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buddyjesus
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Reged: 07/07/10

Loc: Davison, Michigan
Re: Enckes new [Re: rgm40]
      #5803672 - 04/16/13 10:46 PM

happy you made lemonade out of lemons rgm

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Ziggy943
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Reged: 08/11/06

Loc: Utah
Re: Enckes new [Re: buddyjesus]
      #5803820 - 04/17/13 01:06 AM

I have seen Encke's exactly twice. Both observations were made from some of the better locations in Utah with the 9" Clark and in the company of confirming observers. The first observation was made at an elevation of 10,500 feet at Monte Cristo, the second at the Wedge Overlook. In both cases Encke was a fine line at the ansae of the A ring. It was not seen all the way around. It makes my my list of top 5 observations.

I almost had it in 2003 during an incredible morning in an TEC 8" F/15 MAK. Mars, the previous night had shown an incredible image at 19.6", the best ever in that scope that I had to try Saturn. It was sooo close and so good but not quite there. Seeing Encke depend on everything being just right.


Edited by Ziggy943 (04/17/13 01:13 AM)


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george golitzin
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Re: Enckes new [Re: Ziggy943]
      #5803950 - 04/17/13 05:17 AM

Quote:

... Seeing Encke depend on everything being just right.





I agree. I've seen it once, in a well-cooled 16-inch on a great night with the rings wide open and the planet very high in the sky (in Taurus, or perhaps Gemini--I'd have to check my notes...). One of my favorite observations ever. I was at 360X, which I think is near the minimum power necessary to pick out such a fine line.

-geo


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: Enckes new [Re: David Gray]
      #5805682 - 04/17/13 10:18 PM Attachment (44 downloads)

I've seen the Encke Gap with my past 20" f/4.3 Zambuto Starmaster dob during the winter of 2006 when Saturn was in its northern-most apparition in the sky and the rings were open all the way. I was bino-viewing at about 500X with Saturn directly over head. The Gap was seen steadily as a fine black line with a contrasty appearance, not the gray, blurry and thicker line shown in the photos. It was a lot thinner appearing, but very black. See attached NASA image. The Gap appeared more like 'this' image -- very thin and black.




Quote:

Quote: David, what about Enke's division, ever seen it in your 16 incher

This is what I said in reply to Asbytec [not Ivano] on my "Saturn April 4" thread (Sketching Forum). [Edit Note: apologies for the original error]
.


If you mean the Encke Minima (what I call the ‘classical Encke’): yes on very many occasions. If the IAU Encke then on average some five or so times per apparition (edge-ons excepted!), but only during better seeing. This latter to me is the true Keeler Gap: the IAU compounding the silliness by calling an impossibly fine line even nearer Ring A’s outer edge the Keeler. Can I see the IAU Encke as a ‘black’ gap like Cassini? Definitely not. On the BAA intensity scale (0 = White/Bright; 10 = Black) I usually make it twixt 7 & 8. Appropriately it looks to me quite like a fine lead-pencil line tho’ often a little diffuse – especially on the inner edge. I can’t rule out contrast effects entirely, but in my view perhaps 60/40: and undecided which predominates: real or illusion!! Nature seems to like hiding real features, at least to some eyes, under illusion/contrast effects; Saturn’s rings seemingly being particularly prone.

Somewhere in the BAA Saturn archive is a drawing of the only time I saw IAU Encke in my 10” (1970s?) also in their Journal – will need to check.


Attached is a graphic to illustrate what I was trying to get across: I have digitally photo'd the 2003 drawing and rescaled vertically to nearer the Hubble image




Edited by Peter Natscher (04/17/13 10:23 PM)


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azure1961p
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Reged: 01/17/09

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Re: Enckes new [Re: Peter Natscher]
      #5805758 - 04/17/13 10:43 PM

Amazing how light the hex is in that image. Ok back on topic...

