An “opposition” happens on the day that Earth and an outer planet line up on the same side of the Sun. For Earth observers, a planet in opposition will rise when the Sun sets and will be in the sky all night. Around the time of opposition, the planet is brightest, practically fully illuminated, and displays the largest angular diameter for the year. Right before, during, and after opposition are prime-time for viewing and imaging a planet!
Amateur and large observatory scopes can do best when imaging planets at opposition. It was just announced this summer that amateur astronomer Kai Ly discovered an unknown moon of Jupiter while examining opposition images taken with the 3.6-meter Canada-France-Hawaii Telescope at Mauna Kea Observatory in Hawaii. This news comes just in time to take some confirmation images as Jupiter opposition season is upon us now!
Imaging Planets with Powermates
Attempting to image a planet at opposition? Just sticking a camera at the end of your longest focal length scope will likely produce tiny planetary images. It’ll need a “boost” to achieve the images seen on this page. Tele Vue Powermate™ photo / visual amplifiers increase the focal length of your scope with reduced aberrations, greater magnification potential, and compact size compared to typical Barlow lenses. Also, Powermates™ can be stacked with no adverse impact. Tele Vue Powermates™ are available in 2″ barrels (2x & 4x) with 1¼” adapters and 1¼” barrels (2.5x & 5x). They can be used with diagonal or without using a short extension.
Imaging with Powermates™ is easy: the visual tops all unscrew to accept a specific Tele Vue Powermate™ T-Ring Adapter for use with standard camera T-rings. Otherwise, a camera just needs a slip-in 1¼” or 2” nosepiece to slide into the visual top.
The gas (Jupiter and Saturn) and ice (Uranus and Neptune) giant planets will reach opposition this summer and fall in the northern hemisphere. In calendar order, here are the opposition dates for the outer planets. You don’t have to wait until the opposition date for any observing and imaging projects.
August 2nd: Saturn
Saturn enters opposition at 0.17 magnitude with an equatorial diameter of 18.6-arcseconds. But if you include the ring system, the diameter of the object swells to 42-arcseconds. The planetary body stays above 18-arcseconds until mid-September. By that time it will have dimed slightly to 0.44 magnitude.
I’ve found that first-time views of Saturn through a telescope typically elicit gasps of delight followed by inquisitive questioning.
Saturn’s startling beauty can open the door to wonders and knowledge about the universe that can inspire a love and appreciation of all the arts, sciences, and history.
Understanding something of the vastness and nature of the universe and our unique position as the only species possessing such knowledge suggests we commit to fostering the best in us: love, kindness, respect for learning and for all the amazing life-forms we’re so fortunate to share on this wonderful planet.
So let’s use Saturn as a means to enrich our future and help preserve our earthly paradise.
Spread the word to change Saturday to Saturnday through all media and contacts, in every social venue, to start dialogues that can open the minds and hearts of our earthling friends. Caring for our precious planet and its lucky inhabitants will make future generations proud of our time here.
Saturnday can change the world with your help!
– Al (10715) Nagler
August 19th: Jupiter
When Jupiter rises at sunset it will be an unmistakable sight: the brightest celestial object on the eastern horizon at magnitude -2.87. It’ll be a whopping 49-arc-seconds in diameter — the largest it will be all year. It’ll be about this size and brightness for the ten days before and after opposition.
Because Jupiter takes 12-years to orbit the Sun, it will have moved 1/12 of the way around the Sun at this time next year. It takes us about a month to catch up to it. So every year the opposition takes place a month later. So you can plan for future oppositions in September 2022 and October 2023.
WinJUPOS software can be used as a tool for collaborative research on visible features in the Jovian clouds. It also contains a tool useful for planetary imagers: WinJUPOS has a built-in de-rotation tool to allow imagers to break the “2-minute rule” for stacking Jupiter images. (Due to the planet’s speedy rotation rate, you normally can’t stack raw images made more than 2-minutes apart.) There are many tutorials on the Internet on how to do this.
September 14th: Neptune
Our solar system’s “other” blue planet reaches opposition at a faint magnitude of 7.7 and dims to 7.8 by early December. At 2.4-arc-seconds, even at 100x it just looks like a field-star. So don’t expect to see a Voyager 2 quality image through your eyepiece.
Neptune is so far away, that it wasn’t until the year 2011 that it completed its first orbit since its discovery in 1846. If you’re able to catch sight of it, you’ve viewed the last major planet in the Solar System.
Uranus & Neptune Observing Advice
While Jupiter and Saturn appear planet-like in a finder of binocular the “ice giants” Uranus and Neptune will appear star-like. One way to eliminate suspects in a telescope field is to look for Uranus’ green and (if you have enough aperture) Neptune’s blue hue. You may need to defocus slightly to see the colors. But ultimately you’ll have to point at the likely targets and turn up the power. Our Tele Vue Nagler 3-6-mm Planetary Zoom (mobile site) is excellent for turning up the power in short to medium focal length scopes. Just twist the black barrel to zoom in and be rewarded with the sight of a planetary disk. No disk visible? Then you landed on a star. Move the scope to the next suspect and try again.
With an 8″ or larger scope you can try observing the giant moon Triton (mag. 13.5) the major moon of the Neptunian system. Use the Sky & Telescope Triton Tracker to help locate it.
