SteveNickolls

Not long after first getting the GEM28 mount I spent time going over the various mount control options and made notes on the procedures for future reference. I attach below an excerpt which goes through the steps for mount control that may prove helpful to others- Using the Hand controller and USB cable provided with the mount. iOptronCommander/Stellarium control. Using iStarFi Wi-fi and iOptron Commander/Stellarium. Changing Wi-fi settings on the Internet-alter channel, change password, enable encryption. Cheers, Steve iOptron Gem28 SGL Excerpt.docx

Hi Adrian, thanks for your post. I'm sorry you are having no joy getting to control your equipment using Sky Safari expecially when it's meant to work. Unfortunately I am not able to help over the intricasies of wi-fi control and have never used Sky Safari. Have you been able to control your HEQ5 Pro directly with SkySafari (over USB cable) and without involving the Eagle Core unit at all just to check it does control your mount that way? Might your firewall software be preventing access to this port? Perhaps try once disabling your firewall to test? You can enable ports to be open for certain software. Cheers, Steve

I’ve had my iOptron GEM28 (non-EC) mount since late October 2021 and due to the British weather have had only a few chances to get out under starry conditions but had plenty of time to look into controlling the mount by USB and Wireless connection indoors. I hope over time to add to this report as I get more experience using the various features of the mount to serve as general advice to other prospective purchasers and perhaps a focus around the iOptron GEM28 mount for others to contribute. When a shipment of iOptron mounts arrived at FLO after a delay due to shipping logistics I bought the GEM28 as a bundle with the 1.75” LiteRock tripod, iPolar and case. This did not include either the GPS unit and proprietary iGuider unit. My reasons for choosing the GEM28 were several and included wanting a replacement for my large and heavy (and feeling heavier now) Celestron CG-5 AS Go-To mount that has seen good service since 2005. Some technology in the hobby has come a long way in the intervening time and I wanted a mount that was compatible with modern protocols. This included the ability to explore using USB and Wi-Fi control something I had been unable to achieve with the ageing CG-5. I was also taken with the relatively lighter weight of the GEM28 weighing in at 4.5kg for the mount head plus counterweight arm, counterweight (4.7kg) and tripod (7.5kg) making the whole assembly portable rather than requiring to be set up in several loads, as the CG-5 previously required, at the imaging pad in the garden. As I intend to use lightweight payloads for astro-imaging with wide-field equipment in the future the entire assembly with payload will be very portable. Unboxing The mount was delivered in two well packaged boxes by courier from FLO, the longer box containing the tripod the other the protective metal case with the mount head and accessories. Opening the longer (tripod) package revealed the tripod, this came well packaged in its box with the legs covered by a protective large plastic bag. However in the daylight two of the legs were seen to be scuffed and I considered returning them for replacement. As the tripod was well package for delivery the scuffing must have originated at the assembly factory with poor, rough handling causing the scuffing. I thought it ironic that this new mount came with far from pristine scuffed legs while the tripod for my 16 year old Celestron CG-5 tripod after all its years of use are still perfect. Tthe tripod legs came ready attached with anti-vibration pads which I thought was a neat and unexpected touch. One of the scuffed legs- The other box contained the metal carrying case which held the other items- GEM28 mount head with iPort for an optional GPS accessory. Go2Nova 8409 hand controller and cable (for CEM26 and GEM28 mounts). Mains power supply unit. 1 x 4.7kg counterweight. Counterweight bar (comes stored inside mount head). Short extension piece to the counterweight bar. USB 2.0 cable to connect hand controller to PC. Mini USB cable to connect the iPolar to the mount. A short RJ11 cable connecting DEC control unit to the DEC port on the RA main control unit. Tripod spreader and eyepiece tray. Quick start up guide. well written 49 page manual was download from iOptron’s site. Set Up I removed the Az alignment peg from its location between two tripod legs to above one of the legs which wil be the north facing leg. The alignment peg has a useful hole drilled through it to allow a thin screwdriver blade to be used as a tommy bar to secure the peg firmly in place. Having previously read the product manual online I took time to read the quick start guide instructions. The GEM28 has gear switches which swing freely if disengaged and care needs to be taken when taking the mount head from the box and when performing adjustments in RA and DEC balance so not to damage the worm/drive system. I took care to ensure the mount head sat flat onto the top of the tripod. Unlike my CG-5 mount which secures the mount head using a long bolt the GEM28 has a central locating peg in the top of the tripod and the Az alignment peg, the mount head is secured by two hex bolts that can be tightened with a 4 mm hex key. These two hex bolts also play a role in polar alignment when they need to be slightly slackened off to allow adjustment of the mount head by the Az adjustment screws in the mount head. The size of the mount head was dinky compared to my CG-5 but the whole assembly is rated to hold 12.7kg (28 lbs) of payload. The main counterweight bar comes tucked away inside the mount head, a neat storage feature. Once all fitted together my overall first impression was of a very well designed and constructed product. Balancing When I came to