Priesters

Hi, can you see any light at all or is it just black?

Hi, Does anyone have experience of using the above or can suggest cheaper alternative kits (I.e less than £450 for this unit) for simple motor control of a Crayford or Rack and Pinion focuser attached to the visual back of an SCT? I’m not looking for autofocus btw, just the ability to fine focus without having to touch the scope and also preferably control the focuser via a laptop rather than hand controller. The OTA is an 8” Meade LX90. Thanks Andrew

Update just in case anyone else comes across a similar problem and reads this thread. Using the correct physical USB ports on both the extender and the laptop meant the JMI unit was consistently discovered and connected to the JMI control software. Unfortunately, it then consistently crashed after several operations (continuous in/out, pulse in/out etc). It didn’t matter which other devices were connected (or not) to the extender. It consistently worked fine when connected directly to the laptop. On reflection I think the cause is actually quite obvious. The remote extender requires 5v 3amp DC power input which In my set up is supplied exactly by a 20 mah power bank. The JMI focuser is a 9v motor unit so I am assuming that is where the problem lies and have resigned myself to having two cables after all.

Think your question may have led to a solution. I just tested using the MotoFocus on its own via the StarTech Extender and it initially failed but then it occurred to me that if it was fussy about which physical USB port it was connected to on the laptop maybe it was also fussy about which physical port it was attached to on the Extender. Last port I tried worked! Same experiment with the USB Hub - same result. Don’t have time to test out with all devices attached until after next week as setting off to Lake District this aft. but happy bunny for now. Extender and Laptop now have stickers on the relevant ports 😂. Thanks v much for your help.👍

Hi, Hoping someone can help me complete my mission. So far I have successfully connected the Mount and two Cameras to the Laptop via a StarTech USB Extender and Cat 6 cable. My problem is with also using the laptop to control a JMI MotoFocus unit which, after much experimentation, seems to only play to very specific rules. It will only reliably connect if it is plugged in to the same physical USB port. When plugged in to that same physical port it will not tolerate being connected to it via either the StarTech extender or a USB hub, both of which I think are sufficiently powered. When I say ‘will not tolerate’ I mean it either doesn’t connect at all or if it does, it loses connection soon after and then the motor runs until I disconnect power which is somewhat alarming. As a result I currently have to have one cable for the JMI Focuser and another for the Mount and Cameras. I’m using the JMI MotoFocus Plus 1.0 software to control the Focuser and have tried uninstalling and reinstalling it. The Mount and Cameras are connected via SharpCap. I have experimented with various different configurations of different devices being connected via the USB Hub and StarTech extender, such as just having one other device and the JMI unit being connected via these methods and all failed so it looks like the Hub/Extender is part of the problem rather than the other devices. Weirdly, I can get the JMI Unit and one other device connected to the same physical port via a simple two way USB splitter. If anyone has any experience of this or any suggestions they would be gratefully received. I am no computer whizz, however, so if it involves messing about with Com ports etc please assume minimal knowledge 😳. There’s also no more budget for buying ASI Air or similar btw so I have to stick with a cable solution. Thanks Andrew

Perfect, thanks. Looks like I’ll be making the purchase 👍

Thanks Alan - that’s useful info

Hi, thanks for your reply I have a 10 ah powerbank supplying the USB 3 hub. It is possible for me to get 240v AC to the scope as I have an external socket about 10m away from the scope but I was hoping to just having one cable trailing across the patio I.e the USBs or Cat5/6 cables. If I can power the Star Tech hub at the Mount through DC supply that would be ideal. cheers andrew

Hi, Thinking of buying one of these as my Powered USB Hub and Active USB cables set up seem a little unreliable. I think a few SGL people use these but I was wondering how everyone powers the Remote Unit at the Mount end. It’s not easy for me to get 240v AC to the Mount for the AC adaptor that comes with the Star Tech kit. Does anyone have this set up and power it using a DC supply such as a power bank and if so what connector does the Remote unit accept? Thanks Andrew

Great, thanks for the advice.

Hi, Yesterday I collimated my SCT using a ZWO camera, SharpCap reticule to get the artificial star dead centre and 'Al's collimation tool' to make the adjustments and everything looked spot on. Unfortunately I then defocussed in the other direction and collimation looked out. Not massively but enough to be annoying! Is this likely to be mirror flop I'm experiencing or something else? I did have a reducer in the optical path so could that be a factor? Any help would be much appreciated. Thanks

Thanks for the update Colin, that’s useful info.

Ok, fair enough. I had read that but as it involved different software and there was a suggestion it was something to do with J2000 v JNow rather than slew v guide commands I thought it worth mentioning. I’ll just keep testing (whenever there’s a break in the clouds 🙄) and wait to see if there is an outcome to Colin’s research.

Hi Colin (and anyone else who can help). I have just set up plate solving in SharpCap using AVNSR with my Meade LX90 audio star handset and the Meade Generic Driver. The plate solve is successful but the mount sync and re-centre isn’t. The mount moves to somewhere near but certainly not central. That said I have only had one evenings’ opportunity to test this. There is a post on the SharpCap forum from someone who had exactly the same issue which persisted despite various different tests including using a different driver. There didn’t seem to be a resolution to the issue (I have asked but no response!). Earlier in the post the SharpCap author suspected it was to do with a translation issue between J2000 and JNow. SharpCap converts whatever the mount reports it is using to J2000 apparently so if the mount reports incorrectly then an unnecessary conversion will happen or a necessary conversion won’t happen which results in an inaccurate sync. There is no option to change the settings via the handset. If anyone can provide any guidance (even if it’s to refer me elsewhere) it would be very much appreciated and thank you Colin for providing the Driver thanks Andrew

Thanks for your help everyone. The picture below is where I'm up to now with my collimation efforts. I added some nylon washers behind the collimation screws which really helped as the back of the secondary holding plate had become a bit dimpled. I can see from the photo that the secondary needs to go about 1mm or 2mm down the OTA. Question I have is, what difference will that make? I'm going to start EAA soon but definitely not full astrophotography.

Thanks, I appreciate the response. I had pretty much followed the procedure described in the link apart from the first bit about checking the spider vanes were positioned centrally. I'll do that and follow the full procedure again and see where I get to.

Hi all, I'm pretty new to the world of collimation and need some help. Tools I have to hand are a Cheshire, a Collimation Cap and a Laser. The scope is a Skywatcher 130 PDS. When I've convinced myself I've centred the secondary under the focuser tube usIng the Cheshire as a sight tube the laser misses the primary centre dot by a good inch or so and I get the same view with the Cheshire. If I try to correct it using the collimation screws the outcome is awful. After a couple of hours I gave up trying to centre under the focuser tube and the picture below shows where I am am up to now. It looks to me like the primary and secondary are pretty square and the laser shows that too but clearly the reflection of the primary is (unsuprisingly) not centred in the secondary. I think I can sort the 'front to back' misalignment using the centre bolt but I'm a bit lost about the side to side misalignment. Do I need to adjust spider vanes to get this right or all there a whole host of other things going on that I'm just not seeing with my novice eyes. Any help would be much appreciated. Thanks Andrew