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• Free shipping in the contiguous United States. No surprise fees. The price you see is the price you pay.
• Unbeatable 30-Day return policy. WE pay for the return shipping AND any restocking fee enforced by the supplier so you can shop worry free.
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Features

• Dark-Sky filter
• Contrast increase in aurora & deep-sky photography
• Reduction of stray light from street lights, for example
• Wide-angle shots of the starry sky, time-lapse shots
• Blocks yellow light, not possible with image editing
• Black anodized aluminum housing
• 77mm filter thread for photo lenses
• Construction height only 4mm (Slim)
• Suitable for wide-angle lenses
• Made of special optical glass with neodymium oxide

Description

Universally applicable dark sky filter with 77mm filter thread for photo lenses. Particularly suitable for increasing contrast in aurora and deep-sky photography.

The wavelengths of 550nm (green) and 630nm (red), which are particularly relevant for aurora photography, are transmitted to more than 90%. A special feature of other so-called CLS filters is that only the yellow light of the sodium line is effectively blocked at 590nmwill. This effectively suppresses sodium vapor lamps from street lighting and greenhouses (assimilation light). This is a clear advantage because the yellow light for the digital camera is always registered as a mixture of red and green. Especially with aurora photography or recordings of emission nebulae, later removal of the light pollution by post-processing the photos would be virtually impossible.

A reduction in yellow tones also ensures a better differentiation between red and green tones.

With the Explore Scientific Dark-Sky Filter, weaker aurora events from cities can also be detected photographically.

Especially in times of increasing light pollution, this filter does an extremely good job. In contrast to widely used interference filters (CLS, UHC), this filter can also be used without restriction in front of a wide-angle lens, which is not possible with interference filters. Such filters require perpendicularly incident light and have to be installed between the lens and the camera in a complex manner for wide-angle recordings.

The dark sky filter is not only of value for the ambitious astrophotographer, it also ensures natural color reproduction of the night sky without complex image processing .

In nature and macro photography red and brown tones (e.g. twilight colors, sunset, autumn leaves) are emphasized and better differentiated.

Due to the very flat design (slim) of only 4mm, this filter is also fully suitable for wide-angle lenses. This means that vignetting-free recordings are possible.

Test images taken by Bernd Pröschold - www.sternstunden.net

Comparison test at: http://www.sternstunden.net/filter-testing.html

CA Residents: Prop 65 WARNING(S)

• We are happy to offer free shipping to all bordering states in the United States
• Shipping typically takes 2-5 business days and is sent directly from the manufacturer
• A tracking number will be provided when the manufacturer ships out the items. Please allow up to 5 business days to be provided with a tracking number

30-Day Return Policy: no postage, no restocking fee, no worries!

Astraeus Optics will cover shipping fees as well as any restocking fee that the manufacturer enforces.

To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging. Custom made items are not eligible for returns or refunds.

There are certain situations where only partial refunds are granted: (if applicable)

• Any item not in its original condition, is damaged or missing parts for reasons not due to our error.
• Any item that is returned more than 30 days after delivery

You can request a refund by Contacting Us.
We will credit you for the total purchase price upon the receipt of your return. Products returned under this policy are eligible for a refund to the original method of payment.

Defective Product Returns

We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at support@astraeusoptics.com

Refunds

We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method within 10 business days. Please remember it can take some time for your bank or credit card company to process and post the refund too.
If more than 15 business days have passed since we’ve approved your return, please contact us at support@astraeusoptics.com