Optolong IR685 IR-Pass Planetary Filter 1.25"

Optolong IR685 IR-Pass Planetary Filter 1.25"

The Optolong IR Pass 685nm filter is designed to block wavelengths below 670nm and can be used in IR-LRGB imaging to produce a sharper luminance image for the best planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths.

What filters are used for Planetary photography?

Photography of planets and deepsky objects can be achieved by the use of a monochrome camera and a range of filters. Planetary photography is different from deep sky imaging in a way that deepsky images are taken through Ha, SII, OIII filters, whilst planetary photography would be often taken through IR, UV, R,G,B and other specialist filters.

The main aim is to capture the specific spectrum, such as rich carbon dioxide. One of the most common filter we use is IR-pass through filter- infrared filter. 

In nature, the longer the wavelength of light, the less affected by atmospheric disturbances, so taking images at the red or infrared part of the spectrum has its advantages. 

Thus when we image a planet, we usually use an IR-pass filter, that transmits only infrared, or near-infrared ligth, in order to reduce the negative influence of bad seeing conditions. 

In visible light, photographers use classical RGB filters. For Mercury, Venus, Uranus and Neptune, IR685 comes fist, and for Saturn, Jupiter, UV/IR Cut, R, G and B are good, therefore the portfolio of IR-RGB is popular. 

IR685 Introduction

Optolong IR-Pass 685nm filter is designed to block most visible lights and can be used in IR-LRGB imaging to produce a sharper luminance image for improved planetary contrast as atmospheric seeing and distortion is much reduced at longer IR wavelengths. The advantage of the IR685 filter is to reduce the effects of atmospheric jitter. 

Sensors of CCD or CMOS cameras are usually capable of detecting light in the 350nm -1100nm range including infrared wavelengths. Optolong IR685 cuts off the visible part of the spectrum and allows near infrared light to pass so that cause the most sensitive to bad seeing is rejected. It will highly improve images on visibility, contrast and details of planets and the moon. Besides, IR685 is usually used as a key factor of the portfolio IR-RGB. 

Imaging Target:

IR685 is for imaging of bright planets, stars, and comet, like Uranus, Neptune, Jupiter, Saturn, Mars, Moon, etc. 

This filter will certainly help to create sharper images of the Moon and the planets.

IR685 Spectrum for Reference

How to read the chart?

• The horizontal axis is the Wavelength in Nanometers(nm).
• The vertical axis is Transmission in %.

IR685 characteristic:

• Sbustrate: B270
• Thickness: 1.85mm
• Tave:  T>90%
• Blocking range: 350-1050nm
• Blcoking depth: light pollution  line blocking >99%
• Surface quality: 60/40
• Transmitted Wavefront RMS: λ/4
•  Parallelism: 30s

Packaging Style 

• Outer Box: silve box
• Plastic Box: PP material
• Lining: imported high pressure white EVA material

Testimonials

Surface part of the valley ring mountain, shot by "星空狩猎"

Using Optolong IR685, he said it is darker and less difficult to focus when using IR685.

Notes

●About color: due to the influence of ambient light, color difference of the display and flash photography, the color of the product may have some color difference. Detailed color is in accordance with the final product.

●About coating: the interference filter will show different colors under different light, which is a normal phenomenon. Please refer to the material specification.

●About the description: the series of this product have the same material, technology and design, different sizes only, please note.