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watcher
Carpal Tunnel
*****

Reged: 11/21/07

Loc: St. Louis, MO
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: HCR32]
      #5186591 - 04/23/12 03:17 PM

Quote:

MY vote goes to what ever is going to be visually a better performer!!!!




A longer scope will almost always be the better performer, but I do believe that an F/7 140mm FPL-53 doublet designed by Markus Ludes will be plenty good enough for pretty much the entire group of people that these threads about big semi-Apos have attracted. It's pretty much a different audience than the "performance at any cost" group that buy the APM LZOS triplets. This is a bold new frontier!


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WilRobinson
sage
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Reged: 02/04/08

Loc: Near the cloud machine
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: watcher]
      #5186612 - 04/23/12 03:35 PM

I've been asking for a 6in. doublet for the last 3 years, 140mm is to close to all the 127-130mm scopes out there right now. Just my opinion.

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Sol Robbins
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Reged: 12/01/03

Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: Cyclop_si]
      #5186631 - 04/23/12 03:48 PM

I think the views between a 150mm and a 140mm to be very, very close.

I would be interested in seeing your proposed 140mm lens in a cell that can simply be put on a Celestron/Skywatcher tube assembly for owners of existing 150mm f/8 achromat refractors.

Best,


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hfjacinto
I think he's got it!
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Reged: 01/12/09

Loc: Land of clouds and LP
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5186657 - 04/23/12 04:03 PM

Quote:

what do you mean with EON like ? EON use FPL 53 as doublet, we design with chinese FK61 = FPL 51 as doublet , means of course less colorfree




Ok, I like the 140MM EON like scope


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watcher
Carpal Tunnel
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Reged: 11/21/07

Loc: St. Louis, MO
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: WilRobinson]
      #5186677 - 04/23/12 04:16 PM

Quote:

I've been asking for a 6in. doublet for the last 3 years, 140mm is to close to all the 127-130mm scopes out there right now. Just my opinion.




If there were a 130mm doublet on the market, I probably would have already settled for that. I understand the desire for a 6" doublet. I truly believe there is a need to max out the CG-5 though. Even an Atlas class mount is double the cost of a CG-5. I think even though Celestron puts their 6" F/8 on the CG-5, many have had to upgrade to be happy. And Atlas class mounts aren't as easy to tote around. That's why I say start with the 140 F/7 and the replacement lens for Syntas. The 140 cause anybody can use it, and the replacements because most people with a C6-R already have the mount they need for a 6" doublet. I just think if it's done in that order, everyone will be happy sooner.


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APM M.Ludes
Vendor (APM Telescopes)
*****

Reged: 05/01/03

Loc: Germany
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: watcher]
      #5186746 - 04/23/12 05:04 PM

1, before we start we will publish spot diagrams, longitudinal aberration and strehl curve.

2, personaly I ote for the 140/7 FPL 53 in any case and the 152/8 too, becasue there is a big market for the 152 for those who want to replace here achromat and by a simple tube adapter this is a very easy tak for anybody.

3, we will match both to our Riccardi Apo Reducer/Flattener 0.75 x for the imagers of you, too


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Radim
sage


Reged: 11/06/05

Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5186815 - 04/23/12 05:58 PM

Quote:

2, personaly I ote for the 140/7 FPL 53 in any case and the 152/8 too, becasue there is a big market for the 152 for those who want to replace here achromat and by a simple tube adapter this is a very easy tak for anybody.





Markus, but 152 F/8 doublet ...dont get me wrong - you are already offering 6inch doublet on your website as LZOS 2 elements NOW so why to offer another doublet with similar diameter?


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Bill Barlow
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Reged: 12/03/07

Loc: Overland Park KS
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5186818 - 04/23/12 06:03 PM

Hi Markus,

Would there be a big difference in the weight between the 140 f/7 and 140 f/8 OTA's? How much might the 152 f/8 weigh?

Bill


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WarrenS
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Reged: 03/04/08

Loc: Orange County New York
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5186996 - 04/23/12 07:56 PM

Hi Markus, welcome back and thanks for the good news! Question however, your projected 6" price, is that for a complete OTA or just the objective in a cell that's been discussed?

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saemark30
Pooh-Bah


Reged: 02/21/12

Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: WarrenS]
      #5187495 - 04/24/12 03:31 AM

I would be interested in both.
What glass would mate with the 140mm FPL 53?
Would this be better than the Synta 120ED doublet?
Or would this be more like Takahashi FS152?


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tomharri
sage
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Reged: 09/19/08

Loc: USA
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: saemark30]
      #5187687 - 04/24/12 09:14 AM

Dear Markus of APM

I'm old, weak and broken (you will be too). I can't handle a 6" meade f/9 ed at 30+ lbs (15 kilos).
Make the 140mm f/8 lightweight. Use thin wall tubing-no tube threads. Bolt your collimatable flange on with 3 screws+locknuts. No baffles. Use removable flocking inside. No finder shoes, we will drill, install our own. Extra threaded holes in focuser for shoe. Lightweight, long travel focuser to satisfy everyone for 1.25" or 2" diagonals, binocs etc. Optional $$$ focusers. Fixed-removable dewshield like meade's. For transport dewshield should mount on focuser flange to protect focuser from damage. No case or optional. I'm gonna use the scope not store it. Thin rolled metal rings like Istar uses.
GOAL 12 Kilos=26.4 lbs. MAXIMUM.
Send email when ready, thank you.

