Explore Scientific


Explore Scientific FirstLight 90mm f/5.5 Refractor with Alt-Azimuth Mount

The Explore Scientific FirstLight 90mm f/5.6 Achro Refractor Alt-Az Telescope combines portability and simplicity to provide new users with a complete observational platform for viewing the moon and planets.

Each of the combinations in this line comes complete with all of the essentials: a telescope, a sturdy mount, an eyepiece and a red dot viewfinder.

The OTA is carried by an easy-to-use "U"-style yoke alt-azimuth mount, and supporting the mount head and OTA is an adjustable-height aluminum tripod that comes with a center tray to add stability and offer a convenient place to hold accessories such as eyepieces, filters, and adapters.


  • Achromatic lens configuration corrects for spherical and chromatic aberrations to reduce distortion, especially at the edges, and transmit accurate color rendition without halos or off-axis fringing
  • Anti-reflection fully multi-coated optics improve light transmission through the optical path for improved color, clarity, and contrast
  • Unlimited field of view makes alignment and star-hopping celestial navigation fast and easy
  • 1.25" drawtube accepts the most common size of eyepieces and accessories
  • Manual alt-azimuth
  • Manual alt-azimuth
  • "U"-style yoke design adds stability
  • Aluminum alloy legs
  • Adjustable height to accommodate a variety of users and observation positions
  • Center tray adds stability and offers a place for accessories such as eyepieces and filters

Accessories Included

  • 1.25" diameter barrel
  • 20mm focal length yields 25x magnification
  • 9mm focal length produces 56x power
  • 1.25" snout and eyepiece holder
  • 90° angle puts head at a comfortable viewing angle, especially when OTA is pointed at or near the zenith
  • Integrated erect-image prism corrects image horizontally and vertically to the telescope to be used as a conventional spotting scope
  • Red dot design
  • Unlimited field of view makes alignment and star-hopping celestial navigation fast and easy
  • Projects a red center aiming reticle that won't obscure small objects
Smartphone Adapter:
  • 1.25" diameter barrel
  • Capture photos or video through telescope to text, email, share, and post immediately
Type Achromat
Focal Lenght 500mm
Focal Ratio f/5.5
Optical Diameter 90mm
Magnification 125x
Lens Coatings Full Coating
Adapter 1.25" draw tube focuser; 1.25" Erect Imaging Diagonal
Eyepiece 1.25" K9 and K20 eyepieces
Mount type Alt/AZ “U” Yoke mount
Mount Alt-Azimuth