SESTO SENSO robotic focusing motor

[RayD]

On 03/06/2018 at 11:49, dodi said:

Questions guys, for those use the Primaluce focuser:

- I assume on a Takahashi TOA/FSQ, you loose the fine focus button if I understand correctly, right? That's where the focuser is mounted, with no possibility to mount it on the other side

- I do use the scope for visual too. In the manual I read that if you do not power on the unit, you can still use the focuser knob on the opposite site, be it a bit stiffer. Now, how stiff is stiff... Is it
a workable solution for visual work, given there is no hand controller for the focus motor (which does is available at the be it more expensive Lacerta focuser solution).

Thanks

 

Dodi

Sorry just seen this so may be way too late for the answer.

Yes you do lose the micro focus knob.  I think you may be able to fit it on the other side, but it is designed to go on this way.

You can focus manually, provided you power down.  With the power on you have a holding torque which prevents movement.  However, this is fairly stiff and I think ok for moving manually to a position before focusing using it, but a little too stiff and 'coggy' (due to turning the motor) for visual use in my opinion. 

[wornish]

Took the plunge and ordered one as an early Christmas present for myself.

It arrived today.  Its so small and neat !

Was very easy to fit on my Esprit and it works with APT.  Now just need some clear skies to give it a go.

[AZAFATO]

I've been thinking in buying the Sesto Senso to motorize the standard focuser of my SW Esprit 100ED however, I have hesitated because this motor drives the fine focuser and not the coarse one. I know all these focusers can experience different levels of slippage and that this can be somehow addressed with the backlash compensation feature envided in some softwares.

The other option I have considered is the FocusCube from Pegasus Astro. The advantage of this one appears to be that it is coupled to the coarse focus knob.

Comments/thoughts about either option?

Thanks, Diego

[wornish]

17 hours ago, AZAFATO said:

I've been thinking in buying the Sesto Senso to motorize the standard focuser of my SW Esprit 100ED however, I have hesitated because this motor drives the fine focuser and not the coarse one. I know all these focusers can experience different levels of slippage and that this can be somehow addressed with the backlash compensation feature envided in some softwares.

The other option I have considered is the FocusCube from Pegasus Astro. The advantage of this one appears to be that it is coupled to the coarse focus knob.

Comments/thoughts about either option?

Thanks, Diego

It works great, just ran the Backlash Aid using APT and everything seems fine.

If a focusser is only using the course control then I guess the accuracy of focus will suffer.  On my Esprit 100 the Sesto Senso  takes over 90,000 steps to move the focuser  from fully in to fully extended . that works out at 0.887 micron per step.

[blinky]

Cant bring myself to pay the money for these commercial robo focusers - it costs about £6 to but a stepper, controller and Arduino and install the free Ascom compatible software.  The only tricky thing is mounting it to the focuser as my DIY skills are non-existant!

[SteveA]

Well...finally I gave in!

Under extreme pressure from Mrs A, demanding ideas for this year's Christmas present I've opted for the Sesto Senso.

I would have liked to have at least had the opportunity to view the Baader offering, but it's been a year now since they talked about re-engineering their product and still nothing to look at. Unfortunately a potential  lost sale Mr Baader !!

Money is unfortunately an object around here and although I can think of plenty of pieces of kit I would dearly love,  I do need to be reasonable. Luckily the price of this sat nicely in the annual Christmas pressie budget. As has been the case in previous years, Mrs A passed me the heady responsibility of ordering my own pressie this year. 

Ordered on Saturday...delivered today (Thursday), all the way from Italia....super efficient and faultless service, though one wonders how Brexit will mess us all  up in the future ? (Opps..sorry for the political point of view...but what the hell)

Slightly unimpressed however...Mrs A has put her foot down!

No looking touching etc... etc. until  Dec 25th....damn  it!   ???

Steve

 

 

 

 

 

 

 

 

[IanL]

Thinking about what to do here myself. I've got a Baader Diamond Steeltrack (refractor), but likewise frustrated by the disappearance of the steeldrive and seems to be no urgency to replace it.

I "successfully" built a DIY setup using a stepper, easydriver and pro-micro (arduino clone). It was all working earlier in the year, except I had problems with the belt drive. The Steeltrack has a HTD pulley machined in to the fine focus knob, and is designed to be driven by the steeldrive (contrary to a lot of advice not to drive the fine focus, the Baader is engineered for it).  I couldn't find a matching flanged HTD pulley, and having tried a wider pulley the belt wanders and causes the focus to slip.

So recently I got a pair of pulleys and switched to driving the coarse focus shaft on the other side, plus an improved bracket and spacer to mount it all. Should be OK with 1/8th stepping and the 2:1 gear reduction through my belt drive. Having done all that, the stepper won't budge (even off load and with max current set in easydriver), have had it all apart, resoldered everything, etc. and no joy.  I'm sure it's either a dodgy connection, the easydriver has been fried or the stepper coil burned out.

Fixing it would be a few quid to replace the suspect parts but I'm at my wit's end with the whole thing. Last decent imaging run was January this year and don't want a whole year to slip by without getting some use out of my kit.

