Sky-Watcher 90/900 EvoStar EQ-2 Teleskoop

The lenticular telescope designed for beginner astronomy enthusiasts. With a diameter of 90mm, it is a telescope that offers greater possibilities than the basic models with a diameter of 60mm or 70mm. The greater stellar range and better resolution allow you to see more objects with better image quality. It is a telescope with f / 10 aperture and a focal length of 900mm. The tube is suspended on the EQ2 equatorial mount, this mount allows for convenient manual tracking of objects (it is also possible to mount an optional electric drive). Equipped with a 1.25 “prism cap, it allows you to obtain a non-inverted terrestrial image.

Optical system

The BK909EQ2 telescope is a classic achromatic refractor. The lens diameter is 90mm and the focal length is 900mm. The aperture of the lens is equal to f / 10. It is a typical achromatic doublet made of two elements with different refractive indexes, covered with anti-reflective coatings. On the side of the eyepiece lens, in the optical axis, there is a 45-degree prismatic cap that gives an inverted image and 2 Kellner eyepieces with 10mm and 25mm focal lengths. The telescope’s equipment should be supplemented with two eyepieces: short-focus (6-7mm) for the Moon and planets, and another with a focal length of approx. 40mm in order to obtain a wider field of view and greater image clarity.

Installation

The telescope is suspended on the EQ2 equatorial mount. It is a structure slightly stronger and heavier than the basic EQ1 mount, guaranteeing good stability for a telescope of this size. The parallactic mount is a structure typically intended for astronomical observations. The axes of the mount are tilted in such a way that one of the axes points to the blue pole, near the Pole Star. When properly positioned, objects in the sky move across the field of view in a way that allows them to be tracked in one axis without the need to make corrections in the other plane.

Two types of drives that allow tracking the blue sphere can be connected to the assembly. The first of them with a lower precision is the so-called economic drive for the EQ2, the second, much more precise and possible, is the drive in one axis for mounting the EQ2.

Astronomical observations

Solar system:

Sunspots (with an appropriate filter), details on the lunar surface – larger than 2 km, stripes in the atmosphere of Jupiter, shadows of the moons on the planet during transits, Cassini’s break in the rings of Saturn, in good conditions 4-5 moons of this planet. Uranus visible as a tiny disk at high magnification, Neptune as a point object.

Celebrities:

About 1.1 million stars across the sky, up to about magnitude 11.5-12, binary and multiple stars separated by more than 1.5 “angularly.

Deep Sky Objects:

Dozens of globular clusters, emission nebulae, planetary nebulae and galaxies, all Messier objects and brighter NGC objects (with many brighter objects visible detail) most of the galaxies remain blurry.