Earth has been moving closer to Mars this spring as we orbit the Sun. We reach inferior conjunction, our closest to the planet, in late July 2018. Mars will appear larger in telescope views until then. No, it will not appear as large as a full moon contrary to an internet meme that has gone around for years.
Saturn is in the distant backround when viewed early in the mornings. Because Mars is closer to the Sun than Saturn, it passed by the slower moving Saturn. This short animation illustrates the passage. Watch Saturn slowly move across the frame. Also, watch for the Moon to pass by at the end of the animation. That happened on 7 April 2018.
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🔭 Updates an earlier post to include recent changes and new information.
As an amateur astronomer, I use desktop planetarium software to plan viewing sessions and keep track of the planets and Moon. There are many products available for all computer platforms and smartphones. A Google search yields links to many sources. I downloaded and use the open source Stellarium on my desktop computer. It can be customized to your location and is free. For Android and Mac phones and tablets, I like SkySafari. It isn’t free but is inexpensive.
Online planetarium sites are popular and offer many features. Below are highlights of some I find interesting. Each has multiple features, a unique look and feel, and different levels of detail. They can help satisfy your curiosity about astronomical events.
I have included only a few select sites and links since so many are available. I welcome reader questions or reviews about using these tools or others you find helpful.
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Two days earlier I posted some photos of Venus and Mars in the pre-dawn light. The positions of Venus and Mars were getting closer each morning. October 5th was to be the day they would be closest at 1/4˚ apart. For comparison, the Moon’s diameter is only 1/2˚ wide.
Our weather forecast said it would be raining on the morning of the 5th. I assumed that previous post was going to be all I would get to share about their conjunction. Today I looked outside before 6 am and was thrilled to see a clear sky. I got the camera and tripod to capture the unexpected scene.
First is a screen capture from my planetarium software showing the planets on the 3rd and the 5th of October.
Next is my photograph of Venus and Mars at 6 am on the 3rd of October. It is adjusted to be the same scale as the first image.
Finally, my photograph of the two at 6 am on the 5th of October. It is adjusted to be the same scale as the first image. They were about half the width of a full moon apart. Mars was hard to see without the aid of binoculars. By 6:30 am, the sky was too bright to see Mars. Venus remained bright and easily seen. In fact, in clear skies, Venus is not hard to see in the daytime if you know where to look.
Venus has been gracing the morning pre-dawn sky for several weeks. It raced past Earth in its orbit around the Sun and is receding from us quickly. It will pass behind the Sun early in 2018 before emerging as an evening apparition.
Mars is positioned farther away from us than Venus and nearly along the same line of sight. On 5 October, early morning risers can see the two nearest to each other. Look at about 6 am low in the eastern sky on a clear morning. Binoculars will help spot dim Mars. It appears we will suffer from cloudy skies here in the midwest.
This morning I was up early and looked for Venus. It was hidden by low clouds to the east. I waited and was able to see both Venus and Mars emerge from the clouds. Notice the faint outline of a tree on the right side of the image. All images have been slightly modified to make them more easily viewed. They look best enlarged on a monitor screen. You might not see anything on a phone or tablet.
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Saturn’s north pole features a hexagon shaped pattern in the clouds driven by fast winds that wrap the planet. The hexagon is about as wide as 2 Earths. This image taken by Cassini on 2 Apr 2014 is in greyscale.
On 26 Apr 2017, Cassini passed over this same hexagon region but at a much lower altitude. This pass was the first of 22 during the coming months in the Grand Finale of the mission. It will enter the cloud tops 15 Sep 2017 to end the 20 year mission at Saturn. As Cassini made this recent close pass, it imaged the hexagon in greyscale 3 time with filters of red, green, and blue.
Using Photoshop, I combined these RGB greyscale images into one with color. The colors are not necessarily what the eye would see. They are my choices in order to enhance differences in regions and appearance. The large blue object at the bottom is like the eye of a hurricane on Earth, but much larger.
The hexagon pattern can be produced in a laboratory evidenced in this post.
Launched 15 October 1997, the Cassini Mission is in its 20th year. It reached Saturn and entered orbit on 1 July 2004. Details of the mission can be read at this Wikipedia summary. This post is mostly about the maneuvers by Cassini to change its orbit and make 22 close encounters with Saturn in what is called the Grand Finale. End of mission is scheduled for 15 Sep 2017 when the spacecraft plunges into the atmosphere of Saturn ending a long and brilliant exploration of the famous ringed planet, its rings, and 62 moons.
Clean Room Workers Ready Spacecraft | NASA | 1996
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So many stories today about the new Earth-like planets found around a Jupiter sized star. It is hard to keep up and make sense of the new information. This NASA news conference explains the importance and why scientists are so excited.
I will be away from the computer this evening. Comments are welcome but my responses will be delayed.