The discovery of Neptune is a story of missed opportunity. Galileo was the first person to observe Neptune — way back in December of 1612 — with his scope. He noted that it changed position relative to the fixed stars, but his best scope was only good for 30x and could not show the disk of the planet. At the time he was too enthralled in studying the motion of Jupiter’s moons to pursue this moving “star” any further.
Over the centuries, others ran into Neptune along the ecliptic (the paths the planets take in the sky) but didn’t discern its true nature either. Neptune’s existence to astronomers would have to await the discovery of Uranus first. After some decades of observation, it became apparent that the orbit of Uranus was being influenced by another body. Cambridge Observatory director, James Challis, unknowingly spotted the planet twice, in August 1846, based on other astronomer’s predicted location of a planet that was perturbing the orbit of Uranus. But he lacked the proper sky charts to identify it as a planet.
French mathematician Urbain Le Verrier predicted an unknown planet’s location to account for Uranus’s motion. On September 23, 1846 astronomer Johann Galle (Berlin observatory) received Le Verrier’s prediction in the mail and Neptune was “discovered” and verified within a degree of the position that very night — after just an hour of searching. Seventeen days later, the major moon Triton was discovered orbiting the planet.
November 5th: Uranus
The slow-moving planet will remain at least 3.7″ of arc in diameter and at magnitude 5.7 for the next month. Even months later in January when it hits quadrature (90-degrees from the Sun) you’ll still see the full face of the planet because the phase is imperceptible from our distance. This makes it a naked-eye target in dark skies and easy to locate in a binocular or finderscope with a good chart.
The green planet’s star-like appearance allowed Uranus to masquerade as a “fixed star” for most of the history of humanity. Read our 2018 Uranus Opposition blog post to learn how the planet was cataloged many times by astronomers before being identified as a planet.
Fun Fact: Uranus is the only major planet that uses a Greek name for a god — all the others have names of Roman origin. (The Roman equivalent of “Uranus” was the god “Caelus”)
Uranus Observing Advice
How to know you’ve spotted this ice-giant and not a field star? You’ll need to go to planetary power to detect the disc of the planet. See the Neptune advice in the prior section.
The Uranian moon are hard to spot in anything smaller than an 8″ aperture scope. You can use the Sky & Telescope Moons of Uranus observing tool to help you locate the brightest.
Planetary Viewing with Tele Vue Eyepieces
All our medium to short focal length eyepieces are great for planetary viewing. It all depends on the desired magnification range you want to achieve with your scope. With today’s modern multi-coatings, contrast robbing internal reflections are thing of the past. No need to follow old advice and buy an uncomfortable, narrow-field eyepiece!
“Despite the presence of no less than seven optical elements, these [Nagler] eyepieces provide images which are noticeably brighter than those obtained with many quality orthoscopics, with superb image sharpness and contrast.” — D. Parker, et al. Introduction to Observing and Photographing the Solar System. p. 14.
The Nagler Zoom was conceived as our ideal planetary eyepiece. Like all Tele Vue eyepieces, it’s designed for full-field sharpness in any speed telescope, as well as high contrast and transmission for natural color rendition, low scatter, and comfortable eye-relief. Use it to fine-tune magnification for the seeing conditions — no need to swap eyepieces to find the highest usable power. It’s parfocal through the zoom range, maintains its eye-relief and has click-stops for each focal length. It’s 50° apparent field of view makes it more appropriate for scopes on tracking mounts. Read more about it on our website Nagler 3-6-mm and (mobile site).
Contrast is king when it comes to planetary observing and every Tele Vue eyepiece is designed to maximize it. All lens surfaces are index matched multi-coated and have blackened lens edges, mechanical barrels and spacers are fully baffled or have anti-reflection threads where necessary. Other features include chrome-plated barrels that resist scratching and marring better than black anodized barrels, and include safety undercuts and filter threads. Upper barrels are black anodized aluminum with a rubber grip ring, engraved identification, and fold-down rubber eye guards.
To assure outstanding manufacturing and flawless image quality, our in-house NY staff performs optical and cosmetic testing on every eyepiece made, using our patented 5″ f/4 flat field “MPT” test refractor. We even ship Japanese-made eyepieces to our Chester, NY facility for 100% quality control and then re-ship them back to our Tele Vue Japan distributor for sales in Japan.
We are pleased to offer a Lifetime Limited Warranty on all eyepieces, Barlows, Powermates, and Paracorr products for the original owner. You also have the security of knowing that every current Tele Vue eyepiece can be repaired, serviced, or cleaned at the factory. See our Smashed Eyepieces blog post for examples.
Tele Vue Optics designed and is in the process of manufacturing the optical lens assembly for the Wide Field Imager cameras that are part of Southwest Research Institute’s Polarimeter to UNify the Corona and Heliosphere (PUNCH) microsatellite mission. This multi-satellite mission aims to better understand how the energy of the Sun’s corona fills the solar system and how coronal mass ejections evolve on their way to the Earth and other planets. The satellites will launch in 2023.
There was a recent update on the mission on the NASA Night Sky Network by Dr. Nicholeen Viall that is available on YouTube. The link here is queued to where Tele Vue is mentioned.
Did you observe, sketch, or image with Tele Vue gear? We’ll like your social media post on that if you tag it #televue and the gear used. Example:
#televue #Ethos #Jupiter
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