Motorized focuser options for SCT & Refractor

[souls33k3r]

After months of deliberation (i know too slow but i had to make the correct choice) i have finally pulled the trigger on William Optics Star 71 II (Check & Tuned).

Next purchase will most certainly be for the motorised focuser and i think i have two options

1) Lakeside Focuser

2) Sharpsky Pro

Now my question is firstly whether either of the above will work for both my Celestron EdgeHD 8" and WO Star 71 II stock focusers?

Do i need an extra motor for each scope or can i use the same motor with both? <---- Sorry this is the naivety in  me on the subject question.

Lastly, which one is just going to work day in and day out without messing about?

I'll be using Maxim DL and my imaging camera with be the ZWO ASI1600MM-C.

Thanks in advance

[ollypenrice]

I doubt that any IT-controlled product is going to work day in, day out without trouble... 

If you pull it off one scope and put it on the other on a regular basis (with hardware and software issues in doing so) the chances go down still further!

What are you wanting to acheive with your motorized focus? I'd have thought that the only important reason for wanting it would be to do unattended imaging with automated refocus. Then you do need it for sure.

OK, I'm a bit stone age, but here are some of the things I don't have. Motorized focus. Robotic auto focus. Plate solving. Ascom compatibility. Auto mosaic.

Is the drift into 'IT everything' really necessary? Forgive me if the question is ut of order.

Olly

[pete_l]

On 7/12/2017 at 19:05, souls33k3r said:

Lastly, which one is just going to work day in and day out without messing about?

Change is the enemy of reliability.

If you want stuff to work "day in, day out" then the best approach is to set it up, get it working, then get it working reliably, then leave it alone. ISTM a big issue that many people have (and this isn't just an astronomy problem) is that they skip the third step.

[snowy911]

I've been using a lakeside attached to a moonlite focuser and Altair Astro 250TT RC for nearly 2 years without any issues, and fairly recently purchased another lakeside to attach to my older WO ZS70, mounted on top of the 250TT. Make sure you get the correct bracket for your scope and from my experience these run day in, day out.

If you are swapping the focuser between scopes, then you probably need a separate bracket and coupler for each scope, however this of course would mean unscrewing the stepper motor from the first scopes bracket and attaching to the second scopes bracket.  Another solution would be to have a separate stepper motor and bracket/coupler for each scope, and attached, then when you swap scopes, you simply swap the cable to the control unit.

It would be great if the control unit could manage 2 stepper motors, but given it's currently limited to 1, you would need a complete kit for each scope encompassing stepper motor, bracket, coupler and control unit if you wanted to use both simultaneously or in the case of a remote setup with 2 scopes dual rigged.

i use the lakeside control unit for my 250TT, and the hitech astro mount hub pro (MHP)for my Williams Optics. The benefit is that the MHP also controls my dew heaters to both scopes, and power and USB connectivity to various other devices, making the cabling a lot tidier!

[ollypenrice]

1 hour ago, pete_l said:

Change is the enemy of reliability.

If you want stuff to work "day in, day out" then the best approach is to set it up, get it working, then get it working reliably, then leave it alone. ISTM a big issue that many people have (and this isn't just an astronomy problem) is that they skip the third step.

Never a truer word spoken. If you change the colour of your dewshield your guiding will go to pot!  (Actually I almost mean that...)

Olly

[Davey-T]

I have several Lakeside focusers permanently mounted (including 2 on Star 71s ) and 2 controllers, swopping the motor and bracket is a fiddly job especially if you've got bananas  for fingers like me, so if you can afford it one controller and extra motors / brackets is the way to go.

It has been mentioned to Peter at Lakeside that a lot of people are using dual setups and that a controller that could run 2 focusers would be a good idea.

Dave

[RayD]

As noted above, swapping between OTA's is probably not a good idea, as once set up and working, it is best left alone.

