Astro Essentials 1.25'' #23A Light Red Filter

Astro Essentials 1.25" #23A Light Red Filter

  (1 Review)
✓ 2 year warranty


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About this product

Model:  ae_fltr_23a_125
Part Number:  AD060

Astro Essentials 1.25" #23A Light 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 #23A Light Red Filter

  • This filter is very similar to filters #21 & #15, but gives a lot more contrast.
  • However, due to the low light transmission of this filter, it does need to be used with a telescope larger than 6”.
  • It really helps to improve the contrast between Mercury and a bright daytime sky. This filter is really useful to help reveal the surface features on Mercury during the day.
  • With Venus it can often reveal variations along the terminator.
  • Used on Mars, it increases the contrast between the dark and bright surface features.
  • Jupiter & Saturn benefit by darkening blue features in their atmospheres to help them stand out.
  • When used on bright comets, this filter helps to improve definition in the dust tail.


  • Wratten #23A Light 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

Customer reviews

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Light red filter
22 December 2020  | 

Purchased 4 filters and 1 included for free. The red one is also great for the moon and larger planets. Very bright image when used with a lower power plossl.


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