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General Astronomy >> Beginners Forum

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FlorinAndrei
scholastic sledgehammer


Reged: 09/28/10

Loc: California
when to see Jupiter's Great Red Spot new
      #5537537 - 11/24/12 05:02 PM

The GRS rotates with the planet, so it's not always visible. Here's one way to calculate when it should be visible:

http://www.wolframalpha.com/input/?i=great+red+spot

More examples related to astronomy:

http://www.wolframalpha.com/examples/Astronomy.html

They also have an app for the iPhone, Android and all the tablets, which works just like the website.


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: when to see Jupiter's Great Red Spot new [Re: FlorinAndrei]
      #5537548 - 11/24/12 05:08 PM

if you have Skysafari plus or better for android or iOS i have confirmed on multiple observing sessions that it accurately depicts both the location of the GRS as well as the 4 Galilean moons and shadow positions when they pass in front of the planet. if you move forward in time within the program it will accurately show you where they will be later on that day etc.

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jfaust75
professor emeritus


Reged: 10/04/11

Loc: Central Florida
Re: when to see Jupiter's Great Red Spot new [Re: frito]
      #5537658 - 11/24/12 06:36 PM

It should be visible tonight around midnight here. Hoping to see it

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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: when to see Jupiter's Great Red Spot new [Re: jfaust75]
      #5537669 - 11/24/12 06:43 PM

it should be easily visible from 8 pm PST till past 11 pm so i would start looking for it around 11 pm eastern time for you. i regulary see it with good or better seeing in my XT8 with 6.3, 7.5 and sometimes my 10mm Plossl so you should not have problems seeing it if conditions are right in your area tonight

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Seldom
scholastic sledgehammer


Reged: 08/05/12

Loc: N of Cedar City Light Dome
Re: when to see Jupiter's Great Red Spot new [Re: frito]
      #5537795 - 11/24/12 08:24 PM

Interesting, Sky & Telescope puts the transit at 4:53 UT 11/25, and that works out to 9:53 MST 11/24, and S&T says the GRS (Great Latte Spot) should be visible for 50 minutes from transit to rise or set. Wolfram Alpha puts transit an hour earlier and says it should be visible for more than two hours either side of transit.

Who do you trust? (10:00 PM MST, and S&T was right on time.)

And kudos to Starbucks for managing a spill that would drown the earth.

Edited by Seldom (11/25/12 12:03 AM)


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: when to see Jupiter's Great Red Spot new [Re: Seldom]
      #5537800 - 11/24/12 08:29 PM

skysafari hasn't been wrong yet for me so ill trust it

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wky46
Carpal Tunnel
*****

Reged: 12/12/05

Loc: west Ky.
Re: when to see Jupiter's Great Red Spot new [Re: FlorinAndrei]
      #5537859 - 11/24/12 09:14 PM

Thanks for the links Florin

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Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: when to see Jupiter's Great Red Spot new [Re: Seldom]
      #5538312 - 11/25/12 06:40 AM

Quote:

Interesting, Sky & Telescope puts the transit at 4:53 UT 11/25, and that works out to 9:53 MST 11/24, and S&T says the GRS (Great Latte Spot) should be visible for 50 minutes from transit to rise or set. Wolfram Alpha puts transit an hour earlier and says it should be visible for more than two hours either side of transit.

Who do you trust?




Wolfram Alpha is using very old data for the GRS position. They state it's at longitude 138, whereas we're currently using 184. As you can see from the JUPOS website, even we are a bit low -- I should update it to 190 or thereabouts.

Tony Flanders
Associate Editor, Sky & Telescope


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Skooter
member


Reged: 08/30/12

Loc: middle TN
Re: when to see Jupiter's Great Red Spot new [Re: Tony Flanders]
      #5538347 - 11/25/12 07:49 AM

S&T has been precise to the millisecond, as far as I can tell from 600 million miles away.

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Eric63
scholastic sledgehammer


Reged: 06/16/12

Loc: Ottawa, Ontario
Re: when to see Jupiter's Great Red Spot new [Re: FlorinAndrei]
      #5538409 - 11/25/12 09:20 AM

I have the Jupiter Atlas app for Ipod but does not properly compute the transit time when a time zone lag is computed based on your location. After you enter your location in the app, you need to set the time lag to 0 hours each time you start the app. With that done, it then matches sky safari and S&T.

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BoriSpider
Carpal Tunnel


Reged: 08/10/04

Loc: S.W.FLA
Re: when to see Jupiter's Great Red Spot new [Re: Eric63]
      #5538586 - 11/25/12 11:44 AM

I use the computer program Jupiter2 . It's free
and works well.


