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gnowellsct
Postmaster


Reged: 06/24/09
Posts: 5275
Re: Losmandy G11 with Gemini new [Re: deSitter]
      #3281962 - 08/19/09 01:20 PM Attachment (61 downloads)

You should read this about the Losmandy G11. It answers two questions. One, that it is easy to get the G11 from very good performance to excellent performance (with the Ovision). That's an option down the road for when your imaging demands get tougher.

Two, as you can see from the picture, this G11 is on a wooden Berlebach tripod. In fact is is on the first Losmandy compatible Berlebach tripod every made, because I approached them with the idea!!

Losmandy G11 turbocharged, with Berlebach

However, the default Losmandy tripod is one of the best default tripods in the business.

Some people have custom designed trays for the inside of the Losmandy tripod, it's not hard to do. But in these sorts of situations a tool bag provides plenty of spaces to store stuff. For example, on my ATS pier. I find that the tool apron around the tripod or pier is actually better than a tray. Things fall off trays (I do use the tray on the Berlebach) and it's not a good place for eyepieces because they will dew and chill down leading to eyepiece fogging.

regards Greg N

Attachment

--------------------
Scope will get you through times of no money better than money will get you through times of no scope.

’FRACTOR WARS

hp mini
color test!
C14 movie
C14 article
C14_EdgeHD
ExtremeAstronomy
Losmandy


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blueman
Vendor Blue Sky Accessories


Reged: 07/20/07
Posts: 4303
Loc: California
Re: Losmandy G11 with Gemini new [Re: gnowellsct]
      #3282048 - 08/19/09 02:01 PM

Of course the mount pictured in your post is very nice too!
Blueman

--------------------
14.5" Starmaster with ServoCat and Argo Navis
1966 Unitron 4" Model 152 EQ
Tec 140
TV NP101 f/5.4 APO Telvue .8 Focal Reducer
FLI ML8300 and CFW-2-7 filter wheel
Astrodon Gen2 RGBL 2" filters
Baader 2" Narrow Band Filters
Borg 50mm Guide Scope/ATIK Titan Guide Camera
AstroPhysics AP900
Losmandy GM-8 Gemini


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deSitter
Still in Old School


Reged: 12/09/04
Posts: 6438
Re: Losmandy G11 with Gemini new [Re: gnowellsct]
      #3282138 - 08/19/09 03:04 PM

That's a great article, thanks for pointing it out. I forget that Astromart has reviews and reports.

-drl

Quote:

You should read this about the Losmandy G11. It answers two questions. One, that it is easy to get the G11 from very good performance to excellent performance (with the Ovision). That's an option down the road for when your imaging demands get tougher.

Two, as you can see from the picture, this G11 is on a wooden Berlebach tripod. In fact is is on the first Losmandy compatible Berlebach tripod every made, because I approached them with the idea!!

Losmandy G11 turbocharged, with Berlebach

However, the default Losmandy tripod is one of the best default tripods in the business.

Some people have custom designed trays for the inside of the Losmandy tripod, it's not hard to do. But in these sorts of situations a tool bag provides plenty of spaces to store stuff. For example, on my ATS pier. I find that the tool apron around the tripod or pier is actually better than a tray. Things fall off trays (I do use the tray on the Berlebach) and it's not a good place for eyepieces because they will dew and chill down leading to eyepiece fogging.

regards Greg N




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gnowellsct
Postmaster


Reged: 06/24/09
Posts: 5275
Re: Losmandy G11 with Gemini new [Re: blueman]
      #3282667 - 08/19/09 08:18 PM

Quote:

Of course the mount pictured in your post is very nice too!
Blueman




Thank you. It is a 900QMD, not a go-to unit. So I saved some bucks but it is still pricey relative to a lot of what is out there. I found that with the refractor on the c14 I needed more stability than in the years when I just used the C14 on the G11.

I am very fortunate to have two completely independent telescope rigs of very good quality. They ain't cheap if you add 'em up. And yet there is a method to the madness: a doublet ED instead of a triplet APO, a QMD900 instead of the go-to version; a push-to G11 instead of go-to, etc. And I use an FS128 on the G11 instead of a triplet like TEC 140.

