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LOSMANDY GEMINI 2 GOTO SYSTEM

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#26 neilson

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Posted 03 February 2013 - 02:44 AM

Hi,
My CGEM DX always put stars and deep space objects dead center in the eyepiece and camera chip, the ASPA always got my polar alignments extremely close, I was always able to do guided images 10 minutes with round stars. I never had any problems with the Nexstar.

My 2 month old G11 Gemini 2 has runaway goto slews after the first East model every night. The system freezes up requiring me to restart and realign sometimes. I have trouble getting DEC to calibrate with PHD and after 5 or so images Phd will not guide RA but will guide DEC, most nights this happens. My periodic error is 28 arcseconds. Mine is one of the ones from December with bad worms. Mr. Losmandy is trying to resolve the worm problem.
After making an East model I have to manually slew both RA and DEC to start the West model. It wont do a meridian flip yet.
The PAC on my Gemini doesn't get the Polar alignment as close as Celestrons ASPA.
I am required to make seperate models with many stars on each side and the accuracy does not center anything like the 2+4 on Celestrons Nexstar.
All my images have football shaped stars with my Gemini 2. Yes I drift align. The mount doesn't track very well and the balance is extremely criticle with the Gemini 2.

At this time my opinion is it is ok for visual use and should be permanantly mounted to save the trouble of making models with many stars on both the East and West sides. Unfortunately I mostly do imaging and on a tripod.

The Celestron Nexstar is better in every catagory except that the Gemini 2 can be hooked up through ethernet. I am using the ethernet hookup but USB would of worked fine for my purposes. I had no ideal that this was a work in progress or that it was being written by one man in his spare time. Or that it wasn't done and might be a while longer. (It is impressive that he wrote all the firmware)

I wonder what it would of been like if Losmandy was still teamed up with Celestron and the G11 would of had the nexstar controlling it.


Neilson

#27 Raginar

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Posted 03 February 2013 - 10:25 AM

I finally turned on my MI250 with a Gemini-2 system installed yesterday. G2 is pretty awesome; built-in webserver, easy to navigate menus, and the hand controller seems functional. Mind you, I didn't do an alignment but I was very pleased to see that it looks usable.

Patrick, have you been to the Gemini-2 website and messed around with their demo? I think it would help you make an informed decision. I found it matched the physical uses to a 'T'.

Good luck!
Chris

#28 Charlie B

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Posted 03 February 2013 - 11:37 AM

it forgets the PEC curve all the time, meaning the check box for the PEC goes gray.



I've had this issue too. I usually do guiding and don't really need the PEC, so it's not been a problem, but, when it gets warmer, I will likely try to track this problem down.

Regards,

Charlie B

#29 pfile

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Posted 03 February 2013 - 02:46 PM

Mine is one of the ones from December with bad worms. Mr. Losmandy is trying to resolve the worm problem.

Neilson


this is the first i've heard of this. i don't know when my mount was manufactured, but it had to be prior to march 2012. are you talking about december 2011 or december 2012?

from reading around i thought that +/- 15arcsec was at the outer range of performance for a G11 with the high precision worm and regular worm block, but still within range.

should i be in contact with losmandy regarding the RA performance?

#30 neilson

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Posted 03 February 2013 - 03:24 PM

Hi,
This was Dec 2012. I have been told 10 arc seconds total by many of the big telescopes stores except company 7 who told me 15 arcseconds total PE. Most of the stores told me it would probably be less than 10 total. I have researched it and many people report 5 to 7 arcseconds total on mounts made since 2010. This is with everything adjusted just right and under the best of conditions. Older mounts have higher PE. Losmandy does not list the mounts PE or guarantee it from my understanding. Just on the Titan.

I had spoke with Mr. Losmandy a number of times about my PE. He sent me a second worm back in December and my PE went up to 31 so I put the first one back. He told me he was working on trying to find the problem causing this. I am still waiting. I was under the impression he knew of a problem especially after I was reading several people on another thread complaining about the same poor PE on mounts they got in Dec 2012. I am unable to guide out enough of my PE for imaging. And I specifically bought this mount expecting to do some short unguided imaging.

