how good is a 402x power telescope?

Answer 1

A professor once gave me some advice regarding scopes. If you take the apeture (diameter of the mirror), than the maximum USEFUL magnification is about 30 - 50 times the apeture. Why a range? Well, it can vary depending on the scope. Take for instance a 6" scope. Your range is 180x - 300x for magnification. One scope may be better around 220x while another may get you to 280x. It can vary. Eyepieces also make a difference. A 9mm Nagler will outperform a 9mm Plossel.

I've seen 3" department store scopes advertise 400x or higher. Here's how they get that number. They will throw in some high power eyepieces (cheap and useless ones). Then they throw in a 2x, 2.5x, or 3x barlow. That means that you take the magnification with that high power eyepiece and you multiply it that much to get your highest magnification. Anything over 150x would be too high and therefore not useful at all. If the highest power eyepiece gets say, 135x, then you add a 3x barlow, you find yourself at 405x power. This is well beyond maximum useful magnification.

Don't use those numbers to determine if a scope is good. It's a marketing ploy to try and make their scopes sound powerful when they really aren't. It's a combination of the optics and apeture with the right (notice I said right, not most powerful) eyepieces that make the difference.

Answer 2

I agree with Geoff G. 100%. Do not buy a telescope that uses power as a marketing tool. It will be a big dissappointment. 402x would be about the maximum power you could rationally use with an 8" diameter telescope. (50 times the aperture size in inches is a good rule of thumb for maximum usable power of a telescope). (Power is derived from the focal length of the telescope in millimeters divided by the size of the eye piece in millimeters).
I own a 10" telescope and most of my viewing is done between 35x and130x. Sometimes I will try to squeeze a little more power out of it but the conditions need to be very good. At 402x you would also need a telescope able to track objects (motorized). In a scope without a tracking device, the object will move thru the field of view in your eyepiece rather quickly.

Do some research and go to a local observarory for some public nights and see what others are using and they will gladly answer any if not all the questions you have about telescopes. Stay away from department store telescopes. Order one from a credible telescope dealer, who will also answer your questions. http://www.astronomics.com and http://www.telescope.com is a good place to start.

Never look at the sun without a proper solar filter on a telescope. It will burn your retina.

Answer 3

Good telescopes are measured by their aperture (diameter of main lens or mirror) not their magnification. Any telescope can give any magnification with the right eyepiece, but if the aperture is small, the image will be so blurry as to be useless. Most astronomical observations are made in the 40x to 200x range, no matter what the aperture. 402x would only be usable with a large aperture telescope with perfect optics and a perfectly steady sky. I've been an astronomer for 50 years, and can count on the fingers of one hand the nights when I could use 400x.

In short, a telescope advertised as "402x" is almost certainly a worthless piece of junk. Look elsewhere.

Answer 4

The Power of a telescope is the third in importance in my opinion.
Good optical quality is the most imoportant characteristic one should look for and that comes at a price.
Next would be the size of the objective lens which is the first thing that light strikes as it travels through a telescope.
The bigger the lens the more light that is gathered. The higher the power the more light you
need also.
Next would be your mounts good quality mounts are esential.
Next would be the power and really anything over 300x is pointless as atmospheric distortion becomes an issue also higher power require high quality lenses and alignment.

Answer 5

Simple Answer:
NEVER buy a Telescope advertised by it's magnifying power.!!!
It is a sure indication of a Junk telescope and is meaningless hype since the magnifying power of any Telescope can be changed at will by simply changing the eyepiece.

Adolph

Answer 6

What matters most in a telescope is not magnification but aperture. Bigger telescopes provide brighter and sharper images and have a higher useful magnification.

Since magnification is done only by the objective lens, even the image in a small telescope can be magnified hundreds of times, but this only magnifies the defects in the image without providing any more detail, and it also reduces brightness and field of view.

402x would only be useful in telescopes of 8 inches in diameter or more.

Answer 7

The important thing in a telescope is not how many powers (X) it has but the diameter of the objective (the main tube). A 12" telescope will collect more light than a 4" telescope, so the wider the diameter the farther you will see. The quality of the eyepieces is also important.
A 402x telescope will be good if you see a sharp, clear image of a galaxy, a planet, or a star.

Answer 8

This is a very high power,and even if you can reach this, it's really too high to enjoy the view but is certainly reachable if your aperture, optical quality and sky conditions will support this magnification and you have a tracking drive. Manual slow motion controls won't do much good due to the high rate at which the object moves in your view at this high power. I've observed at this mag. w/ a meade ED 7" refractor on a tracking drive and also on an 8" reflector with custom built optics well above the diffraction limited limit and excellent atmospheric conditions and had an equatorial mount with tracking.
An idea for you would be to find an astronomy club in your area. Ask yourself first what you want to see for your time at the eyepiece. Do you love planetary?double stars?solar observing? deep sky? nature observing/astronomy x over?There you would find people who may have the different telescope designs, such as a reflector, schmidt-cass,refractor,ect. all in different apertures/glass types/magnifications/portability f/ you to see for yourself how objects look to you and what size these scopes come in before you buy a scope. I use an orion 10" intelliscope that is perfectly collimated and in Michigan I've never been able to exceed 180x with it. I love the push to operation of this scope with the computer database.My most beautiful views with this scope are at mags of 50x for deep sky to 170x. for planets and double stars/globular clusters. At the 170x (nagler 7mm)it takes about 2 minutes for an object(depending on it's position) to drift across the field of view before I need to nudge the scope again.Some of the newest optical improvements are becoming very affordable to amateurs now, such as custom reflector mirrors and the extralow dispersion/apochromatic refractor telescopes along with the schmidt cass scopes with goto drives and better coatings on the optics.Buying a cheap department store scope (if this is what kind of scope you are referring to here)will only frustrate you. I've been observing since 1969 and have used all those cheapies when I started out. They have'nt changed.The optics in some of those refractors are plastic and not even glass and the tripods are wobbly. Most scope stores /companies online offer 30 days return.
I've had very good service from anacortes telescopes, orion telescopes, william optics,riders hobby and televue.

Answer 9

If that's how it's described on the packaging, then it's probably cheap rubbish. If you want a good scope, then go to a telescope shop. Not a department store, and not a camera shop that happens to sell scopes.

Much more advice to give, but that's the answer to your question.

I don't mean that "402X" is poor magnification (it's actually unrealistically high for many scopes), I mean if the magnification is what's advertised on the thing, then it's rubbish because scopes advertised like that always are.

Answer 10

It's total crap. The only relevant criteria are aperture, aperture, aperture and deviation of the primary mirror from its mathematical ideal. lambda/10 would be great. Your 402x power scope will probably be hardly lambda/2 on a good day and if you are lucky to pick the right box.

I bet they will not tell you the last one. Right?