Eyepieces provided with the Celestron Astromaster 130EQ

[adarshajoisa]

I have recently bought a Celestron Astromaster 130 EQ. There were 2 EPs supplied with the telescope - a 20 mm erecting EP and a 10mm. I read through the manual, the specifications on the celestron website, etc, and I couldn't find out what type the EPs were. Even on the EPs, there's no mention of whether it's a kellner or a plossl, etc. It just states 10mm/20mm on the respective EP. 

Does anyone know what type of EPs these are? The number of elements, type of EP, FOV, etc would be appreciated!

[Dave In Vermont]

I just checked the Celestron website, and it would only show me a picture (below). I will hazard a guess that they are Kellner. Celestron usually promotes it's house-brand Plossl's when they supply those.

I'd use them until I couldn't stand it anymore, and then get something better. The Kellner's should at least give you some ideas of what would be better. Such as a wider field-of-view if you find you love nebulas, or sharper optics if planets are your preference. So forth.

A 20mm will give you 32.5X, and a 10mm = 65X.

Clear & Dark Skies,

Dave

[John]

I think Dave is right about the 10mm. It will likely be a Kellner or similar 3 element / 2 group eyepiece with an apparent field of 45 or 50 degrees. The 20mm erecting eyepiece will have some more glass of one sort or another to turn the image the right way up but we don't need that for astronomy and the extra glass may well add optical issues such as light scatter and ghosting.

In due course you and the scope might be better served by some plossl eyepieces or better, depending what is available to you where you are.

[Dave In Vermont]

Yes, that 20mm is a bit of a mystery. I couldn't figure why that would come with a newtonian reflector. I'd still wager it is Kellner, with some other odd piece added to qualify it as an 'erecting eyepiece.' Plossl's would be a step up. But I'd hold off until you find what objects up there interest you the most.

John: I love your quote from Fred Hoyle! He was the last hold-out on the 'static-universe' theory.

Clear Skies,

Dave

[adarshajoisa]

Yes, that 20mm has some extra bit of glass. It looks like a prism when viewed from underneath, but I'm not sure. The 10mm gives much better optical quality compared to the 20mm, though. As to why the erecting eyepiece was provided, Celestron advertises it as a telescope ideal for both terrestrial and celestial viewing, though I have no idea how one's supposed to do terrestrial observing comfortably on a EQ mount! 

Thanks, John and Dave for your inputs! 

[goose35]

The 20 mm uses a mirror to correct the image. Its supplied because the scope is marketed for celestial and terestrial use so supplies an ep for each

I have just had a vixen npl 25mm ep to replace the 20. Hardly had the 10mm out since i just use the 25 and a barlow

[Alfian]

Its a bit of a shame that Celestron have tried to cover terrestrial and astro uses and have not succeeded very well in either. Both are usable  but the 10mm has quite tight eye relief. The good news is that if you  upgrade to an even modest quality plossl you should notice quite a difference.