Optolong Clear Focusing Filter 1.25 inches

Optolong Filters Clear Focusing 1.25″ is specially designed to make focusing during astrophotography easier and more precise. When using narrowband filters, the image often becomes too dark or out of focus to focus accurately. This clear filter allows 98.5% of visible light (420-680 nm) to pass through, giving you a clear and contrast-rich image during focusing.

By using this filter, you can find the right focus at lightning speed and then switch to your narrowband filter for the actual exposure. This produces sharper astrophotos and saves valuable time under the stars.

The Optolong Clear Focusing Filter also has a dual function. It can remain permanently in your optical train as a dust cap and protective filter, preventing dust or dirt from getting onto the sensor or optics during long exposures. For astromodified DSLRs, it also offers increased efficiency and sensitivity by allowing the full visible spectrum to pass through virtually unhindered.

Observation goals
Ideal for astrophotographers who work with narrowband filters and have difficulty focusing in dim light conditions. This filter is suitable for use with CCD, CMOS and DSLR cameras and can also serve as a protective filter during extended shooting sessions.

Specifications

• Type: Clear focus and protection filter
• Diameter: 1.25″ (31.75 mm)
• Transmission: 98.5% in 420-680 nm range
• Suitable for: Astrophotography, focusing and optical protection
• Additional feature: Prevents dust accumulation during long exposures
• Housing: CNC-machined aluminum filter cell