Moonlite at f8- single or dual speed?

[A McEwan]

Hi all. The Helios 150 f8 is about due its Moonlite focuser upgrade... but I can't decide whether to go for a single-speed or dual-speed model. I-ve used dual-speed ones in the past and found them excellent but at f8 I don't know if the fine-focus is required.

But... I'm open to persuasion either way! Which would you go for? (the single-speed is £75 less costly...)

Ant B-)

Sent from my GT-I9100 using Tapatalk

[nightfisher]

go for the single speed, more in keeping with the traditional long tube achro, and get a bahtinov mask to ensure focus is perfect, my Tal100 has single speed crayford and i use the bahtinov mask to great effect

[ollypenrice]

Imaging or visual? The scope is not going to be ideal for broadband imaging so if it's visual the single speed should be fine. I only use the slow motion knobs for imaging on my own scopes.

Olly

[Merlin66]

The critical depth of focus at f8 is 0.141mm (141micron) - a single speed should do the job.

[Moonshane]

I agree that a single speed should be fine but for me even for visual, once used to fine focus, it's so nice to have and use. Personally, I will always buy dual speed for my (visual only) scopes no matter what the focal ratio. In the scheme of things it's not a big price difference and for me, it's 'forever', enhances the whole experience and for all eyepieces and targets.