1.T>98%@entire passband 2.T<0.1%@annoying wavelength 3.AR coating and high parallelism 4.Both sides polishing 5.ISO9001:2008

S-II anti reflective astronomical filters     

1. Introduction

Astronomical filters are necessary tools for astronomical observing. Yulong company has more than 13years experiences on astronomical filter manufacture. The special and professional processing methods guarantee the filters quality, some filters coating are more than 60 layers. Just have a try and you will find Yulong astronomical filters are your best choice at anytime.

2. Optical Index

Outstanding transmission of 98% across the entire passband;

Entire blocking of prominent light pollution lines;

Maximum image brightness and contrast;

Completely resistant against high humidity, scratches and aging effects.

3.Optical Curve

4. Dimensions

Our astronomical filters are available in a wide range of sizes as mounted and unmounted filters. They are usually available from stock. listed the dimensions as below for your reference.

Filter mounted in 1.25" cell (thread M27.5*1.85mm)

Filter mounted in 2" cell  (thread M46*1.85mm)

Unmounted round filter with diameter 27.5mmx1.85mm

Unmounted round filter with diameter 48mmx1.85mm

Unmounted square filete with 50mmx50mm 

If you require special sizes filters for special application, we can supply them upon request. You can get one piece or 100pieces as well.

5. Applications

Our astronomical S-II filters are great choice for any application of astronomy.

Imaging system;

Imaging with chemical film;

Visual observation;

Observation with cooled CCD cameras;

DSLR imaging;

Webcam astronomy;

Cleaning filters.

6. Principle of Ion Source Ion-assisted Deposition

Adding ion generator-ion source in the film coating technology of thermal evaporation to produce ion beam. In the heat of the evaporation, bombard the growing membrane layer with ion beam so that the compact uniform structure can be formed. It will improve the membrane stability, and reach the purpose of achieving continue improvement of optical and mechanical properties.

7. Perfect Processing Chain and Quality Assurance

Processing

Stept 1:Prepare tooling to mount optics in chamber.

Stept 2:Clean optics and load them into tooling.

Stept 3:Clean chamber and refill with source material needed to produce coating evaporates. Prepare monitoring system.

Stept 4:Load tooling containing optical components into chamber.

Stept 5:Reduce chamber pressure to<2*10-5 Torr and heat chamber between 200 and 300.

Stept 6:Deposit coating layers as per coating design.

Stept 7:Cool and vent coating chamber.

Stept 8:Remove optics from chamber and test optics for coating performance.

Stept 9:Inspect and wrap optics.

8. Packing

Optolong astronomical filters are delivered in a high-quality, long lasting with excellent filter box.

First, we use fashion PP(Propene Polymer) material box for astronomical packing. which is wear-resisting, anti-shock, solid and long lasting.

Second, inside liner material is white EVA (Ethylene Vinyl Acetate Copolymer). It looks beauty and fashion, protect your filter perfectly as well.

Third, thin plastic bag to protect the PP box so that we can send you totally new item. The outer bag is excellent multi-wall corrugated board that is environmental enough.

Fourth, in order to prevent the products scratching, bruising, and smashing during shipping, we usually use PE foam, density cystosepiment, anti-static bubble bag, etc to equip the goods.

S-II anti reflective astronomical filters