BGO

[Charon]

Hi

Can someone tell me what the BGO's FOV is please.

Cheers

[MjrTom]

40 degrees

[Charon]

Thanks Mark. Any idea about their eye relief?

[MjrTom]

approx 80% of the focal length of the eyepiece

i.e 5mm BGO has approx 4mm eye relief, the 12.5mm has approx 10mm eye relief.

[Stu]

That's why I've stayed away from the shorter focal lengths. Presumably they are manageable though, any comments positive or negative?

Cheers

Stu

[MjrTom]

Presumably they are manageable though, any comments positive or negative?

I have the 5mm, 7mm and 9mm.

The 7mm and 9mm are very easy to get on with if you do not wear glasses like me.

The 5mm has very tight eye relief and you need to push the eyepiece very close into the eye socket to see the whole 40 degree FOV but it is manageable.

Performance wise BGO's are sharper and more contrasty than my Naglers at a similar focal length.

[Stu]

Thanks Mark

So you've compared the 7mm bgo with the 7mm t4 and the bgo is sharper/contrastier? (I know there's no such word but I liked it :-) )

I like my 3-6 nag zoom but may pick up a 5mm and 7mm for planetary use. I never wear my glasses when observing so can cope with shorter eye relief

Stu

[MjrTom]

Yes I compared my BGOs to my T6 Naglers and my Nagler Zoom.

here is a quick first light report.

http://stargazerslounge.com/2016638-post58.html

Subsequent sessions have cemented these findings, I compared the 7mm BGO to the 7mm T6 since that first light report and the BGO are just that little bit better for planetary viewing.

[Charon]

Thanks again Mark. I have to decide either the 7 or the 9mm.

[Stu]

Thanks both, and sorry for any 'thread hijacking', guilty as charged and I humbly apologise :-)

Stu

[MjrTom]

Thanks again Mark. I have to decide either the 7 or the 9mm.

Hi ya

If its for your C8 SCT I would go for the 9mm which gives 225x where as the 7mm is 290x which will get used a lot less often IMO

[Stu]

I would certainly agree with that. I used to look for higher mags but x250 is about as good as it gets generally

Stu

[Charon]

No problem Stu you asked good questions. Cheers Mark.

[faulksy]

i would say the 9mm as well as it will get used a lot. a question to mark i did a comparison with the bst 8mm and the 9mm bgo and there wasnt much in it apart from eye relief was lovely in the bst. did the comparison on planets and dso,s bgo was very slightly brighter on dso,s but not much in it. have you tried the bst,s or anyone else? sorry to spam derek but you could gain from this as well

[John]

The difference between good and premium eyepieces is often barely noticeable under most conditions. Under really excellent conditions the premium units seem to pull ahead a little more and seem to reveal the most subtle details a little more readily.

[MjrTom]

As John said it's the law of deminishing returns.

The difference is slight but still noticeable.

[faulksy]

As John said it's the law of deminishing returns.

The difference is slight but still noticeable.

yes true. i surpose it depends what you want and if you have anything to compare against:)

[Charon]

I am getting a bit confused here but of the two makes- BGO and the BST which is the best? Sorry if it has been asked a million times before, if I don't ask I will never learn.

[John]

Depends what you mean by best - The Baader Genuine Orthoscopics will be capable of really sharp, contasty planetary and lunar images under good conditions - top drawer optical performance at the expense of eye relief and a narrow field of view (as have all orthoscopics). The BST Explorers are a good step up from the standard eyepieces supplied with scopes, have a wider field of view and comfortable eyerelief but won't quite rival the Baader GO's for ultimate planetary and lunar performance in my opinion.

[MjrTom]

John has hit the nail on the head

[johninderby]

I did a head to head between a Celestron 9mm X-Cel LX and a 9mm BGO recently. Result sold the BGO as there was so little difference in performance, and the LX had the 60 degree FOV and better eye relief.

John

[Charon]

Eye relief has to be an issue. So before buying a BGO or similar when I am back in the UK next month I will try to find a local group and see if I can try some out. Thanks again for your input guys.

[Ben Ritchie]

Very good idea to try out Orthoscopics before buying - personally, while I recognise their performance, I can't abide the (lack of) eye relief; for short periods it is ok, but for longer periods I much prefer plenty of eye relief, and don't mind sacrificing the ultimate few percent in on-axis performance to get it. So I pick a 5mm Radian over a 5mm Ortho any day.

Others aren't bothered at all by the short eye relief of high-powered orthoscopics (and Plossls). I'm not wrong, and neither are they, we just prefer different things. So the only way to figure out what works for you is to try as much as you can, and decide..

[MjrTom]

I am willing to live with the short eye relief for the ultimate performance the BGO provide however it is not to everyone's taste

Using the orthos to split tight doubles is one area they excel.

I was able to split alnitak and Rigel plus a few other tricky doubles in Orion a few nights ago and the BGO out performed the Naglers by a noticeable margin

[4lefts]

just to sling in my inexperienced 2p. i have a 5mm and 8mm bst, and 6mm volcano top ortho. i actually prefer the ortho to the 5mm bst - that ep doesn't seem all that crisp to me. my best views of jupiter so far have been with this ep. the eye relief is tight, but i find it ok. it's weird, and this may make no sense to experienced observers, but the eye relief i find less of a problem with the tiny eye lens - if it was a bigger lens with short eye relief, it bothers me more, because i end up getting eyegrease on it. this was how i felt about the tv 10.5mm smoothside plossl.

get a used ortho to try. if you don't like it, lots of people do, and you'll get back what you paid. also, i've read that some people like the volcano top shape, and some like the bgo shape. see how you go.