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2″ StarguiderOptolong H-Alpha 7nm filter – 7
SPECIAL 2″ Starguider/Optolong H-Alpha 7nm filterClick images to enlargeDescription
We are delighted to offer for sale this superb quality2″Hydrogen Alpha 7nmFWHMdeep sky and nebulafiltermade forStarguiderbyOptolong.
All filters arenotthe same.
Only Sky’s the Limit:Test every filter soldInclude an individual data graph for each filter (sent by email)Inform you of all the transmission and cut off frequencies before you buyCan provide a complete test result for your filter on requestLet you name the price you are prepared to pay starting at cost
It is a narrow band filter and can be used to improve contrast, capture new details and to combat light pollution.
This is a premium quality 2″Starguider/Optolong H-Alpha filter with a 7nm bandwidth.
This Starguider filter is manufactured by Optolong and verified in the UK. Each filter is individually tested (see below).
LOWEST PRICE IN THE WORLD? CHEAPER THAN CHINA! NO CUSTOMS DUTIES TO PAY!
At Sky’s the Limit we test each filter individually. No between this and that figures – what you see is what you get. Each Ebay listing is individual to the filter being supplied.
It is a very narrow band filter and can be used to improve contrast, capture new details and to combat light pollution.
H-a filters work particularly well on emission nebulae, but can also be very effective inreducing the effects of light pollution and in reducing star saturation and bloat. It is for use with a CCD camera or DSLR camera -it must not be used for solar viewing.
Aswell as the manufacturer’s supplied graph you will receive an A4 sized colour spectrum graph with readings made with our own Avantes spectrometer. We test each filter to ensure that it meets the specification quoted. Our graph shows the peak transmission %age and at what frequency. Our spectrometer also measures the bandwidth (also known as FWHM – Full Width at Half Maximum). We also supply the data relating to the transmission at H Beta, Oxygen III and Sulphur II. Upon request we can also supply the full spectrum readings as an Excel file.Here’s the actual graph for this filter that you will also get with this purchase (less watermark):PerformanceStarguider/Optolong filters offer performance as good as, and in some cases better than, the top brands currently on sale.We have printed data on this listingso that you can compare this to similar curves from other suppliers.And here are the very important figures derived from the spectrometer readings:
Nebula’s light (nm)Transmission T%H- 478nm0.11%H- 479nm0.09%H- 480nm0.06%H- 486.1nm0.04%O- 495.9nm0.17%O- 500.7nm0.05%H- 656.3nm89.03%SII – 672.4nm0.56%Artificial light (nm)Transmission T%Hg 435.8nm0.28%Hg 546.1nm-0.05%Hg 577.0nm0.02%Hg 578.0nm0.03%NA 589.6nm-0.01%Na 615.4nm0.05%Na 616.1nm0.05%
Peak Transmission = 91.01% @ 656.96nm
FHMW = 7.86nm
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. Thefilter 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.
Manufacturer’s InformationSize1.25″2″31mm (unmounted)36mm (unmounted)EOS-COther customized size please send email for inquirySpecificationsCWL(centre wavelength): 656.3nmFwhm: 7nmTpeak:
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Category: Cameras and Photography:Telescopes and Binoculars:Telescope Parts and Accessories:Filters
Location: Welwyn Garden City