Astro Essentials 1.25'' #25 Red Filter

Astro Essentials 1.25" #25 Red Filter

£9.00✓ 2 year warranty


22x in stock shipped 1-2 working days

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About this product

Model:  ae_fltr_25_125
Part Number:  AD059

Astro Essentials 1.25" #25 Red Filter

Astro Essential colour filters for astronomy are most often used to enhance contrast when observing the Moon and planets.

Results depend on seeing conditions, the telescope and the target being observed or photographed but the right filter can make a significant difference when, for example, viewing the lunar surface or teasing detail from Jupiter's weather bands or Saturn's rings. 

See our handy guide to colour filters and how they can help improve your lunar and planetary visual observing.

Wratten #25 Red Filter

  • A red filter helps to reduce glare.
  • This really helps observations of Mercury in the twilight when the planet is low down.
  • If observing the inferior planets during daytime this filter helps to reduce the brightness of the daytime sky, increasing the contrast.
  • Used on Mars it gives great definition between the dark and bright surface features and polar caps.
  • This filter gives great contrast between Jupiter’s dark belts and brighter zones.
  • One disadvantage is that the low light transmission of this filter means that it can only really be used with larger telescopes.


  • Wratten #25 Red Filter
  • 1.25" Filter Size with M28.5x0.6 Threads
  • Premium optical glass with dyed-in-the-mass colour mounted in a precision metal cell
  • Threaded both sides to enable stacking
  • Supplied in a protective storage case
  • Manufactured by GSO in Taiwan

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