The ASKAR FMA135 is a premium optical instrument that features a 30mm ED fully multicoated triplet objective to deliver superb image quality for astronomical and terrestrial imaging. It also works as a finder/small telescope/guide scope.

The heart of the FMA135 is an air-spaced 30mm apochromatic f/4.5 triplet with an ED element to minimize chromatic aberration. With a focal length of 135mm, the objective lens is optimized and tested for demanding astronomical applications, and it is carefully matched to an integrated three-element field flattener that yields flat fields and sharp images.

For the price, this fast apochromatic lens offers excellent value and can approach the performance of telescopes that cost three or four times as much. This is especially true when matched with astronomy cameras with smaller 1" and 4/3" sensors. Cameras with larger APS-C sensors may reveal slight aberrations at the edge of the field, especially when using the focal reducer. This lens is not recommended for use with full-frame cameras.

The camera side of the FMA135 includes a standard M42x0.75 male thread for attachment to most astronomy cameras or T-rings. The instrument has a 55mm back focus. The top tube ring, which acts as a light/dew shield, includes standard M28.5x0.6 female threads that accept 1.25” astronomical filters. The body of the FMA135 includes a rotatable focuser to ensure precise and repeatable focus.

For straight-through observing with an eyepiece, there’s a standard 1.25” adapter that threads onto FMA optical tube. The FMA135 also includes a mounting ring with standard Vixen-style dovetail.

The overall tube length is 113mm. The FMA135 weighs just 280g (0.62 lbs).

Specifications:

• Aperture: 30mm
• Focal Length: 135mm 
• Focal Ratio: f/4.5
• Objective Type: Air-spaced APO Triplet (including an ED Glass). Sextuplet Refractor for APS Imaging
• Overall Length: 113mm (photographic mode with flattener)
• Weight: 280g
• Rear-end Adapter Type:
  • M42 x 0.75 Thread (for imaging)
  • 1.25" Visual Adapter (for visual use)