SIX moons around Jupiter? - Obs report Takahashi FC-76 and Stellalyra CC 8", Bortle 8, 14 June 2021

[Commanderfish]

Surprisingly clear and transparent sky last night/this morning between 2am and 3am.  Lovely wide fields in the FC-76 DCU, particualrly around the summer treasures region.  Located the Wild Duck cluster easily and (since my phone was out of battery) located the Swan/Omega nebula from memory - and it's been three years since I've seen it, due to viewing angles at my previous house and a break from astronomy.  The Omega nebula was a little faint in the 76mm (unsurprisingly) but the views in the CC8, particularly with a DGM NPB nebula filter were bright and clear.  Really lovely. Very pleased with what a nice clear view that is from SW19 in London, and is proof of concept for what I bought the CC8 for - not primarily for planetary, but for DSOs like M42 and the summer treasures.

I didn't find the Lagoon, Eagle or Trifid for certain although there were a number of clusters that looked very much like they might have been suspects, I couldn't remember their locations relative to the Swan.  This will be easier when my replacement Tak FC-100 arrives as it should be better at sweeping for faint objects.

Saturn looked lovely in both scopes.  The CC8 hadn't had a chance to cool at all (and it was a very hot day (28C)), but both scopes showed the Cassini Division and polar caps.  The Tak was a little sharper but I'm sure that's because it doesn't need much cooling time, which the CC8 didn't get.

Jupiter was good, although not taking more than x140 before going soft.  Again more cooling time would have made all the difference but I hadn't planned a session at all.  Nonetheless, North and South equatorial bands and further banding both north and south, with polar regions showing.

Finished the night with wide field sweeps of Cygnus near zenith, with the FC-76 easily and clearly showing the principal 6 stars of the water tower.  Ring Neb in Lyra and Coat hanger Asterism south west of Cygnus nice and clear.  Finished with Albireo's bright colourful double.

Now to address the phantom(s) in the room. 

Is it my imagination or are there five, possibly six moons showing readily around Jupiter at the moment?  This is the second recent night that I've seen a minimum of 5 in the CC8.  They do not appear to be stars because they move with Jupiter.  Last night there were the four Galilean moons to the left in the usual neat row, a fifth to the upper right (which is probably on the far side of  Jupiter from our perspective), and another to the upper left (similarly may be on the far side of Jupiter).  Has anyone else seen these?

Edited June 14, 2021 by Commanderfish

[Starwatcher2001]

Looking at Stellarium, there were a couple of bright stars in the same field as Jupiter this morning: HIP 109998 and an undesignated one. One clue is that they are not on the same plane as the planet and moons.  Centering Jupiter in the software and scrolling the date shows that you're right, they have been in the same field for several days as Jupiter drifts very slowly. Pretty nice view though, and worth a look for the next few days!

[Commanderfish]

Ah thanks Mark, that makes perfect sense!  Coincidental, lasting synchronous movement of background stars with a planet. 

I did think that it was wrong that a moon could be that high above the plain of orbit of the other Jovian satellites!

I'll be taking another look.

Although it does seem odd that those one or two stars are apparently moving with Jupiter across the star field across multiple nights?

Edited June 14, 2021 by Commanderfish

[Starwatcher2001]

Jupiter is over 5 times further out from the Sun than we are, so has a slower orbit, and given its distance from us (686 million km - says SkySafari), the angular distance moved from night to night isn't very large.

Had you been looking last saturday between 02:41–03:33 GMT, there was a double "shadow transit" where the shadows of Ganymede and Io could be seen against the planet. It blew me away the first time I saw one. I wonder if there were any local Jovians watching their own eclipse on Saturday?

  https://www.space.com/16149-night-sky.html
 

[Stu]

You can check in SkySafari to match up the stars you saw. I’m sure they will have been background stars, you can only see 4 Galilean moons in normal amateur scopes.

 

[Nik271]

The next brightest moon of Jupiter after the four Galileans is Amalthea at magnitude 14. I doubt many people have seen it visually. It was discovered by Barnard in 1892 with the 91cm Lick refractor. The magnitude itself is not too dim for a big telescope but the proximity to the bright Jupiter makes is very difficult. A big refractor is needed

[SuburbanMak]

Nice report & nice setup! 

I had a similar experience in the wee hours of Sunday morning - convinced I could see a fifth moon trailing Jupiter close in. Did an action replay in Stellarium and realised that what I'd done is mistake a nearby star (HD211360, 7.4 Mag) for one of the 4 Gallilean moons then when I saw a fifth object trailing the planet, convinced myself I was seeing Althea - which is slightly beyond the limiting magnitude of my Mak 127.   

In fact I was watching Io rise in real time - which was actually pretty cool!  Am really enjoying how dynamic planetary observing can be - stuff can change in front of your eyes! 

Edited June 15, 2021 by SuburbanMak

[John]

7 moons around Saturn are possible with small to moderate aperture scopes 

I've also managed 2 at Uranus (2 more possible I believe) and 1 (Triton) at Neptune.

 

[Voyager 3]

Catching the moons of Mercury/Venus is the toughest thing 😂 .

[Commanderfish]

I observed Jupiter and Saturn again this morning at 2.30 am (so 48 hours after the initial report), and indeed the two suspects are now slightly further to the east than Jupiter and the Jovian satellites!   So it was of course two background stars.

During a patch of clear/cloudless seeing last night using the CC8, I briefly spotted 5 Jovian satellites - but then light cloud started interfering and I could only reliably see and identify 3, including Titan.  I didn't screenshot my Sky Safari screen at the time but I think from memory the other two were Rhea and Dione.