Nice to have the 12 inch dobsonian out under darkish skies again !

[John]

My main aim this evening is to observe Saturn, Jupiter and possibly Neptune with my 12 inch dob. So far this gas giant "season" I've been using my refractors.

While I wait for the above to rise from behind the nearby rooftops, I've been having some other planetary fun - planetary nebulae in and around Sagitta.

To kick off I went straight to Messier 57 in Lyra which, towards the zenith, was looking pretty good as usual. Then to Messier 27 in Vulpecula which again was bright and well defined. The central star of this nebula was gleaming dimly at the central axis of the "dumbbell" lobes.

Having "got my eye in" so to speak I moved on to some more challenging planetary nebs. My "browsing" magnification for this task was 122x (Ethos 13mm) but more was needed at times. No filters used, unless mentioned:

- NGC 6886 in Sagitta which is just 7.6 arc seconds in diameter and glowing at magnitude 11.4.

- NGC 6879 in Sagitta which is even smaller at around 5 arc seconds - I needed 250x or more to show that this was clearly a PN rather than a star.

- IC 4497 in Sagitta, another really tiny one at about 3 arc seconds but elongated. Needed 338x to definitely ID this one !

- NGC 6905, the "Blue Flash nebula" in Delphinus. Somewhat larger in diameter at 23 arc seconds and a clearly defined glowing patch between 2 stars. Very faint central star visible intermittently.

- NGC 6891 in Delphinius. Smallish patch 18 arc seconds in diameter and again showing a very faint central star.

- NGC 6765 back in Lyra. Very faint, small, irregular patch set in a triangle of dim stars. This one needed a UHC filter to see anything of it. An O-III filter was not quite as effective, oddly.

While moving around the sky between the above, I also had a look at the globular clusters M71 (Sagitta) and M56 (Lyra) to throw into the deep sky mix.

So that was a very nice way to give Saturn and Jupiter time to show themselves - I'd better get outside again !

 

Edited August 26, 2021 by John

[Buqibu]

Great report! My session today was a mix of clouds, wonky seeing, bright moon. Still quite fun😁

[John]

Part 2 of this session comprised the 3 gas giant planets, Saturn, Jupiter and Neptune.

Saturn was subject to variable seeing conditions. During the steady periods the detail was nice but not outstanding I feel. The advantage that the 12 inch dobsonian had over my smaller aperture refractors tonight was that the "C" ring was showing clearly in the gap between the ansae of the "B" ring and the planetary limb. The "C" ring could be seen as a sharp edged change in contrast about halfway across that gap, on both sides of the planet. Like this (but smaller even at 338x of course):

The extra light grasp of the 12 inch also showed a 6th moon, Enceladus, along with Dione, Tethys, Rhea, Iapetus and Titan. Enceladus was quite close to the outer edge of the "A" ring which made it tricky to tease out of the glare from the ring system and the planetary disk. What I was hoping for 

Moving on to Jupiter, the giant planet showed best at 199x. The Great Red Spot was not on show but the 6/7 belts that crossed the disk showed lovely tones of brown, tan, rust, grey and cream. Rather lumpy edges to the north and south equatorial belts but no obvious white ovals and I could not see any barges on this occasion. The 4 Galilean moons were strung out in a 3 + 1 formation either side of the planet with Europa on it's own tonight.

Finally I managed to find Neptune which was a little tricky with the moons glow starting to invade that part of the sky. Once in the eyepiece I upped the magnification to 338x again and the pale blue planetary disk showed nicely. I do feel that the colour of Neptune and Uranus seems more saturated if the planets are observed with the moon relatively nearby

I did some careful observation of the planet using what I call my "1000 yard stare" method where I'm trying to de-focus my eye and look beyond / past Neptune if that's possible. It is rather like the technique used to view those "Magic Eye" 3D pictures. This does work, for me at least, in picking out faint point sources of light and sure enough one such pinpoint did pop in and out of view a little to the S and W of Neptunes tiny disk. A check on Stellarium confirmed that this was Neptune's largest and brightest moon Triton and I always get a thrill from seeing it 

So observing these 3 planets with the 12 inch scope delivered a few "extras" as I'd hoped it would.