Pete


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buddyjesus
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Reged: 07/07/10

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Re: Enckes new [Re: azure1961p]
      #5805895 - 04/17/13 11:43 PM

beautiful picture!

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John Boudreau
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Reged: 04/06/08

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Re: Enckes new [Re: azure1961p]
      #5806227 - 04/18/13 08:20 AM

Quote:

Amazing how light the hex is in that image. Ok back on topic...




That image shows the south polar region--- Only the north polar region has a hexagon feature. That image was probably taken about 10 years ago. The north polar hex does show in HST images taken in the early 90's though.


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David Gray
sage
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Reged: 08/06/12

Loc: Co. Durham UK
Re: Enckes new [Re: Peter Natscher]
      #5806294 - 04/18/13 09:06 AM

Quote:

I've seen the Encke Gap with my past 20" f/4.3 Zambuto Starmaster dob during the winter of 2006 when Saturn was in its northern-most apparition in the sky and the rings were open all the way. I was bino-viewing at about 500X with Saturn directly over head. The Gap was seen steadily as a fine black line with a contrasty appearance, not the gray, blurry and thicker line shown in the photos. It was a lot thinner appearing, but very black. See attached NASA image. The Gap appeared more like 'this' image -- very thin and black.




It used to be said that 20" was about the aperture to get Encke as a true black gap.

Looking back through my old observations the darkest I got it, in excellent conditions, was intensity 9 which roughly equates to 90% black but still a little diffuse - so perhaps my 415mm D-K is on the edge!


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azure1961p
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Reged: 01/17/09

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Re: Enckes new [Re: David Gray]
      #5807778 - 04/18/13 09:42 PM

John,

Thanks for the clarification. I didn't realize it was pole specific. How odd.

Pete


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Mark Harry
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Reged: 09/05/05

Loc: Northeast USA
Re: Enckes new [Re: azure1961p]
      #5813821 - 04/21/13 06:48 PM

Once for Encke, and once for 8 Trap stars 3 years ago- Both times with 8" F/6, and the UO VT 9mm Ortho. Fantastic eyepiece. Conditions have to be essentially perfect; the least disturbance makes them disappear.
M.


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

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Re: Enckes new [Re: Mark Harry]
      #5814334 - 04/21/13 10:38 PM

8 Trap stars in an 8"...wow, well done.

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azure1961p
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Reged: 01/17/09

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Re: Enckes new [Re: Asbytec]
      #5814371 - 04/21/13 11:02 PM

8 Trap stars????????

Ok there goes a gauntlet!

Pete

Ps: I agree on the UO volcano top 9mm - an excellent ocular.

Edited by azure1961p (04/21/13 11:03 PM)


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David Knisely
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Reged: 04/19/04

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Re: Enckes new [Re: Mark Harry]
      #5814566 - 04/22/13 02:11 AM

Quote:

Once for Encke, and once for 8 Trap stars 3 years ago- Both times with 8" F/6, and the UO VT 9mm Ortho. Fantastic eyepiece. Conditions have to be essentially perfect; the least disturbance makes them disappear.
M.




The Encke "minimum" in a 8 inch I would believe (especially at lower powers). However, seeing the actual 325 km width division in that aperture is problematic at best due to diffraction effects between the division and the darkness at the edge of the A-ring. Even under the best conditions, the division is just too close to the darkness at the outer edge of the A-ring (0.496 arc seconds from the edge at mean opposition). For this reason, I may have some doubts about claims for visibility of the gap itself in only an eight inch aperture, although I won't dismiss them entirely. Clear skies to you.


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Mark Harry
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Reged: 09/05/05

Loc: Northeast USA
Re: Enckes new [Re: David Knisely]
      #5814686 - 04/22/13 06:48 AM

Read EDZ's discussion on the link.(?)
***
Oh well, folks have been telling me I can't see squat for decades anyhow. Up to 2 years ago, I had 20/10, and almost reached senior citizen status with it. I feel fortunate. May your skies be clear as well.
M.


