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Report: Mars 2020

2020 December 27
by Russ

Unlike deep sky astrophotographers, we planetary imagers don’t need clear dark skies.  We need clear steady skies.  Steady seeing is good seeing. And good seeing is essential to capturing a crisp detailed image of a planet. In the case of the planet Mars, however, we need more than good seeing.

Because Mars is a relatively small telescopic target, it also needs to be at a place in its orbit where it is closest to Earth. When Mars is closest to Earth, it appears larger. A larger-appearing Mars allows planetary imagers to capture more detail in their images of the Martian surface and atmosphere.

Raw Video
Processed Image
Mars on October 10, 2020, four days after closest approach, and three days before opposition. The image on the left is a snippet of the raw video that produced the processed image on the right. Imagery was captured with a Celestron C8 Telescope (203 mm f/10), 3X Barlow lens, and a ZWO ASI224MC camera.

Mars was especially well placed for imaging in October. Mars was at its closest approach to Earth on October 6th, and reached opposition on October 13th.  At this opposition, Mars grew to an angular size of 22.6 arc-seconds.

Mars reached its maximum apparent size of 22.6 arcseconds for this opposition cycle on October 6th. This illustration shows how the Martian disc changes in size in the months before and after opposition and how that change in apparent size affects the amount of detail that can be seen from Earth and captured in telescopic imagery. Image Credit: Jeffrey Beish/ALPO-Astronomy.org

Knowing that nights of good seeing are rare at our home in Oklahoma, we set out for Rusty’s RV Ranch in southwest New Mexico in search of steady skies for imaging Mars during its 2020 close approach. Rusty’s prides itself on its clear dark skies and caters to amateur astronomers.

Unfortunately, while the skies at Rusty’s were clear and dark (ideal for deep sky astrophotographers, of which there were many present), for the week we were there, there was considerable movement in the atmosphere at both lower and upper levels.  This movement in the overhead ocean of air caused unsteadiness in the nighttime seeing.

At the high magnifications used for planetary imaging, this atmospheric turbulence caused the planet’s disc to bubble and boil in and out of focus.  And, to compound matters, southwestern New Mexico was covered at the time by a lingering persistent smoky haze from wildfires throughout the western U.S.  The smoky haze affected the transparency of the atmosphere and made it difficult for my one-shot color camera to draw out color from the small Martian disc, especially blue.  The lack of blue light making it through the haze is what I think caused Mars to have the off-yellow color shown in the raw video snippet above. It also means that my images show only Martian surface features and almost none of the atmospheric features (bluish haze, wispy clouds) captured by other planetary imagers.  All-in-all, while the planetary alignment was perfect for acquiring good images, the atmospheric conditions were not.

Nevertheless, while the seeing conditions throughout the week varied from extremely poor to poor-average, there were occasional short periods when the seeing improved enough to obtain the images shown here.  But, don’t get the idea that these images were just snapped at the telescope as one-time shots. It’s a little more complicated than that.

My observing and imaging setup at Rusty’s RV Ranch near Rodeo, New Mexico. The tiny red dot at the back of the telescope is the ZWO ASI224MC planetary imaging camera.

If you look real close at the picture of my imaging setup, you will see a little red object at the back end of the telescope. That little red dot is a sensitive video camera especially designed for planetary imaging.  The camera sends a high speed video stream of up to 100 frames per second to the laptop computer. Each frame in the video stream is a complete single image.

The idea is to capture a two or three minute video sequence consisting of several thousands of frames knowing that despite the constant wavy atmospheric distortions, with luck, some of the individual frames will be in better focus than others. Later when the video sequence is run through a specialized program, those higher quality frames are culled out, aligned, and stacked together into a single image. That single image is then manually processed using other specialized programs that apply sharpening magic and allow for adjusting color balance, removing noise, rotating, cropping, and other refinements.

This “lucky imaging” process is designed to get the best image possible when shooting through the undulating ocean of air between us and the planets.  The two images of Mars shown here are stacked images of the 2000 best frames taken from video sequences of six thousand frames each.

