Optolong UBVRI Photometric Filter Set 2″

The Optolong UBVRI Photometric Filter Set 2″ is designed for scientific and semi-professional astrophotography. The set contains five carefully crafted filters: U (ultraviolet), B (blue), V (visual green), R (red) and I (near-infrared). Together, they provide the standard photometric bandwidths used worldwide in astronomy for accurate measurements and comparable data.

Each filter is made of high-quality Schott glass (1.85 mm thick) and equipped with a multi-layer anti-reflection coating. Thanks to the IBAD (ion beam assisted deposition) process, the coatings are scratch-resistant, color stable and insensitive to temperature fluctuations. The filters are double-sided polished to an accuracy of λ/4 and meet a polishing grade of 60/40 according to MIL-O-13830. This ensures high transmission in the pass range and strong blocking in the blocked range.

The set comes in a sturdy plastic box with EVA foam lining to keep the filters safely protected during transport and storage.

Application
The Optolong UBVRI Filter Set is ideal for:

• Accurate photometric measurements of stars and variable objects
• Scientific deep-sky observing projects
• Astrophotography requiring international comparability of data
• Use in 2″ filter wheels for CCD and CMOS cameras

Specifications

• Filters: U, B, V, R, I (ultraviolet, blue, green, red, infrared)
• Mount: 2″ round mount (suitable for filter wheels)
• Material: shot glass
• Optics coating: multi-coated
• Transmission: approx. 70% in passage range
• Surface accuracy: λ/4
• Polishing quality: 60/40 (MIL-O-13830)
• Application: photographic, not visual
• Protective packaging: plastic box with EVA foam lining