Re: Meridian flip sanity check please?
On 5/1/2021 11:57 AM, Paul Kanevsky wrote: Meridian flip is a function of a German Equatorial mount. Most people would prefer not to do a meridian flip. If you can get away with safety limits at 120 degrees or even more, then you can continue to image much longer on the same side of the meridian, possibly even avoiding a flip. It's a tradeoff between safety and convenience :) I used to image with an 8" SCT and my safety limits were WAY larger. But I am now using an AT115EDT refractor and with the camera hanging off the back and no pier extension, 95 is as good as it gets to the west for guaranteed clearance regardless of DEC. Maybe I need to look into a set of risers or a pier extension...... Too bad you can't set safety limits that take DEC into consideration. There is only a small range of DEC where the camera is likely to hit the tripod leg. But if I can get the meridian flip parameters figured out I guess it doesn't matter. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: Meridian flip sanity check please?
Yes, that's right: set the goto limit of 3.45 degrees before the safety limit.
Meridian flip is a function of a German Equatorial mount. Most people would prefer not to do a meridian flip. If you can get away with safety limits at 120 degrees or even more, then you can continue to image much longer on the same side of the meridian, possibly even avoiding a flip. It's a tradeoff between safety and convenience :)
Regards,
? ?-Paul
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On Sat, May 1, 2021 at 11:18 AM, Paul Goelz wrote:
On 5/1/2021 10:46 AM, Paul Kanevsky wrote:
Gemini interprets Goto limit set to zero as the default, meaning 2.5
degrees before the safety limit. Maybe that's the reason the mount
didn't flip.
Regards,
? ? -Paul
AH, I missed that the western GOTO limit is not degrees past CWD..... it
is degrees EAST of western safety limit, right? That would explain it.
So with tracking = 0.25 degree/minute if I want the flip to occur at or
after 5 minutes after meridian with a western safety limit of 95, I set
the western GOTO limit in Gemini to "3:45". Did I get that right?
It is tricky working in minutes of time in NINA and degrees in Gemini ;)
Paul
--
Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com
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Re: Meridian flip sanity check please?
On 5/1/2021 11:18 AM, Paul Goelz wrote: So with tracking = 0.25 degree/minute if I want the flip to occur at or after 5 minutes after meridian with a western safety limit of 95, I set the western GOTO limit in Gemini to "3:45".? Did I get that right? And a related question.... is there any reason not to simplify things and always set the western GOTO limit = western safety limit - 90? Ie., coincident with the meridian. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: Meridian flip sanity check please?
On 5/1/2021 10:46 AM, Paul Kanevsky wrote: Gemini interprets Goto limit set to zero as the default, meaning 2.5 degrees before the safety limit. Maybe that's the reason the mount didn't flip.
Regards,
? ? -Paul AH, I missed that the western GOTO limit is not degrees past CWD..... it is degrees EAST of western safety limit, right? That would explain it. So with tracking = 0.25 degree/minute if I want the flip to occur at or after 5 minutes after meridian with a western safety limit of 95, I set the western GOTO limit in Gemini to "3:45". Did I get that right? It is tricky working in minutes of time in NINA and degrees in Gemini ;) Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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Re: Meridian flip sanity check please?
Hi Paul,
I can't validate the NINA logic, as I don't know what it does to perform a meridian flip. Maybe looking in some logs will tell you what and when it tried to do?
Gemini interprets Goto limit set to zero as the default, meaning 2.5 degrees before the safety limit. Maybe that's the reason the mount didn't flip.
Regards,
? ? -Paul
On Sat, May 1, 2021 at 10:19 AM, Paul Goelz wrote:
Losmandy GM811 / Gemini 2
NINA
Last night was the first time I tracked an object through the meridian.
I had NINA programmed to flip 5 minutes past the meridian, with a
maximum of 10 minutes. Use pier side was ON.
I'm using a refractor, so my safety limits are:
EAST=94
WEST=95
WESTERN GOTO=0 (I think... I found it set to 0 but I had it set to 2.5
the last I looked)
The target crossed the meridian and when the exposure completed (I was
using 8 minute exposures, so between zero and 8 minutes after meridian
crossing), NINA said it was doing a meridian flip. All the steps
completed and it re-centered and began tracking again. However, the
meridian flip never actually occurred and a couple minutes later the
scope tracked into the western limit and stopped. I backed it up
manually, did another GOTO from NINA and it flipped and I continued
imaging normally.
I am trying to figure out why the flip never actually occurred in spite
of NINA saying it did. I assume NINA does a meridian flip simply by
commanding a GOT and my guess is that the issue is my western safety
limit in conjunction with the NINA settings?
