Lens Barlow is one of the most popular accessories in service with astronomers, both professionals and amateurs. She is important in this field of activity. This device is a concave simple lens (negative) in shape, which significantly increases the effective magnification of the telescope. This element was invented in the 19th century by mathematician Peter Barlow. Hence the name of the indicated device.
Product Application
Due to its multifunctionality, the Barlow lens is quite widely used by astronomers of various qualifications. With the help of this device it is possible to carry out the maximum possible increase in the object that is observed with the telescope.
This is an important property. For example, a Barlow 2x lens, when placed between the eyepiece and telescope lens, giving a standard magnification of 100x, increases this figure to 200x. But since a useful increase depends on the stability and state of the atmosphere, the use of this product is not always relevant. For example, if with an increase of 100x the air currents blur the image, then the Barlow lens, having doubled the level of approximation to 200x, will only aggravate the situation. The most effective is the use of this device in combination with a short-focus telescope. The Barlow lens will give this device considerable efficiency due to the fact that these telescopes have a limited ability, since they use standard short-focus eyepieces. Barlow's lens is also an indispensable tool for shooting planets on film or digital cameras.
It makes it possible to โstretchโ small details or to increase the scale of the resulting image. Due to the smaller thickness of the glass in the path of light, a high-quality lens will give a more consistent result than the projection through the eyepiece to the photodetector.
Dignity
The main advantage of this device is that it increases the amount of available increase. For example, if any astronomer has eyepieces 10 mm, 18 mm, 26 mm, then with a Barlow 2x lens, his instrument stock would expand by the indicated devices by 5 mm, 9 mm and 13 mm. It is economical in this case. In other words, one Barlow lens can replace three eyepieces.
Diversity
The most common Barlow lenses are double (2x). However, the multiplier of the increase in these products manufactured to date is very diverse. The Barlow 3x, 4x, and 5x lens is quite common, and you can also find 1.5x and 2.5x. There are models with variable magnification from 2x to 3x. Complicating the use of these lenses may not be a high enough offset focus of the telescope.
Tip
When selecting the necessary Barlow lens for an existing telescope, special attention should be paid to the diameter of the landing sleeve. Its size can be 0.965, 1.25 or 2 inches. It should be identical to the diameter of the focuser and the fit of the eyepieces. In order to obtain a twofold magnification of the image using the Barlow 2x lens, it is necessary to place it between the diagonal mirror and the eyepiece. These products of really high quality should have enlightenment and ideally it should be multi-layered.