Together with the planetary nebulae hunting session earlier, a very enjoyable night of observational astronomy

Here is the Stellarium view of Neptune and Triton tonight. Triton is a LOT fainter than shown in this (newtonian view) simulation though:

 

Edited August 27, 2021 by John

[globular]

Nice report John.  Sounds like a fun night.

I too had my telescope out for the first time in what seems like a lifetime.

Your description of your Jupiter observing mirrors mine.  Best detail was at 180x although it looked lovely in different ways in a host of different EPs.  Two broad brown belts with numerous thinner ones of exactly the colours you describe. My wife was particularly taken by the grey one she picked out after lingering at the eyepiece longer than I've ever known her to. (Her bad back usually limits her to quick glimpses at a time).  We both had our best views of Jupiter yet and a thoroughly enjoyable hour dedicated to it. 

Wife went to bed when we lost Jupiter to the trees and I had another hour touring various globular and open clusters - many of which I've made a note to return to with my sketchpad - and some planetary nebulae.  Thoroughly enjoyable.

Saturn, sadly, remained hidden by trees on this occasion.  I did view the lovely blue Neptune - only the colour giving away that it was not just another star.  I didn't try for it's moon.... but now I know it's possible I'll give it a go next time.  I suspect my 8" might not be enough though??

Edited August 27, 2021 by globular

[Stu1smartcookie]

10 hours ago, John said:

My main aim this evening is to observe Saturn, Jupiter and possibly Neptune with my 12 inch dob. So far this gas giant "season" I've been using my refractors.

While I wait for the above to rise from behind the nearby rooftops, I've been having some other planetary fun - planetary nebulae in and around Sagitta.

To kick off I went straight to Messier 57 in Lyra which, towards the zenith, was looking pretty good as usual. Then to Messier 27 in Vulpecula which again was bright and well defined. The central star of this nebula was gleaming dimly at the central axis of the "dumbbell" lobes.

Having "got my eye in" so to speak I moved on to some more challenging planetary nebs. My "browsing" magnification for this task was 122x (Ethos 13mm) but more was needed at times. No filters used, unless mentioned:

- NGC 6886 in Sagitta which is just 7.6 arc seconds in diameter and glowing at magnitude 11.4.

- NGC 6879 in Sagitta which is even smaller at around 5 arc seconds - I needed 250x or more to show that this was clearly a PN rather than a star.

- IC 4497 in Sagitta, another really tiny one at about 3 arc seconds but elongated. Needed 338x to definitely ID this one !

- NGC 6905, the "Blue Flash nebula" in Delphinus. Somewhat larger in diameter at 23 arc seconds and a clearly defined glowing patch between 2 stars. Very faint central star visible intermittently.

- NGC 6891 in Delphinius. Smallish patch 18 arc seconds in diameter and again showing a very faint central star.

- NGC 6765 back in Lyra. Very faint, small, irregular patch set in a triangle of dim stars. This one needed a UHC filter to see anything of it. An O-III filter was not quite as effective, oddly.

While moving around the sky between the above, I also had a look at the globular clusters M71 (Sagitta) and M56 (Lyra) to throw into the deep sky mix.

So that was a very nice way to give Saturn and Jupiter time to show themselves - I'd better get outside again !

 

Hoping to give my Dob first light tonight as its meant to be clear ( we will see) , some great targets there John . Nice report 

[John]

7 hours ago, globular said:

...  I did view the lovely blue Neptune - only the colour giving away that it was not just another star.  I didn't try for it's moon.... but now I know it's possible I'll give it a go next time.  I suspect my 8" might not be enough though??

I have seen Triton with my 130mm refractor on a clear, steady night of good transparency so it should be possible wtih a 200mm. It helps to use high magnifications, eg: 250x - 350x to tease out the faint point source of light. Some type of averted / de-focussed vision technique is also worth trying. I find that helps as well

Triton is usually found around 10-15 arc seconds from Neptune's disk.

 

Edited August 27, 2021 by John

[Mark at Beaufort]

Very enjoyable on both reports John. I used my 6" Newt last night but in hindsight should have taken out the 12" Dob especially reading your reports.

