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Ive got it ordered...

Sonia

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Sonia

Sonia

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How big do things appear?

An image with X100 magnification is the same size in a 10" scope as a 2" scope, the image is magnified 100 times.

The diffence is a larger scope can take more manification than a small one and also will show more detail on most objects for a given magnification.

That doesnt quite make sense to me lol

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GazOC

GazOC

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Sonia,

If you have an image and magnify it by, say, x300 then it will just be 300 times bigger, the aperture of the scope doesn't matter.

The advantage of bigger scopes is that they allow more effective magnification, if you had a 80mm scope and used x300 Mag then you would probably get a blurred image as the scope is not large enough to gather enough detail to allow that magnification to be used, you can't magnify effectively detail that the primary is too small to have captured.

Have you seen those little 2" scopes in toy shops that advertise "x600 magnification"? Strictly speaking it is true, you can magnify an image as much as you want in any scope but a 2" scope cannot collect enough detail to magnify an object by anything like x600.

Gaz

Gaz

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FLO

FLO

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Sonia,

Put another way:

A telescopes magnification is determined by its focal length and the eyepiece used, not its aperture.

(Surprisingly, your ETX90 has a slightly longer focal length than the 10" Dobsonian so has slightly higher magnification).

The aperture does determine how much detail is shown. For example, a four inch aperture will show several weather bands across the planet Jupiters surface. But, a 10" scope will show actual structure/swirls within the bands. As for the moon, it is impressive thru a 4" scope but thru a 10", you will feel you can reach out and scratch the plaster!

The aperture also determines image brightness. Simply put, the larger the aperture, the more light is collected and delivered to your eye. Your new 10" scope will be great for seeing faint deep-sky objects such as galaxies and nebula that your smaller ETX90 cannot.

Hope that helps,

Steve :lol:

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FLO

FLO

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Always one to put ya down!

He didn't mean it that way Sonia,

Its just that a lot of Deep Sky Objects tend to be quite large so are best viewed at low magnification; an eyepiece around 30mm would be ideal.

For example: Pleiades, Andromeda galaxy and the Double Cluster all look better when viewed at low magnification.

Hope that helps,

Steve :lol:

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Ant

Ant

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Whilst I agree that it's nice to use higher mag (for Glob's) to see just how far your scope can resolve I still maintain (IMO) that there is no better sight than a nice globular cluster in the middle of a large FOV - just sort of sitting there in space with errrrrr lots of space round them.

Sorry Sonia, didn't mean to come accross like that. It's just that I'm very partial to DSO's at low mag - I don't even own a high power EP. 10mm is the highest I have (and thats a cheapy) giving me 100x.

The EP that I use most is the 2" 32mm which is about 30x, even small things like the Ring Nebula look nice in that!

Ant

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The Warthog

The Warthog

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You know when you say you need a 'low power ep' for DSO, how low are we talking?? :lol:

Like Ant, I use my 32mm Plossl (30x) almost exclusively for looking for, and at, DSOs. And for the same reasons as Ant. Praesepe or the Pleiades look magnificent in the wide FOV. You can find globs and galaxies with it, and switch to a higher power if you want, or just put a tick on the map and move on. If I had a larger scope, I probably wouldn't use much more power for open clusters and other DSOs.

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The Warthog

The Warthog

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So will my 26mm plossl be ok?

Yes. It will give you nice views at about 44x. You will get better eps as you go along, but take your time making up your mind about what to get, and how much to spend. You dont' have to rush out and buy anything just now. :lol:

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mark RD

mark RD

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good choice Sonia, I'm sure we are in for alot of cloudy nights though :lol: :lol:

I think the biggest difference you will notice with a 10inch will be that everything will be alot brighter, you will be able to see more distant dim objects with greater detail.

Let Us know how you get on when it arrives :lol:

Mark

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