Jupiter/Saturn conjunction (21 Dec 2020)

 Jupiter, Planet, Saturn, Solar System  No Responses »
Dec 222020
 

Here is my contribution to the 2020 Great Conjunction hoopla. While it is rare to see a conjunction where both celestial bodies can be seen in the same telescopic field of view, from an astronomical point of view, the event was no big deal. On average, Jupiter and Saturn have a conjunction every 19.76 years. The frenzy was only due to the apparent closeness of the two as viewed from planet Earth.

Jupiter/Saturn conjunction

Even so, I tried to get an image when the two planets were actually closest to each other at 1200 CST but even though they had cleared the trees they were just not bright enough against the sky to get a good photo. The pair would be obscured by trees before it got dark so that meant packing up equipment and heading to another location. In fact, it involved two sets of equipment since my oldest son Chris would be joining in.

I really should have taken my planetary camera off the main telescope and brought it along but that camera would have meant additional cabling, a PC, another power supply, much longer setup and a more precise telescope alignment. My DLSR doesn’t require such an extensive life support system so I brought it instead. I chose poorly. The field of view the camera saw through the telescope was huge. This meant I had to zoom in quite a bit in order to see any detail at all. But since each planet only covered a small patch of pixels, very little detail is apparent.

The annotated image identifies the three Jovian moons that are visible. Ganymede is the one that is missing. It just started to cross in front of the planet and is lost in the glare on Jupiter’s left edge.

Jupiter/Saturn conjunction (annotated).

This photo is a composite of three separate images. Saturn is roughly 500,000,000 miles further from the Sun than Jupiter, so it is much dimmer when photographed. To make it visible, the exposure is lengthened to the point that Jupiter is grossly over exposed. To make the moons visible, the exposure is lengthened even more. So the image is a composite of a long exposure for the moons, a shorter exposure for Saturn and an even shorter exposure for Jupiter.

 Posted by at 19:28

Sucker hole Astronomy – Jupiter & Mars (24 Sep 2020)

 Jupiter, Mars, Planet, Solar System  No Responses »
Sep 252020
 

I spent last night repeatedly opening and closing the dome to counter the clouds. The clouds would open just long enough to convince me to open the dome, find a target, focus and start imaging. They would then slowly move back in prompting dome closure just to be safe.

Eventually though, I was able to piece together a series of Jupiter. Saturn was never visible through the gaps long enough to even start a set.

First up was Jupiter. It was already well past my meridian and closing on the western tree line before the planet made appearances through several gaps in the clouds. The GRS was just coming into view as well as the white spot indicating the newly discovered storm in the north temperate belt. It is expected that the material dredged up by the storm will react with solar energy and darken the belt as it spreads out to encircle the planet.

Jupiter
[(V)R:1259×1.21ms;
G:1254×1.12ms;
B:1245×1.79ms]

Mars was a little easier. The clouds broke open long enough to get one full series and the start of another before they finally brought the session to an close. The clouds forming the north polar hood are more apparent than in the image I took on the 2nd of Sept.

Mars
[(V)R:13725×0.17ms;
G:13685×0.27ms;
B:13678×0.50ms]

The Mars illustration is courtesy of WinJUPOS.
 Posted by at 19:23

August planets (17 Aug 2020)

 Jupiter, Mars, Planet, Saturn, Solar System  No Responses »
Aug 212020
 

Right now there are three naked eye planets easily seen in the evening / night time sky. Jupiter and Saturn are visible as the sky darkens after sunset. Jupiter will be a bright enough object that it can be viewed during dusk. Saturn will be just east of Jupiter, a little lower, noticeably fainter and will need a darker sky to be seen. Ultimately, Mars will join the other two in the sky around 2200(CDT) when it rises above the eastern horizon.

These pictures were all taken on the evening of the 17th / morning of the 18th of August. Jupiter and Mars are oriented south up; Saturn is north up.

When this image was taken, the GRS was just about to rotate around to the far side of the planet. Just coming on to the near side above the North Temperate Belt (NTB) is the small dark shadow of the Jovian moon Europa. The moon is visible but very hard to identify as it is also in front of the NTB but almost directly below the GRS. To ID the cloud bands see Jupiter’s belts and zones.

The image shows Jupiter with its cloud bands and zones. The great red spot is on the left upper side of the planet and is close to rotating around to the far side. A small sharply defined black spot is at the lower right of the planet denoting the shadow of the Jovian moon Europa.

