Jump to content


Photo

Enckes

  • Please log in to reply
84 replies to this topic

#76 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10352
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 10 May 2013 - 05:51 PM

Ahhhh thanks for the tip - and encouragement!

Pete

#77 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10352
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 10 May 2013 - 05:55 PM

I’ve really learned a lot from this tread.

With a new secondary and insanely great seeing for VT I was able for the first time on Saturn to boost the magnification in my 10” Dob to around 400x, 5/14/13. Because of this thread I was trying really hard to see the Encke Division. Never did manage it.

The interesting thing is that I kept seeing a darker line bisecting the A ring. I knew the Gap was near the outer edge of the ring so I just dismissed what I saw as an optical aberration. At that time I didn’t know there was a Encke Minima, or that there was a difference between the two. But now I do!

I also realized that with the excellent mirrors I now have, I’m really going to have to do my home work on what’s possible to observe on Saturn and really knuckle down and pay more attention. I didn’t have any reference material with me because my previous viewings were “nice to look at” but not detail rich. That nights quick look turned into two hours of “WOW I can see all sorts of banding”, and “I wish I knew more about the finer details of ring structure”!


Brian I wish you all the luck. As I mentioned in another post its still a great view without the E-gap (heh take THAT Bill!). Still how can you NOT look for it? You have the golden key aperture apparently under the better circumstances. Hang in there and I look forward to your reports. And u kno how it is - even a negative result is a positive observation!

Pete

#78 bremms

bremms

    Mercury-Atlas

  • *****
  • Posts: 2592
  • Joined: 31 Aug 2012
  • Loc: SC

Posted 11 May 2013 - 07:58 AM

I do remember from the late 70's early 80's warm misty 4am till dawn planet viewing leaving the RV6 set up from the evening with a loose cover and getting the best images of Jupiter Saturn and Mars with a couple 9-10/10 seeing mornings.

I can see the A ring darkening easily, thought we glimpsed the Encke division in a 16" F5 Cave(backyard observatory of a friend of a friend)but the seeing went sour that evening.
Great mirror in that Cave, but seeing never cooperated when we went to observe with him. (The beer probably didn't help either)

#79 azure1961p

azure1961p

    Voyager 1

  • *****
  • Posts: 10352
  • Joined: 17 Jan 2009
  • Loc: USA

Posted 29 May 2013 - 06:44 AM

This is very interesting...

An excellent imager in South America with a C8 has successfully imaged Enckes almost to the point I thought it was via C11 or C14. His name is
Rafael Defavari and he's something on par with Damien Peach with an 8.

I thought it shed light on the Enckes Division question with an 8". Wether or not the eye can detect the low levels of contrast Rafael has is still a point of contention among some, but with the imager its at least there as a line on SOME level. I'm to locate the smallest aperture that can still image it but it looks like it ends with c8. I'd wonder if a 150 Mak in Rafael's hands (and seeing) would show it but for now there's no one making pix to his level of clarity as the rings are wrought with ringing effects and softness comparably.

Here's the link:

http://500px.com/rafaeldefavari

Pete

#80 leviathan

leviathan

    Mariner 2

  • -----
  • Posts: 296
  • Joined: 29 Nov 2011
  • Loc: Azerbaijan

Posted 29 May 2013 - 06:59 AM

Pete, astrophoto is another story. I saw several Encke's imaged with 8".

#81 Schaden

Schaden

    Mariner 2

  • -----
  • Posts: 224
  • Joined: 30 Jun 2008
  • Loc: Sonoran Desert

Posted 29 May 2013 - 09:11 AM

[quote name="BillFerris"][quote]

Your description is of the Encke Minima, a broad low contrast feature roughly in the middle of the A-Ring. I would describe this feature as trivial in a 10-inch aperture. It was regularly visible in my old, contrast-challenged Meade Starfinder 10-inch equatorial Newtonian. Based on that experience, I see no reason to doubt it can be observed in a good 6-inch aperture.

Bill in Flag [/quote]

Recently I read an article in the latest Astronomy magazine where the author said he'd seen Encke's Minima in a 4" reflector.

#82 Ziggy943

Ziggy943

    Gemini

  • -----
  • Posts: 3288
  • Joined: 11 Aug 2006
  • Loc: Utah

Posted 31 May 2013 - 12:04 AM

Although I have met him only a couple of times, I count John Pons among my friends. He related to me and observation of Encke's division through an 8" refractor. I forget the name of the owner but he said Encke's was visible all around. I have no reason to doubt John's observation.

As stated ealier in this thread, I have seen it twice in my 9" Clark.

#83 Mark Harry

Mark Harry

    Vendor

  • *****
  • Vendors
  • Posts: 6162
  • Joined: 05 Sep 2005
  • Loc: Northeast USA

Posted 08 June 2013 - 05:39 AM

Thanks for posting that, Ziggy.
M.

#84 E_Look

E_Look

    Soyuz

  • *****
  • Posts: 3891
  • Joined: 06 Mar 2008
  • Loc: near New York

Posted 08 June 2013 - 08:27 PM

Ziggy, would that be true through a 8" reFLEctor?

#85 Starry eyes

Starry eyes

    Vostok 1

  • -----
  • Posts: 131
  • Joined: 30 Apr 2010

Posted 18 June 2013 - 12:47 AM

I hesitate to add my two cents worth but... Over the course of several decades I have seen Encke division and shown it to others fairly often with a 6.75" off axis mask on a 18" split ring equatorial. I attribute this to a effective slow F ratio, a smooth mirror, unobstructed aperture, Naglers, great seeing in California's coastal mountains, an extremely steady mount with tracking, great ergonomics for the eyepiece giving a comfortable view, and, I guess we didn't know better. Never could trace it all the way around. I bring this up to demonstrate that perhaps there are a few more factors to consider in this civil discussion about the interaction of the human eye.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics