newtonian telescope optimisation

Fed up of constantly losing collimation? Fed up of this?

If you insist on using a separate guide telescope, give yourself a chance. Newtonian reflectors are notoriously wobbly, especially the cheepo varieties right out of the box.

Here are suggestions essentials which enable you to get decent stars throughout. This has been tested with myriad of Newtonian reflectors. The dimensions here are for the 200mm range, tested specifically on both a sw 200pds, a gso203-f4.9 and an ES pn208-f3.9.

Identical essentials for any other tube. yes, carbon fiber included; simply change the spring wire -beginning with 1.2mm for a 130mm mirror- and dovetail accordingly.

Working from the mirror cell upwards:

• Fit six 1.6mm wire springs. 3 replacements, plus three passive springs over the locking screws. Leave the latter loose.
• Seal the primary mirror to the cell using three generous blobs of neutral silicone sealant to coincide with the manufacturer's cork. Leave to seat under gravity for 24h.
• Remove the mirror clips
• Set the tube rings at least 50cm apart on a Losmandy dovetail
• Tie the top of the rings with a rigid aluminium box section
• Remove any rubber o-ring spacers in the focuser
• Replace any metal or metal/plastic guide telescope retaining screws with all nylon types
• (sw only) Drill and tap a third screw to the focuser collar

a stiff gso203
ready for imaging

Now you can start to think about the guide telescope. If you're not using an off-axis-guider, our preference is direct mounting to the top rail.