Sesto Senso / NINA questions

[Oyaji]

I'm thinking of buying a Sesto Senso 2.  I have a 900 mm f/l refractor that I use mainly for astrophotography but on occasion, for visual.  It is equipped with a ZWO EAF, which does not allow the scope to be manually focused--to achieve rough focus, I have to use the slow and cumbersome EAF hand controller.  (And, for visual, I have to use the hand controller exclusively to achieve focus.)  My hope is to replace the EAF with a Sesto Senso 2, and with that device, to achieve pretty good focus manually before turning control of the focus over to NINA's excellent autofocus routine.  So the questions are:

1.  If I manually focus the scope, will Sesto Senso 2 know my rough focus position, and will NINA start the autofocus routine from that point, as it does with an EAF when I achieve rough focus using the hand controller?

2.  Is it necessary to recalibrate the Sesto Senso 2 every night if I'm using ASCOM and NINA?  

3.  For visual, I assume I can focus manually OR wirelessly using a smartphone.  But using the smartphone, can I achieve fine focus?

I assume the answers to these questions are, respectively, 1-yes; 2-no and 3-yes.  But as we all know, making such assumptions in this hobby can be costly--in the case of a Sesto Senso 2, about USD 300.

One more question:  some folks on  Cloudy Nights have complained about the Sesto Senso 2 slipping, while others say that if you set the "Hold" parameter properly, there is no issue.  I'm won't be loading it with a lot of weight--just an IMX571-based camera and no filter wheel--on the focuser.  Any thoughts about that?  

Incidentally, there don't seem to be a whole lot of people where I live  (USA) with a Sesto Senso 2, and I cannot find ANY information relating to using a Sesto Senso 2 with NINA and SS ASCOM driver.  But I have noticed some discussion of the issue here in Stargazers Lounge, so here I am!

Thanks for any guidance you can give.  

[newbie alert]

13 hours ago, Oyaji said:

 

As with any focuser, you have to set a few things... Max position out and max position in, ( calibration)...max in position is set as 0 or NULL ..

 For auto focus routine,say your focus point is say position 1000 and you set it as that ,when Nina calibrates it throws that out by a number of steps then plots the hfr on the chart to defy what is best focus position

The other thing to do is work out your backlash compensation of your motorized focuser, it will differ from the EAF and the Sesto senso...

Pretty sure you should have done that with the EAF?

Some people I know sold their Sesto and bought a EAF

I'm not sure that you can use Nina with a smartphone?   I'm aware that you can use Ekos and ASI air with a smartphone 

Edited July 12, 2022 by newbie alert
Re-worded

[Richard_]

On 12/07/2022 at 05:52, Oyaji said:

 So the questions are:

1.  If I manually focus the scope, will Sesto Senso 2 know my rough focus position, and will NINA start the autofocus routine from that point, as it does with an EAF when I achieve rough focus using the hand controller?

2.  Is it necessary to recalibrate the Sesto Senso 2 every night if I'm using ASCOM and NINA?  

3.  For visual, I assume I can focus manually OR wirelessly using a smartphone.  But using the smartphone, can I achieve fine focus?

I assume the answers to these questions are, respectively, 1-yes; 2-no and 3-yes.  But as we all know, making such assumptions in this hobby can be costly--in the case of a Sesto Senso 2, about USD 300.

One more question:  some folks on  Cloudy Nights have complained about the Sesto Senso 2 slipping, while others say that if you set the "Hold" parameter properly, there is no issue.  I'm won't be loading it with a lot of weight--just an IMX571-based camera and no filter wheel--on the focuser.  Any thoughts about that?  

Incidentally, there don't seem to be a whole lot of people where I live  (USA) with a Sesto Senso 2, and I cannot find ANY information relating to using a Sesto Senso 2 with NINA and SS ASCOM driver.  But I have noticed some discussion of the issue here in Stargazers Lounge, so here I am!

Thanks for any guidance you can give.  

1. You can only use the manual mode if you disconnect the power to the stepper motor, to prevent damage. When you manually adjust focus, the sesto senso will "forget" the position so when you power it back up you will need to recalibrate. 

2. If you didn't adjust the manual focus, then no need to recalibrate! 

3. I've only used mine with manual focus or with PC (NINA and Primelucelab PLAY software) so I cannot answer this. 

As an aside about weight, that's the trouble I've been having. The sesto senso is attached to the fine focus knob of the focuser. I found that when pointing at the zenith, my light ASI533 with mini filterwheel was slipping. I tried all manner of hold/acceleration settings with no impact. I even took the focuser apart, adjusted some screws to to improve connection between coarse and fine shaft, and was able to significantly reduce the slipping, but not eliminate. At zenith, if I slewed out and in the same amount of steps which would give me 50mm, 0mm and 50mm position on my focuser, it would actually read about 51/52mm. A very small amount of slipping, but enough to annoy me. 

I've recently upgraded to a QHY268M and 36mm filterwheel setup and the above scenario yielded me 55mm! A huge amount of slippage. I'm not able to fine tune my focuser anymore so sadly I've had to replace it with a different auto focuser which attaches to the coarse knob (Pegasus Focus Cube v2). There is zero slippage now and I wish I had bought the Focus Cube from the start! 

With regards to the ASCOM driver, I had zero issues. Before use, you should perform the calibration routine within the PLAY software, save, close down PLAY then connect within NINA. It should know the current position and the maximum limit you set during calibration. 

It's a real shame, because I really liked some of the features of the sesto senso but it seems it's been let down by attaching to the fine focus shaft instead of the coarse focus shaft. I imagine it would work well for a lot of people (eg reflectors where the axis of the camera  is more parallel with the ground so the focuser isn't fighting gravity) but for people like me, the slippage is a bummer. You'll probably have seen some of my posts on here discussing this 😊

[Oyaji]

As we say in the States, "Thanks, Y'all."   I guess I'll keep my 12V EAF at least until Prima Luce comes out with Sesto Senso 3 that runs off the coarse focus knob--or until ZWO comes out with an EAF2 with a clutch that allows manual focusing.  

In answer to a question from Newbie Alert, however:  NO, I have never set min and max with the EAF.  It reliably starts beeping when it can't go any further in or out!  Plus, by moving the camera in or out of the focuser a bit,  I always make sure that I'm achieving rough focus with plenty of room on either side of the rough focus point for NINA to autofocus.  NINA has never driven the focuser to the limit.  

Edited July 13, 2022 by Oyaji

[newbie alert]

6 hours ago, Oyaji said:

 

In answer to a question from Newbie Alert, however:  NO, I have never set min and max with the EAF.  It reliably starts beeping when it can't go any further in or out!  Plus, by moving the camera in or out of the focuser a bit,  I always make sure that I'm achieving rough focus with plenty of room on either side of the rough focus point for NINA to autofocus.  NINA has never driven the focuser to the limit.  

So your figure of your focus point figure will change on every use.. it won't rack it all the way out but it will keep racking it in until it flags up that your figure is too low..

So if you've not calibrated and tested for your backlash,what are you using guestimated figure and the overshoot method ?

One thing in astro to keep things consistent is accuracy... If it's inconsistent then accuracies will fail..