The Duration of Telescope Lifespan: An Inquiry
Tough-as-Nails Telescopes: A Durable Guide
Telescopes, despite their delicate appearance, are surprisingly robust instruments. Even with neglect, they can often be restored to their original state, except when made of low-quality materials. For those intrigued, here's a sneak peek into the typical lifespans of common telescope components, gathered from hands-on experience and deep immersion in the telescope niche for almost a decade:
- Optics: A Lifetime
Glass, both solid and hard, combined with protective optical coatings, usually shields the glass beneath from chemical damage. Small micro-scratches on lenses often don't hinder performance significantly in numerous cases. The existence of working telescopes from the 1800s, used daily in observatories, is a testament to their durability.
HINT: How to Clean Telescope Mirrors and Lenses*
- Mirror Coatings: Decades to a Century
Aluminum mirror coatings can succumb to chemical decay within years or decades if not well preserved. However, with proper care, even frequently-used reflecting telescopes may continue using their original mirror coatings. Silver mirror coatings, on the other hand, tarnish within a few years, even in ideal conditions.
HINT: How to Care and Recoat Telescope Mirrors*
Schmidt-Cassegrain telescopes' sealed optical systems make them more resilient against corrosion caused by polluted air, pollen, and moisture. These robust units are still going strong even after pushing 50-60 years, with their mirrors showing no signs of age.
- Mounts & Most Metallic Fittings/Parts: A Century-Long Lifespan
Precision-machined mounts can be refurbished, even when somewhat corroded. Clock drives comprise simple electronic parts that are easy to repair.
- Metal Focusers: Decades to a Century
While many metal focusers, such as those employing rack-and-pinion or helical designs, will eventually wear down some components to the point of being unusable, this normally doesn't occur for an extended period.
- Tubes: Decades to a Century
Tubes constructed from high-quality materials, like steel alloy, phenolic resin, and cardboard, often boast sealant or paint coatings that retain their condition for at least half a century.
- Simple Electronics (finders, clock drives, motor focusers): 30 to 50 years
Even simple electronics experience wear over time with heavy usage. Some older clock-driven telescopes are encountering drive failures. Interestingly, I've observed that the mechanical parts within these drives, particularly older ones made using materials such as rubber and cork for shims, usually give out before the electronics do.
- GoTo Mounts: 20 to 30 years
GoTo mounts often employ plastic gears, which will eventually wear away. However, other than that, the complex circuitry can eventually fail or succumb to software issues. I've witnessed and heard of numerous older GoTo mounts from the 1990s and early 2000s that are now faltering. Newer, more expensive models might fare better but will inevitably require upgrades and replacement parts after a while.
- Shims, Eyecups, Grips, & Similar Parts: 20 to 30 years
Even today, many mirror cells and drive systems still make use of cork shims, a material that can dry rot or disintegrate. Replacements are straightforward, and other materials like rubber used on eyepiece eye guards, focuser grips, et cetera, also give out after several decades owing to dry rot.
- Dobsonian Bases: 20 Years
Plywood or chipboard Dobsonian mounts, even decades old, are in good working condition with basic paints or varnishes applied. However, the particle board bases in cheap, mass-produced Dobsonians eventually warp when exposed to moisture. The melamine laminate covering it can peel due to moisture, temperature, or sunlight damage.
Before it begins deteriorating, an accident can however destroy your mount. Particle board is inherently brittle, getting weaker with time.
- Plastic Focusers: 10 to 20 years
While many plastic rack-and-pinion focusers can be remarkably resilient, especially if used frequently, the teeth are vulnerable to wear and jamming, even when not accidentally destroyed. Fragile and expensive to replace, they are arguably one of the most vulnerable components of an entire telescope.
Telescopes with optics made of robust glass and protected with optical coatings can potentially last a lifetime, as demonstrated by functioning telescopes from the 1800s. With proper care, aluminum mirror coatings can maintain their integrity for decades to centuries. Schmidt-Cassegrain telescopes, with their sealed optical systems, continue to perform excellently even after reaching half a century. Mounts and most metallic telescope parts can last for a century, while simple electronics, such as finders, clock drives, and motor focusers, may operate effectively for about 30 to 50 years.
