25 September 2005

I finally completed Some Assembly Required today. I went to Adorama and bought an eyepiece so I can finally use the scope.

I had been looking for a Plossl design eyepiece in the 18-22mm range on Astromart but the only thing that is showing up there is TeleVue Plossls that are going for around $75. A new TeleVue costs $95. So I started looking at what Adorama had to offer in the lower priced eyepieces.

I was wanting something with long eye relief and a large exit pupil so it will be easy for the public to see through it since I do most of my observing in Central Park and people are always stopping by to take a look. I figured that combination would make it less likely that they would need to touch the scope and get fingerprints or mascara on the glass.

Of the eyepieces Adorama carries I had narrowed my decision down to a Celestron X-cel 18mm six element eyepiece and a Celestron Omni 20mm Plossl. The X-cel was around $55 and the Omni around $35. The salesman recommended going with the Omni since the public will be looking through it and it isn't a good idea to spend a lot of money on an eyepiece they will use.

The Plossl is a four element symmetrical design optical formula. Celestron multi-coats all glass to air surfaces and edge blackens the lens elements.

Here are the numbers when used in my scope:

Manufacturer:	Celestron
Model:	Omni
Focal Length:	20mm
Magnification:	21.6x
Exit Pupil:	5mm
Apparent FOV:	52mm
True FOV:	2.4mm 141.7 arcminutes
Transit Time:	9.6 minutes

I don't know how it will look on the stars or the Sun, but the cracks in the paint on the wall under my foyer light look great.

Now I just need some clear skies.