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Five Jovian Satelites?

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#1 StarAlert

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Posted 04 June 2020 - 11:56 AM

I got out at about 4:30am to take a look at the planets. To my surprise, when I looked at Jupiter, I saw five satellites. Three in very close proximity and one on each side, about the same distance from the planet. Does anyone know what I was looking at? I couldn’t take a picture so I made a drawing from what I remember. 
 

57EC1E98 1A56 4D75 AE2A 4995A1CDF8A0

After about 30 minutes, the nearest western satellite disappeared. There were two shadows on the surface at the point. I don’t recall seeing both shadows, initially. I definitely saw one, though. 



#2 Dave Mitsky

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Posted 04 June 2020 - 01:07 PM

Only the four Galilean satellites are typically visible in amateur telescopes.  Amalthea wasn't discovered until 1892 with the 36" Lick refractor and the eagle eyes of E. E. Barnard.
 

https://www.if.ufrgs...ug/amalthea.htm


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#3 Keith Rivich

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Posted 04 June 2020 - 01:19 PM

I looked at Amalthea at TSP last year in my 25". Was pretty tough to separate it from the background stars. Had to see it move. 

 

Methinks you picked up a field star.


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#4 StarAlert

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Posted 04 June 2020 - 01:32 PM

I looked at Amalthea at TSP last year in my 25". Was pretty tough to separate it from the background stars. Had to see it move. 

 

Methinks you picked up a field star.

That’s what I think happened, too. 
 

After looking at Jupiter for about 15 minutes, I moved over to Saturn for a few minutes and then to Mars for a bit. When I went back to Jupiter there were just four satellites. I wish I had stayed on 
Jupiter, now, so I could have seen what happened to the extra one. Grrrr. 
 

But in the end, it was a great 45-minute session. 



#5 Dave Mitsky

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Posted 04 June 2020 - 01:33 PM

Here's a screen capture from Stellarium from my location at 7:30 a.m. EDT which would be at the time you observed Jupiter.  Unfortunately, the sky is too bright to reveal field stars that would be near Jupiter.   Amalthea is very close to the planet's limb but does not show up in the screen capture.

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  • Jupiter June 4 CN.jpg

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#6 spereira

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Posted 04 June 2020 - 01:39 PM

Moving to Solar System Observing, for a better fit.

 

smp


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#7 Keith Rivich

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Posted 04 June 2020 - 01:54 PM

Here's a screen capture from Stellarium from my location at 7:30 a.m. EDT which would be at the time you observed Jupiter.  Unfortunately, the sky is too bright to reveal field stars that would be near Jupiter.   Amalthea is very close to the planet's limb but does not show up in the screen capture.

Turn off the atmosphere and the fainter stars will be displayed. 


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#8 StarAlert

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Posted 04 June 2020 - 01:54 PM

Here's a screen capture from Stellarium from my location at 7:30 a.m. EDT which would be at the time you observed Jupiter.  Unfortunately, the sky is too bright to reveal field stars that would be near Jupiter.   Amalthea is very close to the planet's limb but does not show up in the screen capture.

That’s exactly what I saw! 
Thanks!


Edited by StarAlert, 04 June 2020 - 01:57 PM.


#9 StarAlert

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Posted 04 June 2020 - 01:57 PM

So the two shadows are from JII and JIII? And I suspect JI orbited out of sight. 
 



#10 JOEinCO

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Posted 04 June 2020 - 01:59 PM

There were no field stars in the plane of the moons at a similar magnitude to the moons at that distance you indicated to the West (approximately the same distance as you have Callisto to the East). Brightest star close to the plane in that area was about magnitude 14. So I have no idea what you saw. shocked.gif lol.gif 

 

That was Io that "disappeared". Only it didn't disappear into Jupiter's shadow. It was visible until it went behind Jupiter's limb. 

 

Ganymede & Europa's shadows were on Jupiter.



#11 StarAlert

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Posted 04 June 2020 - 02:37 PM

Here's a screen capture from Stellarium from my location at 7:30 a.m. EDT which would be at the time you observed Jupiter.  Unfortunately, the sky is too bright to reveal field stars that would be near Jupiter.   Amalthea is very close to the planet's limb but does not show up in the screen capture.

Am I (Is anyone) able to get on Stellarium and pull up a view of a certain planet from my location at a given time? If so, I need to figure out how to do that. 



#12 Napp

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Posted 04 June 2020 - 02:46 PM

Am I (Is anyone) able to get on Stellarium and pull up a view of a certain planet from my location at a given time? If so, I need to figure out how to do that. 

