A decent 9mm eyepiece ..... the search continues ....

[John]

I'm still considering my options for a 9mm wide(ish) field eyepiece to fit in a gap between my Nagler 7mm and 13mm's - trouble is I can't afford another Nagler having blown some dosh on the Skywatcher 250PX which was not entirely planned but was too good to miss

At the moment the favourite is the Burgess / TMB 9mm which offers a 60 degree FoV and has received favorable comments from SGL members but on another forum the Orion Expanse / Skywatcher Ultrawide 9mm (66 deg FoV) has come forward as a suprise contender - it seems to be viewed as the best of these ranges of eyepieces by some margin, even performing well in shorter focal length scopes.

I used the 20mm and 6mm of these ranges and, while they were fine in longer focal length scopes, the performance away from the centre of the field fell off at F7 and less (understandable given their low cost). I wonder what makes the 9mm special and whether these views on it's performance are matched by SGL members experiences ?.

Cheers,

John

[GazOC]

The 9mm Expanse is OK (and great value) at f10 but doesn't work well at f5. I know, I've got one!!

I've also owned the 6mm, the 9mm is a better eyepiece but not what you are looking for I don't think...

[John]

The 9mm Expanse is OK (and great value) at f10 but doesn't work well at f5. I know, I've got one!!

I've also owned the 6mm, the 9mm is a better eyepiece but not what you are looking for I don't think...

Thanks Gaz - thats very helpful feedback. Methinks it's the 9mm Burgess / TMB for me - have to phone FLO in the morning !.

John

[GazOC]

I can send you the Expanse in a Jiffy bag if you like John? Its been in the wars (the eye guards on all 3 of my Expanses have rotted off!!!) but it'll give you an idea how he eyepiece performs.

[The Warthog]

I'm going to be a bit whatchamacallit and suggest that if you have a 7 and a 13, you don't really need a 9. There is nothing the 9 will show you that you can't see in either the 7 or the 13. Save the money for important things, like beer.

[John]

I'm going to be a bit whatchamacallit and suggest that if you have a 7 and a 13, you don't really need a 9. There is nothing the 9 will show you that you can't see in either the 7 or the 13. Save the money for important things, like beer.

Good point WH - I think I'd agree with you with the 4inch refractor - I could do without a 9mm. For the 10inch dob I'm not so sure - the magnification with the 13mm is 92x and the 7mm gives 171x - that seems a pretty big gap, but maybe I'll give it some time and see how big that niche really is in practice.

Cheers,

John

[John]

I can send you the Expanse in a Jiffy bag if you like John? Its been in the wars (the eye guards on all 3 of my Expanses have rotted off!!!) but it'll give you an idea how he eyepiece performs.

Thanks for that kind offer Gaz - I think I'm going to go for a Burgess / TMB 9mm - all the reports are favourable and it seems like a premium eyepiece on a budget, if you can have such a thing

John

[MortonH]

I have an Orion Stratus 13mm and the Burgess/TMB 9mm. In my 8" f/6 Dob, I find it handy to have both. The 9mm is particularly good for bright globulars (I can see 47 Tucanae from my balcony here in Sydney) whereas the 13mm still seems 'wide' in comparison. When I go below 9mm I feel like I'm really pushing up the power and need brighter objects, such as the planets. Of course, you'll have a bit more light grasp with a 10", so this may not be an issue.

Either way, the Burgess/TMB is a very nice eyepiece for the price and it's not out of place beside my Televue and Pentax eyepieces.

Morton

[John]

I have an Orion Stratus 13mm and the Burgess/TMB 9mm. In my 8" f/6 Dob, I find it handy to have both. The 9mm is particularly good for bright globulars (I can see 47 Tucanae from my balcony here in Sydney) whereas the 13mm still seems 'wide' in comparison. When I go below 9mm I feel like I'm really pushing up the power and need brighter objects, such as the planets. Of course, you'll have a bit more light grasp with a 10", so this may not be an issue.

Either way, the Burgess/TMB is a very nice eyepiece for the price and it's not out of place beside my Televue and Pentax eyepieces.

Morton

Thanks for that Morton - sounds encouraging

John