Uranus and companions

[John]

Following my success in spotting Neptune's brightest moon Triton earlier this evening, after a good session observing Mars, I turned my 12 inch dobsonian towards Uranus.

The seeing is steady tonight and Uranus was showing a well defined disk at 398x magnification. Careful observing of the area surrounding the planet showed a faint suspect to the North of the planet with direct vision and another a touch fainter to the West which needed a little averted vision to confirm.

I made a quick sketch of the relative positions of these dim objects and consulted Cartes du Ciel and Stellarium. I was pleased to see both applications showing the two brightest Uranian moons, Titania (magnitude 13.9) and Oberon (magnitude 14.1) in just the positions that I had noted my suspects to be in. I might also have glimpsed Ariel (magnitude 14.3) but that is closer to Uranus as well as fainter and I was not convinced of that one. Titania is currently around 30 arc seconds North of Uranus and Oberon around 34 arc seconds West of it.

I was very pleased to find these two distant moons as I had earlier not been able to see Phobos or Deimos at Mars. I think these Martian moons are somewhat more challenging because they are close in to their much larger (apparent diameter) and brighter parent planet.

While I have seen Triton at Neptune a number of times now, this is just the second occasion that I've been able to see these companion worlds of Uranus

 

Edited October 10, 2020 by John

[Captain Scarlet]

Nice.

I had a very nice view of Uranus tonight with my own 12" newt, a startlingly obvious disc, but it didn't occur to me to look for moons. Last night I did look quite hard for Martian Moons but couldn't see anything despite looking up where they were supposed to be. Neptune's and Uranus' moons are next on my list now. Our Moon is getting less obtrusive over the next fortnight so with luck I'll get more clear nights.

M

Edited October 9, 2020 by Captain Magenta

[globular]

Nice report John.

A previous post of yours on Triton inspired me to go looking too. And this post has me itching to get hunting even more.

Clouds have skuppered  me for nearly two weeks now.... grrr.

Edited October 9, 2020 by globular

[Nik271]

Congratulations, John! It's amazing to see such small objects so far away. Sadly they are beyond the ability of my scope in light polluted skies. Titania and Oberon both have about 700-800km radius, by comparison with most of the other visible gas giants moons they are tiny. (Rhea, Tethys and Dione are a bit smaller but of course much closer, brighter and easier to see.)

I think if you can see Phobos or Deimos that will be an amazing feat: a pair of rocks just about 10-20km wide from 60 million km away!

 

Nikolay

Edited October 10, 2020 by Nik271

[John]

On 10/10/2020 at 10:20, Nik271 said:

Congratulations, John! It's amazing to see such small objects so far away. Sadly they are beyond the ability of my scope in light polluted skies....

 

You should be able to see Triton at Neptune with your 180. I've managed that with my 130mm refractor.

 

[chiltonstar]

11 hours ago, John said:

You should be able to see Triton at Neptune with your 180. I've managed that with my 130mm refractor.

 

An earlier post re Uranus moons. I've managed 3 moons on many occasions, and 4 a couple of times using a 180 Mak (I'm not far from Oxford Nikolay, but in a village location that is reasonably dark). Using a high magnification is necessary IMO.

Chris

 

[Nik271]

Thanks, John and Chris!

Its encouraging to know it's doable. My skies are Bortle 4/5 (I can see the Milky way vaguely overhead in summer), the main difficulty is dark adaptation as there are  lots of streetlights everywhere where I live. Some day I'm planning to take the scope and set it up in a field nearby to give it a proper change at dim objects.

Nikolay

[globular]

If dark adaptation is the problem and you're mono-viewing then you could try keeping your viewing eye closed when it's not at the eyepiece.
Getting used to doing everything else with only your non-dominant eye is the hard part. 

[chiltonstar]

1 hour ago, Nik271 said:

Thanks, John and Chris!

Its encouraging to know it's doable. My skies are Bortle 4/5 (I can see the Milky way vaguely overhead in summer), the main difficulty is dark adaptation as there are  lots of streetlights everywhere where I live. Some day I'm planning to take the scope and set it up in a field nearby to give it a proper change at dim objects.

Nikolay

I use a hood to help dark adaption, as I have a neighbour with gigawatt security lights that turn on whenever his alsatian yawns.

Chris

 

Edited October 17, 2020 by chiltonstar

[pjsmith_6198]

This is the time for trying to find Mars Moons.   I think Phobos  is too close to Mars to see but Deimos is further away,  maybe about 2 Mars diameters away.   It's a bit faint at about 11.8 magnitude.   I've tried a few times but I haven't been able to see it.   It was in a position where it was trailing Mars and I was hoping as Mars left the field of view I would have have a couple of seconds without the glare to be able to see it before it to leaves the FOV.    Maybe with a little better seeing I'll have better luck.

 

Phil

[John]

13 hours ago, pjsmith_6198 said:

This is the time for trying to find Mars Moons.   I think Phobos  is too close to Mars to see but Deimos is further away,  maybe about 2 Mars diameters away.   It's a bit faint at about 11.8 magnitude.   I've tried a few times but I haven't been able to see it.   It was in a position where it was trailing Mars and I was hoping as Mars left the field of view I would have have a couple of seconds without the glare to be able to see it before it to leaves the FOV.    Maybe with a little better seeing I'll have better luck.

 

Phil

I have also tried a few times to see Phobos and Deimos with my 12 inch scope. No luck as yet for me. I agree that Deimos is likely to be easier than Phobos despite being dimmer.

 

[Littleguy80]

Excellent report, John. With the report in mind, I spent a long time hunting moons around Uranus. I’m confident I got Oberon. There was a mag 12 star very close to the planet that I initially thought was a moon too but SkySafari helped me to identify it a star. Another far off moon added to the list. Thanks for the inspiration  

[chiltonstar]

On 20/10/2020 at 17:43, John said:

I have also tried a few times to see Phobos and Deimos with my 12 inch scope. No luck as yet for me. I agree that Deimos is likely to be easier than Phobos despite being dimmer.

 

I managed to spot Deimos last night with the 180 Mak at x270. No luck though with Phobos - too much glare from Mars although transparency and seeing were both excellent (until the temperature dropped a bit and it started to haze up). The view was only transient, but it was in the right place I think. Interesting though how easy the 3rd star of Pi Cep was at mag 12.2, well away from the glare of Mars or the Moon*. Shows how important it is to have a dark background to see something like Deimos though.

Chris

*This double (actually a triple) is featured in this month's AN - the main star and its mag 6.80 companion are a nice colour contrast. The two principal stars were well resolved despite being only 1.1 arcsec apart - a tribute to the seeing.