So this very high end stuff is, somehow, second rate economy models compared to the top tier options out there!

regards
Greg N

--------------------
Scope will get you through times of no money better than money will get you through times of no scope.

’FRACTOR WARS

hp mini
color test!
C14 movie
C14 article
C14_EdgeHD
ExtremeAstronomy
Losmandy


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Joselo
professor emeritus


Reged: 02/26/08
Posts: 541
Loc: Texas
Re: Losmandy G11 with Gemini new [Re: gnowellsct]
      #3289245 - 08/23/09 01:07 PM

Buy the G11, DO IT. I had an Atlas for a year, and this mount has it's limits. A G11 will satisfy you for a long time, plus, it is very easy to service, and upgrade.

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bseltzer
professor emeritus


Reged: 10/28/07
Posts: 517
Loc: East S.F.Bay, CA
Re: Losmandy G11 with Gemini new [Re: Joselo]
      #3289270 - 08/23/09 01:24 PM

Like Joselo, I had an Atlas for a while before got a G-11. The Atlas was a serviceable mount, but it quickly became a "hobby" in and of itself. Three months of tinkering, testing, and tinkering some more got it to an acceptable level of PE performance, but it still had its limits.

The G-11 beat the PE of my extensively tuned/modified Atlas by a very significant margin out of the box, and once I got past the Gemini learning curve, the mount has all but "disappeared" in terms of the attention I need to pay to it in any given session.

Like Joselo said, "Do it!"

-Bert

--------------------
8" F4 Newtonian (Royce Mirror)
AT8RC
SV 130 EDT APO
SV 80/9D (Erstwhile guide scope)
A-P Mach1GTO
SBIG ST-2000 XM
A whole bunch of other stuff...


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Joselo
professor emeritus


Reged: 02/26/08
Posts: 541
Loc: Texas
Re: Losmandy G11 with Gemini new [Re: bseltzer]
      #3289298 - 08/23/09 01:39 PM

Ohhh. yess.... The Gemini learning curve.....
It is steep, but once you learn it, you can align, slew, park with you eyes closed.

It is very intuitive....

--------------------
APM 115 design by TMB
SV80S, and bunch of accessories


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gnowellsct
Postmaster


Reged: 06/24/09
Posts: 5275
Re: Losmandy G11 with Gemini new [Re: bseltzer]
      #3289532 - 08/23/09 04:07 PM

Quote:

Like Joselo, I had an Atlas for a while before got a G-11. The Atlas was a serviceable mount, but it quickly became a "hobby" in and of itself. Three months of tinkering, testing, and tinkering some more got it to an acceptable level of PE performance, but it still had its limits.

The G-11 beat the PE of my extensively tuned/modified Atlas by a very significant margin out of the box, and once I got past the Gemini learning curve, the mount has all but "disappeared" in terms of the attention I need to pay to it in any given session.

Like Joselo said, "Do it!"

-Bert




What was the PE out of the box of your Atlas and G11, and what were they after you tweaked? Did you try the Ovision yet?

thanks Greg N

--------------------
Scope will get you through times of no money better than money will get you through times of no scope.

’FRACTOR WARS

hp mini
color test!
C14 movie
C14 article
C14_EdgeHD
ExtremeAstronomy
Losmandy


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bseltzer
professor emeritus


Reged: 10/28/07
Posts: 517
Loc: East S.F.Bay, CA
Re: Losmandy G11 with Gemini new [Re: gnowellsct]
      #3290031 - 08/23/09 08:54 PM

Quote:


What was the PE out of the box of your Atlas and G11, and what were they after you tweaked? Did you try the Ovision yet?
thanks Greg N




After replacing ALL the RA and DEC bearings in the Atlas with SKF or Timpken high quality equivalents and the worm bearings with ABEC-5 ceramic equivalents and going to an Aeroquest worm and carefully optimizing the worm mesh, I got its PE down from 20" peak to peak to about 12" P-P.

By way of comparison, the G-11 out of the box produced a peak to peak PE of 7" (RMS ~0.97) measured with PemPRO. These measurements were repeatable over 3 separate sessions. I do have a bit of the dreaded 76 second "bump", but luckily its magnitude is low enough that it guides out pretty easily.

