I was just looking at Jupiter and Venus, both in the west. Venus looked slightly gibbous and Jupiter had Io's shadow on it. It was neat to see that the shadowed part on Venus and Io's shadow both pointed towards the below-horizon sun (after correcting for the upside-down field of view).
I hadn't done much astronomy lately. I did notice lately that Venus was getting very far in the sky from the sun, and it was gratifying to see this coordinated with the slightly more than half-illuminated face of it. I suppose it will now be getting closer to it, culminating in the transit this summer.
Showing posts with label Jupiter. Show all posts
Showing posts with label Jupiter. Show all posts
Tuesday, February 21, 2012
Sunday, November 20, 2011
Sunspots
I've tried to see sunspots by using solar projection with a 68mm refractor, with no luck. Last night, close to sunset, I pointed my 8" Coulter towards the sun, with a 30mm eyepiece and a card in front of it. I got a very sharp image with a number of distinct sunspots. Couldn't see any detail in the spots themselves--they were just dots--but they were there.
Normal solar safety rules apply here: Don't ever look through a telescope or eyepiece pointed in the vicinity of the sun. (I took care of that by making sure that all the observers were on the side of the scope opposite to the eyepiece.) Cover up any magnifying finder scope (a red dot finder is fine--just don't use it!). Don't look at the sun while pointing the telescope (my best method for pointing was to move the scope until the size of the shadow red-dot finder was minimized, and then to wiggle the scope until I saw solar glare on the card). Don't keep the scope pointed at the sun for too long--give it some cool-off time between observations.
On reflection, I should have stopped down the aperture to prevent eyepiece melting. I didn't have the eyepiece melt, but maybe that was because it was close to sunset. I am going to try to make a more comfortable projection setup today. This is all a sort of preparation for the transit of Venus in June 2012.
My solar viewing was before the Waco star party. Later that night, we were showing Jupiter to girl scouts, waiting for clearings between clouds. I think everyone who stuck around got a view. Some of the time the seeing was horrid, but at one time I did see a fuzzy barge atop the northern belt. After the girl scouts left, the sky mostly cleared up.
Normal solar safety rules apply here: Don't ever look through a telescope or eyepiece pointed in the vicinity of the sun. (I took care of that by making sure that all the observers were on the side of the scope opposite to the eyepiece.) Cover up any magnifying finder scope (a red dot finder is fine--just don't use it!). Don't look at the sun while pointing the telescope (my best method for pointing was to move the scope until the size of the shadow red-dot finder was minimized, and then to wiggle the scope until I saw solar glare on the card). Don't keep the scope pointed at the sun for too long--give it some cool-off time between observations.
On reflection, I should have stopped down the aperture to prevent eyepiece melting. I didn't have the eyepiece melt, but maybe that was because it was close to sunset. I am going to try to make a more comfortable projection setup today. This is all a sort of preparation for the transit of Venus in June 2012.
My solar viewing was before the Waco star party. Later that night, we were showing Jupiter to girl scouts, waiting for clearings between clouds. I think everyone who stuck around got a view. Some of the time the seeing was horrid, but at one time I did see a fuzzy barge atop the northern belt. After the girl scouts left, the sky mostly cleared up.
Friday, October 21, 2011
Jupiter
Had a look at Jupiter in my 13" during the Live Oak school star party. The south equatorial belt that was missing last year is back--somehow I had forgotten about the disappearance and hence didn't really notice that it had reappeared.
I was surprised to see a very dark spot a little bit east of center on the north equatorial belt at JD 2455856.5754. It looked a little fuzzier than a moon shadow, and possibly slightly elliptical. It moved in the same direction as Jupiter was rotating. Experimenting with my collection of gel filters showed that the spot got much harder to see through a magenta filter. Vivid pink, red and orange also decreased contrast. Green may have enhanced contrast slightly. I hypothesize that the spot was dark red in color.
I also saw the Great "Red" Spot--in the words of a colleague, it looked like an empty area.
Both the dark spot and the Great Red Spot looked very good in my colleague's 8" F/6 with a binoviewer.
Update: I looked on Cloudy Nights. The dark spot is nicely seen here. I am pleased to note that I got the color and shape right with my filter swapping technique: it's definitely dark red and oval in the photo. These spots are apparently known as "barges". More information and links here.
I was surprised to see a very dark spot a little bit east of center on the north equatorial belt at JD 2455856.5754. It looked a little fuzzier than a moon shadow, and possibly slightly elliptical. It moved in the same direction as Jupiter was rotating. Experimenting with my collection of gel filters showed that the spot got much harder to see through a magenta filter. Vivid pink, red and orange also decreased contrast. Green may have enhanced contrast slightly. I hypothesize that the spot was dark red in color.
I also saw the Great "Red" Spot--in the words of a colleague, it looked like an empty area.
Both the dark spot and the Great Red Spot looked very good in my colleague's 8" F/6 with a binoviewer.
Update: I looked on Cloudy Nights. The dark spot is nicely seen here. I am pleased to note that I got the color and shape right with my filter swapping technique: it's definitely dark red and oval in the photo. These spots are apparently known as "barges". More information and links here.
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