Just received my GM811G, assembly complete, went quite well. Installed and checked the polar scope alignment and it's a bit out of calibration to the mount. Question is for visual observing only, how critical is spot on polar scope calibration to the mount? I know how perform calibration on a polar scope but have never bothered to concern myself with this in the past. However, this is the first mount I've owned that is go-to and want the go-to to be accurate.

If the consensus is to calibrate the polar scope, how does the Losmandy scope adjust? I can see the three opposing adjustment points however they are extremely?small openings and do not appear (under magnifying glass) to have turn-ability...as in I can not see allen screw heads or slotted screw heads.

Your help is appreciated.?

Cheers,

Bob Pitney

Great advice George.? Let me explain why I said in my first response that OnStep is a lot of work.? It does not have to be if you know what to build, like the kit that you sell.? I chose to go the more COTS part (fewer features, but almost no soldering) based way and design my own pin map, which requires tracking the pins from CPU to Arduino clone board to CNCv3 board.? This was because the stable version had no CNCv3 support at the time IIRC, while the later versions that are stable enough, do - I chose the stable version.? I just wanted the basic features and use a Pi for the high level control and also WiFi.? Then in addition to the Wemos Arduino clone I got a Teensy 4.0 additionally, and just spent a lot of time playing with parts and combinations, different drivers, and the code too.? None of that is necessary so if you select something standard from the OnStep Wiki, which makes it a lot easier.? And absolutely, the OnStep user groups is very helpful, many members go to extreme lengths to help if you can't get it working.

Maybe someday Losmandy can support this with a partial BOM for an easy-to-make OnStep system.? It would be a great help to include BOM links to suitable female ethernet connectors for the motors, flexible ethernet cables, stepper motors, flex connectors for the motor shaft and custom connector plates for the stepper motors (or specifications on how to build them - a flat square plate with hole locations, basically), and proper screws.? For instance, soldering the motor cables to the crappy connectors that I bought was a major PITA, if someone had pointed me to the right stuff online it would save some aggravation.? I could probably help with that so long as it's not for a belt driven tucked away motor.? For the actual controller choice, see the OnStep site.? It would also be good to point at higher level control hardware and firmware in a small package alongside such as a Pi that runs Ekos, or any Ascom or Alpaca based Windows alternative.? The Pi with Ekos lets me get away with a very basic OnStep system, yet it is a powerful combination combined.

I got the G11S because of the budget limit I had set, and also because I wanted to buy a US made system.? I figured I could build my own controller, from scratch, or find a vendor kit.? My first move was to get a cheap Losmandy goto kit from a commercial vendor.? I could not get it working probably mostly due to mechanical problems in retrospect (by no fault of that vendor's kit), and switched to OnStep just to have full control over my build, including the firmware.? I re-used the mounting plates and flex connectors from the kit, and after I built my DIY spring loaded worms and the Ekos/OnStep system I finally had an operational working system.? It could be a marketing opportunity for people with a limited budget, or for upgrading old systems cheaply that have no working or adequate controller.? So there are alternatives, not just through OnStep.

Sounds like one giant step backwards to me.
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SonnyE


(I suggest viewed in full screen)

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I’ve been imaging M42 and NGC2264 and find the GM811G isn’t very good past 30 seconds, its not about tracking its like the image is on a bumpy road with stars moving left/right/up/down like too much coffee. ?Since I am just hunting for new objects in the sky I am NOT using guide software (PHD2) but everything is level and balanced. ?I thought the Nikon DSLR was bad but its really this GM811. ?Serious imaging will require Guide software which is easy to setup and gives good results. ? ? ? ?AT115 reflector and Nikon DSLR bare bones tonight.
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Liam,

The majority of Losmandy owners, at least those on this forum, seem to have the Gemini control system. That being the case, there are many who can advise you with mount operation, guiding, and trouble shooting. Also the Gemini will accept upload of PEC curves from PEMPro, to further smooth guiding performance. Once you get into astrophotography, the price of the Gemini unit is not that much of the whole expense, compared with scopes, cameras, filters, auto focusers, etc.

For guiding, ST4 seems like it is becoming less used, with direct mount control over USB or Ethernet supposedly more responsive. If you have the expertise to use some of the less expensive control units that is fine too. But you may not have the same level of tech support from the forum or the manufacturer. Just my opinion, others may advise differently.

