6mm vs 8mm

[toml42]

ok, so I feel my hunt for a new eyepiece is coming to an end. I wanted something to plug the gap between 100x and 200x in my new scope, which i could also 2x barlow on nights of good seeing to push my scopes capabilities on planets, binaries and the like.

I'm pretty much settled on a TMB planetary, Skiesthelimit on ebay has a great deal going on them at the moment. The only problem is... i can't choose between 6mm or 8mm

my scope is the skywatcher 200p f5, so 6mm is 167x (333x) and 8mm is 125x (250x)

Living in the UK, how often would i be able to make use of 333x, or alternatively, how much of an improvement over my standard 10mm skywatcher at 200x would the TMB at 250x provide?

anyone with experience of a similar setup, or any other suggestions for under £50?

[toml42]

ah, may have found a compromise solution! meade 4000 6.4mm gives 156x and 313x, slightly lower FOV at 52 vs 58, but i think i can deal with that

[Doc]

I would say a 8mm TMB planetary would be a step up from a standard skywatcher 10mm in every department. If you bought this 8mm I can see you not using your 10mm very much.

The 6mm eyepiece is only going to be used very rarely, maybe a couple of times a year when those skies are pretty awesome. But then during those times the views will be great.

Hope this helps

[michael.h.f.wilkinson]

I find 250x a very useful magnification on my 8" scope. Skies frequently support this, whereas 288x (14mm + 2x TeleXtender) is not used that often.

[stafford_stargazer]

I have just recieved from the same place the tmb 6mm planetaryII today,looking forward to see if i can use it tonight,not looking to good.

Im using it instead of my old 9mm revalation astro eyepiece,im curious of its quality too compared to my old one.

Id go for the 6mm

Oh its much bigger than bog standard ones,and looks quality built,eye relief seems good.

[simon84]

I just had a dilemma about 6mm or 8mm. I decided to go with the 8mm in the end as I would probably get more use from it with a barlow but decided I probably wouldnt use a 6mm barlowed very much at all. My Equinox 120 has a highest practical power of 240x so an 8mm barlowed will give me about 225x which is pretty close to the scopes max.

[stafford_stargazer]

Im gonna use my 6mm barlowed on the c80ed Im sure it will cope

[johninderby]

It's a pity that SkysTheLimit doesn't have the 7mm TMB. Telescope Service does, but then there's the additional shipping cost from Germany.

John

[toml42]

Thanks for all the advice everyone, i've decided to go the path of the 8mm TMB, thinking about it, for starters i definitely want something i can use every night, to replace my stock 10mm ep.

Most people seem to agree that 250x is an upper end for planetary on normal-good seeing and from what i can tell, 125x should be near optimal for fuzzy viewing. Cheers for the help!

[michael.h.f.wilkinson]

Keep us posted on your experience!

Clear skies

Michael

[russ]

You won't regret the 8mm, i have it. And it's a whole nicer experience than the tight eye relief of the Meade 4000 6.4mm. Plus 4000 quality on the Chinese versions sold now varies hugely.