I don't think there is much between your 2 selections, and I know Steppenwolf uses the Sharpsky obviously with great success.  One benefit of the Lakeside is if you order through IKI he will have you a custom bracket and connector made for your OTA, which does make life easier.

I've not had a day's problem with my Lakeside, but then neither have I with my second hand and much cheaper Pegasus.  However, the Lakeside is very good and if buying again, for me, that would be my selection.  I wanted a shorter motor lead for my controller which is mounted between my 2 OTA's, and Peter at Lakeside had a custom made 550mm one out to me next day.

As Olly notes, it isn't essential to have motorised or auto-focus, but it's another one of those things whereby once you've had it you wonder how you ever managed before.  If you are remote imaging like me and many others, then yes it is definitely essential I'd say.

Good luck.

[souls33k3r]

Thanks everyone for the great input. I will definitely look in to buying a separate motor for the other scope.

What i like about SharpSky is that everything is concealed within a box apart from the connection from the motor going to the hand controller. People are successfully using Lakeside but those cable from the motor to the connector looks a bit flimsy but then i really haven't seen one of the lakesides in person so not sure how sturdy it is once you have it on the bracket and not touch it.

The only reason for the motorized focuser is that i do not have to step out and do the routine of checking focus manually. Call me lazy but i like being lazy

What do you think about having that much weight on one side of the WO scope for example, would balancing the scope be a bit fiddly?

[Davey-T]

Doesn't affect balancing, I managed to balance this lot with 3 Lakeside focusers, never had and problems with the cables though the Sharpsky looks neater the bracket is flimsy and universal so you'll need to make your own.

Dave

[souls33k3r]

3 minutes ago, Davey-T said:

Doesn't affect balancing, I managed to balance this lot with 3 Lakeside focusers, never had and problems with the cables though the Sharpsky looks neater the bracket is flimsy and universal so you'll need to make your own.

Dave

wow, that's some serious kit you've got there mate. You sure you don't need one more to go on there?

How does these motorized focusers hold up when they get wet with dew? are they durable enough to withstand that?

[Davey-T]

Doesn't seem to bother them the oldest one is about 3 years old and has had plenty of dew on it over the years.

Dave

[souls33k3r]

11 minutes ago, Davey-T said:

Doesn't seem to bother them the oldest one is about 3 years old and has had plenty of dew on it over the years.

Dave

Cheers Dave, that's very helpful.

Noobish question, based on your experience how often one really should perform the autofocusing routine and typically how long does it take to perform these routines per filter?

 

[Davey-T]

I've used FocusMax 4 which is quite expensive and the focusing routine in Maxim is quicker and works just as well, I usually autofocus once then check it later, usually only do one filter per night  but it only takes a minute or so, I also sometimes do a quick check in Maxim using the large display and subframe in fact you can achieve a pretty good focus manually using the Lakeside utility and taking continuous exposures.

Dave

[kirkster501]

Swapping an engine between cars depending on which one you are driving that day is fraught with potential issues.....

[souls33k3r]

3 hours ago, Davey-T said:

I've used FocusMax 4 which is quite expensive and the focusing routine in Maxim is quicker and works just as well, I usually autofocus once then check it later, usually only do one filter per night  but it only takes a minute or so, I also sometimes do a quick check in Maxim using the large display and subframe in fact you can achieve a pretty good focus manually using the Lakeside utility and taking continuous exposures.

Dave

I've got hold of the older version of FocasMax (3) which i intend to use. Ideally i'll want to capture all of the filters data per night during winters when the nights are reasonably longer.

Going to give it a go with bahtinov mask first and by the time it starts getting cold, i'll want to start feeling cosy and comfy inside

[Davey-T]

I couldn't get Focusmax 3 to work on Win10 so bought FM4 which worked but ended up using Maxim.

Why don't you try the Maxim focuser I think it's the same as FM3 anyway no point having another program running, even if you don't use the Maxim focuser routine it's easier to focus manually in Maxim than using BM and more accurate.

