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Observing session, July 21-22, 2019

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#1 Astrojensen

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Posted 22 July 2019 - 04:03 AM

Last night was very clear, and since I am on vacation, I took advantage of that and set up my 102mm f/11 ED, on its heavy Vixen Saturn mount, in the late evening. First look at Jupiter showed that the seeing was quite good and I watched Io slip behind the planet. The image was fairly sharp, for a change, and I could see some hints of structure in the belts. Still, the image clearly suffered from the low altitude. 

 

Later, Saturn put up quite a show as well. The view in my 9mm ES100 (125x) was very good. 

 

As darkness fell, I began looking at some double stars, but first I looked at Vega, with the intention of comparing my two prism diagonals, a Baader/Zeiss 2" and a Baader/Zeiss T2. To my surprise, the 2" was clearly better on this particular scope and the star test improved a bit and the color of the first diffraction ring changed from reddish-purple in the small prism, to much closer to neutral in the 2" prism, though still with a hint of purple. The image was also a bit cleaner overall. And the seeing was INSANELY GOOD at high altitude. The first ring around Vega was solid and unbroken most of the time, wavering slightly in the slight turbulence and occasionally fuzzying a little, only to suddenly freeze again a moment later. 

 

But this is the deep-sky forum, so let's get on with it. First object was M13. I could resolve a fair amount of stars, but it wasn't as dark yet, as it would be later (though we're still in the white nights season). I didn't spend much time on it. The view at 125x (9mm ES100) was quite good. 

 

M57 showed the mag 13 star close to the nebula at 125x. 

 

M56 showed granulation and hints of resolution. 

 

It was getting darker now and I could start to see the Milky Way faintly in Cygnus, close to zenith. Sadly, the Moon was rising in the SE, but what can you do? The MW remained visible, even with the Moon up, until well after midnight, where the combined light of the Moon and the increasingly bright twilight dimmed it to invisibility.

 

But it was still relatively dark and the seeing was excellent. This means planetary nebula time!!

 

First target was IC 4593 in Hercules. I saw this one a few days ago in my 63mm Zeiss, but was unsure whether I saw just the central star or also the nebula. Unfortunately, I had placed the scope tonight so that at the time I wanted to observe it, IC 4593 was almost starting to slip behind a tree. But I made it in time (the star hop is easy) and at 239x (4.7mm ES82) I could clearly see that my impression in the Telemator was right. A small, somewhat faint, central star, surrounded by a quite bright, round nebula. 561x confirmed it.  

 

Next was Campbell's Hydrogen Star PK 64+5.1. I didn't have a very accurate map with me, only U2000.0, and it was a long time since I saw this planetary the last time, so I was unsure, if I could identify it, but I didn't need to worry. It was immediately visible at 125x as an extremely small disk, just ever so slightly larger than the nearby stars. At 561x (2mm LET eyepiece) I could clearly see the central star, surrounded by a small, bright, round nebula. I didn't see any color in it. 

 

On my way to PK 64+5.1, I also observed an old favorite "anonymous" object: Minkowski 1-92, the Footprint Nebula. Even at 321x (3.5mm LER eyepiece) it was only a small, elongated glow, but I could see that it consists of two parts, one slightly larger than the other. It was clearly suffering from the less than dark skies, since I couldn't get fully dark adapted and even at 321x, I could still see the field stop. 

 

NGC 6826, the Blinking Planetary, was next. Immediately visible at 125x as a bright, round, fuzzy star. Central star visible. No blinking effect of the nebula noticed. At 561x it was a large, fuzzy glow with somewhat ill-defined edges, surrounding the bright central star. 

 

NGC 6543 was last, as twilight was starting to get fairly bright (it was almost 2 A.M.). The star-hop to this nebula is also pretty easy and I had it in view within a few moments. It was even visible in the 6x30 finder, as a stellar point. At 125x (9mm ES100), it was immediately visible as a small, very bright, slightly elongated nebula with rather sharp edges. At 561x it was still very bright. Despite the good seeing, I had trouble seeing details in it, so I experimented with even higher magnifications. At 963x (3.5mm LER + 3x GSO barlow) the planetary began to show subtle hints of LOTS of details. I could see vague hints of a spiral shape and knots in the bright disk, but it was impossible to hold steadily and as soon as I accidentally let some light through my fingers, which I had cupped around my eye and the eyepiece, my dark adaption would suffer and glare ruined the view. Surprisingly, the central star popped out at this magnification and could be held steadily. Now I am eagerly waiting for a darker night, with just as steady seeing. BTW, even at 963x, NGC 6543 is BRIGHTER than M57 is at 125x!!! You shouldn't be afraid to go nuts with the magnification on this one. Another fun fact: Even at 963x, NGC 6543 appears just 4.8° wide! 

 

 

Clear skies!
Thomas, Denmark


Edited by Astrojensen, 22 July 2019 - 04:05 AM.

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#2 payner

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Posted 22 July 2019 - 03:52 PM

Enjoyed reading your fine observations, Thomas. Thanks for posting and more clear skies to you over your holiday.

 

Randy


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#3 azure1961p

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Posted 26 July 2019 - 01:47 PM

Amazing Thomas.  You got more of of 6543 with your 102mm refractor than I've gotten with my 150mm act (@ 576x), albeit under mag 4.7 sky's.  Incredible how hard you were pushing the optics but results is results and the retina prefers the larger, if even fainter, image.

 

I chuckled a little bit with Campbell's only because it can LOOK like it's trying to pass itself off as a star if you can imagine it.  Isn't it a great example though of how the high-power techniques really come to play in ferreting out it's secrets?  Here's two kinds nds of resolution, stellar point and extended nebula really tightly tucked together.  You did it justice and your accounts nts were really satisfying to read!

 

M56 not far from the Marquis M13 and 92 requires a different approach (patience) but it works out some details and egf cts as you mention.  They day interstellar dust in the milyway is dimming the view, which in itself kind of compelled one to try more to get it's features.

 

I didn't Kno anything about "White Nights' (beyond the Def Leopard song ;)) until you mentioned here.  You really do have a different sky perspective / dynamic than I get here in the NE US.  Reminds me of Alaskans and their midnite sun, or twilight if you will.

 

Glad you got superb seeing on Vega!!! With full dark adaption it's blue white light reminds me of an arc light from a torch.   I envy your views here, superb seeing is something to behold when it arrives.

 

A nice report Thomas!!

 

Pete


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#4 Astrojensen

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Posted 26 July 2019 - 03:46 PM

 

I didn't Kno anything about "White Nights' (beyond the Def Leopard song ;)) until you mentioned here.  You really do have a different sky perspective / dynamic than I get here in the NE US.  Reminds me of Alaskans and their midnite sun, or twilight if you will.

It's the same thing. 

 

 

Clear skies!
Thomas, Denmark




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