August 2021 - Utah-Astronomy - mailman.xmission.com

Another good day for H-alpha solar viewing
by John M. Craig 31 Aug '21

31 Aug '21

Hi Folks, Looks like there's more prominences today than in a long time. The large, involved active region 12860 is approaching the limb where it should lead to some interesting prominences too. There's two other active regions that have numbered designations on the near side and a slew of them on the far side. Sorry I don't have any white-light experience to report, but if it doesn't start raining or get totally clouded out, it'd be a good day to take a look. Tomorrow should be good also. Sol is definitely waking up! John

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Some great sunspot activity today
by John M. Craig 27 Aug '21

27 Aug '21

Hi All, Whether you have a white-light solar filter or an H-alpha scope, take a look at the sun today, if you have a chance. There's a huge complex group of sunspots. At the moment there's also an amazing plume of a prominence but it seems to have faded somewhat. I haven't seen anything that far out from the limb in a long time. Got an informal star party going tonight up at the top of the Provo Canyon South Fork Road. We'll see how many people show up. Last time I invited maybe 30 people and ended up observing all by myself. But, that's fun too, of course. Happy watching!

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Recurrent nova RS Ophichi in outburst
by John M. Craig 13 Aug '21

13 Aug '21

Hi Folks, Wanted to get in a separate subject heading for this so didn't include it in earlier email. I wasn't able to find it Wednesday night when I was out for the Jupiter moon show. https://skyandtelescope.org/astronomy-news/recurrent-nova-rs-ophiuchi-just-… It apparently faded fast the last time it popped off. But it was bright enough to be visible naked eye, if you had good dark skies in that direction. Interestingly enough, on my somewhat impractically large Sky Atlas 2000.0, it's plotted as N1967. I don't know if that was it's first official outburst, but no indication of recurrence. Sky Safari Pro has RS Oph as a searchable object and lists its coordinates as: RA (2021.6) 17h 51m 22.09s DEC (2021.6)-06* 42' 49.6" I'd be interested to hear if you see it as it fades. John

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Anyone else see the fun w/ Jupiter's moons on Wed night?
by John M. Craig 13 Aug '21

13 Aug '21

I should perhaps have put a notice about this before it happened--sorry about that... For a good while before 11 pm on Wednesday night, only Jupiter's most distant Galilean moon, Calisto, was visible--or at least obvious (Ganymede and Io were occulted and Europa was transiting--I didn't have clear enough seeing or a big enough aperture to see Europa against the planet). Within about 7 minutes all 3 became visible as they appeared next to the limb of the planet. It was really fun to see. The amazing thing was that I've never seen any of the moons look anything but star-like (even in my best scopes--need to get the 10" RC Cass fixed up and working again). But with them right close to the limb of Jupiter, I was seeing them as disks at 125x with my low-budget 4" C102 achromat. Most unexpected! I think it may be a question of contrast--when they're distant from Jupiter, against the black of open space, my eyes (at least) do not see their disks: they look like bright stars. But as Ganymede and then Io emerged on one side (right close to each other almost in line with the N equatorial belt) you could definitely see that it took a fair amount of time before they became separated from the planet and then it was easy to see that Ganymede was substantially larger. Same effect with Europa: a bump on the limb, then a bigger bump, and finally a tiny disk. Amazing! Both my wife and daughter (not experienced observers) saw the moons as disks too. All this from my front yard--which is about as light polluted as it gets: we have one of the stupid acorn-style street lights just across from us and Orem is all Bortle Class 5 or worse. Hurray for bright things to see! I'm going to have to watch for times when the moons reappear from occultation and transit and check them out again. John

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