In January 2014 I purchased a second robotic focuser, this one for control of my Megrez 90 APO, and this time a SharpSky Pro rather than a second RoboFocus.
The SharpSky Pro appealed a little more than the RoboFocus in this circumstance because:
- The Megrez is used portable and permanent. I preferred the finish of the SharpSky Pro when considering portability.
- The Megrez is used manually and under automation. The SharpSky Pro has a neat little hand controller of unique design which I thought might be easier to use manually than the two push buttons on the control box of the RoboFocus.
- I had a desire to try something different, to see if I was missing out on anything with the RoboFocus.
Purchasing & Delivery
I purchased my SharpSky Pro directly through the SharpSky Pro website after contacting the operator Dave Trewren to ask about international shipping etc. I was keen to receive the unit in time for a series of astrophotography workshops I was commencing in January. Dave did everything he could to ship the unit as soon as possible and with a customised fitting for attachment to my Megrez 90. The unit arrived on my doorstep in Australia promptly, quicker than I was expecting. Dave was friendly and helpful to deal with throughout the purchasing and delivery process.
Attachment and Setup of Hardware
You can see in the below photographs that I have used the supplied SharpSky Pro mounting plate for attachment to my Megrez 90. I have needed to bend it somewhat, to bring the plate closer to the Megrez mounting point but this was easily done using a vice, rag to protect the bracket from scratches, and a bit of arm muscle. It took me a couple of goes but was quite straight forward. I needed to find a bolt to fit the Megrez mounting hole as nothing suitable was supplied with the Megrez.
It’s not immediately clear from the below photographs but the focuser is attached only to the Megrez 90 and not the mounting plate upon which the Megrez is attached. This was intentional as the mounting plate stays on the permanent pier configuration when I take the Megrez out in the field on my Losmandy GM8, so now with the SharpSky Pro attached I can just lift the Megrez out of the scope rings without having to detach the focus motor at all.
Cables and Components
The SharpSky pro has the following cables involved:
- Motor cable from controller box to motor (9 pin serial)
- Hand controller cable from controller box to hand controller (s-video type plug)
- Power cable from power to controller box
The cables are pretty much the minimal of what is required (in a good way). Probably my only problem with the cabling has been that the cable going to the hand controller is quite stiff and inflexible making it prone to tangling with other cables or not sitting where it is wanted. If you don’t have the controller box secured, moving the hand controller around easily pulls the controller box about because the cable is so stiff.
Length of the supplied hand controller cable is quite short. While I appreciate this reduces clutter I would much prefer a longer (if made of more flexible material), perhaps coiled to stay out of the way when not stretched. For example something like the coiled cable used by the Paramount for it’s joystick controller is much more friendly. I need to extend my cable to the hand controller but have not yet achieved this, it requires making/modifying a custom cable which I haven’t got around to, partly due to finding suitable coiled cable and plugs to use. The cable in question is an s-video type cable and Dave at SharpSky has been helpful in providing information on this.
The RoboFocus has less cables in my case only because I have no hand controller unit for it. Having said that, one advantage of the RoboFocus is that the controller box does have the minimal functionality built in required – a button for “move in” and a button for “move out”. I could do essentially the same with the SharpSky either remove the hand controller (which is not required for PC operation) or somehow attach hand controller to controller box with cable tightly coiled out of the way, this is something I need to look in to.
I primarily use the Sharp Sky Pro through BackyardEOS. Backyard EOS connects to the focuser through ASCOM and this interface works quite smoothly. Control through BackyardEOS is quick and responsive.
Initially when installing SharpSky Pro software I had issues connecting using ASCOM. Un-installing and re-installing all ASCOM components solved this problem and we weren’t able to identify the cause of the problem, even though I had great support from Dave at SharpSky.
I do not at this stage use the SharpSky together with FocusMax on a regular basis due to the complexities of ensuring it does not interfere with the automation of the rest of my setup, which has FocusMax working together with my SBIG camera on a different OTA but run through the same computer. Two copies of FocusMax can operate at the same time on one PC but when organising the safe automation of these I haven’t yet been confident enough that they don’t get confused. For example opening up FocusMax I haven’t been confident it will always open the desired profile for the desired focuser rather than me having to manually re-open the desired profile. These FocusMax discussions are of no fault of SharpSky, instead simply relating to running two focusers on the one computer under an automation scenario.
It is worth noting that the SharpSky Pro comes with the additional capabilities of providing power ports suitable for dew heaters. This may (depending on your setup and requirements) save on other components or help standardise your setup. The supplied four ports on the controller unit can have their power adjusted in increments of 25% power. For me these ports are not a useful feature because the controlling of dew heaters needs to be automated (turned on/off) at different times to the focuser, but it could be a bonus for some people. I have not tested the heater ports.
In the end, I have found that the motor/mechanics and software drivers of SharpSky Pro are of apparently equal quality to that of the RoboFocus, such that from a end user perspective, once installed, the two are identical. Both units function transparently when used with 3rd party software such as FocusMax or BackyardEOS. As such, from a PC use perspective there is no material difference from my perspective and you may as well go with the cheaper option. The SharpSky was cheaper and that included the hand controller which provides somewhat more functionality than the standard two buttons on the RoboFocus controller box. In the end, I’m happy with my decision to go with the SharpSky Pro.