Free Shipping On All Orders Over £250 | Call us today on 020 8064 2095

0

Your Cart is Empty

Telescopes
  • TELESCOPES

  • ACCESSORIES

  • FEATURED

  • Binoculars
  • BINOCULARS

  • FEATURED

  • Sporting Optics
  • SPORTING OPTICS

  • FEATURED

  • Brands
  • Shop by price
  • ANTLIA ULTRA 2.5nm OIII Ultra Narrowband Filter - 2" Mounted

    .

    Antlia ULTRA OIII 2.5nm QUARTZ Ultra-Narrowband Filter - 2" Mounted

    Now with a 2.5nm bandwidth! 

    Antlia H-a, SII and OIII 2.5nm Ultra Filter - Extra Narrowband filters   2" mounted

    The Antlia SHO 2.5nm Ultra series filters are made with quartz glass and undergo precisely controlled coating processes to ensure optimal performance. The 2.5nm Ultra series is designed with a FWHM (full width half maximum) of 2.5nm +0.3/-0.1nm and a transmission efficiency >92-95% at the Central Wavelength.

    The quartz glass possesses an ultra-low thermal expansion coefficient with outstanding thermal and mechanical properties. When combined with advanced coating processes, these filters exhibit remarkable durability for imaging and research in the most challenging environmental conditions.

    Compared to the 3nm Pro series, the 2.5nm Ultra series coated on quartz glass exhibits higher transmittance with Ha/SII95% and OIII92%. These filters are estimated to improve signal by 20-30% in your images. Additionally, the Ultra series boasts a narrower FWHM of 2.5nm+0.3/-0.1nm, resulting in an exceptionally high Signal to Noise Ratio for deep sky photography.

    TECHNICAL SPECIFICATIONS

     

    Hydrogen-alpha

    Sulfur-II

    Oxygen III

    FWHM

    2.5nm +0.3/-0.1nm

    2.5nm +0.3/-0.1nm

    2.5nm +0.3/-0.1nm

    CWL (Central Wavelength)

    656.3nm

    672.4nm

    500.7nm

    Peak Transmission

    95%

    95%

    92%

    Blocking

    ≥OD5

    Filter Thickness

    2mm+/-0.05mm

     

    SIZES:

    currently available in a 2" standard filter cell

    MAIN FEATURES and APPLICATION

    - High transmittance (Ha/SII≥95%,OIII≥93%)and the narrow FWHM 2.5nm +0.3/-0.1nm to maximize contrast;

    - Flat-top spectrum minimizes the loss in transmission due to the Center Wavelength (CWL)-shift;

    - Out of band blocking specification is designed to OD5 (0.001%) to block interference from other wavelengths and minimize halos around bright stars;

    - Made of quartz glass, excellent durability and thermal stability, better fracture resistance and scratch resistance, improved coating resilience to cleaning;

    - Filters are resistant to scratches;

    - Identical filter thickness to existing standards and double-sided fine polishing , with utmost care for parfocality;

    - The SHO 2.5nm Ultra filters are recommended for use in optics with a Focus Ratio of ≥ f/3.5 for best optical performance;

    - 100% of production are scanned individually, all transmission and blocking (OD) data in the box are actual, measured spectra and transmission;

    - All Antlia filters are coated to the edge of the substrate and unmounted narrowband filters are edge blackened to eliminate internal reflections from stray light;

    - Warranty: 3-years against delamination

    As authorised dealers for all our products they come with a full manufacturers warranty along with our satisfaction guaranteed, no-questions-asked full refund policy for a full 30 days.

    Please see our returns policy for full details.

    We ship direct from UK warehouses and provide free shipping on all purchases within England, Scotland and Wales (Excluding highlands and Islands)

    We use UPS, DHL, DHL Express, Parcelforce or Royal Mail for all orders.

    Estimated delivery time is displayed at checkout.

    See our shipping policy for more details.

    Should you be outside the free shipping area then please contact us to discuss shipping options as prices vary depending on products and delivery location.

    Got questions? Read through our FAQ list to see if it's answered there! If not, please contact us via this form.

    Customer Reviews

    Be the first to write a review
    0%
    (0)
    0%
    (0)
    0%
    (0)
    0%
    (0)
    0%
    (0)