Helical focus on a MAK

[kilix]

Hello,

I own a SW SkyMax 127/1500 and one thing, that is kinda annoying is the rough focus. Especially now in winter, the focuser is stiff and when moving it, the entire telescope+mount assembly shakes. Also, it's kinda hard to get nice focus with that tiny knob, especially at higher magnifications. It gets to the point, that it discourages me from using higher mags and I opt to use my favourite 15mm eyepiece and don't bother with 10mm or a barlow.

Yes, I am aware of modifications to the knob, attaching a bottle lid, or a clothespin and so on. But you know, it's not that kind of elegant solution, that I like. I plan on attaching a lid from my perfume, as today morning I had an epiphany when using the perfume, the perfume bottle lid is a perfect accessory for a MAK It even looks like a focusing knob with a nice rubber grip around it.

Also I am aware of modifications to the lousy mount and atm, I am working on it, I plan on pouring some concrete down the legs and modifying the spreader, I already poured epoxy in the cracks in plastic-metal interface, which helped a bit.

But my question is - is anyone using Baader helical microfocus or some other similar helical focus device with a MAK? Does it work? How well does it work? Are there any issues with mounting the helical microfocus to the MAK or does it work out of the box? I do not plan on doing serious photography, I am more inclined towards pure visual. I may do some lousy photos of the moon, or M42, M31, but really nothing serious. Visual is more satisfying for me.

At 38€ it is not a big investment and may be worth it, instead of some homemade solutions.

[Ben the Ignorant]

I thought my C5 had a VERY rough focusing mechanism, but there was nothing wrong with it. The knob is attached to the focusing rod via a small lateral (hexagonal) screw. The knob had been set too close to the tube's frame before tightening the screw, thus it rubbed real hard on the frame when I changed focus. When I finally found out, simply moving the knob back one millimeter solved the prob. It was a great relief because one of the C5's selling points was a smooth and accurate focus, which it really had save for a temporary fault in assembly. Maybe your issue is just that.

[kilix]

Thanks for advice, but that's not the problem here. The focus knob is moving OKish. In cold temperatures, the rotation of the knob is more stiff than before, but that's probably due to the grease cooling down and also, all clearances are tighter.

This issue is more about getting accurate focus, small movement of the knob translates to a big change in focus, which makes higher mags focusing really challenging, especially now in winter, when everything moves not so smooth as in summer. I do not prefer to go the clothespin route, I like more elegant solutions. But maybe I'll have to.

[Dave In Vermont]

I simply installed a GSO Dual-Focus 10:1 Crayford-Focuser on my 150mm F12 Maksutov. Works beautifully!

Have fun,

Dave

 

 

 

[kilix]

In case anyone else is trying to solve something like this, this is how I did it:
I ordered a Baader prism with T2 threads on both ends. This fits the SkyMax visual back, which has a T2 male thread. And I also ordered a Baader 1.25" focusing eyepiece holder, which also fits on T2. Now I tested the focusing during the day and it is butter smooth and with great precision. Also, the vibrations are not as big as they are using the classic Mak focuser. Can't wait for the skies to clear (which will take about a week according to forecast).

What immediately struck me, is the Baader build quality, which seems of a professional standard, far far better than what I need as an unexperienced hobbyist. And the diagonal is on a whole different level than the stock SkyMax diagonal, Baader is made with cast (or sintered?) metal body with powder coating, which feels really solid and sturdy. Can't really compare that to the squeaky skywatcher plastic one.

The operation of the helical focuser is smooth and with a good resistance to it. It feels as if the focusing mechanism was coated with some heavy grease (I know it isn't).

Additionally, I gained brass compression ring retaining mechanism instead of those horrible grub screws. My eyepieces are pretty basic atm and I don't care that much about their wellbeing, but in the future I may upgrade and I would hesitate to put something nicer (like a hyperion) into that stock eyepiece holder with grub screws.

 

careful observers may notice pimped out Tom Tailor perfume bottle focusing knob

[CraigT82]

Baader kit, in my opinion, represents the best value for money on the market! 

I too have that focusing EP holder and its a very useful bit of kit.

[kilix]

The best thing about it is the fact, that now everything is as good or even better than I wanted. Nothing annoys me even in the slightest on the telescope and I may focus on comfortable observing only, with no technical annoyances whatsoever.

Yesterday the mostly cloudy skies cleared for an hour, so the focuser and prism got their first light. Very good 130€ investment, probably the best upgrade I've made so far. I encourage anyone with this telescope to consider this upgrade, or some other upgrade to the stock focuser. Even before buying new EPs.

[Louis D]

Does the eyepiece rotate when the helical focuser is turned?  I have a simple 2" to 1.25" adapter/helical focuser that does.  I find it so annoying that I never use it.

[kilix]

yes, it rotates. But it's not like I do multiple revolutions with it. I focus roughly with main focusing knob and use this helical focuser to fine-tune with really tiny adjustments, something like <20° of rotation.