Jupiter, GRS & Europa’s shadow
[(V)R:1211×1.57ms;
G:1260×1.70ms;
B:1260×2.91ms]

Right now, Saturn is in the portion of its orbit where we are looking down on the ring plane. This is why I rotated the image 180° from the view in the telescope. Now we see the rings as they truly are. Our view of the upper side of the rings will remain until March 2025 when we will see the ring plane edge on. At that time the rings will be nearly invisible. Saturn will continue on in its orbit and our view will shift to the underside of the rings for the next 14.5 years.

If you look closely, you can see a bit of Saturn’s shadow on the far side rings and you can see some of the planet’s disk through the Cassini division and just a bit of it below the rings.

The image shows Saturn with the orientation looking down on the rings. The planet shows subtly colored bands in the atmosphere and a a bit of the planet's shadow on the far side of the rings. There is also a hint of the planet visible both through the main gap in the rings as well as a tiny amount of the planet visible below the rings.

Saturn
[(V) R:3597×2.81ms;
G:3591×7.27ms;
B:1826×16.32ms]

The most obvious object in this image of Mars is the southern ice cap. There is a distinct notch in the lower edge. Mars was at perihelion on the 3rd of August. The southern hemisphere season is heading towards summer and the ice cap we see is starting to shrink.

This image shows the rusty colored planet in the normal orientation with south up. The planet's bright white southern ice cap is not only plainly visible but has an obvious notch in the lower edge. The upper portion of the planet is much darker and with more complex surface markings than the lower.

Mars
[(V) R:6838×0.21ms;
G:6837×0.35ms;
B:6832×0.73ms]
This image is an accurate illustration of Mars matching the picture taken of Mars through the PTO's telescope. The illustration shows Mars' equator, central meridian and a line showing the planet's axis of rotation with North indicated.

The Mars illustration is courtesy of WinJUPOS.

For an explanation of caption information see exposure data.

 Posted by at 21:23

Jupiter (16 Aug 2020)

 Jupiter, Planet, Solar System  No Responses »
Aug 172020
 

The skies finally cleared last evening. Just after sunset I was able to record a low probability of success occultation and after that re-configure the PTO for planetary imaging. Jupiter was very close to the meridian so it was as high in the sky as it was going to get before the mount needed to do a meridian flip. I was able to get two quick series before the computer locked up. I guess it was out of shape from sitting so long in between sessions.

This image shows the planet Jupiter. The planet has several horizontal cloud bands. The image is south at the top.

Jupiter [(V)R:1254×1.183ms;
G:1253×1.264ms;
B:1182×2.063ms]


To ID the cloud bands see Jupiter’s belts and zones.
 Posted by at 15:32

Jupiter & Io and Mars (14 Jul 2020)

 Jupiter, Mars, Planet, Solar System  No Responses »
Jul 162020
 

Clouds cleared fairly early the evening of the 14th. I took several series of Jupiter images , skipped Saturn and then waited for Mars to clear the tree line.

Jupiter had the GRS and its inner moon Io visible right off the bat. However, both were headed for obscurity. Io was on the far side of Jupiter and only 8 minutes from eclipse. The GRS hung around for another hour and twenty minutes before Jupiter’s rotation sent it to the far side.

Due to Jupiter’s fast rotation (9h 55m) each exposure must be fairly short to avoid smearing the cloud details. At my focal length I take a 40 second stream of data through each of the three color filters. There is a 5 second gap in between each to ensure the next filter has settled into place. Although there is no perceptible movement in the cloud tops, you can see how much Io has moved in 45 seconds since each of the color images is offset from the others. You can just see Io’s bright yellow color where the separate red, green and blue exposures overlap to produce the final color.

Jupiter & Io
[(V)R:1251×0.93ms;
G:1254×1.33ms;
B:1253×2.35ms]

Io (detail)
[(V)R:1251×0.93ms;
G:1254×1.33ms;
B:1253×2.35ms]

This Mars image is the result of some experimentation. My previous Mars pictures ended up with the southern ice cap very overexposed even though I adjusted the individual exposures short enough to prevent saturating the detector chip. The contrast between the ice cap and the rest of the planet was just too much to process out. So, this time I reduced the exposure duration quite a bit. This appears to have worked except for one small hot spot in the ice cap. The reduction also lets you see the ice cap is not symmetrical.

Mars
[(V)R:2739×0.22ms;
G:2738×0.44ms;
B:2741×1.01ms]

The matching Mars illustration is generated by WinJUPOS

For an explanation of caption information see exposure data.

 Posted by at 13:07
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