Neilson

#31 pfile

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Posted 03 February 2013 - 07:09 PM

strange - it seems that when you put in the losmandy "one piece" block, the PE gets better. and it gets better still if you put in the Ovision one piece block and worm. so it kind of seems like there's not a lot of research to do.

#32 neilson

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Posted 03 February 2013 - 08:49 PM

Hi,
Not in my case, The stock worm gave me 28 arcseconds and Scott sent me the OPW complete with a new worm and gear box. I just installed my motor and the OPW setup and my PE went up to 31. I then removed the worm and put the original worm in the OPW and it went back to 28 arc seconds. Each time I tested the PE many times over several days.
The research I was refering to was the PE reported on newer mounts out of the box. And yes installing the OPW should help a little and the Ovision should make a big improvement to about 2 arcseconds they told me. Ovision even sent me a copy of the PE results from the last worm he had sent out to show me how good it was. But the Ovision isn't cheap.
The problem is Losmandy had a batch of worms that were around 30 arcseconds and Scott told me he is trying to figure out why. Then correct it and then he will send me another worm that will give better results.

neilson

#33 Patrick

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Posted 04 February 2013 - 12:49 AM

Patrick, have you been to the Gemini-2 website and messed around with their demo? I think it would help you make an informed decision. I found it matched the physical uses to a 'T'.



Yes, but I'd have to spend some time with it under the stars to really get a feel for it.

Thanks!

Patrick

#34 Raginar

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Posted 04 February 2013 - 10:52 AM

Patrick, definitely. So far, I've found it 'usable'. I'll be interested to see if I have the PEC forgetting issue... but so far I've found it just as easy to use as my CGEM remote. Some of it might just be I'm getting more 'experienced' at using GOTO mounts too.

BTW, how do people hand the Gemini 2 in the cold? Obviously I'm in a frigid North and I'm worried about the screen being un-responsive.

#35 pfile

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Posted 04 February 2013 - 11:48 AM

Hi,
Not in my case, The stock worm gave me 28 arcseconds and Scott sent me the OPW complete with a new worm and gear box. I just installed my motor and the OPW setup and my PE went up to 31. I then removed the worm and put the original worm in the OPW and it went back to 28 arc seconds. Each time I tested the PE many times over several days.
The research I was refering to was the PE reported on newer mounts out of the box. And yes installing the OPW should help a little and the Ovision should make a big improvement to about 2 arcseconds they told me. Ovision even sent me a copy of the PE results from the last worm he had sent out to show me how good it was. But the Ovision isn't cheap.
The problem is Losmandy had a batch of worms that were around 30 arcseconds and Scott told me he is trying to figure out why. Then correct it and then he will send me another worm that will give better results.

neilson


you know, it could be your worm wheel as well... in that case no worm gear is ever going to solve your problem.

#36 Hilmi

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Posted 04 February 2013 - 12:48 PM

I have not tried the touch screen in what you would refer to as cold, but I know it will work with gloves because it depends on pressure so it will work without needing direct screen contact. I heard that in what you folk call cold, all forms of LCD screens tend to have sluggish refresh rates, but then again, you'r not going to be watching a movie on this screen.

#37 Charlie B

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Posted 04 February 2013 - 07:53 PM

BTW, how do people hand the Gemini 2 in the cold?



Wirelessly over ethernet, from the toasty warm house. I had one issue where it "froze", but I loosened the case screws and it worked fine again (24 degrees F).

Charlie B

#38 Raginar

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Posted 04 February 2013 - 07:56 PM

How about in 1F? :D

Anyone using a heater?