[globular]

42 minutes ago, John said:

I have seen Triton with my 130mm refractor on a clear, steady night of good transparency so it should be possible wtih a 200mm. It helps to use high magnifications, eg: 250x - 350x to tease out the faint point source of light. Some type of averted / de-focussed vision technique is also worth trying. I find that helps as well

Triton is usually found around 10-15 arc seconds from Neptune's disk.

 

I read somewhere that Patrick Moore's formula for limiting magnitude puts a 130mm at about 13.1 - so you must have close to perfect optical train, viewing conditions and good eyes - better eyes than Patrick at least. 🤣
The same formula gives mag 14.0 for an 8" - but I'd imagine, as an SCT with a central obstruction, it will be slightly dimmer in reality?
Definitely worth a go though.

 

edit: my secondary is 2.5" so I'd expect a limiting mag equivalent to an aperture of  2 * root( sqr (8" / 2) - sqr (2.5" / 2) )  = 7.6" ...  which is mag 13.9.  So not that much dimmer!

Edited August 27, 2021 by globular

[John]

20 minutes ago, globular said:

I read somewhere that Patrick Moore's formula for limiting magnitude puts a 130mm at about 13.1 - so you must have close to perfect optical train, viewing conditions and good eyes - better eyes than Patrick at least. 🤣
The same formula gives mag 14.0 for an 8" - but I'd imagine, as and SCT with a central obstruction, it will be slightly dimmer in reality?
Definitely worth a go though.

The figure that I get for the 130mm refractor is mag 13.4 under dark transparent skies observing close to the zenith. It was a few years back when I got Triton with the 130mm. I'll give it another try at the next opportunity. I agree that it's on the very limit for the aperture and for me. The scope has a LZOS triplet objective so most of the light goes where it's supposed to go

Neptune is lower in the sky now which scubs a little of the brightness off.

 

[Buqibu]

9 hours ago, John said:

Part 2 of this session comprised the 3 gas giant planets, Saturn, Jupiter and Neptune.

Saturn was subject to variable seeing conditions. During the steady periods the detail was nice but not outstanding I feel. The advantage that the 12 inch dobsonian had over my smaller aperture refractors tonight was that the "C" ring was showing clearly in the gap between the ansae of the "B" ring and the planetary limb. The "C" ring could be seen as a sharp edged change in contrast about halfway across that gap, on both sides of the planet. Like this (but smaller even at 338x of course):

The extra light grasp of the 12 inch also showed a 6th moon, Enceladus, along with Dione, Tethys, Rhea, Iapetus and Titan. Enceladus was quite close to the outer edge of the "A" ring which made it tricky to tease out of the glare from the ring system and the planetary disk. What I was hoping for 

Moving on to Jupiter, the giant planet showed best at 199x. The Great Red Spot was not on show but the 6/7 belts that crossed the disk showed lovely tones of brown, tan, rust, grey and cream. Rather lumpy edges to the north and south equatorial belts but no obvious white ovals and I could not see any barges on this occasion. The 4 Galilean moons were strung out in a 3 + 1 formation either side of the planet with Europa on it's own tonight.

Finally I managed to find Neptune which was a little tricky with the moons glow starting to invade that part of the sky. Once in the eyepiece I upped the magnification to 338x again and the pale blue planetary disk showed nicely. I do feel that the colour of Neptune and Uranus seems more saturated if the planets are observed with the moon relatively nearby

I did some careful observation of the planet using what I call my "1000 yard stare" method where I'm trying to de-focus my eye and look beyond / past Neptune if that's possible. It is rather like the technique used to view those "Magic Eye" 3D pictures. This does work, for me at least, in picking out faint point sources of light and sure enough one such pinpoint did pop in and out of view a little to the S and W of Neptunes tiny disk. A check on Stellarium confirmed that this was Neptune's largest and brightest moon Triton and I always get a thrill from seeing it 

So observing these 3 planets with the 12 inch scope delivered a few "extras" as I'd hoped it would.

