LOSMANDY GEMINI 2 GOTO SYSTEM
Posted 08 February 2013 - 10:25 PM
BTW, did my first 'full' setup with modeling. Surprisingly easy to accomplish, completely spot on with not being that accurate. And, you definitely need to build models on each side of the meridian.
Edit: So I was examining the data I got from my new pointing model after using PEMPRO. Have you guys ever paid attention to how sensitive it is to the pointing model? The numbers for it's polar alignment significantly changed depending on where I was in the model. Perhaps that is the issue we're running into when using PAC?
Posted 08 February 2013 - 11:27 PM
Wow thats great. I wonder if different models of mounts make a difference on quality of accuracy.
I am thinking of swapping out my gearbox to see if it helps. I had noticed on mine that I definately have to make a model of both sides for goto's also.
What ota are you using on it.
I am glad you are getting good results with that real nice mount.
Posted 09 February 2013 - 02:09 AM
Posted 09 February 2013 - 02:54 AM
Posted 09 February 2013 - 03:29 AM
Posted 09 February 2013 - 10:25 AM
I have rechecked that information many times. In fact the Gem 2's internal battery died within a few weeks of recieving the mount. Scott sent me a replacement battery that started with 3.3volts but in a few weeks it was down to 2.5v and I had to keep reentering the info. I bought 2 more batteries and its been a couple weeks and this one started at 3.4volts and is already down to 2.9v. I haven't had to reset the info yet but I check it every day. I get the voltages from the Gemini web server page then checked the batteries with my multimeter when I replaced them. I find the Web server's volts reading to be accurate. I expected the batteries to last around 5+ years but you never know how long they might have been in the packages. Thank you for your help.
Yes, several weeks after I got the mount I followed the procedure to update the firmware. Even though it was up to date. Flashing the sram was part of that process if I remember correctly. But I will try flashing the sram today. Thank you for your help.
Yes, At least I would buy one, but I would prefer the Gemini 2 to be improved similar to the NexStars level.
Posted 09 February 2013 - 12:46 PM
When I flipped to get the other side, I expected the GOTOs to be 'more' accurate. They weren't. It was essentially the same as starting over. This makes sense since each side of the sky has separate models.
Now the interesting part. I'd polar aligned with PEMPRO, so I assumed I was within a arc-minute of the pole on each axis now. When I started the model on the East side, It had a large number in pole azimuth and a smaller number in pole elevation (15000 and around 300). As I refined, that number got smaller (around 1000 in each when I got to my 5th star). What surprised me is that the pole numbers became significantly off when I started the W side of the model! It again went large to 15000 for the azimuth and a smaller number for the elevation. But, as I got to the 4th star on the W side, it became what I expected of around 1000 in each value.
So, maybe PAC is very dependent on our modeling behaviors. If you're not putting in enough data points on the E and W side, perhaps it isn't capable of calculating a precise polar alignment?
Anyways, just thought I'd share.
Hilmi, thanks for the help! I finally figured out how to use the semi-automatic modeling, and it really works well. That definitely made the difference for me. Oh, and I had the scope slew to my only real target last night (M81) and it put it within arc-seconds on my ST-10. No plate solve required. I was definitely happy with it . That was with 6 stars on each side of the meridian in my model.
Finally, I want to see how it does when I wake it up next. My CGEM was never accurate after 'sleeping'. I always had to use plate solving after putting it to sleep (or just knock out a new alignment). If my G2 wakes up and can point, I'll be VERY happy indeed.
I agree, I like the color screen and features of the G2. The ASCOM driver is AWESOME compared to Nexstar. I hate that I needed another program like Nexremote (which wasn't free :/) in order to control it. Also, the fact that the ASCOM driver works with the data in the mount and vice versa... I hated creating two mutually exclusive models with Nexremote/Nexstar HC.
Overall, I'm extremely pleased with G2.
Oh, anyone wanna tell me how to do PEC? I did a 30-minute run in PEMPRO.... Made the curve, and unlike my CGEM, it didn't have a way to 'upload' it directly to the mount? It required me to play it back.... which took the worm time for a full rotation obviosuly. And then the ASCOM driver wouldn't let me turn on PEC? Any ideas?
Oh, and my PE was around +/- 2" I love this MI-250. I've never had guiding so easy! My RMS was .11 and my oscillations were around .48 (where they should be).
