Category: Planets

Dwarf planet Ceres, formerly asteroid 1 Ceres, was visible just before midnight on the evening of December 29th and into the early morning of December 30th. It was west of the celestial meridian, but still high in the sky at 57° at the start of the imaging session.  The seeing was fair-good.

Some of the images I captured of this dwarf planet follow. All were captured using a Meade LXD-75 SN-8 (203mm f/4) telescope and ZWO ASI224MC camera with UV/IR cut filter.

Dwarf planet Ceres on December 30, 2021, in the constellation Taurus at 05:54:26 and an hour later at 06:54:57 UT.  The field of view is 20×15 arcminutes.  North is up. East is left. Compare this image to a finder chart prepared with the Lowell Observatory’s Asteroid Finder Chart tool here.[1]
Ceres was traveling through the constellation Taurus at the time of this session, and at magnitude 7.9 appears quite bright against the background field of stars.  The very faintest stars visible in this 30-second image are magnitude 16.

Dwarf planet Ceres in motion against a background of fainter stars. Field of view is 20×15 arcminutes. North is up. East is left [2]
This animation puts Ceres in motion with respect to the background star field.  The animation is a 21-image time-lapse sequence covering 60 minutes. During this session, Ceres was moving across the sky at the rate of 0.33 arcseconds per minute, or 19.80 arcseconds per hour.

With a diameter of 964 km (600 miles), Ceres is the largest object in the asteroid belt between Mars and Jupiter. It is so large in fact, that it contains 25% of the asteroid belt’s total mass. Ceres’ large mass allowed gravity to pull it into a planet-like spherical shape, unlike most of its much smaller irregularly-shaped companions in the asteroid belt. Because of its shape, size, and mass, Ceres was reclassified as a dwarf planet in 2006. Although it is no longer classified as an asteroid, Ceres retains its official designation of 1 Ceres in scientific literature and databases.

Ceres orbits the Sun at an average distance of approximately 2.8 AU (413 million km/257 million miles). Ceres completes a lap around the Sun every 1,680 days, or once every 4.6 years. On the night of these observations, Ceres was 1.89 AU (283 million km/176 million miles) from Earth.  

Notes:

1.December 30, 2021, 05:54:26 and 06:54:57 UT. Stack of two images, each a stack of 6 frames at 30 seconds (total 180s). Gain: 320. Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.

2.December 30, 2021, 05:54:26-06:54:57UT. 60-minute, 21-image, animation sequence. Each image a stack of 6 frames at 30 seconds each (total 180 seconds). Gain: 320. Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.

 

 

Jupiter reached opposition on the night of August 19-20. I wasn’t able to image during August, but did capture Jupiter in late July as the planet was approaching opposition.

The seeing during this period was exceptionally good and allowed me to capture my best images yet of the giant planet.  The seeing was so good during two observing sessions that I was able to produce short animations showing Jupiter’s rotation as well as some of its prominent features.  Nights with seeing this good are rare in central Oklahoma.

July 23

The Great Red Spot is just rotating out of view to the right In this 20-minute animation from the morning of July 23rd. North is at top. Preceding limb is right. Following limb at left. [1]
July 30

In this eight minute animation, the Great Red spot is again about to rotate out of view, but the seeing was so good that a little detail is even visible inside the Red Spot itself. North is at top. Preceding limb is right. Following limb at left.[2]
In this snippet of raw video from July 30th, Jupiter’s disk is solid and stable. The disk shows good contrast, little undulation, and some smaller details. This is the definition of “excellent seeing.” See A Modern Scale of Astronomical Seeing for Imagers by Damian Peach.

