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Hello, posting about this this telescope in the AstroBin equipment database: Astro-Physics StarFire EDT 155mm f/7 (2.7") It's been brought to my attention that there might be a naming issue with this telescope, and the "EDT" part of the name should be "EDFS". Can any owner here please confirm whether the specimen they own is labeled EDT or EDFS, and if this is safe to rename? I'm looking at 3 possible scenarios here, in order to clean up and improve this entry:
I'm mentioning the owners here just to improve the chances of this reaching you: @Manuel Jimenez @John Jennings @Ross Salinger @Gilles Chapdelaine Thank you for your cooperation! Salvatore |
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The Astophysics 155mm f/7 Starfire with 2.7" focuser is called "155mm f7 Starfire EDFS". https://astro-physics.info/index.htm?products/telescopes/155edfs/155edfs The EDF version is with a larger 4" focuser: https://www.astro-physics.info/index.htm?products/telescopes/155edf/155edf AP has a page listing the history of every scope they've made. There is no EDT version of the 155mm: https://www.astro-physics.info  |
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| I have the EDFS and the flattener. They sill make them apparently as I got mine about 5 years ago when I bought my EDFS third hand. |
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Actually, if you read the history page of the EDFS, it becomes clear where the confusion with "EDT" comes from. "In the test report entitled "Astro-Physics Refractors Big & Small", in the September 1993 issue of Astronomy, Alan Dyer described the performance of the 155mm f7 EDF during his winter observing sessions. Please note that the article referred to this instrument as an EDT."Optical performance of the 155EDT was impressive. It produced nary a trace of false color even on Venus. Equally impressive, this scope provided superb images as soon as it was set outside. Even in sub-freezing temperatures, image quality, though not perfect at first, was surprisingly sharp from the start. In cold weather, after a modest settle-down time of 30 minutes, in-focus star images were textbook Airy disks with a well-defined first diffraction ring and a trace of a second outer ring. There was no sign of spherical aberration, lens figure changes, heat plumes, or distorted Airy disks due to tube turbulance." So Astro-Physics never called it an EDT, it was a mistake in Astronomy magazine. The only versions are the EDF (4" focuser) and EDFS (2.7" focuser) so the correct nomenclature is either EDF or EDFS, depending on focuser used. |
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| All these scopes can be unique. Most of them are truly different objective designs with specific types of corrections and glasses use to manufacturer. That's why accessories like reducers and flatteners are are made specific to each scope model by Roland C. Only a few are derivatives of another scope. Th 155EDF and 155EDFS are the same oil filled objective but different tube and focuser systems. It's important to AP scope owners to be specific about their scope. Due to the limited manufacturing numbers of scopes, some are a lot more rare than others. |
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Interesting that the AP scope listing failed to list my scope. The 130mm f6.3 Starlight GTX with a 3.5" focuser. It has a very different tube design form the 1st 130mm Gran Turismo version. Lynn K. |
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The listing has probably not been updated by AP. I have not checked. I own a 130GT as well. Not only is the tube and focuser different, the GTX is an oil filled objective. The 130 GT is an air spaced objective. That's why Roland makes specific flatteners for those scopes. The design is slightly different. These differences are significant, but performance for both is similar and great as Roland would say. I'm guessing it has to do more with what glass was available when Roland made the new GTX runs. As a long time AP owner, that's usually what's been the difference between a lot of outwardly similar scopes. John Jennings |