#39 neilson

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Posted 05 February 2013 - 12:24 AM

Hi,
I know most of you don't consider this cold but a few weeks back I was using it outside and the temperature dropped fast down to 34 deg (that's cold for south Texas. The touchscreen froze up. I turned the Gemini off, then on, and it started working for about 1 or 2 minutes then the touch screen froze up again. After it repeated this cycle 3 times I gave up. I was too cold also and I called it a night. I do think that one time was from the cold.
My Gemini 2 screen does freeze up from time to time but it always starts working after I cycle the power once. These other times are not on extreme cold days. I don't know what causes it.
I haven't heard of any one else actually using the handbox outside in the extreme cold that had a touchscreen freeze up. The ones I read about that were operated in the extreme cold were operated remotely from inside so they weren't using their touchscreen handbox.

neilson

#40 neilson

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Posted 05 February 2013 - 01:16 AM

Hi Patrick,
I don't know if you saw Celestron has just came out with a new accessary called Starsense. It mounts on your Ota and hooks to your mount. It has a built in camera and it will automatically find and center the alignment stars doing a complete alignment automatically. It will even let you add more stars to your model. And it comes with a more advanced replacement handbox. Its about $309. and due to come out in April 2013 I think. It fits almost all Celestron mounts. Wow!

It will not work on a Losmandy Gemini 2 mount. I wish I would have known about this 2 months ago.

neilson

#41 Raginar

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Posted 05 February 2013 - 10:22 AM

Neilson,

Starsense is a gimmick like adding GPS to your scope. I could align my CGEM (2+4) and get an ASPA completed with another alignment (2+4) in about 15 minutes. 300 bucks is alot of money to automate your alignment routine and really once you get it down, it's easy. If you have a CCD, take a look at Astrotortilla. It allows you to do platesolving for free (as in beer) if you're looking for something similar.

One other thing that G2 has built into it is a pointing model (assuming you're permanently mounted). Spend a few minutes added 10-15 stars on each side of the meridian and it should get you fairly precise :).

#42 pfile

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Posted 05 February 2013 - 12:49 PM

supposedly the problem with the hand controller can be mechanical in nature. if the temperature changes and the box expands/contracts, it can put pressure on the touchscreen and cause the computer to think that your finger is being held on the display.

some people have loosened the screws a little bit and the problem goes away... i have never had that problem with temperatures down to about 34F.

#43 neilson

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Posted 05 February 2013 - 03:25 PM

Hi Pfile,
Thanks for the advice on the handbox. I will definately give that a try. I appreciate the help.

Hi Raginar,
I know it's just a gimmick but I like things like that.
My G11 G2 is not permanently mounted so going through all the trouble of making a 10 star model of the East then manualy slewing the RA and DEC to the other side and making a 10 star model of the West every day gets old fast.
I definately feel the G2 was designed mostly for those who are permanently mounted. It would have been nice if it had the 2+4 like Celestrons. Its very accurate with 2+4 and if you want you can add more stars to the model. My CGEM DX always put the item dead center in my eyepiece with the 2+4. With my G2 I do a 10 + 10 and it never gets the item centered, Its in my eyepiece but off to the side every time. I mostly image DSO's and getting them centered would be nice.

neilson

#44 tboss70

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Posted 05 February 2013 - 07:10 PM

I've had my G11G2 out in 12F. No issues.

I am very happy with my G11G2. I've always read about the "difficulty" of Gemini but when I first received mine I had trouble understanding what people were talking about. Keep in mind my only other mount was a Celestron ASGT. Still, I find Gemini II easy to work with...even in the dark.

I might also mention i added the Ovision worm to mine. When I first received my mount I didnt take a PEC curve. My first photos had the football shapes after 1-2 minute exposures. This was at 900mm FL. I adjusted the mount multiple times and finally got my best, +-7 peak to peak.

the football shapes only came about once per worm rotation.
After the ovision upgrade, I have not seen this issue. Now I get +-3 peak to peak.

So while it did take a little patience and fiddling, I am happy where I am at with it now.

Lastly, and back to Gemini, Here is my method for aligning every night.

Point mount to north star; enter polar scope and get it close; take polar scope out. Perform PAA between two stars then go to modeling. I only have access to the north and east skies so I just model the east side (about 3 or 4 stars) then go to PAC. After that I build another model of about 3-4 stars and I am done. Then i just autoguide.

