Mk 25/30, latest version

My “small” Dobsonian telescope. Constructed and modified between December 2019 and May 2025, this instrument is designed to do everything: wide-field vistas, sharp planetary views, and deep views of galaxies and globular clusters. The primary mirror is 0.8" thick quartz and made by Nova Optical. The secondary is a 3.1" Antares unit, accurate to 1/20 wave.

The whole telescope weighs just 45 pounds, and fits in my passenger seat if I need it to. It can be assembled in as little as five minutes. Tracking is provided by a Poncet equatorial platform. With a 21mm Ethos eyepiece, I can get a 1.7-degree true field of view - 3.5 full Moons across!

The most recent major changes I made to the scope were in May 2025; I added whiffletrees machined by a friend to properly support the edge of the mirror and repainted some of the rocker box. It finally has sharp stars after 5 years.

Version History

Mk 7

• Ridiculously tall upper tube assembly
• Bearings were too small
• Siliconed mirror warped severely at high magnifications
• Needed counterweights
• HC-2 focuser

Mk 11

• Trimmed upper tube assembly and mirror box
• New rocker box and bigger bearings
• Ball and socket pole clamps
• Better mirror edge support

Mk 14

• Moonlite focuser
• Baffle
• Shroud

Mk 15

• Fans, dew heater controller & battery
• EQ platform for 42 North latitude
• New rocker box

Mk 19

• Reinforced upper cage
• Baffle removed
• New shroud from Shrouds by HEater

Mk 20

• Temporarily no EQ platform due to moving 10 degrees south to Arizona
• Future upgrades added a new platform and a QuInsight finder in place of the Rigel