Depending on what image quality you're trying to achieve I don't think it's worth trying to capture all filters in one night, you're better off capturing HA first one night  as you will then have enough data for a finished mono image

Dave

[ollypenrice]

I do things manually precisely because I'm lazy. I find it so much easier than fighting with software/USB/updates etc etc etc...

Olly

[souls33k3r]

sorry about the late reply lads. Thank you all for the valuable input. I think i'll put this thread to bed and stay with manually focusing it for the time being. New house is now on the agenda and need to start saving up up  Maybe i will get the permission officer (wife) to look the other way just this one last time before we move nut that discussion remains to be seen and maybe a bunch of flowers just might do the trick. 

[Davey-T]

14 minutes ago, souls33k3r said:

sorry about the late reply lads. Thank you all for the valuable input. I think i'll put this thread to bed and stay with manually focusing it for the time being. New house is now on the agenda and need to start saving up up  Maybe i will get the permission officer (wife) to look the other way just this one last time before we move nut that discussion remains to be seen and maybe a bunch of flowers just might do the trick. 

So how are you focusing ATM

Dave

[souls33k3r]

Just now, Davey-T said:

So how are you focusing ATM

Dave

bahtinov mask

[Davey-T]

1 minute ago, souls33k3r said:

bahtinov mask

Have you tried using Maxim ?

Dave

[souls33k3r]

By Maxim, do you mean by going to Camera Control  > Expose > Exposure Present and then do a 5 sec exposure and hit continuous or is there a different way of doing this? Sorry i know very basics of Maxim DL and have only just started to use it to platesolve as well as guiding and exposing.

[Davey-T]

Aim where you're going to image and take a pic' find an average star mag 4 ish and draw a box round it using mouse / touchpad .

On the expose tab click on use subframe and set it looping on continuous, 

On the options tab select display large statistics, you will then get a continuous readout of the FWHM / 1/2 FD then you can adjust the focus to get the lowest reading which is basically what autofocus does for you.

If the Max reading goes over 64000 ie over exposed reduce your exposure time.

I can easily get down to under 2.0 FWHM on my Star71 using this method.

Don't forget to deselect subframe when you start imaging, a forgetful person could end up with a very small 30 minute sub 

Dave

[ollypenrice]

1 minute ago, Davey-T said:

Aim where you're going to image and take a pic' find an average star mag 4 ish and draw a box round it using mouse / touchpad .

On the expose tab click on use subframe and set it looping on continuous, 

On the options tab select display large statistics, you will then get a continuous readout of the FWHM / 1/2 FD then you can adjust the focus to get the lowest reading which is basically what autofocus does for you.

If the Max reading goes over 64000 ie over exposed reduce your exposure time.

I can easily get down to under 2.0 FWHM on my Star71 using this method.

Don't forget to deselect subframe when you start imaging, a forgetful person could end up with a very small 30 minute sub 

Dave

I, too, use this method (and have the 'Hundreds of saved subframes' T-shirt...)* and find it excellent with refractors. Don't use ultra short subs because they don't average out the seeing. I tend to go for around 2 to 3 seconds.

Olly

*In several colours...

[RayD]

20 minutes ago, Davey-T said:

Aim where you're going to image and take a pic' find an average star mag 4 ish and draw a box round it using mouse / touchpad .

On the expose tab click on use subframe and set it looping on continuous, 

On the options tab select display large statistics, you will then get a continuous readout of the FWHM / 1/2 FD then you can adjust the focus to get the lowest reading which is basically what autofocus does for you.

If the Max reading goes over 64000 ie over exposed reduce your exposure time.

I can easily get down to under 2.0 FWHM on my Star71 using this method.

Don't forget to deselect subframe when you start imaging, a forgetful person could end up with a very small 30 minute sub 

Dave

Nicely explained Sir.  

Just to clarify Dave, does the lowest FWHM level go up or down with better or worse seeing conditions, or would you expect to see this level whatever the conditions (within reason)?