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Equipment Discussions >> Refractors

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Astrojensen
Post Laureate
*****

Reged: 10/05/08

Loc: Bornholm, Denmark
A question about AP objectives new
      #6074411 - 09/11/13 05:23 AM

A Starfire 130 EDT has come up for sale here in Denmark. And no, before you guys go on cheering me up to buy it, I can't afford it. However, a discussion has broken out on the forum where it has been offered, about whether this particular scope was air-spaced or oil-spaced. I claim that all EDT's were oil spaced (apart from the 155mm f/9 prototype) and that it's the EDF's that were air-spaced (because they were much faster f/ratio). Others claim this one is air-spaced. The lens cell clearly say: 130mm f/8 EDT. It's NOT the later 130mm f/8.35.

So, who is right? I'm fairly sure I'm correct here. Also, the fairly good pictures we've seen of the lens show no hint of spacers.

Links to solid documentation I can use to beat them with (or myself!!) would be much appreciated!


Clear skies!
Thomas, Denmark


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Jon Isaacs
Postmaster
*****

Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: A question about AP objectives new [Re: Astrojensen]
      #6074434 - 09/11/13 05:59 AM

This is a question that would be best answered by Roland himself, the A-P users group, Astromart or an Email...

Jon


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Paul G
Post Laureate
*****

Reged: 05/08/03

Loc: Freedonia
Re: A question about AP objectives new [Re: Astrojensen]
      #6074438 - 09/11/13 06:14 AM

I have a 130 f6 EDF and it is oil spaced, I believe the EDT's were as well, Can't find an appropriate post by Roland on the ap-ug since Yahoo changed the format.

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Fomalhaut
scholastic sledgehammer


Reged: 08/16/08

Loc: Switzerland
Re: A question about AP objectives new [Re: Astrojensen]
      #6074527 - 09/11/13 07:54 AM

In 1992, I went to Baader Planetarium in Mammendorf/Munich in order to buy a new AP-130 EDT. I was shown two scopes which I tested by means of the edge of a roof against the sunlight. These two scopes did not meet up to my criteria. At that time I owned a Vixen-Fluorite 102/900 the color-correction of which they couldn't meet. Mr.Baader told me this was due to a wrong batch of Schott-glass having been delivered to Mr.Christen and not knowingly been implemented at least in these two objectives.

Finally, Mr. Baader provided a beautiful and even air-spaced (!) AP-130 (identified by its spacers in the objective). This instrument indeed was in the same visual class as my Vixen mentioned above. After carefully scrutinizing, I wanted to buy that instrument right away but was told it had been made "on special order" for a special client. I was offered instead to wait for a new oil-spaced 130 but this time I refused and went Tak.

Hence, at least one of these air-spaced AP-130 triplets exists or existed.

Chris


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vahe
professor emeritus


Reged: 08/27/05

Loc: Houston, Texas
Re: A question about AP objectives new [Re: Astrojensen]
      #6074591 - 09/11/13 08:53 AM

130, 155 and 180 EDT’s were introduced in late 1992, with few exceptions they were all oil spaced.
I ordered my 155 F/9 EDT from the very first run, when the scope was ready and just before shipping I received a letter from Marj asking me how I wanted my EDT to be assembled, air spaced or oil spaced, she recommended going oil spaced for many reasons including much higher light transmission due to lack of internal reflections, a problem with all air spaced lenses.
Oil spaced was not very common at the time and some folks preferred air spaced just to be on the safe side, I went with oil spaced.

Vahe


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M13 Observer
scholastic sledgehammer


Reged: 12/09/06

Re: A question about AP objectives new [Re: Astrojensen]
      #6074922 - 09/11/13 11:41 AM

Quote:

A Starfire 130 EDT has come up for sale here in Denmark. And no, before you guys go on cheering me up to buy it, I can't afford it. However, a discussion has broken out on the forum where it has been offered, about whether this particular scope was air-spaced or oil-spaced. I claim that all EDT's were oil spaced (apart from the 155mm f/9 prototype) and that it's the EDF's that were air-spaced (because they were much faster f/ratio). Others claim this one is air-spaced. The lens cell clearly say: 130mm f/8 EDT. It's NOT the later 130mm f/8.35.

So, who is right? I'm fairly sure I'm correct here. Also, the fairly good pictures we've seen of the lens show no hint of spacers.

Links to solid documentation I can use to beat them with (or myself!!) would be much appreciated!


Clear skies!
Thomas, Denmark




All AP130EDF, sometimes erroneously called AP130EDFS OTAs and all AP130GT are oil spaced. The "S" letter stood for "small focuser" and there is only one size of focuser ever offered on the AP130 scope. As far as I know, all f8 and f8.35 AP130EDT OTAs are oil spaced as well. Why one was engraved f8 and the other f8.35 I have no idea since they are identical focal lengths (155mm f7 oil spaced objectives which failed testing likely due to edge defects machined down to 130mm). Just to denote the two different runs made I guess.


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sg6
professor emeritus


Reged: 02/14/10

Loc: Norfolk, UK.
Re: A question about AP objectives new [Re: Astrojensen]
      #6075100 - 09/11/13 01:28 PM

Thomas, oddly stumbled across this:

AP Lens

Doesn't say, or I cannot see, which are oil/air spaced, but a good read.


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RussD
member


Reged: 04/20/06

Loc: Minnesota
Re: A question about AP objectives new [Re: Astrojensen]
      #6075586 - 09/11/13 05:42 PM

Ask for a picture of the lens. On some of the early airspaced AP lenses, it looks like Roland used thin kapton tape like material as a spacer. It is orange in color. These short spacers were mounted radially between the lenses. The oil spaced lenses had the same orange tape wrapped around the edge of the lens stack making it difficult to see from the front. The air spaced lenses are obvious when looking down the front end because you can see all the spacers.