Posted 09 February 2013 - 01:50 PM
IIRC there are 2 gemini mount types in PEMPro and only one of them supports the direct upload.
Posted 09 February 2013 - 01:51 PM
anyone wanna tell me how to do PEC? I did a 30-minute run in PEMPRO
You need to run the mount setup wizard in PEMpro and select Gemini as mount type
Posted 09 February 2013 - 03:50 PM
I havent been able to figure out how those pole numbers work on Gem 2. With NexStar they made sense to me. My pole numbers on my Gem2 were usually around 400-800 for the first and 1300- 6000 for the second. Does it mean its 6,000 arcseconds off?
I'm glad your mounts working out good.
You just have to build a model on the East side for PAC. I believe you need 4 stars but more is better. The quality of that model effects how good PAC will figure the Polar alignment.
My alignment stars on both sides were just as you described yours were.
I found it was best to use one or two stars that overlap the East and West models or after doing the West model the East model stars were off a little. That was just my experience, you might check it out.
Posted 09 February 2013 - 08:46 PM
I'll keep that in mind about using repetitive stars on each side of the meridian. That's good advice!
pfile, I'll have to go through the mount setup and see if there is an option for a G2/MI250. I'm sure PEMPRO thinks I have a G1/MI250 right now.
This thread has been very fortuitous! I learned a lot over the last few days going through everything with ya'll.
Posted 11 February 2013 - 10:52 PM
Finally, if I do hit a safety limit, it seems to really jack up the driver? Is there any way to keep it from doing that?
Posted 11 February 2013 - 11:13 PM
Posted 11 February 2013 - 11:28 PM
i think by default once you hit a limit, the mount really refuses to move. it will move if you use the handpad to back it out though. the driver has an "automation" setting that will automatically nudge the mount out of the safety limit, i assume so that mount control programs can move the mount or do a meridian flip or what have you. but when you enable this the driver warns you about it, so i was a little afraid to turn it on
Posted 12 February 2013 - 12:16 AM
Posted 12 February 2013 - 11:28 PM
Is there a special setting if I want to image unguided. I am in sidereal rate but the mount runs slow in RA.
Posted 12 February 2013 - 11:33 PM
Posted 12 February 2013 - 11:48 PM
My mount is a G11 and that is what I set it too. I haven't messed with anything else except the TVC I set to 25 and I also set the mount limits.
I found the default gearing settings on line I will check them tomorrow. Both worms 360, spur gears 25, motor encoders 256. I have never messed with them but I will check them. Thank you.
Posted 13 February 2013 - 12:21 AM
But to my understanding the speed is set in the hand controllers and the speed is maintained by the motor encoders. So If mechanically the mount is turning at the right speed, but you are still falling behind in RA, that indicates to me you'r clutch isn't doing its job.
The clutch is A) Easy to replace B) A consumable item C) Very cheap.
Posted 13 February 2013 - 02:52 AM
My clutches were slipping bad. I thought it was the cause of my problem. Scott sent me some different clutches and now they hold very good. Very stiff, no more slipping at all. But the RA is still slow.
I checked balance over and over, I even tried making it heavy to the West to speed it up but the mount slows it back down.
Posted 13 February 2013 - 06:17 AM
Posted 13 February 2013 - 12:35 PM
King is for imaging near the horizon. Increased refraction makes things go at a different speed than the normal sidereal rate near the horizon. King rate compensates for that. I think thats right.
Posted 14 February 2013 - 12:08 PM
I posted my complaint on the Gemini 2 Yahoo group.
It wasn't long before someone with a fairly new G11 Gem2 replied that he is having all the crazy problems that I am with his. There appears to be some kind of bug in the Firmware or defective units. I don't know how this is going to be resolved. I sent an email to Scott and Craig the owner of OPT where I bought it. I have been sending both of them complaints about this ever since I bought it in December. Now I have proof that it's the mount, not me.
Posted 14 February 2013 - 12:25 PM
Posted 14 February 2013 - 01:47 PM
The choice would be easy for me after all the problems the one I got has. But I am biased. You might get a good one. If Scott fixes all my mounts problems to my satisfaction then my opinion might improve.
The Alt/Az Eq-6 Pro is a mount I would like to own.