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Mark Harry
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Reged: 09/05/05

Loc: Northeast USA
Re: Enckes new [Re: Mark Harry]
      #5819936 - 04/24/13 02:36 PM

No offense meant; almost as if this thread has shut down. Lets just say, I'm trying to grow old as gracefully as possible!!!
M.


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azure1961p
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Reged: 01/17/09

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Re: Enckes new [Re: Mark Harry]
      #5819961 - 04/24/13 02:45 PM

Mark,

I don't think any offense was taken. Its merely the momentum or lack there of in the topic. Without having seen it myself I don't think its impossible merely exceptional to rare.

Pete


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Schaden
sage


Reged: 06/30/08

Loc: Sonoran Desert
Re: Enckes new [Re: azure1961p]
      #5832120 - 04/30/13 12:09 PM

I saw Enckes in my Nexstar 8 last weekend. The seeing in Phoenix was phenomenal. Cleardarksky predicted 4/5 in the early evening and 5/5 after 1am for transparency and seeing. I was using an 11mm es82 barlowed to 360 x.

I've never seen it look so good at that high of power. It revealed more detail than 180. Don't know the name, but I saw the crisp shadow of a large lunar crater. Inside I could see the smooth wall that looked like a giant sand climb challenge and an endless array of tiny craters everywhere, they emerged into view with the higher mag, the seeing was superb. I used one extremely tiny one to focus on, the inside walls only visible momentarily.

When I saw Saturn it immediately looked better than it's ever looked in the C8 or Z10 before or since. The planet's bands were vibrant. The rings were tack sharp. I could see shades of contrast within each ring. I could see the rest of the A ring around Enckes, the gap appeared as a thin black line out on the edge of the A ring, flickering in and out in clarity from minute to minute but no doubt visible with direct vision.

That taught me seeing is the single most important variable in planetary observing. I got an amazing view from a light polluted city with a nearly full moon.


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David Knisely
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Reged: 04/19/04

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Re: Enckes new [Re: Schaden]
      #5832666 - 04/30/13 04:07 PM

Despite excellent seeing, I have never seen the Encke division in my Nexstar 9.25GPS XLT at any power. Seeing has sometimes caused a "doubling" of the outer edge of the A-ring that mimics a division there (especially if I have any tube currents in the scope or I have not used my Cat Cooler enough). However, once seeing settles down, the effect vanishes. I often use the visibility of Enceladus to check on seeing, as if it isn't rock stable, that faint little moon is often not seen in the 9.25. Indeed, my sighting of Enceladus so easly in the 9.25 when I was reviewing the scope for my Cloudynights review of it was one thing that convinced me that the scope was of excellent optical quality (and I eventually ended up buying the instrument). Clear skies to you.

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Schaden
sage


Reged: 06/30/08

Loc: Sonoran Desert
Re: Enckes new [Re: David Knisely]
      #5833466 - 04/30/13 11:36 PM

I didn't see it until my scope had been outside for 2 hours. There is no doubt in my mind it was Enckes, it wasn't a mirage of Cassini. I think you just need perfect seeing. That was the best night I've had in the last 4-5 years and approximately 100 sessions. I regret not staying up later but I was dead tired at 2am. The website had predicted 5/5 seeing again the next night but when I checked again the next afternoon it was only predicting an average 3/5 night. So I feel lucky to have had the hour of perfect seeing. It really was an exceptional night, knowing what my scope is capable of doing given the conditions is a good thing, but it's depressing to think of going out on an average night now, given how much I know is missing.

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azure1961p
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Reged: 01/17/09

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Re: Enckes new [Re: Schaden]
      #5833726 - 05/01/13 06:41 AM

I agree that when truly pristine seeing comes in its a revelation and you finally get to see all the precision in your optics at work - its awe inspiring! Too, as you mention, it is a but of a let down when you realize what you've been missing!!! Thanks for your account here. It sounds like your cass is a keeper.

Pete


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