My images from Mars 2020 opposition week are on the left. The image on the right was taken by the Hubble Space Telescope during the August 2003 opposition. The Hubble image is annotated to show some prominent features.  Comparing the two, it’s pretty obvious that this year, Mars’ south polar cap is much smaller than it was in 2003. My images also show the Hellas Basin, an ancient impact structure that formed when a comet or asteroid struck Mars. Hellas is approximately 1,100 miles (1,800 km) in diameter. Also, just barely visible in my images is Schiaparelli Crater, another impact structure. Schiaparelli is approximately 277 miles (461 km) in diameter.  Lucky Hubble. It’s high above the atmosphere and always has good seeing! Image Credit: NASA and the Hubble Heritage Team (STScI/AURA).

In October when I captured these images, Mars was only 35 million miles away. As I write this in late December 2020, Mars is 79 million miles distant and presents a much smaller target. Some planetary imagers with larger telescopes at locations with more favorable seeing conditions continue to tease detail from the Martian disc, but this Mars apparition is over for me. I’m looking forward, however, to the next opposition, which will occur on December 8, 2022.  At that time Mars will once again be close, only 38 million miles distant, and back within the capabilities of my humble equipment.

A Christmas Comet

2020 December 25
by Russ

This Christmas season has a visitor to the inner solar system well placed for viewing in the pre-midnight sky. The visitor is Comet C/2020 M3 (ATLAS).

As of this writing, Comet ATLAS is in the constellation Auriga near the bright star Capella.  I happened to catch it last Saturday night.

Comet C/2020 M3 ATLAS on December 20, 2020.  This sequence of images shows Comet C/2020 M3 (ATLAS)  as it crawled through the constellation Auriga on December 20, 2020. This animation was cropped from an animation showing a larger area of sky. The size of this field of view is approximately 9.8′ x 6.6′, or 0.16° x 0.11°. North is up. East is to the left. You can see the full image here.

The image to the left is an animated gif covering a 47 minute period. Although the comet appears to be dashing across the sky, during that time, it moved just 3 arcminutes, or a mere 0.05 degrees.

During this session I estimated the comet’s magnitude as 11.8, although other observers were consistently estimating it as bright as magnitude 9.9. Unfortunately, even at magnitude 9.9 the comet is too faint to be seen without a telescope. Magnitude 6 is about the best the bare eyeball can do, and that’s from a very dark location with dark-adapted eyes.

Each of the seven images that went into this animated gif is made up of a stack of 10 to20 15-second subimages.  Images were live-stacked at the telescope with SharpCap and cropped and processed into an animated gif in GIMP.

Image Details:
Object: Comet C/2020 M3 (ATLAS)
Date/Time:  20 December 2020 06:34:01-07:13:34 UT
Telescope: Celestron C8 (203mm f/10) reduced to f/5
Camera: ZWO ASI224MC

 

 

 

View from the high ground December 27, 2020

2020 June 4
by Russ

December 27, 2020

This recent imagery from NOAA’s GOES-East satellite shows sunset spreading across the United States from east to west leaving a trail of sparkling lights in its wake. We can also see a major winter storm barreling across the upper midwest into the northeastern U.S. and a new storm system entering the northwest U.S. from the Pacific Ocean.  Meanwhile, a large band of moisture-laden air streams into the U.S. from the Pacific and across the southern Rocky Mountains. Quite a busy but beautiful scene from the GOES-East satellite parked in its geostationary observing post 22,000 miles (36,000 km) overhead. GOES-East images are updated every five minutes. You can find the most current GOES-East imagery here.   Track GOES-East (aka GOES-16) here.

Getting ready for Jupiter’s 2020 apparition

2020 June 1
by Russ

This is Jupiter from an imaging session on May 5, 2017. I hope to capture more images like this over the coming months.  The video clip on the left is a short snippet of the raw video sequence that produced the color image on the right. Equipment used during this session was a 203 mm f/10 Celestron C8 Schmidt-Cassegrain telescope, 2X Barlow lens, and ZWO ASI120MC camera.

Amateur astronomers   began imaging Jupiter  in February shortly after the planet emerged from the solar glare into the predawn sky. For me, however, the  2020-2021 season starts next week.

In early June, Jupiter will climb high enough above nearby houses and trees to be visible from my backyard as it transits the celestial meridian in the wee hours of the morning.

Jupiter will rise earlier each day over the coming months. This will gradually move imaging opportunities into earlier evening hours.

