Firstly thanks to all who have posted help here, its apprecated.
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Originally Posted by ausastronomer
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Yes that is my scope although it cost $200 less than the marked down price in that link
Quote:
Originally Posted by ausastronomer
This means you need to stick with 1.25" eyepieces. This is a bit limiting by todays standards but not the end of the world. 25 years ago 1.25" focusers were standard fare on both large and small scopes, but not today. It's a bit like saying an EH Holden (1964) was a great car. Well in 1964 it was, by todays standards and compared to modern cars its not something I would get around in. Alex has already given you sound advice regarding the AFOV. With a 1.25" focuser you are limited to an eyepiece having a product of its focal length and AFOV limited to about 1650. What I mean by this is you multiply the eyepiece focal length in mm by its AFOV in degrees and the product needs to be under 1650, otherwise you do not gain any True Field of View. For instance with a 24mm Televue Panoptic having an AFOV of 68 degrees and a focal length of 24mm its product is 1632, which as Alex correctly pointed out, is about maximum for a 1.25" eyepiece. If you went with a Plossl type eyepiece having a 52 deg AFOV you can go to a maximum focal length of about 32mm. On that basis I would be looking at some second hand eyepieces like the Vixen 22mm LVW, Televue 24mm Panoptic or a 30mm plossl type like the Orion Ultrascopic or Celestron Ultima.
Cheers,
John B
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Ok I hope some of this is sinking in. Crunching the eyepiece numbers and my scope specs into the calculator linked above gives an arc minute value, is a lower or higher value giving a wider view? A couple I crunched..
Vixen 30mm/50 AFOV = 75 arcmin
vixen 40mm/40 afov = 80 arcmin
vixen LVW 22mm/65 afov = 72.2 arcmin
william optics 16mm/82 afov = 65.6 arcmin
Or am I getting lost the more I dig deeper into all this? Haha.
Indio