Telescopes often come with 1 or 2 eyepieces as standard, which usually give an adequate range of magnification. A useful accessory to add is a Barlow lens, which increases the focal length of the eyepiece depending upon the power of the Barlow, such as a 2x Barlow effectively doubling your range of magnifications.
However, there are shortcomings as they use a negative lens, and this can lead to the exit pupil for long eye relief eyepieces being pushed too far out which may cause vignetting of the view.
Televue solve this with their ‘Powermate’ range by adding a positive lens to the negative doublet so that you get the increase in magnification without the vignetting.
The 5x Powermate is the largest of the range and can make a 25mm focal length eyepiece work like a 5mm eyepiece.
Bearing in mind sky conditions and the focal length of your chosen telescope play an important role in the views you see, the 5x Powermate helps when conditions allow for high magnification views.
The barrel has an undercut to prevent it slipping out of the focuser and the 1.25inch eyepiece end has a brass compression ring to grip an eyepiece evenly.
In our tests we found it worked well with our favourite 26mm eyepiece (so equalling a 5.2mm eyepiece) and on comparison with our 6.4mm eyepiece it gave a cleaner view even though the magnification is higher with the Powermate/26mm combo.
Double stars retain their colour rich contrast such as found in Albireo in Cygnus, or Almach in Andromeda.
Planetary detail is also well seen depending on sky conditions, and in some cases we could even move to a 10mm/5x Powermate combo to pick out finer detail, especially on Jupiter or the Moon.
The 5x Powermate can also take 1.25 inch filters to enhance planetary/lunar viewing and it can also be used with high speed planetary cameras so is a versatile addition to your accessory kit.