trial balancing the mount the complete difference between the responsiveness of the GEM28 to the coarseness of my CG-5 mount could not have been more different. No longer do I need to imbalance the mount ‘East Heavy’ to keep gears meshed under load. Polar finding My mount came with a preinstalled iPolar camera which was tightly fastened in the polar hole of the mount head. I have previously used an iPolar on my CG-5 mount and was well versed in its operation but did update the software to v2.6 to stop reported stuttering of the polar axis position during the alignment process. It is useful to check that the preinstalled iPolar device was factory installed in line with the mount such that adjustments of the mount’s pointing position on screen are made in line with the Az and Alt adjustment mechanisms and not at some acute angle which would make alignment frustrating. The iPolar should be periodically checked to ensure it is secure in the polar opening and not able to rotate. The screw cover over the iPolar has a fine thread and tricky to replace at night so I use a rubber bath plug to cover the hole once the screwed cover is removed each session. As part of the iPolar routine I now replace the plug over the camera hole before confirming position 1 in the iPolar software, this prevents the iPolar taking its second image and plate solve before the mount head has been rotated 90 degrees to position 2. At the end of each session I replace the plug with the proper screw cover. I have found the iPolar process quick and simple to perform and the Az and Alt adjustments on the mount very responsive. My CG-5 was modified with Teflon pads to allow easier polar adjustment but the GEM28’s adjustment process is even slicker. Firmware upgrades I updated the firmware to the hand controller, RA and DEC motors using the online Firmware Upgrade manual which worked very well taking me through each step of the process. Mount control I intend to mainly employ the hand controller to control the mount and perform star alignment and Go-To since having to set up each session already requires me to be at the mount. I did not buy the optional GPS accessory with the mount and have found that the hand controller maintains the current time and position. The hand controller provides a number of alignment options including one star alignment and three star alignment. I have found no problems performing alignment with the mount slewing close to the target stars for fine correction. The mount also has the ability to synchronise the mount to a target object to improve the modelling of the night sky. My methods for obtaining precise alignment either involve centering stars in the ‘Live View’ screen of my modified Canon 700D DSLR which has an overlay with the precise centre of the screen marked out or for imaging with an astro-camera using my tablet and ASICAP software with red dot reticule. As regards Go-To noise the mount is whisper quiet in operation, no more coffee grinder levels of noise at night when slewing with the CG-5. I have also spent time indoors resolving mount control problems using both USB and Wi-Fi and installed iOptron’s proprietary iCommander software as well as having the mount run stably both over USB cable and by Wi-Fi under Stellarium. I have read of issues with other users trying to control the mount with Sky Safari. I have documented the mount cotrol processes for future reference. Photo below showing controlling the mount under Stellarium. The GEM28 is one of iOptron’s mounts which comes pre-fitted with a 2.4 GHz Wi-Fi unit and which seems identical to the iStarFi unit available to retro-fit other modern iOptron mounts. The paperwork and guidance surrounding the control of the mount via third party planetarium software was neither complete or up to date when I last checked on the iOptron site and has given some users of other mount models connection issues particularly with SkySafari and which is the only third party control software mentioned directly in paperwork. Users can access the inner workings of their Wi-fi unit to change passwords, alter channel number and update firmware. This is all well documented and users are led step by step through the update process. I have obtained a 'WiFi Analyser' App for use on my tablet which has helped check on the number and channels used by neighbours allowing me to change the channel used by the mount and help avoid interference. iGuider. One accessory that can be fitted to the GEM28 mount is the proprietory iGuider unit but if I perform guiding I prefer to use PHD2 and either a 30mm miniguider + ASI120MM-S or 50 mm + ASI120MM-S. Own Modifications I have made a few modifications to the set up-I have secured the power unit to a tripod leg using a Velcro strap, reused the hand control holster from the CG-5 to take the GEM28M hand controller, use a bath plug with the iPolar as previously mentioned and added a plastic cover screen to my DSLR to help centering alignment stars. A friend kindly bored out a compatible 2kg counterweight for me to use with the mount for lower weight payloads. And finally- I'm looking forward to using the GEM28 more as British weather allows. The mount will allow me to set up more quickly each session and take down more quickly, two processes that can tire when done often. As different targets present themselves over the seasons I hope to make use of the better guiding ability of the mount and dithering while exploring the other capabilities of the mount such as USB and Wi-Fi control. I hope then to add more of a review to this report as I get more experience using the various features of the mount. I hope this serves as general advice to other prospective purchasers of the little gem that is the GEM28. I would be pleased if other users may wish to place their reports and questions to act as a future resource for this mount going on into the future. Cheers, Steve