I have used metaguide, PHD, and Pempro without issue. I have also use Cartes with Gemini without issue.

The only intermittent issue I still get today is occasionally after PAC the hand controller will freeze and i need to unplug it, then plug it back in. I loose about 10 seconds doing this and again, it doesnt happen all the time or that often.

Thus far, I am a happy owner and I dont find Gemini difficult at all.

#45 wasyoungonce

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Posted 05 February 2013 - 10:57 PM

Jeez I don't know what the fuss is.

I've been using a G11 with a G1 for a few years but are secretly hoping it'll die and I'll be definitely be replacing it with a G2. I'd kill for OEM LAN, USB and wireless capability.

#46 Raginar

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Posted 06 February 2013 - 10:51 AM

Well, it doesn't have built-in wireless capability. But you can add a wireless adapter and make it happen pretty easy ;).

12F, good to know. I was looking around for some type of heater case, and couldn't find one.

#47 pfile

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Posted 06 February 2013 - 12:00 PM

Jeez I don't know what the fuss is.

I've been using a G11 with a G1 for a few years but are secretly hoping it'll die and I'll be definitely be replacing it with a G2. I'd kill for OEM LAN, USB and wireless capability.


you'll figure out what the fuss is when you start using it and encounter a bunch of bugs.

the features of the hardware are very nice but unfortunately the firmware still needs help.

by the way, PEMPro might have been the culprit in the pier crash (it definitely unparks the mount when it first connects to the mount, and it was the only "new" software i had running on the night of the pier crash.) to be safe from now on i disconnect and quit PEMPro after i'm done with it.

#48 nganga

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Posted 06 February 2013 - 08:03 PM

It now works as advertised. The developer is great as he has added two features at my request and the 3rd one "electronically assisted mount balancing" is on it's way. There is only one minor bug I know off that is pending a fix. After synchronizing dec axis guiding starts running away out of control. There is an easy workaround till the bug is fixed. Move slightly north then south after performing sync. Other than that I dont know of any bugs.

In short it works great.


Hello Hilmi,

Does the runaway DEC guiding occur with ST4 guiding too, or just ASCOM guiding?

Clem

#49 Hilmi

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Posted 07 February 2013 - 12:20 AM

Havent tried with st4 guiding

#50 Raginar

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Posted 07 February 2013 - 01:14 AM

OK, first night out with the G2 and I thought everyone would love to hear what I thought. First, not as easy as I thought it would be. I hit a safety limit from a bad slew before I powered down last time... and for some reason I couldn't get it to think it wasn't hitting that slew. Finally, after getting pretty frustrated, I manually moved the mount around and that seemed to clear it.

Second, aligning isn't 'great'. Especially when you don't have a polar scope or any really good way to wag your alignment. My mount doesn't have a polar finder nor does it have latitude marks on it... so I have to take a guess and use something electronically (or drift align) to figure it out. My first 'guess' was woefully off! So the first few GOTOs were very poor out of the box. In fact, it wouldn't let me select some of the stars because they were (according to it) below the horizon.

But, as I added stars to the pointing model, it did get better. Was it great? Nope. Was it as good as my CGEM? No. Even after adding 5-6 stars on each side, It was 'close enough' to plate solve but not putting the object on the chip. I'll have to see if there is some way to make this easier. In addition, I didn't have the Semi Automatic Alignment option for some reason... either I missed it or something, but I think that might make it easier and I'll go digging for that tomorrow.

Finally, the last thing I really checked was the Polar Alignment function. Mind you, this is based on your pointing model, so it's only so accurate... It's definitely NOT as good as ASPA. However, I think that is driven by the relatively shoddy pointing model I built randomly as I found stars I knew I could ID in my sky. It did get it accurate enough that I could guide; however it wasn't enough to let me take even 30 second exposures @ 600mm.

So, what do I think of G2? I have alot to learn before I can really make that judgement. I was super-comfortable with Nexstar; it definitely doesn't make sense... yet. I know it took me a few months with my CGEM before I really felt I understood what it wanted me to do too.

Hope this helps.

Chris






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