It is the diameter of the telescope’s objective lens or its mirror which is actually very important to be considered when describing the kind of telescope you are planning to buy. If you can have larger diameter of the telescope mirror or larger diameter of lenses, you can be able to easily gather out more light from that of the faint objects from the sky. But the downside is that they can cost your more. Four inches is the good size for the first telescope. It can be inconvenient to have big telescope mirror and it can be a lot more expensive too. Those bigger one can work better but of course though it is not shockingly so.
The second one is the magnification which is unimportant and is sometimes hyped in the advertising claims for those of the inexpensive telescopes. In the world of astronomy, the reason for the creation of the telescope is to be able to collect those light that is from that of the faint objects and simply not to be able to magnify it. Most visual observing is done through 50 and 200 powers.
If you will have too much magnification then it will give some useless blur. The excellent rule of thumb to be able to determine the maximum usable magnification is to be able to multiply the diameter of the objective in millimeters by 2.5. In the actual practice, on the nights of the extremely unusual atmospheric stability, you may actually make use of the higher power but do not simply count into it.
It will be better also that the eyepiece can be comfortable which means it can be close to the eyes so that it will clearly see the object. If the eye relief can be very small then you will need to bring the eye closer to that of the eyepiece, and it will be but impossible for you to be able to observe for a span of more the few seconds each time.
Last but not the least, you need to also look for the steady mounting or that of the shaky one that can ruin the observing experience and to prevent you from adjusting that of your mount just to make it steady which can often be tasking already into your part. Thus, the more that the mount is massive in its looks, then the better is its performance. When you will be in doubt, then you need to spend more of your time onto the mount of the telescope.