Best Regards,

John

I can't find Part 1 or 2 either.

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I replaced the 492 system of my G11S with a DIY OnStep controller.? It is a lot of work but it's fun to do, it works very well and is a whole lot cheaper.? Mine is controlled be Ekos on a Pi but OnStep also has an Ascom driver for use on Windows.

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On Fri, Feb 26, 2021 at 01:15 PM, <altuttle@...> wrote:

Thanks a ton for these latest replies!!!

Yes, I do know the added costs.... (my spreadsheet is a scary thing to look at).? ?It's the same story with all the next tier mfgrs I've looked at (AP, Paramount, 10micron, & Planewave), in some cases even having to rebuild/modify the observatory.? I can convince myself (& the CFO) that the cost is justified.....? but I have doubts that I really need to go that far.

Chip, your comment really hits home.? I'm looking for a relatively high capacity, strong mount that tracks very smooth.? I have several scopes (mostly mid-tier) and I change them often to suit the season/targets.? As such balance and position often changes a bit, so parking position for easy restart and pointing models are mostly irrelevant for me.? The level of controller I have with the Gemini 1 (or even with my Celestron) is more than adequate.? My problem is drivetrain errors that impact good guiding, mainly backlash and PE (not the averaged PEC, but the higher frequency errors/roughness).? ?I don't know if its really necessary to spend 2 or 3 times the price to get those improvements in the gear train, or would much of that cost be for things like optical encoders and fancier controllers?

I'll think seriously about getting a G11G as a tryout so to speak before going all-in on a Mach2, particularly if the wait for it gets pushed out further.? The G11G may be just the ticket.

Thanks again,
al

Al,

If you can truly afford an AP Mach2 the $3,500 cost of a G11G fill-in mount will be trivial and who knows, you may decide you like your results. It is very hard to see the differences between these mounts unless you are working at a supremely high level of imaging craftsmanship. In that place you know that you are oversampling for a reason and have the sky conditions to take advantage of it. Additionally simply by putting a building around a G11G you will instantly improve your PE over the long haul by eliminating the biggest issue any high payload portable mount has, payload windage. This can push the G11G into the high priced spread territory in terms of performance. Will the G11G give you 100% of the same performance as the AP Mach2? Of course not, not in absolute terms but 99% - maybe. At that point the question is are you that level of imager??

My next question is what level of automation does your observatory have? As in can it open the roof and if it has a slit can it track automatically? If you plan to image from the house in the winter I would buy the AP mount. They have a more robust control system especially the Mach2 with encoders. Put a IR video camera in the observatory and you can probably recover remotely. If you don't plan to do this then I'm still in favor of buying a new G11G while you wait and like I said, who knows you may become a convert.? ?

Just saying.
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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

On Fri, Feb 26, 2021 at 11:39 AM, Arun Hegde wrote:

That is unquestionably true. AP prices are for mount only. You will need counterweights, a counterweight bar, a dovetail to mount your telescope, a flat surface adapter and knobs to mount them on something like a Losmandy tripod all of which add to the price of the mount. Mine came with the counterweights and bar, but I had to purchase the other stuff, along with the V2 chip for the upgrade from the old Q firmware. All that adds up. And I still kept by GM811G because it is a really nice mount and more portable than the Mach 1. Plus the LHD tripod works with both mounts, so that's a win!

I'm well aware of this, I guess I was not clear when I said $10K and add accessories. It should have read $10K plus at about 50% for items Losmandy owners consider standard but AP considers accessories and assuming a fixed non-AP pier.?

For what an AP Mach2 costs - well equipped - for a variety pack of scopes you can buy a several Losmandy G11G moutns sans FHD saving nearly $700 per mount and build a roomy observatory to house them and never have to swap optics allowing for perfect polar, orthgonal alignment and balance for each optical tube design. There are many many images of very high quality produced on Losmandy mounts every year and that number will go up as the newer mounts get out there to serious imagers. Additionally having multiple mounts allows capturing multiple objects at once or a single object with differnt cameras and optics. Or imaging on two mounts while visually observing on the third, so many options whith multiple mounts none of which are possible with just a single mount as nice as it is.? ?
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Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astropheric Weather Forecast - South Pasadena, CA?

Hi All

Is there a Part 4 somewhere ?

If you have the older 'non Gemini I or II' models you can auto-guide and dither.? You will need an ST4 cable.