Jupiter's moons

[Ger]

I was looking just the moon and Jupiter this evening and enjoyed the views of both, when looking at Jupiter and it's moons I noticed what a fifth moon in the field of view just to the top right hand corner, would anybody know which moon it's was ( sorry for the less then precise positioning of this moon )

[John]

It will be a background star. After the 4 bright moons, the next brightest is much, much dimmer and requires a very large telescope to see it.

[Ger]

1 hour ago, John said:

It will be a background star. After the 4 bright moons, the next brightest is much, much dimmer and requires a very large telescope to see it.

Thanks John

[John]

No problem - it was a good question

[rockinrome]

On 07/04/2017 at 23:05, Ger said:

I was looking just the moon and Jupiter this evening and enjoyed the views of both, when looking at Jupiter and it's moons I noticed what a fifth moon in the field of view just to the top right hand corner, would anybody know which moon it's was ( sorry for the less then precise positioning of this moon )

I would use software like Stellarium to get info on this (although it will be a background star), but none the less will show you the names of the moons you are looking at.
Regards

[Stu]

Spica was around 7 degrees away from Jupiter so would not have been in the same telescopic field of view, plus is far brighter than the other moons. I suspect it may have been Theta Virginis which has been close for a few nights, but if it was much dimmer than the Galilean moons then there are a few candidates around.

[Ger]

2 hours ago, rockinrome said:

I would use software like Stellarium to get info on this (although it will be a background star), but none the less will show you the names of the moons you are looking at.
Regards

Thanks I do have this app but didn't think to look at it, was a little distracted as had my son with me who is also getting to know his way round the stars and planets too

[Ger]

2 hours ago, Stu said:

Spica was around 7 degrees away from Jupiter so would not have been in the same telescopic field of view, plus is far brighter than the other moons. I suspect it may have been Theta Virginis which has been close for a few nights, but if it was much dimmer than the Galilean moons then there are a few candidates around.

Thanks stu, I didn't think it was spica for the same reasons you mentioned. Thank you for the suggestion on what it might be. Based on your graphic above I think you are right 

[GavStar]

On 07/04/2017 at 23:18, John said:

It will be a background star. After the 4 bright moons, the next brightest is much, much dimmer and requires a very large telescope to see it.

This statement intrigued me about just how large a telescope you would need to see a fifth moon of Jupiter, so I did a quick bit of research. I guess it's been discussed before but it may be of interest to readers of this thread. The next largest moon is called Amalthea which was the last planetary moon discovered by observation (in 1892). It was discovered using a 36 inch refractor! Apparently you would need at least 24 inches of aperture to observe it. That's me out then... From the surface of Amalthea, Jupiter would appear 92 times bigger than the full moon, quite a sight!

[Swoop1]

So Gavster, are you organising the coach trip?