Skip to content
Saturday April 26th: The store will be closed, we will be attending ACAIQ astroimaging conference.
Saturday April 26th: The store will be closed, we will be attending ACAIQ astroimaging conference.
Optec DSI 3.5" Extension Tube Set - 5 Pieces

Optec DSI 3.5" Extension Tube Set - 5 Pieces

by Optec
SKU OPC-19890
$0
$250.00 USD - $250.00 USD
$250.00
$250.00 USD - $250.00 USD
$250.00 USD
Availability:
Backordered
Contact us to know when we will receive our next ones!

International Shipping

More information

Rich Simons of Deep Sky Instruments and Optec have jointly developed a new, larger diameter standard spacer for large aperture telescopes. Like the Astro-Physics 2.7-inch spacer set, the Optec-DSI 3.5-inch spacers are available in a five different lengths.

The AP 2.7-inch thread has become an astronomy industry standard thanks to the tireless efforts of Roland and his team at Astro-Physics. Optec has produced a complementary extension set and a few new adapters in an effort to extend this industry standard. However, there are times when the 2.5" clear aperture of the AP2.7 spacers will not allow enough light through clipping the edge rays.

Optec-DSI 3.5-inch extension tubes feature female threads on one end with male threads on the opposite end with knurled bases to help attach and detach these tubes. The extensions can be combined and stacked. We believe our four and five piece sets will provide all the needed extension for fixed focal length telescopes with 1/4" (6.35mm) increments using a minimum number of pieces. Click here for a table of the optimized spacer combinations.

All extensions and mounts are made from high strength 6061 aluminum alloy and black anodized. Anti-reflection threading and internal baffles on the largest extension tube help minimize internal reflections. All internal surfaces are painted and baked with a non-reflecting ultra-flat black paint.

  • Includes: 1/2", 3/4", 1", 1-1/2", and 3"
  • Possible spacer combinations:
    0.5" through 6.25" with 1/4-inch increments plus 6.75" with all spacers combined.

You may also like

  • $27.00 USD - $27.00 USD
    $27.00 USD
    $27.00 USD - $27.00 USD
    $27.00 USD

    Baader T-2 Extension Tube- 15mm

    BAA-1508154

    15mm optical path length Telescope side T-2 internal thread Focus side T-2 external thread For eyepiece projection with shift/sliding focuser T-2 ...

    View full details
    $27.00 USD - $27.00 USD
    $27.00 USD
    $27.00 USD - $27.00 USD
    $27.00 USD
  • $25.00 USD - $25.00 USD
    $25.00 USD
    $25.00 USD - $25.00 USD
    $25.00 USD

    Baader T-2 Extension Tube- 7.5mm

    BAA-1508155
    1 in stock

    7.5mm optical path length Telescope side T-2 internal thread Focus side T-2 external thread For eyepiece projection with shift/sliding focuser T-2...

    View full details
    $25.00 USD - $25.00 USD
    $25.00 USD
    $25.00 USD - $25.00 USD
    $25.00 USD
  • $135.00 USD - $135.00 USD
    $135.00 USD
    $135.00 USD - $135.00 USD
    $135.00 USD

    Optec OPTEC-4300 to DSI 3.5"(F) Adapter

    OPC-19830

    The #19830 OPTEC-4300 to female Optec/DSI 3.5" threaded receiver allows any combination of our DSI 3.5-inch spacers to be easily installed on the c...

    View full details
    $135.00 USD - $135.00 USD
    $135.00 USD
    $135.00 USD - $135.00 USD
    $135.00 USD
  • $30.00 USD - $30.00 USD
    $30.00 USD
    $30.00 USD - $30.00 USD
    $30.00 USD

    Baader T-2 Extension Tube- 40mm

    BAA-1508153

    40mm optical path length Telescope side T-2 internal thread Focus side T-2 external thread For eyepiece projection with shift/sliding focuser T-2 ...

    View full details
    $30.00 USD - $30.00 USD
    $30.00 USD
    $30.00 USD - $30.00 USD
    $30.00 USD
  • $19.00 USD - $19.00 USD
    $19.00 USD
    $19.00 USD - $19.00 USD
    $19.00 USD

    PrimaLuceLab 5mm T2 Extension

    PLL-PL3304205
    1 in stock

    PrimaLuceLab T2 extensions are available in different lengths and they present on both sides of a T2 thread (one side is male, the other is female)...

    View full details
    $19.00 USD - $19.00 USD
    $19.00 USD
    $19.00 USD - $19.00 USD
    $19.00 USD