A good illuminator is every bit as important as the microscope itself. You may be able to "get by" using a desk lamp or some such thing, but not for long, and definitely not at higher magnifications.

You can spend several hundred dollars on a good illuminator, and you won't necessarily go wrong doing so. Most people use a fiber optic illuminator system. This keeps the heat away from the specimen and allows a lot of light to be directed where it is needed.

Most fiber optic illuminators are built around a bipin bulb, which will eventually need to be replaced.

I like LED illuminators a lot, but not everyone does. I am somewhat of a do it yourself person, and have been able to arrange an entirely suitable LED illuminator for just a few dollars. It has two great advantages. One is that it is small and easily portable, the other is that it easily runs from batteries. I also have a large, heavy, and very bright fiber optic light source that is really helpful when using higher magnification.

Many people dislike LED illuminators, the usual objection being that they are "so blue". My rejoinder is that tungsten light is "so yellow". Many people are simply used to incandenscent tungsten filament illumination, which is yellow in comparison to daylight. You can get used to either, but a sudden change from what you are used to will be distracting at first.

• More info on LED illuminators