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Optolong Clear Focusing Filter 2"

Name: Optolong Clear Focusing Filter 2"
Brand: Optolong
SKU: OPL-CFF-2
Price: 39.9 EUR
Rating: 4 (1 reviews)

This clear "filter" is used if one works with dark filters. The optical path is the same, but the image is brighter. This makes focusing easy.

Easier focusing than with dark filters, due to 98.5 % transmission

Focus does not change if exchanged against normal filters

Image quality not affected

Also protects from dust

Manufacturer: Optolong

Product number: OPL-CFF-2

EUR 39,90

incl. 19 % VAT (DE)

The VAT indicated refers to that applicable in Germany. After logging in, the VAT amount is adjusted to the applicable VAT of the stored delivery country. Therefore, the final price may vary accordingly.

excl. 6.95 € shipping costs (DE)

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rating: 4.0 of 5

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Optolong Clear Focusing Filter 2"

This clear "filter" is used if one works with dark filters. The optical path is the same, but the image is brighter. This makes focusing easy.

Easier focusing than with dark filters, due to 98.5 % transmission

Focus does not change if exchanged against normal filters

Image quality not affected

Also protects from dust

Details..
Technical data..
In the box..

Optolong Clear Focusing Filter 2"

Clear focusing filter is designed to highly pass the visible spectral region 420-680 nm at 98.5% transmission. Filter thickness is roughly the same as of the other Optolong filters with the same cell.

Use of astrophotography filters, especially narrowband filters, often results in dim images which can be difficult to focus. Clear focusing filter can be used first to clearly focus the image.

Act as an outstanding dust shield, which prevents the possibility of dust settling on the lens during long time exposure.

Warning: The filters of Optolong are not designed for sun observation. DO NOT LOOK AT THE SUN WITH OPTOLONG FILTER. You would be BLIND if you fail to observe the warning!

Substrate:	High-quality optical glass from Schott
Thickness:	2.0 mm
Surface Treatment:	Fine-optically polished
Surface Polish Quality:	60/40 (Refer to MIL-O-13830)
Surface Quality:	1/4 wavefront
Transmission:	approx. 98.5% at passband
Coating:	Muti-coated
Cell:	Filter cell 2", black anodized, laser engraved
Clear Aperture:	45 mm
Cell height:	5 mm without external thread, 7 mm with M48 external thread