# Thread: How much zoom is good zoom?

1. ## How much zoom is good zoom?

Hi guys.

I know that not always the biggest magnification is the best, but I just can't get a view of any planet. I have a very small telescope (50mm) refractor with 600mm focal length. When I got it, it was with an 10mm eyepiece (the others were lost in action), but today I swapped it with 4mm eyepiece. That should give me 150x zoom right? With the first eyepiece (10mm) I could spy on the neighbors and anything, but couldn't see that much in the night sky... And since it has very small diameter, it's waste of time to try to search for something, that can't be seen with naked eye. When I was looking at Jupiter, it looked just like a blob of light the size of rice. So I put on the new eyepiece, and I was expecting much better views, but it made almost no difference. When I was looking at landscape, sure the difference was huge, but when I looked at Venus and Jupiter, the difference was very small. So Jupiter is still just a blob of light, but this time just a little bit bigger haha. So how much magnification (if thats the problem) should I have to get some details on Jupiter?

2. ## Re: How much zoom is good zoom?

With a 50mm scope, the maximum magnification you can reasonably use is 50x. A 10mm eyepiece is already a bit too much for your scope, and the 4mm eyepiece will never give you satisfactory results under even the best atmospheric conditions.

By the way, the term "zoom" only applies to variable focal length eyepieces. Yours are fixed focal length eyepieces, so no zoom.

3. ## Re: How much zoom is good zoom?

Actually not. They are variable, but I was talking at the highest power. On the side of the telescope, it said 35-50x zoom with the original one. The next one is also variable (I measured about 4mm at the highest power), but obviously it's pointless to put it on. Thanks for your reply!

4. ## Re: How much zoom is good zoom?

Oh, okay. It wasn't clear that they were actually zoom eyepieces. So one is 12mm - 17mm (35x - 50x). How did you measure the 4mm? Focal length of an eyepiece is difficult to measure. Does it have any markings on it to identify it? It would be good to know exactly what you are dealing with.

5. ## Re: How much zoom is good zoom?

Well I tried to measure how far does it focus the light, but this is usually totally inaccurate... Well pretty much I did it too see if it has smaller focal length than the original one, and yes it was focusing much closer than the original one. On the telescope, it cloud magnify much more than the 12-17 one, so even if it's not exactly 4mm, it's somewhere in between 12 and 4.

6. ## Re: How much zoom is good zoom?

Even at 35-50x you should be able to see the lines of the two main cloud bands on Jupiter, and the 4 Galilean moons. If you can't see any detail at all at those powers then there is no point trying for higher power.
Realistically, as Keith says, you wouldn't be able to go much higher that 50x unless you have a very good objective lens. Unfortunately, most 50mm scopes don't fall into that category, so if you want to see detail on planets you would be best advised to save up for something a bit better.

All the best,

Dean

7. ## Re: How much zoom is good zoom?

Thanks for your help. And yes... that's what I'm saving money for right now. So I guess viewing landscape and viewing night sky objects has absolutely nothing in common, because at viewing landscape it does pretty good job, but with it I can't even see the Galilean moons, which I managed to photograph only using a small cheap camera and nothing more.

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