SW primary springs

[bosun21]

I just removed the primary mirror on my new scope which is necessary to replace the primary collimation springs. Once I had the mirror out of the cell I discovered that the existing primary springs were actually heavier gauge and stronger than the springs I was intending to upgrade with! I’m pleased to see this now in production dobsonians. The Stella Lyra(12”) i have previously owned had really weak springs which allowed the mirror to shift. It was easier to replace them on the SL though as you could do it with the mirror in place on the scope. Also fitted Bobs knobs on the secondary.

Edited December 9, 2023 by bosun21

[Captain Scarlet]

Keep the unused ones, you never know they might come in useful. For example I refurbished a friend’s 10 year old 130p recently, and it turned out it doesn’t have springs, only (useless) rubber washers, making collimation a real chore of “push-pull” adjusting. I still had my old SW 300p springs, so I cut them in half and installed three on his 130p. Worked like a dream.

Cheers, Magnus

Edited December 9, 2023 by Captain Scarlet

[bosun21]

8 minutes ago, Captain Scarlet said:

Keep the unused ones, you never know they might come in useful. For example I refurbished a friend’s 10 year old 130p recently, and it turned out it doesn’t have springs, only (useless) rubber washers, making collimation a real chore of “push-pull” adjusting. I still had my old SW 300p springs, so I cut them in half and installed three on his 130p. Worked like a dream.

Cheers, Magnus

I always do. I've got several little bags of the springs I've upgraded as well as a bag of heavier gauge springs. It was good to see that this wasn't required with my new 10" Flexitube go to dobsonian. Maybe they're catching on.

[PeterC65]

I've just collimated my new Explorer 200PDS and the primary springs on it seem pretty meaty, 1mm diameter in cross section I'd say, and it doesn't look like the mirror can move about.

With any luck I might get a chance to use it for the first time tonight.

 

[John]

1 hour ago, bosun21 said:

I just removed the primary mirror on my new scope which is necessary to replace the primary collimation springs. Once I had the mirror out of the cell I discovered that the existing primary springs were actually heavier gauge and stronger than the springs I was intending to upgrade with! I’m pleased to see this now in production dobsonians. The Stella Lyra(12”) i have previously owned had really weak springs which allowed the mirror to shift. It was easier to replace them on the SL though as you could do it with the mirror in place on the scope. Also fitted Bobs knobs on the secondary.

GSO made scopes seem to have been supplied with weak springs for more than a decade now, despite it being a much discussed issue on forums like this. Pity nobody at GSO has picked up on that and improved the springs. Once of the main issues for folks contemplating a newtonian scope is collimation so having a decent primary cell with decently robust springs would be a priority for a manufacturer, one would think 🤔