Hi AidyM and thanks for your post. I hope someone using the Eagle Core can assist you with your mount control issue. The subtleties of wi-fi control can tax even a saint and I can only sympathise when you really want help. I take it you have full working mount control using the hand controller but want to extend mount control over wi-fi using the Eagle Core? I realise advances have occurred with wi-fi control with the Eagle Core since the procedure set out in the printed manual (page 110 onwards) supplied with the unit as at one time you needed a SkyFi III connected to the SW Synscan hand controller. I do hope someone who has achieved control this way can walk you through the process. I see Filippo demonstrates the connection process in this video when v2.5 was released in the past. Cheers, Steve

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Really hope this comes to fruition. I've been holding off on the ASI183MM-PRO in case this happened. 🥰☺🤗 Cheers, Steve

Hi Dean, thanks for your message. Pleased you have resolved the communication problem so now enjoy your new mount to its fullest. 😁 Great to find the mount is working well for you. I'm just hoping for some clear sky to try out polar alignment and star alignment. Finger's crossed on this. Sorry to learn of the SkySafari connection issue, maybe have a try with Stellarium? I haven't installed Stellarium on my tablet only the laptop to see if the mount could be controlled that way but see little reason why tablet control should not work. It may be a generational thing but I'm happy using the hand controller but was inquisitive over USB and wi-fi control. Cheers, Steve

Aww thanks for this. Did not mean to cause anguish but it would be good to get my CG-5 working in such a fashion. Cheers, Steve

Pleased to hear you have got the cable arrangement working, really good news. Would you be able to provide a photo of the set up/connections on the mount side? What actual splitter are you using too? Which hand controller version are you using and which firmware version? 👍 Good luck for the future. Cheers, steve

