Focus motor for my StellaLyra 6 inch RC?

[fwm891]

Now I've had an initial play with the scope I'm looking to accessorise and the first thing will be to motorise the focuser. I've been reading specs on the Pegaus Focus Cube v2 and the Primaluce Lab Sesto Senso V2 both offer multiple adapter couplings to fit different focuser units, the Pegasus offers a 6Kg load lift and the Sesto Senso ?Kg (not shown). The Pegasus also comes with a temp sensor and all the hardware to fit to my focuser (via an L bracket). The Sesto Senso doesn't appear to need a bracket for mounting and photos I've seen of the unit don't really show how it fits very well?.

Sesto Senso has wifi so I could use via an iPad...

Anyone use these units (not necessarilly on an RC) how do you find them and their related software etc.

I'd be using via SG Pro mainly.

[Hughsie]

Hi Francis,

I use the Sesto Senso on my William Optics Z103 in conjunction with SG Pro. I also use a Pegasus Astro Ultimate Powerbox as well.

Some observations about the SS (most of the niggles are around the combination with the Powerbox).

• I had to pay extra for a slightly larger mounting bracket. That wasn’t a surprise as I had measured up the focuser on the scope already but just be aware that if you go down the SS route then this may be an added cost.
• The Powerbox came with a temperature and humidity sensor so I have no experience with using what comes with the SS.
• The power cable for the SS is a slightly different size to the power leads supplied for the Powerbox so requiring an adapter.
• I have the v1 of the SS and it has an irritating flashing red light. I understand the v2 has addressed this but some electrical tape sorts out that issue.
• I like the SS as there is no need to figure out how to attach a bracket to the scope. You remove the focus knob on the scope and select the appropriate adapter that slides over the focus spindle. You then slide the SS onto the adapter. The adapter is secured to the SS motor spindle by two grub screws which you can access via an opening in the bottom of the SS. One you have done that you simply clamp the SS to your focusser by tightening a small bolt with an allen key. Smaller grub screws are located around the circumference of the clamp to further secure the unit and make minor centering adjustments if needed. Overall it is a pretty solid connection.
• You can still focus manually and rotate the course focus knob, something I do not think the Pegasus Focus Cube will let you do.
• Calibration of the focuser is quick and easy. That is the only time I really use the SS software.
• However, I have had one occasion when calibration was lost and SG Pro could not focus the scope. As I say it has only happened once but I am keeping an eye on it.
• SG Pro and the SS work fine. You will need to spend some time calculating the step size in SG Pro which allows the SG Pro focus routine to work accurately. If you go on YouTube, the ’Simplified Astro” channel has a great video on how to calculate this. The SG Pro manual has instructions on how to do this as well but I have never met a bloke who has read any instruction manual in his lifetime!
• The focus routine settings are also important in SG Pro to get the best from the software and any motor focuser. Chris Woodhouse YouTube channel has a video on this which is worth a look. I initially set up the focuser in SG Pro to refocus every hour or every 0.5 degree temp drop but didn’t really see any major difference so extended the time to 90 minutes or 1 degree. I see from your signature that you have a ZWO ASI294MC but if you are using filters then you will also need to adjust the exposure time to ensure that you capture enough stars e.g. my luminance filter is set at 10s but my 3nm Ha filter is set at 25s. Another setting to not miss is how much of the focus image SG Pro uses to calculate HFD. I apply a 20% crop as I do not have a totally flat field and this ensures the routine ignores any egg shaped stars in the corners.
• The SS unit is on the heavy side and this may cause concerns around balancing the scope and guiding as it protrudes out the side of my scope but so far this has not been an issue for my EQ6-R Pro mount. I have not experienced any problems with focus slipping from the SS unit.
• Finally, when it comes to mounting the SS just have a thought about meridian flips and your RA limits. It is a large piece of kit hanging out of the side of your scope with cables sticking out so you could run into problems with snags if not positioned correctly.

Hope this helps,

John

[fwm891]

3 hours ago, Hughsie said:

Hi Francis,

I use the Sesto Senso on my William Optics Z103 in conjunction with SG Pro. I also use a Pegasus Astro Ultimate Powerbox as well.

Some observations about the SS (most of the niggles are around the combination with the Powerbox).

• I had to pay extra for a slightly larger mounting bracket. That wasn’t a surprise as I had measured up the focuser on the scope already but just be aware that if you go down the SS route then this may be an added cost.
• The Powerbox came with a temperature and humidity sensor so I have no experience with using what comes with the SS.
• The power cable for the SS is a slightly different size to the power leads supplied for the Powerbox so requiring an adapter.
• I have the v1 of the SS and it has an irritating flashing red light. I understand the v2 has addressed this but some electrical tape sorts out that issue.
• I like the SS as there is no need to figure out how to attach a bracket to the scope. You remove the focus knob on the scope and select the appropriate adapter that slides over the focus spindle. You then slide the SS onto the adapter. The adapter is secured to the SS motor spindle by two grub screws which you can access via an opening in the bottom of the SS. One you have done that you simply clamp the SS to your focusser by tightening a small bolt with an allen key. Smaller grub screws are located around the circumference of the clamp to further secure the unit and make minor centering adjustments if needed. Overall it is a pretty solid connection.
• You can still focus manually and rotate the course focus knob, something I do not think the Pegasus Focus Cube will let you do.
• Calibration of the focuser is quick and easy. That is the only time I really use the SS software.
• However, I have had one occasion when calibration was lost and SG Pro could not focus the scope. As I say it has only happened once but I am keeping an eye on it.
• SG Pro and the SS work fine. You will need to spend some time calculating the step size in SG Pro which allows the SG Pro focus routine to work accurately. If you go on YouTube, the ’Simplified Astro” channel has a great video on how to calculate this. The SG Pro manual has instructions on how to do this as well but I have never met a bloke who has read any instruction manual in his lifetime!
• The focus routine settings are also important in SG Pro to get the best from the software and any motor focuser. Chris Woodhouse YouTube channel has a video on this which is worth a look. I initially set up the focuser in SG Pro to refocus every hour or every 0.5 degree temp drop but didn’t really see any major difference so extended the time to 90 minutes or 1 degree. I see from your signature that you have a ZWO ASI294MC but if you are using filters then you will also need to adjust the exposure time to ensure that you capture enough stars e.g. my luminance filter is set at 10s but my 3nm Ha filter is set at 25s. Another setting to not miss is how much of the focus image SG Pro uses to calculate HFD. I apply a 20% crop as I do not have a totally flat field and this ensures the routine ignores any egg shaped stars in the corners.
• The SS unit is on the heavy side and this may cause concerns around balancing the scope and guiding as it protrudes out the side of my scope but so far this has not been an issue for my EQ6-R Pro mount. I have not experienced any problems with focus slipping from the SS unit.
• Finally, when it comes to mounting the SS just have a thought about meridian flips and your RA limits. It is a large piece of kit hanging out of the side of your scope with cables sticking out so you could run into problems with snags if not positioned correctly.

Hope this helps,

John

Thanks John,

Yes I went with the SS V2 - ordered yesterday after watching loads of videos (the Italian demonstrator's a bit OTT for me!). I liked the idea of no 'L' bracket and the attachment is certainly solid. It arrived this morning (thanks FLO) and it's now fitted and calibrated. I found the travel motion reversed OUT being IN etc... And I didn't read the instructions either. Need some clear skies to try it out now.