5mm eyepiece but which one?

[Perkil8r]

Dangerous I know, but everytime business drops off for a bit I feel the need to spend money

I'm looking at buying a 5mm eyepiece. It will be 1.25" not 2". I don't want to spend silly money on one, £80 max ideally sub £50.

At the minute my rolls royce is my 8mm BST, is the 5mm BST (do they even do one?) comparable in quality to the 8mm, or are there any little gems out there that I should know about? I quite enjoy the thrill of the chase, so bidding on a used EP is not out of the question as long as I know what I'm looking for.

[Guest Kheldar]

You'll be happy with the BST if you like the 8mm.

TMB Planetary are simliar, personal taste though between them.

Next step up the price ladder is probably the X-Cel LX, whether you will appreciate the differences is again purely down to personal taste

For a noticeable improvement, you need to spend the wrong side of £120 on a second hand EP

[BAZ]

The only other one near it in quality and cost would be a Baader Hyperion, keep an eye open for one of these, they retail new at around a ton.

[Perkil8r]

So I should be looking for: 5MM BST, X-Cel LX or Baader then..... Thanks folks, that narrows it down. My aim is to replace all of them except the BST over the coming months. In theory it would be nice to have a matching set, but I read somewhere that not all the BST's are of equal quality? With the TAL 2x Barlow, I should be able to get towards maximum usefull magnification on both scopes with the 5mm. I'll probably go for a big lens next, over 25mm so I have a bigger range before I replace the 25, 20 and 10mm cheapo ones, and fill the gap with a 15?

[Guest Kheldar]

In any range to be honest quality varies. The 25mm BST was the dog of the bunch I believe?

I also think that 5mm is about your max usable on both scopes anyway, the Barlow is pushing them too far.

200P 5mm = 200x (more often useable than not.)

ST80 5mm = 80x (probably over 100x is not usable)

Edited May 29, 2012 by Kheldar

[Perkil8r]

I thought the rule of thumb was 2 x appature? ie, 200p = 200 x 2 = 400 x mag? I realise it all depends greatly on the target and the conditions at the time though.

[Guest Kheldar]

I thought the rule of thumb was 2 x appature? ie, 200p = 200 x 2 = 400 x mag? I realise it all depends greatly on the target and the conditions at the time though.

IMHO that figure is far too high, 30x per inch is more like it in the UK.

[Perkil8r]

Fair play

Just to throw another eyepiece into the mix, what about the Vixen NVL ? I see I can get a 5mm delivered new from USA at just under £100, OK, so it's just over my initial budget, but then budgets are made to be busted

[Guest Kheldar]

Fair play

Just to throw another eyepiece into the mix, what about the Vixen NVL ? I see I can get a 5mm delivered new from USA at just under £100, OK, so it's just over my initial budget, but then budgets are made to be busted

From what I've just Googled they have a 45 degree FOV?

If that's true, for that reason, I'm out

I don't know the EPs personally I'm afraid so can't really advise.

Edited May 29, 2012 by Kheldar

[Perkil8r]

Hadn't spotted that

Hmmm..... If I can be patient enough I will try and get a Baader 2nd hand, if not I'll go for either the BST or The X-Cel Lx then. I did have a feel of Pat's X-Cel the other day (oooer) and it did feel assuringly weighty.

[Rock Doctor]

Mike,

I have just bought a 5mm Baarder Hyperion from Damian. On Astro buysell they normally go for 60-£70. Lovely EP but you will need almost perfect seeing conditions to get the benefit from it. I have used it on Saturn but with the current wind turbulence I find that I get a much sharper view from the 12mm click stop of my BH 8-24mm zoom.

[Perkil8r]

Cheers Dave, I expect I might fair a little better given both my scopes are f5 or am I assuming wrong?

[Rock Doctor]

Mike,

not sure on that you'll have to ask one of the old hands that are much more knowledgeable than me. If you are not in a rush to spend the dosh then I'll bring it with me to the next meet and you are more than welcome to have a go with it.

[Daz Type-R]

Cheers Dave, I expect I might fair a little better given both my scopes are f5 or am I assuming wrong?

I might be wrong but I did not think it mattered what your F ratio is (apart from a higher F ratio being less forgiving of bad quality ep's), what does matter is what is a useable magnification.

I have the 200P but mine is a F6, (1200mm focal length) and while my maximum magnification is x400 I will never acheive that in Britain. I will be lucky to get reasonable views at x300.

Like Kheldar said above, you will get much better views at X200 so a 5mm ep will give you that where in mine it will give me X240 (about the limit for UK).

As to which to get, it is all ways down to personal choice.

If you can, get to a meet and try some out before parting with your cash.

[Perkil8r]

Picked up a X-Cel Lx, just need some clear sky to try it out lol