2.5x APO BARLOW LENS – 2’’

2.5x APO BARLOW LENS – 2’’

The TSB225 extends the focal length of the telescope by the factor 2.5 and offers a very good illumination for 2" eyepieces and also for astrophotography.

Features:

• Focal length increase 2.5x - thus the magnification is significantly increased.
• High-quality 4-element APO design for very good sharpness on axis and in the field for sharp observation and astrophotography.
• Blackened lens edges against reflections and for more contrast
• Telecentric optics with resulting benefits (see details)
• At the same time, the Barlow lens is a photographic 2.5x converter for photography through telescopes with 2" focusers. Even full-frame sensors are illuminated.
• At the telescope side, the 2" Barlow has a thread for 2" filters like nebula filters for increasing contrast.
• The clamping of 2" and 1.25" accessories is done by compression rings. The 1.25" adapter is included.

The TS Barlow increases the magnification of your 2" or 1.25" eyepiece with the factor 2.5x. The premium 4-element optics is fully multi-coated for optimal brightness, high contrast and natural color imaging. The 4-element design allows the use even with very fast telescopes like f/4 Newtonians.

The Barlow lens has a high-quality workmanship. The four elements are mounted in a solid aluminium cell. At the inside, the Barlow is blackened as well as possible for avoiding reflexes when photographing moon and sun (only with solar filter).

1.25" and 2" accessories are locked by compression rings. Clamping is done gently and precisely on the optical axis.

At the telescope side, the TSB225 offers a 2" filter thread where all common 2" filters can be screwed in.

The advantages of a telecentric Barlow lens

In addition to the advantages of a typical Barlow lens, the telecentric design has two other advantages: First of all, the magnification factor is independent of the eyepiece distance, so you can put double polarizing filters, filter drawers and similar accessories between the lens and the eyepiece without increasing the magnification factor.

And second, the telecentric design does not extend the eye relief of the connected eyepiece. This is advantageous for the long focal length eyepieces that are often used in this context with their usually already large eye relief, as if this is too big, one can hardly hold the viewing position, which possibly leads to kidney being.

Photography with the TSB225

This Barlow lens is a high-quality teleconverter at the same time, multiplying the focal length of the telescope with the factor 2.5x. The 4-element design ensures a very high sharpness on the axis and especially in the field. That is an important advantage against simple 2-element Barlow lenses. Even with full-frame sensors, you will achieve a good sharpness even to the edge.