Hi, I can't help over direct cable control (sorry) but I have tried (unsucessfully) using the Celestron SkyPortal wi-fi device with my CG-5 AS mount- https://www.firstlightoptics.com/celestron-mounts/celestron-skyportal-wifi-adapter.html This attaches to the the mount and is meant to permit wi-fi control using a mobile or tablet with the free SkyPortal app. You need however to employ an aux splitter cable on the CG5 of which there are two flavours- https://www.firstlightoptics.com/celestron-mounts/celestron-aux-port-splitter.html However I was unable to get my mount to be controlled this way. You may however be able to perform this miracle. Good luck if there is a cabled solution you can try. Cheers, Steve

Thanks Dean for starting this thread and good to read your comments on the mount. In late October I took advantage of FLO having a new supply of GEM28's after they had been on 2 months back order for what seemed like forever. I too was pleased with the overall quality of the mount and tripod, certainly didn't exect the anti-vibration pads on the ends of the tripod legs-a neat touch. Ought to start a GEM28 Owner's Club thread really but haven't any experience with the mount yet to write up about (the skies really have been that bad recently) but I hope you don't mind me mirroring your comments regarding the CEM26? My reason for getting the GEM28 was it's overall lightness compared to my CG-5, I can now carry the whole set up to the imaging pad each night rather than assemble in several loads. As you commented set up too was painless but as it was my first adventure into ASCOM it meant loading quite a lot of new software. All went well and I updated the mount firmware to the latest version too with no hassle. I have used the iPolar before on my CG-5 but I have been using v 1.6 and know the new iPolar's can use v2.5. I have read of some issues with juddering in use but with the current poor weather haven't ben able to do anything yet outdoors. As geeklee rightly mentions balancing is made very easy but tricky, by comparison my old CG-5 is very unresponsive to even fair amounts of imbalance, so no more 'East Heavy' weighting in the future. I have made a thick Velcro band to secure the power unit to one tripod leg and found my old CG-5 hand control holster fits the GEM28 fine. I use an elastic band to hold the hand controller in place when moving the mount around. I have had the mount working with- The handcontroller directly (I wiill be using this virtually all of the time). My laptop+USB 2.0 active cable (20m)+connecting cable to the hand controller USB port. Both with iCommander control and/or Stellarium. Wi-fi control using my laptop+integral iStarFi in the GEM28. both under iCommander and Stellarium control. I do not have SkySafari to test out but have read of connection issues on other forums, the gist being iOptron did not collaborate with the SkySafari makers so the solution lies at their door. I do disable Windows Defender when using the laptop to control via wi-fi and (whether this does anything or not) created permissions for port 8899 (both incoming and outgoing). I have found that one of the earlier iOptron wi-fi guides available on the Internet is incomplete but found an earlier version that is as unhelpful as any other- 073c1bd163bdc2b0f63c931359dbd4e2263476341d9062327e60101fac18f0e6.pdf Have not seen a 'communication failure' error message on the hand controller. Hope you get more clear skies to use your mount under. 👍 Cheers, Steve

This Internet page may be of interest to others with Eagle series devices. 👍 https://www.primalucelab.com/software/play-prima-luce-astrophotography-software.html Cheers, Steve

Nice photo's. If I were the PM I'd be looking at taxing that access to dark skies. 😲 Cheers, Steve

Thanks happy-kat for the link. 👍 Cheers, Steve

Thanks everyone for your contributions. Yes it was that development that made me consider the 533MC against what I would have instinctively chosen as the set from a DSLR. Can I ask what Bortle scale you image from especially you saying your next astro-camera would be a OSC? What a great site, thanks for pointing me in its direction. It has some extra considerations for me to ponder and I like the approach taken on the topic. 👍 Thanks for your view of the 533MC and Ha filter I appreciate real world experiences most helpful in choosing. It's sounding like the 533MC and a dual band filter may be the way to travel and take advantage of the better specification of the newer OSC option. Can I ask what Bortle zone the images were taken in? Thanks, Steve

