This cover is designed to protect your telescope’s secondary mirror from dust, moisture, and accidental contact during storage or observing breaks.
Its dual-layer construction provides reliable optical protection in both home and field environments.
The outer layer is made from a durable, water-repellent material that effectively blocks dust and environmental exposure. The inner lining features soft microsuede fabric, which is gentle on delicate optical surfaces and will not scratch or damage the mirror coating.
This cover is ideal for both home storage and field use between observing sessions.
An included adhesive hook can be attached to the outside of the telescope tube, allowing you to hang the cover securely when removed — keeping it clean, accessible, and easy to find. The hook attaches safely and can be removed at any time without damaging the tube or leaving residue.
Elastic cords with a locking clamp ensure a secure fit and reliable hold on the secondary mirror, preventing accidental slipping while remaining quick and easy to install or remove.
| Size | Diagonal (in) | Diagonal (cm) |
|---|---|---|
| S | 6.0 in | 15.2 cm |
| M | 7.0 in | 17.8 cm |
| L | 7.5 in | 19.05 cm |
| XL | 9.5 in | 24.13 cm |
| XXL | 12.0 in | 30.48 cm |
Measure Before You Buy – Fit Matters
To select the correct cover size for your secondary mirror, measure the longest diagonal of the mirror or its holder. This diagonal measurement is the key dimension used to determine the proper size.
We recommend choosing a cover with a small amount of extra space to ensure easy installation and a secure, comfortable fit. Our covers are available in five sizes, designed to fit most Newtonian and Dobsonian telescope designs.
| Size | Diagonal (in) | Diagonal (cm) |
|---|---|---|
| S | 6.0 in | 15.2 cm |
| M | 7.0 in | 17.8 cm |
| L | 7.5 in | 19.05 cm |
| XL | 9.5 in | 24.13 cm |
| XXL | 12.0 in | 30.48 cm |
Provides approximately 6 inches (15.2 cm) of diagonal internal space.
Designed for a close but comfortable fit.
Always allow a small margin when selecting your size.
Provides approximately 7 inches (17.8 cm) of diagonal internal space.
Suitable for mirrors or holders with a similar diagonal dimension.
A small size margin is recommended for ease of use.
Provides approximately 7.5 inches (19.05 cm) of diagonal internal space.
Offers a balanced fit for mid-sized secondary mirrors.
Leave a small margin when choosing your size.
Provides approximately 9.5 inches (24.13 cm) of diagonal internal space.
Designed for larger secondary mirror assemblies.
Select a slightly larger size if your measurement is close to the limit.
Provides approximately 12 inches (30.48 cm) of diagonal internal space.
Ideal for large Newtonian and Dobsonian secondary mirrors or holders.
Always allow a small clearance for best fit and easy installation.