Set your location.  Then set the time to desired.  Now enter Jupiter in the search field and push Enter.  Jupiter will appear centered in the field.  Now press PgUp repeatedly to zoom in. 

 

Don't click on the Jupiter image.  If you use the search function to select it you can manually step the clock forward or backward and Jupiter will stay centered.  When you click on the Jupiter image Jupiter will not stay centered in the field when you step the clock.


Edited by Napp, 04 June 2020 - 02:50 PM.

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#13 beatlejuice

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Posted 04 June 2020 - 05:40 PM

SkySafari shows star TYC 6325-0886-1  mag 10.87 as the star in the general plane of the moons at the location in your sketch.

 

Eric



#14 StarAlert

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Posted 04 June 2020 - 07:00 PM

That might be it, but I had no problem seeing all five objects. I brought my binos to focus after wiping the sleep out of my eyes and counted 1, 2, 3, 4... wait, what? 5? Went in the house to put my contacts in and came out to confirm. Yep, five. 


Edited by StarAlert, 04 June 2020 - 07:01 PM.


#15 Dave Mitsky

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Posted 04 June 2020 - 08:54 PM

Here's what I got when I followed Keith's advice.

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  • Jupiter June 4 Dark CN.jpg

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#16 StarAlert

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Posted 04 June 2020 - 10:18 PM

Ok. I believe everyone... 

 

It was my first time seeing a moon shadow (two!) on the surface. Well worth the loss of 90 minutes of sleep. 


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#17 Allan Wade

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Posted 05 June 2020 - 05:53 AM

I looked at Amalthea at TSP last year in my 25". Was pretty tough to separate it from the background stars. Had to see it move. 

 

Methinks you picked up a field star.

Keith, are you certain you saw Amalthea? I believe only a handful of people have ever visually seen it.

 

I’ve been trying for 2 years in the 32” without success, and I have the added advantage that it passes near zenith versus down so low in the Texas sky. That would be quite a fantastic observation. 
 

I’ve learnt a lot from my unsuccessful attempts and am really looking forward to the June and July windows coming up.


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#18 Allan Wade

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Posted 05 June 2020 - 06:05 AM

For anyone looking to claim a fifth Jovian moon, Himalia at magnitude 15 is within reach of a lot of amateur sized scopes. The key is using accurate position data. The plots of these outer moons are very inaccurate in programs like Sky Safari. Ephemeris data from the Minor Planet Centre is spot on and what I’ve used in the past.

 

I’m at 7 Jovian moons, and expect to pick up another 3 fainter ones on my list in the coming opposition. I would love to pick up Amalthea but it’s proving to be as difficult as any observation I’ve attempted.


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#19 Keith Rivich

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Posted 05 June 2020 - 03:18 PM

Keith, are you certain you saw Amalthea? I believe only a handful of people have ever visually seen it.

 

I’ve been trying for 2 years in the 32” without success, and I have the added advantage that it passes near zenith versus down so low in the Texas sky. That would be quite a fantastic observation. 
 

I’ve learnt a lot from my unsuccessful attempts and am really looking forward to the June and July windows coming up.

Positive.

 

I was observing with Larry Mitchell and we were working on his advanced observing list which featured objects observed by Barnard. Hence looking for Amalthea. We had detailed charts and when we found the moon, or suspected it at least, we marked its position on our chart and left the scope tracking on the field. When we checked it again about 30 minutes later and we could clearly see it had moved. 

 

We were using an 8mm Delos, ~400x.

 

We were quite lucky in that two events happened to coincide on the same night: A wonderfully steady and transparent night (anyone remember Tuesday night at TSP last year?) and Amalthea was at (or very near) greatest elongation thus well away from the glare of Jupiter. 

 

Once we had it nailed down we were able to see it in Larry's 20" f/5 and a friends 12 1/2" f/5. At ~15th magnitude it was pretty tough in the 12 1/2", but we could make it out. 

 

We had quite a few people stop by and take a look, perhaps some are reading this thread and can share their observation. 


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#20 Allan Wade

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Posted 05 June 2020 - 08:36 PM

That is quite incredible Keith.

 

When Edward Barnard discovered Amalthea in the 36” Lick refractor it took him 2 years to repeat the observation. Sums up how difficult this is to achieve, and you can’t understate just how few people in history have seen it with their own eyes.