Notes:

1. July 23, 2021 09:18:30-09:39:04 UT  Seeing: Good
9 image time lapse. Each image is a stack of the best 6000 of 10000 frames. 68 fps, 10.72 ms per frame.
Captured with FireCapture. Stacked in AutoStakkert3. Wavelets and color adjustment in Registax. Animation in PIPP.
Telescope:  Celestron C8 (203mm SCT f/10) + Orion 2x Shorty Barlow
Camera: ZWO ASI224MC + UV/IR cut filter

2. July 30, 2021 09:34:47- 09:43:26 UT  Seeing: Excellent
4 image time lapse. Each image is a stack of the best 6000 of 10000 frames. 82 fps, 11.15 ms per frame.
Captured with FireCapture. Stacked in AutoStakkert3. Wavelets and color adjustment in Registax. Animation in PIPP.
Telescope: Celestron C8 (203mm SCT f/10) + Orion 2x Shorty Barlow
Camera: ZWO ASI224MC + UV/IR cut filter

 

09:37:37 UT

09:50:34

10:01:37 UT

Jupiter was well placed in the pre-dawn morning sky of July 4th.  It was nearly due south, approaching the celestial meridian, and 42° above the horizon.  

I got the C8 rig powered up and Jupiter focused on the imaging chip around 04:30 a.m. (09:30 UT). It was still dark. The sky was clear.

I started capturing video right away and kept going until around 05:05 when I noticed it was becoming more difficult to keep the image histogram level at 60%-70%. I kept increasing exposure lengths and gain levels, but Jupiter’s image kept getting fainter. Finally, I looked up at the sky. Clouds!

It was now overcast from horizon to horizon. Jupiter, usually very bright and visible to the unaided eye, was only faintly visible as a pale dot through the clouds.  The imaging session only lasted a little over a half an hour.

At the start of the brief session, the Great Red Spot was not visible, having just rotated out of view on Jupiter’s preceding limb. And, The feature known as Oval BA had not yet rotated into view on Jupiter’s following limb. As usual, my timing was not good. I managed to miss both.

So, what we’re looking at here are Jupiter’s belts and zones. While there are no big dramatic features to see, the seeing was good enough for my small rig to resolve some detail in the belts, and to resolve two small white ovals in the south polar region. These two ovals are the leading end of a string of ovals that precede the much larger Oval BA, which I should have captured if he clouds hadn’t intervened.

Good seeing is relative though. On the imaging scale devised by world-renowned planetary imager Damian Peach, the seeing only rated a “fair” grade.  According to the Peach scale, fair seeing  shows: “Significant fuzziness or undulation. Fair contrast. Larger scale detail well seen. Minor details mostly invisible.”

As this short video snippet shows, the seeing during this session falls squarely into Peach’s “fair”

This video snippet, captured on July 4, 2021, shows a fuzzy, quivering image of the giant planet Jupiter. The atmospheric seeing conditions would probably be rated as fair on Damian Peach’s seeing scale. Contrast is good. Large scale features are visible. Some smaller scale features are occasionally seen, but mostly not.

category. By Oklahoma standards though, the seeing rarely rises even to this level. Compared to the usual blurry soup the sky serves up here, this session’s seeing might be rated “good.” Oklahoma’s flat midcontinent location, with its near-constant surface winds and turbulent jetstream overhead, puts us under a roiling ocean of air that causes the planets to shimmy and dance when they should be holding still for the camera. As a result, here in Oklahoma, when Jupiter holds still enough  to show good contrast and some large scale detail, fair seeing is really good seeing.

Notes:

Date: July 4, 2021
Telescope: Celestron C8 (203mm F10) and Orion Shorty 2x Barlow
Camera: ZWO ASI224MC
Captured in FireCapture. Aligned and stacked in AutoStakkert. Wavelets and color balance in Registax. Color levels, unsharp mask, crop, in GIMP.

[1] 09:37:37 UT    800/3703 frames, 53 fps,  15.7 ms.
[2] 09:50:34 UT   2000/3824 frames, 55 fps, 14.26 ms.
[3] 10:01:37 UT   2000/6663 frames, 69 fps, 14.26 ms.