Thanks vlaiv, Adam J and wimvb for your helpful comments, I had expected the mono-camera to be preferable but there seemed something about the 533MC model that caused me to ponder a left field alternative. I did wonder if the technology had reached a point where it had least met the limiting physics part-way to give a decent image. I've not seen too many images of nebulae using the 533MC under such light polluted conditions as I encounter here. I think had my sky been somewhat darker, say Bortle 5, the 533MC would have been ok especially when the camera can make use of the dual and tri-band filters for OSC cameras now on the market. Cheers, Steve

Thank you vlaiv for your summary and explanations I really do appreciate it. 🙂 Thanks, Steve

Hi, I have been astro-imaging for a little over six years and now wish to purchase a cooled astro-camera to continue my interest in the hobby. I set up my equipment each night and currently use a modified Canon 700D DSLR, clip in Astronomik 12 nm Ha filter and Samyang 135 mm lens (f/2) to capture wide field images of emission nebulae and intend to continue to do this type of DSO imaging but with the benefits that a dedicated cooled astro-camera with lower read noise and higher quantum efficiency could bring. I live in a Bortle 6 area, a typical SQM-L value being around 19.26 so light pollution is always a concern when imaging. My budget is modest in astro-photography terms and I first considered the ASI183MM-Pro model. The intention would be to have a simple set up involving the astro-camera, ZWO filter drawer holding the clip in Ha filter in a 2” adapter sold by Astronomik connected to the Samyang lens. Out of the left field however I have recently entertained the newer and slightly cheaper ASI533MC-Pro model having a largely improved specification compared to the 183 model and has no associated ‘glow’, but this astro-camera is OSC. I am conscious that there would be a hit in terms of resolution between the two cameras but as I am imaging with a short lens (135 mm) the equipment is already under sampling according to the Astronomy.Tools link on our sponsors site but this may not make much real life difference in the images produced. I am also aware of the reduced light grasp with using the OSC compared to the mono astro-camera-this is something I am familiar with when imaging with my modified OSC DSLR. Both astro-camera options will allow me to take much shorter sub-frames for stacking than with the present DSLR, and to stack more of them reducing SNR in the final image and the slightly larger pixels on the ASI533 combined with the 1.5e- read noise make the 533 model able to take even faster sub-exposures than the 183 model-so even more exposures in a given evening’s session. I’ve also thought that the higher full well capacity of the 533 model would permit me to extend exposure times if wanted without saturating stars in the image as fast as with the 183. Before I take the plunge to order what may become my first and last astro-camera for DSO work I would be interested to learn if any other SGL member has used such a combination of OSC 533MC astro-camera, Ha filter and short but fast (f/2) optics in a light polluted sky and how successful has this been in practice? Views would be gratefully received too on whether in the light polluted conditions that I image under the 533 model would be preferable to the monochrome 183 due to its generally better specification or that the monochrome camera wins hands down. I look forward to member’s comments and advice. Best Regards, Steve

Thanks for posting. Could you say what Bortle class you were imaging in? Cheers, Steve

Ha, ha it's not Tuesday yet. 🤣 Cheers, Steve

Why one of these. Mine is a rather old version from Celestron, it's their heavy duty Alt-Az mount-https://www.firstlightoptics.com/celestron-mounts/celestron-heavy-duty-alt-azimuth-mount.html The Az and alt controls are very smooth to operate with the Star Adventurer (SA) mount onboard giving very good control when polar aligning and I've used this configuration for a few years now after finding the original SW wedge for the SA to be very coarse in operation. Cheers, Steve

Get yourself one of these and throw away the wedge. HTH. Steve

An iOptron Gem 28? Cheers, Steve

The clouds didn't help capturing any Perseids this year. This is almost an hours worth of exposures capturing one meteor and an aircraft trail. Note the lovely light pollution hue. Taken with a Canon 600D and 18-55 mm lens (at 18 mm) f/3.5, x225 fifteen second exposures at ISO 400. Compiled using StarStaX software. Cheers, Steve

If you have the motor control firmware to v 5.06 it corrects runaway slews. 😃 Regards, Steve