Antares 1.25" 5x Barlow Lens with Twist-Lock Adapter and T-Thread # UB5STL

Our Price: $70.00
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Our Product ID: OBAR-AN-UB5STL
Manufacturer SKU: UB5STL
Item Can Ship: Worldwide
Antares 1.25" 5x Barlow Lens with Twist-Lock Adapter and T-Thread # UB5STL

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  • Antares 1.25" 5x Barlow Lens with Twist-Lock Adapter and T-Thread # UB5STL

Product Details

This 1.25" 5x Antares high performance barlow # UB5STL features a fully-multicoated achromatic design. This short barlow will work in diagonals or reflectors, has internal darkening and edge-blackened lenses, and is parfocal with most eyepieces. It features a clear aperture of 18mm. Suitable for high contrast, high power applications in any telescope. Made in Canada.

<p>This new version of Antares' popular UB5S barlow features an integrated twist-lock adapter / clamping mechanism to securely center and hold your eyepiece. The inner compression ring is made of polypropylene and will not mar your eyepieces. Unscrewing the twist-lock ring exposes a standard male T-thread (M42x0.75) underneath which can be used to couple imaging devices with the barlow.


  • Barrel size: 1.25" / 31.7mm
  • Magnification factor: 5x
  • Type: Achromatic
  • Coatings: Fully multicoated
  • Clear aperture = 0.71" / 18mm
  • Weight: 5.2oz / 147g
  • Total length: 3.24" / 82.4mm
  • Length of lower chrome barrel: 1.48" / 37.6mm
  • Length of upper black barrel: 1.77" / 44.8mm
  • Filter threads: No
  • End caps: Coming soon
  • Country: Made in Canada

Note that the use of any optical element like barlows and focal reducers changes the focus point of your telescope, requiring additional in-focus or out-focus travel. The exact amount of focus travel required will depend on the optics and mechanics of your specific set-up (telescope, diagonal (if used), barlow, and eyepiece). Hence, be aware that you may not be able to reach focus with all eyepieces or in all configurations with a given barlow.

Please note: This is a very high magnification barlow. It is not for everyone or for common viewing conditions. Before buying, please make sure that you are using realistic magnifications with your telescope. A good rule of thumb is that under very good conditions and with a very good telescope, the maximum power you will be able to use is about 50x of magnification per inch of telescope aperture. With average telescopes and/or average conditions, you should be able to use 30x of magnification per inch of telescope aperture. So for example, if you have a 6" telescope, under typical conditions you will be limited to 6x30 = 180x of magnification, and 6x50 = 300x of magnification at best.

Boosting the magnification beyond this recommended maximum for your telescope aperture is not realistic. This is bound to result in image break-down, causing fuzzy images, focusing difficulties, increased color around objects (caused by other optical elements in the telescope which are magnified by the barlow) and general disappointment, but this is not a fault of the barlow.

Manufacturer Antares
Size Format 1.25 inch
Magnification Factor 5x
Number of Lens Elements 2
Lens Coatings Fully multicoated
Total Length 3.24 inches / 82.4 mm
Length of Nosepiece 1.48 inches / 37.6 mm
Outside Length of Upper Body 1.76 inches / 44.8 mm
Insertion Depth
Max Diameter Excluding Thumbscrew
Clear Aperture 0.71 inches / 18 mm
Weight 5.2 oz / 147 g
Barlow Lens Cell Removable No
Filter Threads at Bottom of Barlow Cell No
Filter Threads Between Barlow Cell and Tube N/A
Barrel Type Smooth-sided
Compatible Agena Bolt Case (with Screw Removed)
Compatible Bolt Case (with Screw Attached)
Number of Thumbscews 0
Thumbscrew Thread Specification N/A
End Caps (Subject to change without notice)
Compression Band/Ring in Eyepiece Holder Yes
Country of Manufacture Canada