Thought my EP was bad

[kalasinman]

Mostly imaging, but bought a 27mm BST when I bought the scope. After trying it, I was very saddened by the rainbows around stars and lack of focus.

Shelved the EP for a few months, then I thought I'd try a new approach. I'm very nearsighted, but decided to try without my glasses and all the problems went away. Stars look lovely and real colors in the MW so good!

[alan potts]

I didn't know they did a 27mm.

Alan

[kalasinman]

http://agenaastro.com/bst-27mm-flat-field-eyepiece.html

[kalasinman]

Hi Alan, when I ordered my kit I guessed that having an EP with similar FOV to my imaging rig would be nice. Now that I've seen some good views, I may go for one with higher power.

[alan potts]

Now that is a different type of BST to the ones so often spoken about on here, so I have leant something today already. My mistake.

Alan.

[ronin]

If you go for a higher power one I would suggest that you look at the Starguider's or as Agena advertise "Dual ED", from Agena if that is the best source for you. They are a BST but I think AgenaAstro may have their name branded on them so they are sold as Agena Starguiders not BST Starguiders. But a BST still.

Easily missed on the Agena site as the "BST Starguider" does not appear in there eyepiece list as either a BST or under the name Starguider, they are listed as "Agena Dual ED".

It partially sounds as if to operate to produce a flat field the one(s) you have might be losing performance elsewhere. Understandable I suppose. I think they are aimed at fast scopes that do not produce a very flat prime image field.

I suspect you will find the "Starguider" under whatever name a better eyepiece then the Flat Field.

[kalasinman]

I'm not primarily an observer, so I suppose my expectations were met very easily by this one.  I have an f/5 Newtonian. It gives me what I bought it for. There wasn't a skyguider in this FL. If I go for another, I'll get a skyguider. I must admit that on a list of my priorities, a Baader MK III, a Hutech Idas d-1 come first.

[xtreemchaos]

hi mate i had the same problem i dont use my glasses at all when looking through EPS, But i need them when using my camera or pc.

[Andy Mitchell]

I sometimes ponder if they could make glasses using a cemented doublet to reduce the CA. Strong lenses add a lot of CA (off axis), even more so when you get high index lenses so they are thinner and lighter. Not noticed the effect down my eyepieces, but I dont do much visual on account of light pollution.