Archive for December, 2020

Jupiter and Saturn on Dec 23

December 23, 2020
Canon 1100D with Meade LX-90 8″ scope, ISO 6400, 1/15 second at 21:51 ACDT (click image to enlarge)

The two planets are slowly separating, tonight to 13 minutes of arc, around one fifth of a degree, up from 6.5 minutes of arc on Monday night.

My main goal tonight was to share the view with Karen, who worked the previous two nights, before Jupiter and Saturn are no longer in the same low power field of view. She enjoyed it.

I didn’t have a lot of time for set up and imaging tonight, but wanted to take an image that emphasised the planets themselves rather than their moons. The focus is not great, and Jupiter is still overexposed, but I like the fact that Saturn’s ring and the planet are distinct here.

The good news is that I have my Meade LX90’s AutoStar back from repair now, and it works well! This will encourage me to start doing tracked, piggy-backed, wide-field photometry again. It’s been awhile.

Jupiter & Saturn in 8″ scope (untracked)

December 22, 2020
Jupiter and Galilean moons plus Saturn with Canon 1100D with LX-90, ISO 1600, 1/5 second at 21:37 ACDT (click image to enlarge)

As mentioned in yesterday’s post, my Meade LX-90 8″ telescope’s AutoStar is being repaired, but tonight I decided to attempt to image the conjunction anyway with manual pointing and no tracking. Fast shutter speed and high gain was important to reduce the effects of rapid movement while obtaining enough detail.

The separation between the two planets was still around one eighth of a degree tonight, well within a low power eyepiece (24.5mm super wide angle) and my Canon 1100D’s sensor frame.

Sky Safari Pro screenshot identifying the four Galilean moons

All four Galilean moons are visible along with Saturn’s rings and the ball of the planet. Io is visible as a “bump” on Jupiter at around 11 o’clock.

Note the reversed telescopic view due to the optics.

The focus is not amazing, but under the circumstances, it turned out reasonably well. The planets were low in the sky as well.

Although I had images containing Saturn’s largest moon Titan, I wasn’t happy with the quality.

I also took a wide-field shot of the pair low on the western horizon, peeping through cloud, not long before the sky became cloud-filled. The exposure and gain make the sky appear abnormally bright.

Jupiter (top) and Saturn with Canon 1100D, 100mm focal length, f2.0, ISO 400, 1 second exposure at 21:53 ACDT

Jupiter-Saturn conjunction view

December 22, 2020

I had a nice view of the Great Conjunction of 2020 last night with Saturn, its largest moon Titan, Jupiter, three Galilean moons (there was a star near Europa that I initially mistook for a moon), all visible in a low power eyepiece.

My Meade LX-90’s AutoStar hand controller is in for repair so unfortunately I had to position the scope manually. With no fine controls or tracking, that was awkward but doable. Imaging, not so doable. There will be plenty from others though.

I expected the two planets to appear a little closer on the sky, but in hindsight, should not have.

I’ll be out again the next couple of nights for another look since, as per my last post, the two planets will still be quite close for the next few nights.

Jupiter & Saturn wide field, Dec 19 2020

December 19, 2020

Two days before the Great Conjunction of 2020 (on Dec 21) in which Jupiter and Saturn will appear at their closest in the sky in nearly four centuries, I took a wide field image of the pair low in the west on Dec 19 at around 9:50pm ACDT (click to enlarge).

Of the two brightest objects near the centre, Jupiter is at left and Saturn at right.

The planets are separated by around 16.5 minutes of arc or 0.275 degrees or a little more than half of the angular size of the full Moon. At the same time on Monday, Jupiter and Saturn will be separated by less than 6.5 minutes of arc or not much more than a tenth of a degree. On Dec 22 and 23 they will still be quite close, at almost 7.5 and 10 minutes of arc respectively.

Jupiter and Galilean moons plus Saturn with Canon 1100D, 100mm focal length, f2.0, ISO 800, 1 second exposure

The following screenshot from Sky Safari pro (iOS) helps with identification. Most of the moons, except for Europa, Ganymede and Callisto are not visible in the wide field image.

Sky Safari Pro screenshot

A cropped portion of the image (click to enlarge) shows the Galilean moons a little more clearly, including Io as a slight bump at lower left of Jupiter. Titan is barely visible at the lower left of Saturn. The resolution is not high enough to see Saturn’s rings or any detail on Jupiter.

Cropped portion of wide field image

I’m hoping that at least one or two nights early next week, the local weather will cooperate for more viewing of the conjunction.