Edited by tomharri (04/24/12 09:30 AM)


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skyjim
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Reged: 01/13/07

Loc: Carmel, NY
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5187851 - 04/24/12 10:48 AM

Hi Markus, thats great news and I think you got the ticket, build a 140/F7 scope which there is already a market for like the folks out here that want a TEC140 but just cant breakl that over $5k price range to afford it, hey in old retail term thats a shoe-in at around $3500 usd. Now there are a vast amount of Synta C6R/CR150/skywatcher 150 F8 scope out there and I would bet my bottom dollar that more than 25% of maybe 1000 of these scope out there would upgrade there lens in a hartbeat and that is being very conservative IMO. You make the lens and a simple adapter or have the lens cell designe with the idea of mounting directly to the flange on these scopes providing they have a collimatable cell and there done.
Markus I want to thank you for reading my post in the refractor forum and you stepted up to the plate with the bat and is taking a big swing instead of being like some out there which said it cant be done, instead you had taken some very excellent ideas that were generated in that post and are going to run with it, I like that . I hope we can talk at Neaf this weekend if you are there.
Jim


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APM M.Ludes
Vendor (APM Telescopes)
*****

Reged: 05/01/03

Loc: Germany
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: skyjim]
      #5187947 - 04/24/12 11:54 AM

many questions > some answeres

1, the show prices is for OTA with focuser , rings, finderbracket, case , lenses in cell we did not asked yet , but will be less of course

2, why make a cheap 6" doublet , while we coming with a expensive model right now ?
- the expensive model has better colorcorrection and better optical quality attest by a interferometrical testreport
- the expensive model ( APM/LZOS) use custommade tubes where we can fullfill any of your wish regards color, backfocuse, focuser etc.

- weight : the 6" doublet OTA should be around 20 to 22 pound, the 140 around 15 pound

we design the optics, the cell and the tubes and then subcontract everything to be made to our designs

see you this weekend at NEAF ...will have again german gummibears with me :-)


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Vondragonnoggin
Post Laureate
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Reged: 02/21/10

Loc: Southern CA, USA
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5188148 - 04/24/12 01:59 PM

140mm F/7 at 15lbs sounds really really good.

I particularly like that you are going to make it compatible with the reducer.

I'm interested again despite not being a true 150mm.

Sounds like it will be very competitive.


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BillP
Postmaster
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Reged: 11/26/06

Loc: Vienna, VA
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5189890 - 04/25/12 01:44 PM

Quote:

A 140 mm F/7 or F/8 FPL53 doublet Apo optical tube can be done incl. 2.5" focuser, set of rings, finder shoe, case for around $ 3,500 retail...if we order minimum 300 pc.

I have a personal feeling the 140 mm should be the way to go and at this price point, I believe we can sell more then 300 pc





A little while ago I was considering an FS152 that was coming available. However, with this size-class scope I would also have to acquire a suitable mount as well. So resulting cost for OTA and mount would have been $7,000 or so!

Now with a proposed 140mm that can be kept to around 15 pounds, I would need no second mount as my existing mount can handle. So $3500 USD for the OTA is a real deal !! This sounds like a very doable proposition for me...I can swing that much cash but not what I would need to raise for a 6" that requires the purchase (for me) of an additional mount.

Personally, having done some extensive testing comparing a 140 vs a 152 for DSO, I found the difference of course seeable but not of enough consequence to matter much. Pragmatically, the 140mm concept sounds like a big winner and would be nice to have an alternative out there to TEC for some more competition (plus I would prefer air spaced).

140mm f/7 or f/8


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5190087 - 04/25/12 03:24 PM

Markus, this is very impressive. Neil English and I have discussed a "volkscope" concept (yeah, I know it was used on Newts in the 70s - so sue me) along these lines. Large FK-61 doublets with "good enough" figure and decent mechanical construction for a low price. I applaud your entrepreneurial effort and wish you great success!

- Jim


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dscarpa
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Reged: 03/15/08

Loc: San Diego Ca.
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5190144 - 04/25/12 03:55 PM

At that weight even after adding rings, finders and such I could use the 140 on my Giro with one counterweight. That would make one killer grab and go! David

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Jan Owen
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Reged: 02/12/06

Loc: Sun City West, Arizona
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: APM M.Ludes]
      #5190827 - 04/25/12 11:20 PM

I was quite interested in this project right up until it took a turn toward a 140 mm aperture.

I am interested in a 6" aperture ED scope with a focal ratio around f/9, to allow a little extra focal length for better correction...

I am not interested in losing virtually half an inch of aperture to settle on a 140. If I'd wanted a 140, I'd already have bought a TEC 140...

So if this continues to drift off course from it's original direction, toward a 140 instead, you can count me out.


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watcher
Carpal Tunnel
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Reged: 11/21/07

Loc: St. Louis, MO
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: Jan Owen]
      #5190843 - 04/25/12 11:31 PM

Quote:

I was quite interested in this project right up until it took a turn toward a 140 mm aperture.

I am interested in a 6" aperture ED scope with a focal ratio around f/9, to allow a little extra focal length for better correction...

I am not interested in losing virtually half an inch of aperture to settle on a 140. If I'd wanted a 140, I'd already have bought a TEC 140...

So if this continues to drift off course from it's original direction, toward a 140 instead, you can count me out.




Jan. Are you actually looking to snatch defeat from the jaws of victory? WE ARE GETTING BOTH! It may be F/8 because of the thousands of potential C6R upgrades, but geez if you need a CUSTOM built scope I don't think ya got a right to gripe.


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: New 6" F/8 ED Doublets from APM Telescopes new [Re: Jan Owen]
      #5190874 - 04/25/12 11:48 PM

I dunno, Jan. The TEC 140 is a $5600 front heavy triplet. Sure, it's oil spaced and cools quickly - for a triplet, but not as quickly as a 140mm doublet, which would also be much easier to balance and to mount and much cheaper. I think the 140 doublet conceptually is a lot like the Eon 120, only on 'roids. Markus should sell a bunch of them IMO.

Regards,

Jim


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