We have all done it - bought a set of things and then lost one making the set incomplete, sometimes useless.  Well, that has happened to us but it could also help if it has happened to you.  We were doing a stock check with our packers and found that what should have been a set of 2" LRGB filters had one missing - the Green.  So, we can't sell them as a complete set but we can offer them to you as individual filters to, maybe, complete a set that you may have mislaid (lost) one from.

These are Optolong filters.  They made them for us when they were trying to establish a presence in the UK and carry our branding but they are genuine Optolong.

You can pick which you want and we will get it  on its way to you.

Below is the usual listing that we used for complete sets so ignore anything that might mention Green.

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We are pleased to offer one of our High Transmission (HT) precision range of filters, this is a set of 2"  LRGB filters which is sure to impress on performance, quality and price.  Each filter set comes with its own individual data sheet.  Results guaranteed!

Made for us by Optolong.

Genuine UK Business

Genuine UK Stock

 

Many of the best astro images seen in the Sky at Night and Astronomy Now magazines are taken with monochrome CCD cameras and colour filters using RGB or LRGB combination techniques (L=luminance, R=red, G=green, B=blue).

By taking separate images through custom filters, and combining the results to make an RGB image, the full resolution of the CCD is utilized and a great deal of latitude is preserved for image processing. The results are that you end up with an image that is how you would see it if your eyes were sensitive enough to see it.

The filters are dichroic meaning that unwanted light is reflected rather than absorbed by the filter.

"In a dichroic filter, instead of an oil film, alternating layers of optical coatings with different refractive indexes are built up upon a glass substrate. The interfaces between the layers of different refractive index produce phased reflections, selectively reinforcing certain wavelengths of light and interfering with other wavelengths." - Wikipedia

The RGB filters each have IR blocking as part of their specification.  The L filter also has UV-IR blocking to eliminate unwanted interference to produce stunning results.
 

Manufacturer's (Optolong) Specification

Astronomical Filter	LRGB-L
Dia Tolerance	0/-0.1mm
Thickness Tolerance	±0.1mm
Substrate	Schott B270
Incident Angle	0°
Optical Data	Tave<0.5 @ 300-470nm±, 735-1100nm Tave>90%@410-680nm
Quality Surface	60/40

 

Astronomical Filter	LRGB-R
Dia Tolerance	0/-0.1mm
Thickness Tolerance	±0.1mm
Substrate	Schott B270
Incident Angle	0°
Optical Data	Tave<0.5 @ 300-560nm±, 735-1100nm Tave>90%@600-680nm
Quality Surface	60/40

 

 

Astronomical Filter	LRGB-G
Dia Tolerance	0/-0.1mm
Thickness Tolerance	±0.1mm
Substrate	Schott B270
Incident Angle	0°
Optical Data	Tave<0.5 @ 300-470nm±, 580-1100nm Tave>90%@500-550nm
Quality Surface	60/40

 

 

Astronomical Filter	LRGB-B
Dia Tolerance	0/-0.1mm
Thickness Tolerance	±0.1mm
Substrate	Schott B270
Incident Angle	0°
Optical Data	Tave<0.5 @ 300-470nm±, 515-1100nm Tave>90%@410-480nm
Quality Surface	60/40

    

 

Performance

Our filters offer performance as good as, and in some cases better than, the top brands currently on sale.  The listing shows a typical performance curve for each filter (if you are unsure how to interpret the graph see our easy to read Glossary guide below).  You can compare this to similar curves from the top brands and we are sure you will be pleasantly impressed.

However, to ensure that you will be impressed with your purchase each filter is individually tested and issued with its own performance data sheet.  This is your guarantee that you are getting exactly what you paid for. 
 

Quality

Each filter is built upon a precision polished substrate of Schott glass. The specification speaks for itself and is supported by the data sheet.  The filter will retain its 'as new' optical performance for more than 10 years.  It is resilient to scratches, moisture, dew, and humidity.

Even the storage package was carefully developed to take the greatest of care of your filter so that it can be a long lasting companion to you and your hobby or profession.

Why buy from us?

Have a look at our feedback and you will see the common theme is that we communicate well. Before a sale, during the processing of the transaction and after you have purchased an item you have access to a telephone number and email address both connected to a human being who knows what you have been sold. We will do our utmost to make things as smooth as possible for you - especially if you are new to astronomy or to Ebay, we all had to start at sometime. There is no such thing as a silly question, please ask knowing that we will treat you courteously and respectfully as we hope you will want to come back to us if you choose to upgrade or buy some extras for your hobby.

We will not leave you in the dark!

Skies Unlimited is the Ebay trading name of "Sky's the Limit".  Feel free to email any questions through Ebay.