 

You are the first person I’ve seen claim the observation in a Newtonian type telescope. The diffraction spikes add another level of difficulty in seeing the little moon.

 

We were quite lucky in that two events happened to coincide on the same night: A wonderfully steady and transparent night (anyone remember Tuesday night at TSP last year?) and Amalthea was at (or very near) greatest elongation thus well away from the glare of Jupiter. 

Just to confirm, it was Amalthea you were targeting and not one of the faint outer moons? It never gets away from the glare of Jupiter, remaining always less than one Jupiter diameter away from the planet. The magnitude delta between Jupiter and Amalthea is over 17, so I’m very impressed you could even pick it out in your 25” with it so low in the sky. Over 17 magnitudes in a 12.5”, I don’t know if that’s possible.



#21 Keith Rivich

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Posted 06 June 2020 - 01:06 PM

I stand corrected! The cosmic police was correct flowerred.gif

 

We did observe a rare moon at TSP last year but it was not Amalthea of Jupiter...it was Iapetus of Saturn. Still a tough observation but not the right moonlet.

 

That will teach me to write without thinking!

 

We did see Amalthea many years ago when Jupiter was much higher in the sky. Larry keeps much better notes then me. He wrote that we were using his 36" at ~800x. Amalthea was at greatest elongation and was visible for around 15 minutes. 

 

Sorry for sending the thread down a rabbit hole!

 

Now, just for fun, I am going to try for Amalthea in my 25". Stay tuned.



#22 StarAlert

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Posted 06 June 2020 - 05:18 PM

I stand corrected! The cosmic police was correct flowerred.gif

 

We did observe a rare moon at TSP last year but it was not Amalthea of Jupiter...it was Iapetus of Saturn. Still a tough observation but not the right moonlet.

 

That will teach me to write without thinking!

 

We did see Amalthea many years ago when Jupiter was much higher in the sky. Larry keeps much better notes then me. He wrote that we were using his 36" at ~800x. Amalthea was at greatest elongation and was visible for around 15 minutes. 

 

Sorry for sending the thread down a rabbit hole!

 

Now, just for fun, I am going to try for Amalthea in my 25". Stay tuned.

No worries! I’ve learned a lot as a result. 


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#23 Allan Wade

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Posted 06 June 2020 - 07:11 PM

I stand corrected! The cosmic police was correct flowerred.gif

 

We did observe a rare moon at TSP last year but it was not Amalthea of Jupiter...it was Iapetus of Saturn. Still a tough observation but not the right moonlet.

 

That will teach me to write without thinking!

 

We did see Amalthea many years ago when Jupiter was much higher in the sky. Larry keeps much better notes then me. He wrote that we were using his 36" at ~800x. Amalthea was at greatest elongation and was visible for around 15 minutes. 

 

Sorry for sending the thread down a rabbit hole!

 

Now, just for fun, I am going to try for Amalthea in my 25". Stay tuned.

Iapetus, that makes sense, that’s a good observation.

 

But still, you’ve seen Amalthea, that’s a great achievement. You are walking among giants.



#24 David Knisely

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Posted 06 June 2020 - 10:39 PM

I have caught Himalia in my 10 inch Newtonian on occasion when it was near its farthest angular separation from Jupiter, although at magnitude 14.6, it was pretty faint and I needed a decent finder chart to confirm it.  Clear skies to you.


Edited by David Knisely, 07 June 2020 - 01:45 AM.

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#25 David Knisely

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Posted 07 June 2020 - 01:54 AM

I stand corrected! The cosmic police was correct flowerred.gif

 

We did observe a rare moon at TSP last year but it was not Amalthea of Jupiter...it was Iapetus of Saturn. Still a tough observation but not the right moonlet.

 

That will teach me to write without thinking!

 

We did see Amalthea many years ago when Jupiter was much higher in the sky. Larry keeps much better notes then me. He wrote that we were using his 36" at ~800x. Amalthea was at greatest elongation and was visible for around 15 minutes. 

 

Sorry for sending the thread down a rabbit hole!

 

Now, just for fun, I am going to try for Amalthea in my 25". Stay tuned.

Personally, I don't consider Iapetus to be particularly difficult for me, as it is usually located far from Saturn and is in the range of magnitude 11.9 to 10.2.  Now Mimas, on the other hand, has been a real toughie for me with the rings fully open, as it takes great seeing and good positioning to show up much of the time. I have done it on occasion in my 10 inch, but it is notably easier to pick up in my 14 inch.  Clear skies to you.




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