If I am analyzing this correctly, with a western limit of 95, I have 20
minutes of tracking past the meridian before it tracks into the limit
and stops. I have reconfigured NINA to perform a flip if the object is
between 2 and 18 minutes past the meridian and I have left the western
GOTO limit at 0. Am I correct in assuming that if an exposure finishes
with the object between 5 and 18 minutes past the meridian, NINA will do
a simple GOTO.... which should succeed because the object will be
between 5 and 18 minutes past the meridian (with a western goto limit of
zero)? And if an exposure finishes with the object at 4.9 minute past
the meridian, NINA will begin a new exposure that will (with 8 minute
exposures) leave the object at a max of 13 minutes past the meridian....
which will trigger a flip on completion?
Kinda makes my head explode ;)
Side question..... what is the easiest way to unlock the mount if it has
hit the safety limit and stopped? Can this be done remotely or does it
have to be at the HC? I went out to the scope and could not back it up
with the HC. I had to do a PARK and then stop it part way. At that
point it resumed tracking and responded to a SLEW from NINA. Since my
target was now west of the meridian, the mount flipped and everyone was
happy. Was there an easier way?
Paul
--
Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com
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Meridian flip sanity check please?
Losmandy GM811 / Gemini 2
NINA
Last night was the first time I tracked an object through the meridian. I had NINA programmed to flip 5 minutes past the meridian, with a maximum of 10 minutes. Use pier side was ON.
I'm using a refractor, so my safety limits are:
EAST=94
WEST=95
WESTERN GOTO=0 (I think... I found it set to 0 but I had it set to 2.5 the last I looked)
The target crossed the meridian and when the exposure completed (I was using 8 minute exposures, so between zero and 8 minutes after meridian crossing), NINA said it was doing a meridian flip. All the steps completed and it re-centered and began tracking again. However, the meridian flip never actually occurred and a couple minutes later the scope tracked into the western limit and stopped. I backed it up manually, did another GOTO from NINA and it flipped and I continued imaging normally.
I am trying to figure out why the flip never actually occurred in spite of NINA saying it did. I assume NINA does a meridian flip simply by commanding a GOT and my guess is that the issue is my western safety limit in conjunction with the NINA settings?
If I am analyzing this correctly, with a western limit of 95, I have 20 minutes of tracking past the meridian before it tracks into the limit and stops. I have reconfigured NINA to perform a flip if the object is between 2 and 18 minutes past the meridian and I have left the western GOTO limit at 0. Am I correct in assuming that if an exposure finishes with the object between 5 and 18 minutes past the meridian, NINA will do a simple GOTO.... which should succeed because the object will be between 5 and 18 minutes past the meridian (with a western goto limit of zero)? And if an exposure finishes with the object at 4.9 minute past the meridian, NINA will begin a new exposure that will (with 8 minute exposures) leave the object at a max of 13 minutes past the meridian.... which will trigger a flip on completion?
Kinda makes my head explode ;)
Side question..... what is the easiest way to unlock the mount if it has hit the safety limit and stopped? Can this be done remotely or does it have to be at the HC? I went out to the scope and could not back it up with the HC. I had to do a PARK and then stop it part way. At that point it resumed tracking and responded to a SLEW from NINA. Since my target was now west of the meridian, the mount flipped and everyone was happy. Was there an easier way?
Paul
--
Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com
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How to free stuck worm rings? (dried grease)
Hello all -
I recently joined the group, having just purchased a G11 earlier this week, and converted it to OnStep.? The seller claimed the mount was "tested" and in "great condition" aside from the missing gemini controller.? As soon as I got home, I immediately noticed the DEC would not move at all, even with the clutch fully removed.?? I had to use a long piece of scrap lumber clamped down in order to get the dec to turn a few degrees.? I spent a few hours with various solvents and a rubber mallet until I finally was able to tap the dec shaft out of the housing.? The roller bearings were completely caked with dried old grease that had turned to varnish.? I was able to clean the upper roller bearing fairly easily, but the lower roller bearing required soaking in lacquer thinner overnight.? The next morning, after a couple more hours of fiddling, I was able to free up the lower bearing.? While I was in there, I wanted to clean up? the thrust bearing under the worm wheel, however I could not get the worm wheel off of the black anodized hub part.? Luckily the thrust bearing appears to spin freely, however I do worry the grease may be caked on like everywhere else.? I tried some gentle tapping to the hub using a PVC fitting to avoid damage.? I also tried mild heat from a hair dryer.? And of course, I tried pulling it off with my bare hands. I cant get it to budge.? I don't want to try any mechanical leverage for fear of damaging the worm wheel.? Any suggestions on getting this thing loosened up?
For what its worth, the rest of the mount was in really nice shape.? The whole RA side looked to have been freshly serviced. I've already swapped out the worm bearings, cleaned and re-greased the shaft roller bearings and worm wheels with superlube. The dec thrust bearing is the only part I can't get to. ? Anything else I should check or address?? I believe the mount is a 2009 model judging by the serial number.? Two piece worm blocks, HP brass worms, single D style saddle, etc.
Thanks for any suggestions,
-Tony
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Hi Brian, Nice to meet you.? I've heard quite a bit about you from dear ol' dad, thanks for helping him out so much over the last year or so.
