Skip to content
IMPORTANT: Starting May 1st, all orders for products that are made in China, regardless of their value, will be subjected to 145% tariffs when imported in the USA. These fees will be billed to you by the carrier, and are your responsibility.
IMPORTANT: Starting May 1st, all orders for products that are made in China, regardless of their value, will be subjected to 145% tariffs when imported in the USA. These fees will be billed to you by the carrier, and are your responsibility.

Features

  • Adjusts back-focus between your camera and telescope for the best astroimaging results
  • Kit includes 3 spacer rings of different lengths (7.5mm, 12mm, 30mm)
  • Threads to your T-Ring and T-Adapter with standard male and female T-Threads

Celestron M42 Spacer Kit

To achieve the best astroimages, it is important to attain the proper back-focus distance for your camera relative to the telescope it is being used with. If the back-focus distance your camera consumes is not exact, the performance at the corners of full frame imaging sensors will suffer—stars will appear elongated and not as pinpoints.
Example: RASA 8 with a ZWO ASI 183 MC PRO camera

  • Required back-focus distance for RASA 8 with included M42 camera adapter: 25mm
  • Back-focus consumed by ZWO ASI 183 MC PRO camera: 17.5mm
  • To achieve equal back-focus distance, a 7.5mm M42 spacer ring is required


Celestron’s M42 Spacer Ring kit includes three different length spacer rings to achieve the proper back-focus distance with our popular Celestron optical tubes and T-thread camera adapters.

How to Use
Depending your method of astrophotography (DSLR or CCD/CMOS), there are two ways to use the M42 Spacer Ring. If you are using a DSLR, place the desired M42 Spacer Ring between your T-Ring and your T-Adapter for your optical tube. If you are using a CCD or CMOS camera, place the desired M42 Spacer Ring between the camera and the T-Adapter for your optical tube.


Below is a quick guide to help you determine which spacer ring to use for our EdgeHD, Schmidt-Cassegrain, and RASA 8 optical tubes:

Spacer Ring Size: Works best with:
7.5mm Provides proper spacing with RASA 8 for many ZWO cameras
12mm Provides proper spacing with RASA 8 for many Atik cameras
30mm Converts ZWO camera w/filter slider to 55mm back-focus standard for use with Schmidt-Cassegrain & EdgeHD


Body
The M42 Spacer Rings are machined aluminum black anodized. The internal surfaces are blackened and glare-threaded to provide the highest contrast. Each spacer ring has a knurled surface, providing a great gripping surface for threading/unthreading. The M42 Spacer Rings are compatible with M42 x 0.75 (T-thread) camera adapters.

Specifications

Thread: M42 x 0.75
Spacer lengths: 7.5mm (.29"), 12mm (.47"), 30mm (1.18")
Construction: Aluminum black anodized
Interior: Blackened and glare threaded
Exterior: Knurled grip surface, each ring labeled with its length

You may also like

  • $60.00 USD - $60.00 USD
    $60.00 USD
    $60.00 USD - $60.00 USD
    $60.00 USD

    QHYCCD M42 All-In-One Adapter Kit

    QHY-020111
    2 in stock

    If you need a specific back focal length, you can use QHYCCD's All-In-One adapter kit to combine your own set of spacer rings to meet your particul...

    View full details
    $60.00 USD - $60.00 USD
    $60.00 USD
    $60.00 USD - $60.00 USD
    $60.00 USD
  • $72.95 USD - $72.95 USD
    $72.95 USD
    $72.95 USD - $72.95 USD
    $72.95 USD

    Celestron 48mm T-Adapter for EdgeHD 9.25”, 11”, and 14”

    CEL-93622
    Only 3 left!

    Features Attaches directly to the rear cell of the larger Edge optical tubes Produces better illumination for today's larger full-frame imaging sen...

    View full details
    $72.95 USD - $72.95 USD
    $72.95 USD
    $72.95 USD - $72.95 USD
    $72.95 USD
  • $39.95 USD - $39.95 USD
    $39.95 USD
    $39.95 USD - $39.95 USD
    $39.95 USD

    Celestron Large SCT & EdgeHD Adapter V2 for Off-Axis Guider

    CEL-93666
    Only 1 left!

    Features Custom-designed adapter works in conjunction with the Celestron Off-Axis Guider to produce a larger area of illumination when imaging thro...

    View full details
    $39.95 USD - $39.95 USD
    $39.95 USD
    $39.95 USD - $39.95 USD
    $39.95 USD
  • $33.95 USD - $33.95 USD
    $33.95 USD
    $33.95 USD - $33.95 USD
    $33.95 USD

    Celestron T-Adapter for SCTs

    CEL-93633-A
    Only 4 left!

    Features The Celestron T-Adapter attaches an SLR or DSLR camera to a Schmidt-Cassegrain telescope for prime focus photography Threads on to the rea...

    View full details
    $33.95 USD - $33.95 USD
    $33.95 USD
    $33.95 USD - $33.95 USD
    $33.95 USD
  • $18.00 USD - $18.00 USD
    $18.00 USD
    $18.00 USD - $18.00 USD
    $18.00 USD

    ZWO T2 Adapter - 11mm

    ZWO-T2-T2-11
    2 in stock

    Double Male T2 Thread Design Durable Aluminum Construction Compact and Lightweight ...

    View full details
    $18.00 USD - $18.00 USD
    $18.00 USD
    $18.00 USD - $18.00 USD
    $18.00 USD