So regardless of it only being a few quid to build your own, looking at a commercial setup. The Senso doesn't appeal as the attachment mechanism seems entirely likely to be the weak point with tiny Allen head grub screws and stripped threads (why not just machine some decent sized holes and screws is beyond me). It's also pricey, as is the Lakeside.

I'm looking at the Pegasus focuscube. It's c. £100 less than all the other options, and I don't need a manual focus control since it's for a permanent imaging setup. I can't see much written about it anywhere so not sure about hardware and software quality.  The main issue is what it the maximum size of focuser shaft the flexible coupler will accept? Can't find that information anywhere and the Baader's is pretty chunky (about 7-8mm dia. I seem to recall but haven't checked).

Of course it would be relatively simple to get a larger bore coupler if needed, but just dread getting in the pulley situation where I can't find the right combination of focuser and stepper shaft diameters.  Anyone know?

Edited November 16, 2018 by IanL

[RayD]

On 08/11/2018 at 19:10, AZAFATO said:

I've been thinking in buying the Sesto Senso to motorize the standard focuser of my SW Esprit 100ED however, I have hesitated because this motor drives the fine focuser and not the coarse one. I know all these focusers can experience different levels of slippage and that this can be somehow addressed with the backlash compensation feature envided in some softwares.

The other option I have considered is the FocusCube from Pegasus Astro. The advantage of this one appears to be that it is coupled to the coarse focus knob.

Comments/thoughts about either option?

Thanks, Diego

I have the SestoSenso and the Pegasus and both work absolutely fine.  Yes if the reduction is by ball bearing, as most are, then over an extended period there will inevitably be some slippage, but not enough to be an issue.

The benefit of being on the reduced shaft is the increased resolution.

[RayD]

18 hours ago, SteveA said:

Slightly unimpressed however...Mrs A has put her foot down!

No looking touching etc... etc. until  Dec 25th....damn  it!   

NOOOOOOOOO!!

Is that even legal?

Oh well, at least it is a nice thing to research, get used to how the software works and know that you will be using it soon 

[wornish]

The forecast is for clear skies tomorrow have you tried saying pretty please ?

 

[RayD]

1 hour ago, IanL said:

The Senso doesn't appeal as the attachment mechanism seems entirely likely to be the weak point with tiny Allen head grub screws and stripped threads (why not just machine some decent sized holes and screws is beyond me). It's also pricey, as is the Lakeside.

I'm looking at the Pegasus focuscube. It's c. £100 less than all the other options, and I don't need a manual focus control since it's for a permanent imaging setup. I can't see much written about it anywhere so not sure about hardware and software quality.  The main issue is what it the maximum size of focuser shaft the flexible coupler will accept? Can't find that information anywhere and the Baader's is pretty chunky (about 7-8mm dia. I seem to recall but haven't checked).

Of course it would be relatively simple to get a larger bore coupler if needed, but just dread getting in the pulley situation where I can't find the right combination of focuser and stepper shaft diameters.  Anyone know?

I honestly wouldn't worry too much about the attachment being a weak point, it isn't.  The small grub screws are only to centre on the shaft, the actual fixing is done by clamping the outside casing of the focuser.  It's pretty secure.

As far as I know, if it's anything like my Pegasus focuser, the Focus Cube is supplied with a generic coupler with 3 grub screws allowing you to use it on anything between 3mm and 6mm.  I'd be surprised if the Baader was bigger than 6mm, that's all my Featherthouch is and that's a pretty big 3.5" focuser.

Drop the guys at Pegasus a line, they are very good and get back to you really quickly.

[IanL]

8 minutes ago, RayD said:

I honestly wouldn't worry too much about the attachment being a weak point, it isn't.  The small grub screws are only to centre on the shaft, the actual fixing is done by clamping the outside casing of the focuser.  It's pretty secure.

As far as I know, if it's anything like my Pegasus focuser, the Focus Cube is supplied with a generic coupler with 3 grub screws allowing you to use it on anything between 3mm and 6mm.  I'd be surprised if the Baader was bigger than 6mm, that's all my Featherthouch is and that's a pretty big 3.5" focuser.

Drop the guys at Pegasus a line, they are very good and get back to you really quickly.

Thanks, will do, but the Baader is definitely larger than 6mm. I'll measure it again and drop them a line.

[SteveA]

On 16/11/2018 at 16:07, wornish said:

The forecast is for clear skies tomorrow have you tried saying pretty please ?

 

My wife has what is called.....a "stubborn streak" ?

 

 

[Lostone]

On 12/02/2018 at 04:10, RayD said:

It is a nice piece of kit, although there is a forum member who had to return theirs due to the grub screw threads twice stripping whilst trying to mount it.  I never had such issues and it fitted very easily and it seems to work very well.  Mine is on my Tak106 but I believe they fix in exactly the same way on the Baader.

The unit comes with a stand-alone programme on a USB stick, and also 32 and 64bit ASCOM drivers, which work perfectly in SGP.

It's pretty quick, but seemingly also pretty accurate.

So far very happy but early days yet.

Bright flashing LED is annoying and can't be switched off, so hopefully they will address that in a future update.

 

Have you hooked this up to your Esprit 100ED,  i'm looking at picking up the V2 of the focuser.  Any issues other than your red blinking light?