Celestron M42 Spacer Ring Kit

050234936187

Celestron

1 in stock
£49.99
£49.99
Tax included. Shipping calculated at checkout.

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Celestron M42 Spacer Ring Kit

Precise Backfocus Adjustment for Optimal Image Quality

Achieving pinpoint star sharpness in astrophotography relies on setting the correct backfocus distance between your camera sensor and telescope optics. The Celestron M42 Spacer Ring Kit makes this easy, ensuring optimal edge-to-edge performance—especially for full-frame imaging sensors.

Why Backfocus Matters

If your camera sits too close or too far from the telescope's required focus point, stars near the corners of your frame can appear distorted or elongated. Spacer rings fine-tune this distance, helping maintain the RASA, EdgeHD, or Schmidt-Cassegrain system’s intended performance.

Example:

  • RASA 8 + ZWO ASI 183MC Pro

    • Required backfocus: 25mm

    • Camera depth: 17.5mm

    • Needed spacer: 7.5mm M42 ring

What’s Included

  • 3x Precision CNC-machined spacer rings:

    • 7.5mm – Ideal for many ZWO cameras on RASA 8

    • 12mm – Ideal for many Atik cameras on RASA 8

    • 30mm – Converts ZWO camera with filter slider to 55mm backfocus standard (Schmidt-Cassegrain & EdgeHD)

How to Use

  • With DSLR: Insert the appropriate ring between your T-Ring and T-Adapter.

  • With CMOS/CCD: Place the ring between your camera and the T-Adapter.

Build Quality

  • Anodised machined aluminium construction

  • Glare-threaded, blackened interior for maximum contrast

  • Knurled edges for easy grip when threading or removing

  • Compatible with M42 x 0.75 (T-thread) camera adapters

The Celestron M42 Spacer Ring Kit is an essential accessory for anyone seeking the sharpest, most accurate astroimages possible—especially when using full-frame or sensitive CMOS imaging cameras.

Shipping Options

Fast & Reliable UK Delivery

We offer flexible delivery options across the UK, with free shipping available on qualifying orders.

  • FREE Next Working Day Delivery (Mon–Fri)
    On all orders £300 and over
  • FREE Express Delivery (1–3 Working Days)
    On orders £49.99 – £299.99
  • Express Delivery – £3.99
    On orders under £49.99
  • Standard Delivery (2–4 Working Days) – £2.99
    A great value option for smaller orders
  • Priority Shipping – £8.99
    A fully tracked, guaranteed delivery service, including Saturday delivery options

Order Fulfilment

Some items, as clearly stated on the product page, may be fulfilled directly by our partners or manufacturers. In these cases, your order will be shipped to you straight from the brand’s warehouse. This helps us provide a wider range of specialist equipment and may result in slightly different delivery times.

Returns Policy

If something isn’t right, we’ll always try to help.

  • Unused items in “as new” condition can usually be returned within the statutory cooling-off period
  • Please contact us before sending anything back so we can advise on the safest way
  • For unwanted items, return shipping is your responsibility, and original shipping may be deducted where applicable
  • If a product is faulty or damaged, we’ll arrange repair, replacement or refund in line with your consumer rights — and we’ll cover reasonable return costs

Telescope shipping is expensive, and specialist — avoidable returns really do impact our business, so we always encourage customers to ask questions before buying. We’re here to help you get it right first time.

Your statutory rights are not affected.
Celestron M42 Spacer Ring Kit

£49.99

Does it come with a warranty?

All our products are UK stock so come with manufacturers warranty

What happens if I don't like it?

We always want you to be happy with your purchase — so if you’re unsure, please ask us first. We’re always happy to give honest advice before you buy.

If the product arrives and you simply decide it isn’t for you, you can usually return it within the cooling-off period — as long as it’s unused, in perfect condition, and returned with all original packaging and accessories.

Because telescopes and optical equipment are large, delicate and expensive to ship, you’ll need to cover the cost of sending it back, and if we originally subsidised delivery, we may deduct our outbound shipping costs from your refund.

We’re a small specialist business, and unnecessary returns genuinely hurt us — so if you’re unsure at all, please talk to us first. We’d rather help you choose the right item than process a return.

How fast is shipping?

We aim to ship in-stock items as quickly as possible.

  • Most in-stock orders dispatch within 1–2 working days
  • Delivery usually takes 1–3 working days after dispatch (UK mainland)
  • Heavier / oversized items and special orders may take a little longer

You’ll receive tracking details as soon as your order is on its way.

Astronomy equipment often requires specialist packing and trusted couriers — we do this to keep your gear safe, not to slow things down. If you need something urgently, just ask and we’ll do our best.

What's the returns policy?

If something isn’t right, we’ll always try to help.

  • Unused items in “as new” condition can usually be returned within the statutory cooling-off period
  • Please contact us before sending anything back so we can advise on the safest way
  • For unwanted items, return shipping is your responsibility, and original shipping may be deducted where applicable
  • If a product is faulty or damaged, we’ll arrange repair, replacement or refund in line with your consumer rights — and we’ll cover reasonable return costs

Telescope shipping is expensive, and specialist — avoidable returns really do impact our business, so we always encourage customers to ask questions before buying. We’re here to help you get it right first time.

Your statutory rights are not affected.

What are your opening hours?

Monday: 9.00am - 5.00pm
Tuesday: 9.00am - 5.00pm
Wednesday: 9.00am - 5.00pm
Thursday: 9.00am - 5.00pm
Friday: 9.00am - 5.00pm
Saturday: 9.00am - 5.00pm
Sunday: Closed