Since Ovision doesn't guarantee anything better than 5" P-P, I haven't felt the need to go that route yet. Right now, I running an image scale of 1.5" - 2.0" depending on which scope I'm using. I do have plans for a KAF-8300 based camera and a longer focal length scope, which would reduce the image scale considerably. If/When that happens, I may well consider the Ovision worm.

Meantime, I'm please with the results the stock mount is giving as seen here

NGC-7000

and here

M-27

Regards,
Bert

--------------------
8" F4 Newtonian (Royce Mirror)
AT8RC
SV 130 EDT APO
SV 80/9D (Erstwhile guide scope)
A-P Mach1GTO
SBIG ST-2000 XM
A whole bunch of other stuff...


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gnowellsct
Postmaster


Reged: 06/24/09
Posts: 5275
Re: Losmandy G11 with Gemini new [Re: bseltzer]
      #3290236 - 08/23/09 10:49 PM

Quote:

Quote:


What was the PE out of the box of your Atlas and G11, and what were they after you tweaked? Did you try the Ovision yet?
thanks Greg N




After replacing ALL the RA and DEC bearings in the Atlas with SKF or Timpken high quality equivalents and the worm bearings with ABEC-5 ceramic equivalents and going to an Aeroquest worm and carefully optimizing the worm mesh, I got its PE down from 20" peak to peak to about 12" P-P.

By way of comparison, the G-11 out of the box produced a peak to peak PE of 7" (RMS ~0.97) measured with PemPRO. These measurements were repeatable over 3 separate sessions. I do have a bit of the dreaded 76 second "bump", but luckily its magnitude is low enough that it guides out pretty easily.

Since Ovision doesn't guarantee anything better than 5" P-P, I haven't felt the need to go that route yet. Right now, I running an image scale of 1.5" - 2.0" depending on which scope I'm using. I do have plans for a KAF-8300 based camera and a longer focal length scope, which would reduce the image scale considerably. If/When that happens, I may well consider the Ovision worm.

Meantime, I'm please with the results the stock mount is giving as seen here

NGC-7000

and here

M-27

Regards,
Bert




Well if you want to keep up on Ovision results I recommend joining the Yahoo Losmandy group. Very hot topic there, much development, including pioneering work done by Floyd Blue who is known here.

Ovision considerably reduces peak to peak error and makes the worm adjustment a "reliable" procedure rather than a difficult game of cat and mouse. It also eliminates the a 76 second repeating error that happens, not always, but often and even usually, as a result of the worm bearings. The system becomes totally smooth and easy to guide.

regards
Greg N

--------------------
Scope will get you through times of no money better than money will get you through times of no scope.

’FRACTOR WARS

hp mini
color test!
C14 movie
C14 article
C14_EdgeHD
ExtremeAstronomy
Losmandy


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bseltzer
professor emeritus


Reged: 10/28/07
Posts: 517
Loc: East S.F.Bay, CA
Re: Losmandy G11 with Gemini [Re: gnowellsct]
      #3290991 - 08/24/09 11:08 AM

Quote:


Well if you want to keep up on Ovision results I recommend joining the Yahoo Losmandy group. Very hot topic there, much development, including pioneering work done by Floyd Blue who is known here.

Ovision considerably reduces peak to peak error and makes the worm adjustment a "reliable" procedure rather than a difficult game of cat and mouse. It also eliminates the a 76 second repeating error that happens, not always, but often and even usually, as a result of the worm bearings. The system becomes totally smooth and easy to guide.

regards
Greg N




Greg,

One of the first things I did after getting my G-11 was join the Y! Loasmandy group. It was also one of the best things I did, and I've followed Floyd's work on the mount closely. Not only has he done some great stuff, but he's tirelessly shared his experiences with others.

I'm sure the Ovision worm is a fine product, but the thing is, I'm still very much a beginner in AP. I've got a long way to go before my skills would justify investing in it, especially since I'm getting acceptable performance from the G-11 in it's box stock form.

And that's why, I'd still encourage the OP to take the plunge and get a G-11....

Regards
Bert

--------------------
8" F4 Newtonian (Royce Mirror)
AT8RC
SV 130 EDT APO
SV 80/9D (Erstwhile guide scope)
A-P Mach1GTO
SBIG ST-2000 XM
A whole bunch of other stuff...


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