Uranus and it's satellites

[John]

Nice clear night at last. I've got the 12 inch dobsonian out and I've been observing Uranus for the past hour.

My specific objective is to see how many Uranian moons I can spot. With this scope in the past I've seen the two brightest - Umbriel and Titania. Tonight, with the help of a freshly washed primary mirror, I'm very pleased to have been able to add two more - Oberon and Ariel.

The brighter pair, Umbriel and Titana are visible, and can be held, with direct vision. Oberon and Ariel are more elusive (closer to the planet as well) and are being glimpsed as they pop in and out of view.

I am using high magnifications for this task. 318x gets me Umbriel and Titania but I needed to push up to 454x to tease out Oberon and Ariel. Oberon is close to magnitude 15 currently which is quite a challenge !

This is the first time I've been able to see four of Uranus's natural satellites and I'm pleased with the result

Miranda would be very nice but that one is currently another magnitude fainter again and even closer to the planet than Oberon and Ariel

Four is nice though

Edited December 2, 2021 by John

[Les Ewan]

What eyepieces do you use? I was observing Uranus this evening and failed to see a satellite!🤬 I have a 16" Newt and have also tried to see Triton a few times and failed also. I usually use a 12.5mm Orthoscopic giving a power of 144X. 

I cant understand it as I have seen field stars around The Ring Nebula that are below magnitude 15 a few times, granted Uranus and Neptune are lower in the sky. 

Your success using high power has inspired me to try a barlow with the 12.5mm or maybe with my 9mm Orthoscopic giving powers  of 200X and 300X.

[John]

9 minutes ago, Les Ewan said:

What eyepieces do you use? I was observing Uranus this evening and failed to see a satellite!🤬 I have a 16" Newt and have also tried to see Triton a few times and failed also. I usually use a 12.5mm Orthoscopic giving a power of 144X. 

I cant understand it as I have seen field stars around The Ring Nebula that are below magnitude 15 a few times, granted Uranus and Neptune are lower in the sky. 

Your success using high power has inspired me to try a barlow with the 12.5mm or maybe with my 9mm Orthoscopic giving powers  of 200X and 300X.

The eyepieces I used for this task tonight were (mostly) the Pentax XW 5mm and 3.5mm.

 

 

 

 

[Barry-W-Fenner]

14 hours ago, John said:

Nice clear night at last. I've got the 12 inch dobsonian out and I've been observing Uranus for the past hour.

My specific objective is to see how many Uranian moons I can spot. With this scope in the past I've seen the two brightest - Umbriel and Titania. Tonight, with the help of a freshly washed primary mirror, I'm very pleased to have been able to add two more - Oberon and Ariel.

The brighter pair, Umbriel and Titana are visible, and can be held, with direct vision. Oberon and Ariel are more elusive (closer to the planet as well) and are being glimpsed as they pop in and out of view.

I am using high magnifications for this task. 318x gets me Umbriel and Titania but I needed to push up to 454x to tease out Oberon and Ariel. Oberon is close to magnitude 15 currently which is quite a challenge !

This is the first time I've been able to see four of Uranus's natural satellites and I'm pleased with the result

Miranda would be very nice but that one is currently another magnitude fainter again and even closer to the planet than Oberon and Ariel

Four is nice though

Nice read that John. I have had no observing time as of late due to extra work in the evenings. I am quite keen to get the 12" dob out on Uranus and hopefully Neptune as some point with my highest power (4.5mm morph) Your report makes me optimistic that i may spot some moons!

 

Baz

[Paz]

Nice report, at the very high magnifications do you use an equatorial platform or track by hand? 

[John]

Just now, Paz said:

Nice report, at the very high magnifications do you use an equatorial platform or track by hand? 

