what magnification am i getting right now?

[Daniel-K]

hey all could any one tell me what magnification im getting right now using a 25mm and a 10mm with a sky watcher 200p

[MikeP]

FLO's site says it has a focal ratio of 5.91 and a 203mm mirror, that means its focal length is 5.91 * 203 = 1199.73, call it 1200mm.

You divide this by the eyepiece focal length to get 120x with the 10mm and 48x with the 25mm.

Mike

PS Magnification is only really useful on the planets and the moon

[Doc]

1200 divided 25 = x48

1200 divided 10 = x120

Beat me to it Mike

[MikeP]

At least we got the same answers.

Mike

[Daniel-K]

thanks guys i was looking at the double cluster last night if i get a barlow i should be able to see more detail right?

[Doc]

thanks guys i was looking at the double cluster last night if i get a barlow i should be able to see more detail right?

Yes a x2 barlow and your 10mm eyepiece will give you x 240 approaching your max for this scope.

[Daniel-K]

know any were i can get one from

?

[acey]

if i get a barlow i should be able to see more detail right?

Not necessarily more detail but it will look bigger. A 2x Barlow will give you magnifications of x96 and x240. The latter may be too high to be useful with your scope, and the former is not far from what you already get with the 10mm EP. My first scope was an 8" that came with two Plossls like yours. I got a very good Barlow (a Meade apo) but soon stopped using it because the high-power views were useless. I saved up and got an 8mm TeleVue plossl which I'm still using with my 12". On the 8" it gave a magnification of x150, and I felt no need of going higher, either on planets or DSOs.

[MikeP]

A 2x barlow will double the magnification and a 3x will triple it. However, the price you pay is a smaller field of view and a darker image. I'd be inclined to look at the double cluster with low magnification.

Also, there is a limit to how much magnification is "reasonable" for your scope and for the seeing conditions. 120x is starting to approach the best you can do on a normal night in the British Isles.

Mike

[TheThing]

I often seen it said that 300x is a pretty good guide as the maximum that you can reasonably use, but this is with perfect seeing and transparency (something we never get in the UK!)

[John]

thanks guys i was looking at the double cluster last night if i get a barlow i should be able to see more detail right?

For the double cluster (the one in Perseus, not far from Andromeda), low to medium powers give the best view - you really want an eyepiece where you can fit both the clusters into the same field of view. Higher magnifications will not really deliver any benefits with this object.

[Chris H]

I agree x70 gives me a great view of the double cluster admittedly through my Ethos 17.

First Light Optics sell Barlows along with Telescope House and Rother Valley Optics all three are very good retailers.

[pvaz]

Don't be too cheap on the barlow, I was on the 1st one I had and it's absolutly garbage. It blurred everything.

The cheapest, most members seam to agree on, is the TAL 2x (though I never used one myself).

As others said, 240x is a good mag and it's the one I use the most for planets/moons. Good conditions may allow up to 300-320x on planets, the moon is a bit less sensitive.

[msinclairinork]

Hi, Recomend you read Andrew's primer on choosing eyepices helped me a GREAT deal!

http://stargazerslounge.com/primers-tutorials/63184-primer-understanding-choosing-eyepieces.html