Mars: Keep on Viewing & Imaging!

Even though we’re past the point of closest approach and opposition, Mars continues to loom large in the sky and is higher each night at the same time. In the northern hemisphere, the nights are coming sooner and lasting longer. Until mid-November, Mars will appear bigger than at any opposition until 2033!

You can use the excellent Mars Mapper 2020-2021  web app (mobile version) on the British Astronomical Association website to identify features on the planet when you observe or image it.

If you’d like to try your hand at imaging the planet, study the next sections carefully as they contain image processing tips from top Martian imagers on the Internet.

Russell Smith’s Mars Images

Russel Smith images from his backyard in Melbourne, Australia. He took the above photos when Mars was between closest approach and opposition. Features visible here include a small south polar cap (it is summer there) at bottom and Niliacus Lacus and Nilokeras reaching down from the north. Sinus Meridiani is on the right (Martian east) limb and a prominent Solis Lacus in the southern hemisphere is on the left. Bluish clouds are visible along some limbs. The central meridian on the face of the planet is at about 40° west longitude.

Clearly, the photos show differences in detail and contrast. Russel explains his approach to imaging the planet and the differences between the images.

With Mars, you find a lot of people striving to get surface detail, but in processing for this surface detail, they totally destroy any clouds in the atmosphere. Mars is the only body we can image which has both a visible solid surface and an atmosphere — so careful non-pushed processing with the blue channel is a bit of a must.

This one [right image] is a different capture to the other picture — so naturally has some differences in processing (I have a rough processing routine, not a rigid one). Initially, I had a lot of detail in the previous one but pulled it back for a smoother look, I wasn’t sure if I was introducing many artefacts or not — and rather I didn’t. This time I believe I was more careful though in taking my time (I do an iterative approach with wavelet sharpening in RegiStax – so have lots of very minor wavelet sharpened images).

Peter Sculthorpe Mars Images

On the opposite side of our planet from Russel is Peter Sculthorpe in Merseyside, England. The 10-hour time-zone difference between the two means they’ll often capture a different side of Mars on the same night.

The next set of images is a glimpse into Peter’s stacking and processing routine for Mars images. He uses Autostakkert 3.0 software to combine images and the wavelets feature of RegiStax software to increase contrast in the photos.

The initial stacked images are often quite blurred and unimpressive, and that you only get detail out of the data after applying wavelets in RegiStax, and then sharpening/tweaking a little further using the tools in a program such as Photoshop.

As you’ll see, the final striking image of the planet in the following sequence is the result of careful manipulation of data through various filters and processes. 

The top row displays stages of working with images made through a  ZWO 850nm Infrared (IR) Pass filter.  (The advantage of IR light is that it is less scattered by the atmosphere).  From left to right the images are:

• The first is the IR images stacked in Autostakkert 3.0.
• The second is the stack with RegiStax wavelets applied to increase contrast in the image and make it appear “sharper”.  
• The final photo is the result of Photoshop manipulation of the wavelets image. Because it is a black and white image that only shows values of brightness, we call this the  “Luminance” (L) image.

The bottom row begins with a stack of images made through red, green, and blue (RGB) filters to produce a color image. 

• The first is the RGB images stacked in Autostakkert 3.0.
• The second is the stack with RegiStax wavelets applied.
• The final photo is the result of combining the second image here with the final Luminance IR image to create a composite LRGB (or  IR-RGB) image.

Meet our Powermates

Like the Barlow, Powermate™ amplifiers (mobile site) give your scope a longer effective focal length to boost the power of your eyepieces for Mars observation. However, the 4-element Powermate design goes beyond Barlow performance by better controlling exit pupil behavior with many long focal length eyepieces and also when it comes to high-definition planetary imaging. 

The Powermate design also has greater magnification potential with better aberration control and compact size compared to typical Barlow lenses. In fact, Powermates™ can be stacked with no adverse impact! Tele Vue Powermates™ are available in 2″ barrels (2x & 4x) and 1¼” barrels (2.5x & 5x).

For imaging, you can place an appropriately sized planetary camera in the eyepiece holder.  However, Powermates™ have a special advantage for imaging: the visual tops unscrew to accept specific Tele Vue Powermate™ T-Ring adapters. This allows for square and secure attachment of cameras and T-threaded accessories. Most any commonly available DSLR, astro-camera, and even some industrial cameras will work with Powermates™.

Keith Johnson Mars Image

The above image was also made using IR and RGB filters (compare to Peter Sculthorpe’s image above). It shows how the appearance of the planet is impacted by technique, processing, and image rotation. 

October 31: Uranus at Opposition & Micromoon / Bluemoon
Several astronomical events are happening on Halloween night.

Uranus Opposition
The orbits of the “ice giant” planet Uranus and our planet Earth will bring them into a straight line with the Sun at an instant in time on October 31st this year. Uranus will be on our side of the Sun and closest and brightest for the year. This means it will rise at sunset and be in the sky all night long. Unfortunately, this year, the opposition day may not be the best time to view the planet (see Micromoon / Bluemoon section below). But don’t worry: the slow-moving planet will remain at least 3.7″ of arc in diameter and at magnitude 5.7 for the next month.

For the story of how Uranus was discovered multiple times, see our 2018 Uranus Opposition blog post.

Micromoon / Bluemoon
The Halloween Full Moon will join Uranus in the sky at sunset. The impact of the companion Moon, moving along the ecliptic path with the Uranus, will be to drown out the feeble light of the planet and make it harder to locate. But look closer at that Moon. Does it look different than other full Moons? It is impossible to tell, but this full Moon is smaller than usual because it will be at the point in its orbit where it is farthest from Earth. This will be a Micromoon. Another interesting fact is that we already had a full Moon on October 1st. Squeezing the 2nd full Moon into the month earns it the title of a Bluemoon.

It’s a neat project to image the Micromoon and Supermoon (full Moon when closest to Earth) with the same equipment/camera settings and then combine the images. You’ll have a permanent record of how the Moon varies in size and brightness to show your friends. The next Supermoon will be on April 27, 2021.