Auto focuser - how do you feel about it?

[bottletopburly]

26 minutes ago, david_taurus83 said:

Ordered! I never thought I'd need one as I used to just focus at the start of the session and it held solid all night. But since switching from DSLR to mono, and checking focus for each filter, it's a bit of a faff to go out each time. How do you find APT works with auto focusing? Or do you manually check HFD and adjust yourself?

Works great through APT  so easy  best gadget I have bought highly recommend , I use with a DSLR and have just been doing once at Start of session,  don’t know if the sequence differs with ccd and filters , maybe others can comment that use a ccd and apt with a auto focuser, maybe @Yoddha can help there with info ,  I know Pavle @sunka uses it with a zwo ccd and sgp , 

Edited November 20, 2018 by bottletopburly

[david_taurus83]

1 hour ago, bottletopburly said:

Works great through APT  so easy  best gadget I have bought highly recommend , I use with a DSLR and have just been doing once at Start of session,  don’t know if the sequence differs with ccd and filters , maybe others can comment that use a ccd and apt with a auto focuser, maybe @Yoddha can help there with info ,  I know Pavle @sunka uses it with a zwo ccd and sgp , 

Ok thanks. Pavle uses the same camera as he's answered some of my questions about his DC power box. Looking forward to it now. Should be here in a few weeks!

[Ouroboros]

I'd like to add an auto focuser to my Evostar 80ED.  But I'm never convinced that any of the available commercial ones will enable me to put the telescope back in the aluminium carrying case for transportation. Anyone else met or better solved this question? 

[PaulR1]

I have this on my system as my "auto" focuser (auto is probably the wrong word here)

https://www.modernastronomy.com/shop/accessories/focusers/sky-watcher-auto-focuser-hitecastro-dc-focus-controller-combo/

This is supposed to only fit the standard skywatcher focuser but by following this video I was able to fit it to my 200 PDS

Here is a video I did last night showing it being used via APT. It also works fine using the focuser controls in APT.

Hope this helps

 

Edited November 24, 2018 by PaulR1

[Merlin66]

Fitting the SW motor - in the video he doesn't show how difficult it can be at times to re-fit those four small O rings on the housing mounting screws!!! Patience......

 

[gazza]

Hi,

have just built a motor focuser that is Moonlight compatible  for very little money. Details here:

https://www.cloudynights.com/topic/594658-pnp-focus-the-simplest-ever-arduino-focus-controller/

Works a treat using either unipolar OR bipolar steppers. The motors I use cost $3 each ? .Works so well I'm building another one for my portable scope. Simply stack arduino shields.....

Hope this helps

Gary

[Astrofriend]

Hi,

I have documented my motor focus project with a USB-Focus as a base:

http://www.astrofriend.eu/astronomy/projects/project-motor-focus/project-motor-focus.html

I have temperature compensation, 1 degree Celscius change and I can see a out of focus, so it's needed. But if you have a good auto focuser I think that's better. It's difficult to build a correct temperature compensation table.

I got some slip problem with the focuser friction coupling that I had to modify, here is the documentation about that:

http://www.astrofriend.eu/astronomy/projects/project-focus-friction/project-focus-friction.html

 

With all these problems are solved you can't live without a motor focuser!

A stronger motor had been good.

/Lars

[iapa]

On 22/11/2018 at 17:09, Ouroboros said:

I'd like to add an auto focuser to my Evostar 80ED.  But I'm never convinced that any of the available commercial ones will enable me to put the telescope back in the aluminium carrying case for transportation. Anyone else met or better solved this question? 

all I can suggest is a Stanley knife and cur away the foam material - i have the same dilema and working up the nerve to do it.

[iapa]

On 24/11/2018 at 20:15, PaulR1 said:

I have this on my system as my "auto" focuser (auto is probably the wrong word here)

https://www.modernastronomy.com/shop/accessories/focusers/sky-watcher-auto-focuser-hitecastro-dc-focus-controller-combo/

This is supposed to only fit the standard skywatcher focuser but by following this video I was able to fit it to my 200 PDS

Here is a video I did last night showing it being used via APT. It also works fine using the focuser controls in APT.

Hope this helps

 

I also added one of these to the 200PDS, and also the Startraveller, but, it does not readily fit the focuser on the 10" Quattro or the Equinox ED80 as the holes fo not match the tension adjustment bolts

Edited December 14, 2018 by iapa

[iapa]

On 24/11/2018 at 22:51, Merlin66 said:

Fitting the SW motor - in the video he doesn't show how difficult it can be at times to re-fit those four small O rings on the housing mounting screws!!! Patience......

 

I used a cocktail stick with the smallest bit of vaseline on the tip, help keep it in place

 

[Ouroboros]

4 hours ago, iapa said:

all I can suggest is a Stanley knife and cur away the foam material - i have the same dilema and working up the nerve to do it.

Yes, I've thought of that. I'm a bit reluctant to do that because I use all those storage holes at the back of the case for reducer and various connectors etc. Might be the only option though. 

[jimjam11]

On 24/11/2018 at 20:15, PaulR1 said:

I have this on my system as my "auto" focuser (auto is probably the wrong word here)

https://www.modernastronomy.com/shop/accessories/focusers/sky-watcher-auto-focuser-hitecastro-dc-focus-controller-combo/

This is supposed to only fit the standard skywatcher focuser but by following this video I was able to fit it to my 200 PDS

Here is a video I did last night showing it being used via APT. It also works fine using the focuser controls in APT.

Hope this helps

 

I cheaped out and did the same. It is completely functional and I initially thought it completed autofocus in sgp perfectly with excellent v curves. However when I looked closer i realised it often misses the optimum point when it 'returns' to its calculated optimum. When focussing manually I averaged 4.5" fwhm and after implementing this as autofocus I also averaged 4.5" fwhm. However, during the routine it would dip into the 3" range so there was room for improvement.

When I start for the evening I run autofocus to gauge my potential best, and I then manually adjust focus until I am acceptably close to that. It takes a few minutes and is somewhat fiddly but it is quite easy to do sitting in the warm! By following this routine my fwhm have been as low as 2.4"; a massive improvement.

Using a filter offset of a few steps in sgp also appears to work well, presumably because the amount of movement is minuscule and its error is therefore tiny as well?

[Ouroboros]

On 14 December 2018 at 17:30, iapa said:

all I can suggest is a Stanley knife and cur away the foam material - i have the same dilema and working up the nerve to do it.

I decided to get one, fit it and take the plunge on cutting the box. As you suggest, a Stanley knife sliced through the foam very nicely. 

The only thing is that the focuser would stick out the wrong side. But by rotating the telescope 180° in the rings it points out the other side and it's at the top which is more convenient for the surgery on the box. It's also necessary to cut a slice out of the foam in lid because the bracket sticks up.  

I can still get all the components like the final reducer in their pockets, and there's also plenty of space in the box for the focuser controller and cable. 

 

 

 

 

[iapa]

Nice and neat

i’ll send mine to you when I’m ready lol