Russ


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Mike Clemens
Frozen to Eyepiece
*****

Reged: 11/26/05

Loc: Alaska, USA
Re: A question about AP objectives new [Re: RussD]
      #6075812 - 09/11/13 08:36 PM

yep here is the AP152/12 lens I had that was airspaced
http://www.pbase.com/mclemens1969/image/68838946


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Erik Bakker
Carpal Tunnel
*****

Reged: 08/10/06

Loc: The Netherlands, Europe
Re: A question about AP objectives new [Re: Astrojensen]
      #6076432 - 09/12/13 07:20 AM

The faster EDF' s from 1996 and younger are definitely all oil spaced.

The first fast 130's at f/6 were called officially EDFS as per Astro-Physics literature (as in short), as opposed to the EDF that was still f/8 (= "longish") at that time. Later on, the 130mm f/8 were no longer made due to the small demand for f/8 and high demand for f/6 lenses. With now only one 130mm in production (the f/6) there was no longer a need for 2 names.



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R Botero
Pooh-Bah


Reged: 01/02/09

Loc: Kent, England
Re: A question about AP objectives new [Re: Erik Bakker]
      #6076543 - 09/12/13 08:51 AM

Yes, my AP152EDF f/7.5 (only two made according to Roland) is oil spaced. Mike Sidonio down under has the other one and has taken some amazing pictures with it. I'm only visual.

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Paul G
Post Laureate
*****

Reged: 05/08/03

Loc: Freedonia
Re: A question about AP objectives new [Re: Erik Bakker]
      #6076665 - 09/12/13 10:06 AM

Quote:

The faster EDF' s from 1996 and younger are definitely all oil spaced.

The first fast 130's at f/6 were called officially EDFS as per Astro-Physics literature (as in short), as opposed to the EDF that was still f/8 (= "longish") at that time. Later on, the 130mm f/8 were no longer made due to the small demand for f/8 and high demand for f/6 lenses. With now only one 130mm in production (the f/6) there was no longer a need for 2 names.






According to Roland, the S stands for focuser type (2.7"):

Link


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: A question about AP objectives [Re: Erik Bakker]
      #6077785 - 09/12/13 09:36 PM

Except the 160EDF and my new 175EDF are air-spaced spherical triplets polished and coated on all six sides.

Quote:

The faster EDF' s from 1996 and younger are definitely all oil spaced.

The first fast 130's at f/6 were called officially EDFS as per Astro-Physics literature (as in short), as opposed to the EDF that was still f/8 (= "longish") at that time. Later on, the 130mm f/8 were no longer made due to the small demand for f/8 and high demand for f/6 lenses. With now only one 130mm in production (the f/6) there was no longer a need for 2 names.






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RussD
member


Reged: 04/20/06

Loc: Minnesota
Re: A question about AP objectives new [Re: Peter Natscher]
      #6084402 - 09/16/13 05:44 PM

I am pretty sure there are some air-spaced 178 f9 starfires out there. The AP literature from the time listed it as an option along with options for color correction...better corrected for visual or at the time photography. One of the 178s that came up on Amart recently appeared to be air-spaced based on the images of the lenses.

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Jeff B
Carpal Tunnel
*****

Reged: 12/30/06

Re: A question about AP objectives new [Re: RussD]
      #6084441 - 09/16/13 06:05 PM

Quote:

I am pretty sure there are some air-spaced 178 f9 starfires out there. The AP literature from the time listed it as an option along with options for color correction...better corrected for visual or at the time photography. One of the 178s that came up on Amart recently appeared to be air-spaced based on the images of the lenses.




Yes indeed, a few were air-spaced as were some of the 6" F9's, of which I had two samples at one time. Thermally slower to respond than the oil spaced jobbies but mighty fine lenses. I wish I had one of them back.

Jeff


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Joe Aguiar
Carpal Tunnel
*****

Reged: 02/10/07

Loc: none of your buss
Re: A question about AP objectives new [Re: Jeff B]
      #6085463 - 09/17/13 08:32 AM

This is a question that would be best answered by Roland himself, the A-P users group, Astromart or an Email...

Why should the poster go to astomart whats so special about that site that can answer this question and not the thousands of users here??
joe

Edited by Scott in NC (09/17/13 08:12 PM)


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Paul G
Post Laureate
*****

Reged: 05/08/03

Loc: Freedonia
Re: A question about AP objectives new [Re: Joe Aguiar]
      #6085747 - 09/17/13 11:15 AM

Well, Roland is a regular poster on Amart. Not going to get that here.

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Joe Aguiar
Carpal Tunnel
*****

Reged: 02/10/07

Loc: none of your buss
Re: A question about AP objectives new [Re: Paul G]
      #6085810 - 09/17/13 11:52 AM

really why would he be a regular poster on there but not here?
joe


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Paul G
Post Laureate
*****

Reged: 05/08/03

Loc: Freedonia
Re: A question about AP objectives new [Re: Joe Aguiar]
      #6085877 - 09/17/13 12:29 PM

You would need to ask him that question.

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Joe Aguiar
Carpal Tunnel
*****

Reged: 02/10/07

Loc: none of your buss
Re: A question about AP objectives new [Re: Paul G]
      #6085885 - 09/17/13 12:31 PM

well i cant iam not a member of that site but instead of me taking over this thread i may post that question but thx for that info paul

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