Quote:
Originally Posted by Indio
Firstly thanks to all who have posted help here, its apprecated.
Yes that is my scope although it cost $200 less than the marked down price in that link 
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 |
Yes that's correct. The only thing I would suggest is that you avoid any eyepiece with a focal length longer than 35mm. The 40mm 40 deg AFOV eyepiece whilst it maximises TFOV is like looking through a drinking straw because of the narrow AFOV.
An excellent choice for your scope would be a 35mm Orion Ultrascopic. These have a 49 deg AFOV and in your telescope would give a TFOV of 85.8 arcmin which maximises TFOV without being too restrictive in AFOV. Further it gives an exit pupil in your scope of about 4.3mm. Whilst a 2mm exit pupil is considered the optimum for most general purpose observing a ~4mm exit pupil is considered to be about ideal for popping dim threshold targets due to a an ideal compromise between image brightness and contrast. These eyepieces are no longer made and haven't been made for over 5 years. However, they are considered one of the benchmark eyepieces in regards to ~50 deg AFOV eyepieces. In your F8 scope they will give tack sharp images right across the entire TFOV. The sharpness, contrast and light throughput is excellent, as is comfort, eye relief and general ergonomics. They are a very high quality Japanese made eyepiece. These eyepieces were sold for a long period and come up on the 2nd hand marked reasonably frequently in the USA less frequently in Australia but they do come up in Icetrade classifieds.
I also suggest you look here under "eyepieces"
The almost exact same eyepiece to the Orion Ultrascopic (all made by the same Japanese Optical factory to almost identical specifications) was also sold as:-
Celestron Ultima
Parks Gold Series
Antares Elite
If you can find any of those other eyepieces in 35mm (30mm would also be good) you can buy them with confidence as a high quality Japanese made eyepiece that will work exceptionally well in your scope. You should get one 2nd hand for <$100. The last one I saw sold on Cloudy Nights classified for $US60.
Cheers,
John B