SW auto focuser + FWHM

[tingting44]

Hi guys i want more precise focusing, and ive used FWHM a few times but its pointless doing it by hand as it through it around way to much and ill just be chasing numbers with FWHM by hand, just wondering if the SW auto focuser is precise enough for a decent FWHM focus? if any one has tried this id love to hear from you

[Coco]

My personal opinion is that it isnt, it seems to store torque in the gear box which it releases at the most inconvenient time knocking the focus out..

I recommend the lolly stick wand method, which is elastic band a lolly stick or cocktail pick onto the micro focuser, use the tip to gently nudge the focus in and out until you get the required FWHM..

What ever method you use you will be going forwards and backwards with either a button or stick...  

[lensman57]

Hi guys i want more precise focusing, and ive used FWHM a few times but its pointless doing it by hand as it through it around way to much and ill just be chasing numbers with FWHM by hand, just wondering if the SW auto focuser is precise enough for a decent FWHM focus? if any one has tried this id love to hear from you

Coco is correct however, the problem is not in the gears but in the rubber Coupling-Clutch mechanism. At the asking price and with a bit of care it can work and it is almost essential on a Newtonian. If you do purchase it do make sure that you take the 9V  battery out after use or it can get very expensive.

 Also when using FWHM  try and go for a 3s exposure loop to even out the seeing otherwise you'd be chasing your tail.

A.G

[JamesF]

If you mod the motor drive by using a couple of timing belt pulleys and a toothed drive belt that may address the problem.  You can also gear the drive down at the same time.

James

[m37]

I found it to be spot on for very fine focusing, although I found getting the right balance of focuser tension was the key. I suspect QC on these is not too hot at this price and from what I have read some are better than others hence the differing opinions.

What camera/software are you using? If it is a DSLR then I found BYEOS had some great focusing options, including bhatinov mask use.

cheers

Chris

[tingting44]

thanks guys, i might just try one and see how i get on with it, if its not accurate enough for FWHM ill re sell it on.....

im using APT not BYE btw...

[JamesF]

I'm sure you won't be short of potential buyers if you do need to sell it on.  There's always an interest in them.

James

[m37]

Just hope you don't get too many people thinking it's a wanted ad when you're trying to sell

[sidelight]

I used one on my 200P with the hitec astro 

[sidelight]

I used one on my 200P with the hitec astro 

Delete and return are far to close when you are typing in the dark ;-)

With the Hitec Astro DC Focus and SGP with great success, took a few nights of mucking about to get things right but once I did it was great.

Cheers

Ross

[Stu_2011]

If you mod the motor drive by using a couple of timing belt pulleys and a toothed drive belt that may address the problem. You can also gear the drive down at the same time.

James

I agree with James, with a belt drive / rubber belt arrangement it seems to work very well, very precise and accurate I find, great value for money in my view.

Stu