I track by hand. I used to have an equatorial platform which worked well but the additional eyepiece height was inconvenient with my F/5.3 12 inch dob. My dob mount is very smooth in both axis so tracking targets at high power is not too challenging. I use the "nudge - let drift - nudge - let drift" approach

[Paz]

17 minutes ago, John said:

I track by hand. I used to have an equatorial platform which worked well but the additional eyepiece height was inconvenient with my F/5.3 12 inch dob. My dob mount is very smooth in both axis so tracking targets at high power is not too challenging. I use the "nudge - let drift - nudge - let drift" approach

That's useful to know. I find nudging a bit of a challenge over 200x and use an equatorial platform above that, but I've never really tried to optimise the balance and friction on my dob, I will take a look at this.

[John]

1 hour ago, Paz said:

That's useful to know. I find nudging a bit of a challenge over 200x and use an equatorial platform above that, but I've never really tried to optimise the balance and friction on my dob, I will take a look at this.

My dob mount was made for me by a skilled member here. It is simple but has worked flawlessly since the day it arrived and I fitted the optical tube into it. He certainly knew what he was about

 

[niallk]

Nice report John!  I haven't observed Uranus this year, but was thrilled to also catch 4 moons before during a run of good seeing and dark transparent nights before (15", ~330x).  Seeing Uranus as sharply defined disk was also fantastic- albeit featureless to my eyes.

Any hint of a lighter polar region??

[John]

2 minutes ago, niallk said:

Nice report John!  I haven't observed Uranus this year, but was thrilled to also catch 4 moons before during a run of good seeing and dark transparent nights before (15", ~330x).  Seeing Uranus as sharply defined disk was also fantastic- albeit featureless to my eyes.

Any hint of a lighter polar region??

Thanks !

Thus far the disk of the planet has seemed fairly uniform in tone.

I'll keep looking for tonal variations though

[chiltonstar]

20 hours ago, niallk said:

Nice report John!  I haven't observed Uranus this year, but was thrilled to also catch 4 moons before during a run of good seeing and dark transparent nights before (15", ~330x).  Seeing Uranus as sharply defined disk was also fantastic- albeit featureless to my eyes.

Any hint of a lighter polar region??

I don't see any polar variation visually  but imaging Uranus seems to show some brightness.

Chris

[johnturley]

I've never ben able to see visually any of the moons of Uranus, or Triton of Neptune through my 14 in Newtonian, put it down to a combinations of my skies being too light polluted, and my poor eyesight.

John 

[Stardaze]

That’s impressive seeing those John. Is that the first time you’ve washed the mirror in your dob? 

[John]

27 minutes ago, Stardaze said:

That’s impressive seeing those John. Is that the first time you’ve washed the mirror in your dob? 

I think it's the 3rd time in the 8 1/2 years that I've owned the scope.

 

[bomberbaz]

well done @John, I managed Titania, Oberon and Ariel at Galloway but Umbriel evaded me. 

As I remember I was at x340 so maybe I should have pushed my magnification a little more. Something to aim for.

Impressive work 👏

[Stardaze]

9 hours ago, John said:

I think it's the 3rd time in the 8 1/2 years that I've owned the scope.

 

I think one day I’ll have a VX12 with a premium mirror, probably my realistic dob goal. A 102 frac is going to be next years present. 

[bomberbaz]

10 hours ago, John said:

I think it's the 3rd time in the 8 1/2 years that I've owned the scope.

 

John. Out of interest for my own purposes, plus anyone else considering cleaning the primary.  What solution do you use to clean the mirror?

Think I used warm water with a little baby shampoo last time I cleaned one but with my memory that might just be wishful reminiscing 😅

[Stardaze]

A couple of drops of washing up liquid is the most common advice. Thats what I used recently. 

[John]

4 hours ago, bomberbaz said:

John. Out of interest for my own purposes, plus anyone else considering cleaning the primary.  What solution do you use to clean the mirror?

Think I used warm water with a little baby shampoo last time I cleaned one but with my memory that might just be wishful reminiscing 😅

I used pure soap flakes dissolved into lukewarm tap water and rinsed off with distilled water. Cotton wool balls to gently swab the soapy water off using just the weight of the wet cotton wool and constant strokes away from the centre of the mirror.