Jupiter reaches opposition with Earth on July 14th and reaches its closest approach to Earth for this cycle on July 15th.

The table below shows the details for June.

Date Rise CDT Transit CDT Set  CDT Angular Size Distance
June 1 23:42 04:44 09:42 44.80″ 4.401 AU
June 15 22:43 03:44 08:42 46.24″ 4.263 AU
June 30 21:38 02:39 07:35 47.28″ 4.170 AU
Angular size is in arcseconds. Distance is in astronomical units (AU)
Source: CalSky

 

Although I am just getting ready to start observing, the 2020 Jupiter apparition is already in full swing for observers elsewhere around the world.  Many have been posting spectacular images on the web since February.

One of the best sites for seeing daily Jupiter images submitted by amateur astronomers is the Jupiter Section of Japanese Association of Lunar and Planetary Observers, or ALPO-Japan.  Be sure to check for images posted there by Christopher Go and Damian Peach.  They are two of the top planetary imagers in the world.

Bright Sky Observing

2017 March 13
by Russ

A portion of the Moon from downtown Oklahoma City on March 3, 2017.

Observing from a brightly lit downtown location can be a challenge.  But, there are interesting sights to be seen.

The Oklahoma City Astronomy Club conducts a Sidewalk Astronomy event in Oklahoma City’s Paseo District on the first Friday of every month in conjunction with the Paseo’s monthly Gallery Walk event.  Our observing location is well situated to attract the attention of many restaurant and gallery goers who assemble in the area.

Unfortunately, while we have a prime location for attracting visitors, our view of the sky is limited because we are set up directly under bright street lights.  Because the sky is awash in light, faint fuzzy objects like nebulae and galaxies don’t present well.  Despite the bright lights, however, there are objects that can be seen through the glare and still wow a crowd of curious passers by.  One of these objects is the Moon.

On March 3rd we were set up at our usual sidewalk location.  The Moon was well placed high in the sky to the southwest.  It was about a day-and-a-half shy of  First Quarter, or about five-and-a-half days old.  We had a relatively small crowd of visitors this night with only about seventy people stopping by.  I kept my telescope trained on the Moon most of the evening, and while looking through the eyepiece, one excited visitor exclaimed it looks like “holes punched in clay!”

Eventually, I hooked up the camera (a ZWO ASI 120MC ) and displayed the moon’s image on a laptop computer.  The Moon’s shimmering appearance sparked some good discussion with visitors about looking out into space from the bottom of an ocean of air.

During a short break between visitors, assisted by my grandson, I was able to snag a short video sequence.  A tiny piece of the video clip is shown above on the left.  The wavy movement of the image is a good approximation of the live view we had on the computer screen.  It is a testament to the fact that we are looking out into space through miles of air with moving pockets and layers of slightly differing temperature and density.  These pockets and layers act like tiny lenses that constantly shift the focus of the image.

To the right of the video clip, is an image derived from the video.  It consists of the best 80 frames of 400 stacked and processed into a single image.  The crater with the conspicuous central mountain peak is Theophilus.  It is about 60 miles in diameter and 2 miles deep.  It’s central peak is a little short of two miles tall.  The dark smooth circular area to the right of Theophilus is Mare Nectaris, or the Sea of Nectar.  There is no water or nectar there.  At one time, however, the broad circular area was a sea of molten lava.  Over the aeons that sea of lava hardened into the dark volcanic rock we know as basalt.

In addition to Theophilus and Mare Nectaris, there are a number of other interesting features in this image.  In total, the image contains seven of the one-hundred must-observe features of the Astronomical League’s Lunar Observing Award program.  The image below is a cropped and slightly enlarged portion of the stacked image shown above.  A particularly noteworthy feature is Rupes Altai or the Altai Scarp. The Altai Scarp is a 275 mile-long escarpment with cliff faces that stand over a mile high along most of its length.

Seven of the 100 lunar features on the Astronomical League’s Lunar Observer Award program list are visible in this single image.  All were seen from a brightly lit location in downtown Oklahoma City on March 3, 2017.

All these features were visible  from a downtown location under bright streetlights.  So, when the  nighttime viewing is washed out by bright lights, and the Moon is up, take a look.  There’s a lot to see.