site with “seeing” that is typically much better that is the case with Michigan skies!
The plan is to be in Florida for the last full week in June, with three days of travel at each end. If all goes well, I should be able to post some truly superior images sometime in late July. It is a complex plan, with many things that could go wrong, but, with just a few sessions with good conditions, the objectives of the expedition can be realized.