Agena 2" Color / Planetary Filter - #25 Red

Our Price: $20.95
Free shipping for this item in the US Click here for more info

Continental US Customers:
All items we sell ship for free within the Continental US. Shipping will be via the cheapest shipping method which will vary depending on the items in your order. During checkout, you may also be shown other optional faster shipping choices.

US Customers in Hawaii and Alaska:
Free shipping applies to almost all products. A few large telescopes and mounts are excluded from this free shipping offer. For these items, please contact us to obtain a shipping quote before you check out using the online shopping cart.

International Customers:
Free shipping does not apply to international orders. During check-out, you will be presented with several shipping choices and costs. However, the export of some items may be restricted outside the US due to size or manufacturer restrictions.

In stock (2 Available)
Ships by Next Business Day
Our Product ID: OFIL-AG-2FIL-25
Manufacturer SKU: OFIL-AG-2FIL-25
Item Can Ship: Worldwide
Agena 2" Color / Planetary Filter - #25 Red

More Views

Product Details

Color filters can be very useful for enhancing your views of the Moon and the planets. Depending on the atmospheric conditions, the telescope being used, the observer's experience, and the planet being observed or photographed, the advantages of color filters can be anywhere from subtle to dramatic. The right filter can make all the difference between seeing several small craters in the floor of Clavius on the Moon or not; seeing five or six swirls in Jupiter's belts or not; or seeing the inner Crepe Ring of Saturn or not.

Agena's 2" color/planetary filters are manufactured from the purest optical glass and are dyed-in-the-mass (not simply "color coated") for premium performance. They thread into the barrels of virtually any 2" telescope eyepiece. Each filter cell has a male and female 2" filter thread (M48x0.75) on opposite sides, so multiple filters can be stacked to achieve selective filtration of the visual color spectrum. The clear aperture is 43mm and each filter comes in a protective plastic storage case.

The #25 Red Filter strongly blocks blue and green wavelengths, resulting in very sharply defined contrast between the blue-tinted cloud formations and the lighter-toned surface features on Jupiter. This filter is also quite useful for definition of the Martian polar ice caps and Maria. However, because of the reduced light transmission, the #25A can only be used on larger telescopes with over 8" of aperture. Try this one on Venus. Not only does it reduce the light glare, it really does some interesting things to the clouded Venusian atmosphere.

Like the light red, this filter enables observations of Mercury at twilight when the planet is near the horizon, and of Venus during daylight, reducing brightness of the blue sky to enhance surface features of the planets.

Useful Resources

Agena Informational Article: Choosing a Color / Planetary Filter

Product Questions & Answers

No questions yet. Be the first to Ask a Question.