Triton

[John]

The past couple of nights that I've had my 12 inch dob out I've managed to glimpse Neptune's brightest moon Triton.

It needs plenty of magnification I've found. 300x or preferably, more. Not often that the 2mm-4mm Nagler zoom gets used with my 12 inch dob but it's rather good for this task.

Neptune's tiny 2.5 arc second disk actually holds it's composure well at these high magnifications. It resembles a pale blue / green ball bearing.

Triton is usually found between 10 and 20 arc seconds from Neptune's disk as a faint point of light at around 13th magnitude. I find the Cartes du Ciel software gets it's location pretty accurately BUT in my opinion it is very important to observe carefully first, making a note of any "suspects" around Neptune and only then to consult the software. That way you can have some confidence that you really saw something rather than your mind inserting something where you think it ought to be.

Triton moves around Neptune fairly quickly making a complete orbit around Neptune every 5.9 days. So it's position angle will change quite a bit night to night.

I find using a sort of averted / deliberate defocused vision technique helps Triton to pop into view more readily. This is done with the eye rather than the focuser of the scope. It's a little like the way you look at those "magic eye" pictures to see the 3D effect.

Tonight I'm going to see if I can get Triton with my 130mm refractor which will be even more of a challenge. I've done it just once with this scope in the past so it will be interesting to see if it was a fluke or not

So the 2mm-4mm zoom will be in action again !

While only a faint and indistinct point of light through the scope, Triton is the most distant rocky/icy body that I've been able to see. Unless I manage to spot Pluto someday !

 

[Barry-W-Fenner]

Good luck with this challenge John. I also have the 12" dob out and I'm sitting here having a look at the stunning Jupiter, the GRS is looking brilliant. I hope to get my 1st look of Neptune later, and maybe Triton one day!

On the subject of pluto, I see it is currently somewhere between jupiter and saturn. Would this give half a chance of seeing it, Or is it to difficult?

Baz

[John]

I've never seen Pluto Baz.

It's possible with a 12 inch I believe but it would be just a tiny dot (no disk - too small) right at the limit (mag 14.3 I think) so you would need to sketch the stars you see including your "suspect" and then repeat the excersize a few nights later and see if anything has moved against the starry backdrop.

I'm observing Jupiter as well just now but the seeing here is currently not so good. I can see the GRS, cloud belts etc but not as well defined as they ought to be.

 

[Barry-W-Fenner]

Well, Neptune evades me again! It was just about getting above the house roof tops and the fog / dew has rolled in big time, conditions deteriorated very quickly.  Up until then I was having a great time viewing globs. I was hoping to see 6 planets. Jupiter, Saturn, Neptune, Mars, Uranus and a naked eye view of Venus around 5-6am. But not to be, the hunt for Neptune continues 😁

[John]

Triton spotted again this evening with my 12 inch dob at 318x (Pentax 5mm XW).

The magnitude 13.5 moon is 14 arc seconds North of Neptune tonight. This is the newtonian view:

 

 

Edited October 9, 2020 by John