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frito
Pooh-Bah


Reged: 10/05/12

Loc: Fremont, CA
Re: when to see Jupiter's Great Red Spot new [Re: BoriSpider]
      #5538683 - 11/25/12 12:44 PM

Quote:

I use the computer program Jupiter2 . It's free
and works well.




i have it and use it to monitor the position sometimes but you must correct the location of the GRS it defaults to 129 degrees and thats wrong. fortunately it has a link to a website with the correct and current location. oh it will also show it when its at the very sides as if you might be able to see it when really you cannot yet. otherwise it is a great program.


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Seldom
scholastic sledgehammer


Reged: 08/05/12

Loc: N of Cedar City Light Dome
Re: when to see Jupiter's Great Red Spot new [Re: frito]
      #5538884 - 11/25/12 02:52 PM

Quote:

you must correct the location of the GRS it defaults to 129 degrees and thats wrong. fortunately it has a link to a website with the correct and current location.




Just guessing, but from the screenshots on the Jupiter2 webpage it looks like the default value for the GRS longitude may have been right for the time the program was compiled, and the data on the link to the correct transit time is a raster graphic that would be hard to extract the correct transit time from. Not really a problem because you can save the correct longitude if you "quit saving parameters".


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Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: when to see Jupiter's Great Red Spot new [Re: Seldom]
      #5539070 - 11/25/12 04:37 PM

Quote:

But from the screenshots on the Jupiter2 webpage it looks like the default value for the GRS longitude may have been right for the time the program was compiled.




No doubt. The GRS has really been zipping along in recent years, often gaining more than one degree per month.

Quote:

The data on the link to the correct transit time is a raster graphic that would be hard to extract the correct transit time from.




Don't fret about it! The GRS is enormous, covering a good 20 degrees of longitude. You would need extraordinarily careful observation to tell a difference of plus or minus 5 degrees.


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Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Re: when to see Jupiter's Great Red Spot [Re: Tony Flanders]
      #5539210 - 11/25/12 06:29 PM

Just to be sure what your all saying. In the Jupiter 2 program. One has to change the "absolute position of Jupiter box" from 129 to 188?

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Seldom
scholastic sledgehammer


Reged: 08/05/12

Loc: N of Cedar City Light Dome
Re: when to see Jupiter's Great Red Spot new [Re: Dennis_S253]
      #5539299 - 11/25/12 07:30 PM

Quote:

Just to be sure what your all saying. In the Jupiter 2 program. One has to change the "absolute position of Jupiter box" from 129 to 188?



If you click the "absolute position ON Jupiter" link you will see a plot of current GRS positions. That plot will show you that 188 is a pretty good longitude for now, but it keeps changing, so check every 3 to 6 months.


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Dennis_S253
Pooh-Bah


Reged: 11/22/11

Loc: West Central Florida
Re: when to see Jupiter's Great Red Spot new [Re: Seldom]
      #5539379 - 11/25/12 08:29 PM

Ok thanks, Stellarium is really close tonight also. I use to think Stellarium was way off but I was using the 129 # in Jupiter 2. I'll have to try it a few more nights.

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FlorinAndrei
scholastic sledgehammer


Reged: 09/28/10

Loc: California
Re: when to see Jupiter's Great Red Spot new [Re: Tony Flanders]
      #5539654 - 11/25/12 11:55 PM

Quote:

Wolfram Alpha is using very old data for the GRS position. They state it's at longitude 138, whereas we're currently using 184.




It is off, indeed, I could plainly see it in the eyepiece.

Well, I sent them feedback on that query, they usually fix their bugs.


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Tony Flanders
Postmaster
*****

Reged: 05/18/06

Loc: Cambridge, MA, USA
Re: when to see Jupiter's Great Red Spot new [Re: FlorinAndrei]
      #5539927 - 11/26/12 08:29 AM

Quote:

Well, I sent them feedback on that query, they usually fix their bugs.




Unfortunately, this isn't a matter of fixing a bug as computer programmers usually view it. This requires ongoing maintenance, since the GRS is constantly drifting in unpredictable ways.

Nobody wants to devote a person to doing periodic maintenance on a computer program; it's a logistical nightmare. It's different for us at S&T. Astronomy is our bread and butter, and we have to publish GRS tables in the magazine anyway. So we need to stay on top of the GRS longitude whether we like it or not.

Tony Flanders
Associate Editor, Sky & Telescope


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Seldom
scholastic sledgehammer


Reged: 08/05/12

Loc: N of Cedar City Light Dome
Re: when to see Jupiter's Great Red Spot new [Re: Tony Flanders]
      #5540130 - 11/26/12 11:15 AM

Too bad that http://jupos.privat.t-online.de/rGrs.htm doesn't publish the data in text/numeric form as well as raster graphic. Then maybe programmers could update the longitude for their applications automatically via the web.

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