Together with the planetary nebulae hunting session earlier, a very enjoyable night of observational astronomy

Here is the Stellarium view of Neptune and Triton tonight. Triton is a LOT fainter than shown in this (newtonian view) simulation though:

 

Saturn looked very nice yesterday, although its steadily dimming as it leaves opposition period, still a great sight. I thought I caught a glimpse of the Cassini Division yesterday for the first time in my 4 inch achro. Though it might've just been my imagination, haven't had a clear view of it yet. Saturn had a nice pale cream band that I could make out, looked a bit like a scoop of ice cream😁

[Stardaze]

Great report John. The next few nights are looking very promising, with no work either to worry about. I fancy having a punt at Neptune too as I haven't ticked her off yet. I've spent the last couple of nights with the 15x70s and they've seemed fairly steady. Looking forward to dragging the dob out somehow over the weekend. 

[Pixies]

Same here - looking good for tonight, the first time in ages.

I've seen neptune in 10x50 binos, recently - but not in the scope since last year. Perhaps it was when I managed to get all the planets in one night. Certainly haven't knowingly seen Triton before, although tonight's moon certainly won't help.

[lunator]

Hi John, nice report

I have never seen Triton. I may have to try with Mr Dobbie. I hope to have another look at Saturn & Jupiter tonight.

Cheers

Ian

[JeremyS]

Great reports @John 👍🏻
Good that you captured Neptune. And some unusual DSOs

Good to hear what the big guns are capable of

[John]

10 hours ago, John said:

The figure that I get for the 130mm refractor is mag 13.4 under dark transparent skies observing close to the zenith. It was a few years back when I got Triton with the 130mm. I'll give it another try at the next opportunity. I agree that it's on the very limit for the aperture and for me. The scope has a LZOS triplet objective so most of the light goes where it's supposed to go

Neptune is lower in the sky now which scubs a little of the brightness off.

 

I've got the 130mm refractor out this evening despite the threat of some clouds. If it stays clear I'll have a go at Neptune / Triton with it and see if it "goes" with that scope this time

[Stardaze]

I’m poised ready, but it’s thick over at the moment…

[John]

11 minutes ago, Stardaze said:

I’m poised ready, but it’s thick over at the moment…

Clouds have moved in here as well. No rain forecast so I'll leave the scope out in case it clears.

 

[JeremyS]

1 minute ago, John said:

Clouds have moved in here as well. No rain forecast so I'll leave the scope out in case it clears.

 

Ditto here too

[Pixies]

8" dob outside cooling down. All clear so far - even reports of possible aurora, tonight.

[John]

Solid cloud now. Thick too

Scopes back in. Nothing doing tonight.

 

[Stardaze]

It cleared for 15 minutes but now it’s thick again 🙄

[ShrewView]

Had a few good moments earlier with the grs just coming onto Jupiter's disk and seeing seemed good. Then it suddenly went downhill and some stubborn cloud has now moved in. 

I'll stick it out a while longer and see what happens.

[Stardaze]

Plenty of detail on both gas giants but the cloud is back again. Going to give it half hour and see what happens. Still to find Neptune.. it’s there in front of me somewhere.

[John]

1 hour ago, Stardaze said:

Plenty of detail on both gas giants but the cloud is back again. Going to give it half hour and see what happens. Still to find Neptune.. it’s there in front of me somewhere.

Still heavy cloud here so I'm not playing.

I use the star Kappa Piscium, the lowest of the stars that form the circlet of Pisces as a starting point for the star hop to Neptune at the moment. Heading down there are 2 distinctive star asterisms (circled) with Neptune sitting between 2 stars in the lower one and just about visible in a 50mm finder:

 

 

 

 

Edited August 28, 2021 by John

[Stardaze]

3 minutes ago, John said:

Still heavy cloud here so I'm not playing.

I use the star Kappa Piscium, the lowest of the stars that form the circlet of Pisces as a starting point for the star hop to Neptune at the moment. Heading down there are 2 distinctive star asterisms (circled) with Neptune sitting between 2 stars in the lower one and just about visible in a 50mm finder:

 

 

 

 

I found it in the end, but the circlet wasn’t that obvious with the moon starting to make it’s presence known. I had the 15x70s setup on the tripod so had a hunt around with those first to familiarise myself with the area. There was light cloud around too, which didn’t help so took me longer than it should. Still, just great to be back out with the dob again, even if it was on the front drive.