Bill, my interpretation of OnStep is completely DIY.? Everything is a custom one-off job.? The brains are a cheap Wemos R1 arduino board and a CNC Shield v3 board to hold the stepper motor drivers.? The motors are some 400 step .9? motors off ebay.? I'm using 3D printed brackets and rigid couplers to mount the motors to the worms directly, no further gear reduction than? the 1:360 of the worm wheels.? At 1/64 microstepping, I have a final resolution of about .14 arc-sec per step, and a max slew rate of around 2.4?/second.? Not speedy, but no too annoyingly slow either.? I also did a very inexpensive RA extension mod using 1-1/4" aluminum standoffs and a 3D printed housing to dress it up.? When I purchased? the mount, I knew the Gemini 1 control had been damaged, and is fairly pricy to replace.? The Onstep system ran about $60 worth of parts and about 10 to 12 hours worth of design and fabrication time.
I have two other mounts, one being my fathers heavy old Meade LXD-650 which was converted to onstep.? It used 1:2.25 belt reduction and 180t worms for a similar final resolution to the G11, and in extremely good conditions I've had it guiding 30+ lbs of OTA and gear as low as .40 arc-sec rms. And I also have an Explore Scientific EXOS2-GT PMC-8, which is very similar to onstep, but on a lighter weight eq5/super polaris chassis.
Here's the worm and coupler.? I originally wanted to use a flexible helical coupler, but turning it down to 5/8 proved to be a challenge.? Instead I used a rigid coupler and let the shaft center the motor and mount before snugging it down.? Pardon my mess.
Here are the stepper motors and 3D printed Brackets.? The zipties are a bit of a eyesore, but otherwise looks OK.
This is the RA extension, using cheap aluminum standoffs from amazon.? It wont quick disconnect like the Losmandy, but it gives me plenty of clearance for the motors.??
Here's the finished mount.? I hope to give it a shakedown run early this evening before? the clouds roll in.
Papagordygrapes, your concerns about OnStep are spot on.? Its certainly made for those who like to tinker.? For visual use, I could see it being troublesome.? I don't use a hand controller, and the android app is indeed prone to lag.? However for imaging, OnStep seems much more well suited.? With good polar alignment, my go-tos have been excellent (with my previous mounts), however I typically plate solve for perfect centering anyway.? While the ASCOM driver will crash under certain situations, like attempting to manually enter coordinates below the horizon, these are uncommon and easily avoidable.? It otherwise seems fairly stable once you get a good routine going.? But you are correct, it's not nearly as polished or mature as a commercial product like the Gemini system.? However for that matter, Explore Scientific's PMC-Eight system isn't any better than OnStep and is prone to similar annoyances, though none of which are dealbreakers for me.
Thanks all, and clear skies.
-Tony
?
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Re: Mutter, grumble, snarl! Issues getting a refund on faulty 12-18V step-up converter
In well over 10 years of using PayPal and ebay I have never lost a dispute yet.? Both PayPal and ebay are firmly on the side of you, the customer.? Provided you lay out your case clearly and stick to verifiable facts and (most important, use only ebay's internal email, you will always get a refund.? At least this has been my experience.??
On the flip side, Chinese vendors will do almost anything to avoid a return/refund situation.? The will offer partial refunds, discounts on other products, almost anything rather than pay the return shipping and give you your money back.? For them, this is not dishonest, just business.
At initial contact, state clearly that your wish a full refund as quickly as possible for your defective item.? It does not work, give me my money back.? Immediately you are permitted by the ebay system, ask ebay to step in on your behalf.? A human will then review the emails and will arbitrate a full refund with seller paying return shipping provided the case is obviously the seller or the items' problem.
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Mutter, grumble, snarl! Issues getting a refund on faulty 12-18V step-up converter
So the 12V to 18V 8A converter that I bought in January to use with my G11
lost regulation (output varying between 18.2V and over 21V).
I'm very glad I have a voltage and current meter on my power distribution
and dew heater control box as I would have been rather upset if my G1 got
fried.
Anyway, I opened a dispute with PayPal (out of time on eBay). The vendor
agreed to a refund after it was returned to them, but I would have to pay
return shipping.
Luckily PayPal offered to refund the return shipping so it is winging its
way back to Hong Kong.
Some good news is that PP are looking at changing their terms so that the
vendor MUST pay return shipping on faulty or not as described goods (don't
hold your breath though as PP are getting a lot of push back ...).
David
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Re: G11 Exploded View... unavailable.
Thank you for your input on this Brian. I understand.
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Re: G11 Exploded View... unavailable.
>>>Then how does Losmandy build the mounts without assembly instructions? Not trying to be a smart ass here, but when most manufacturers build something, there are usually diagrams and instructions on how to assemble, especially when they train new employees.
Internal training is different than external documentation.?
we are a small business with most employees having 10+ years experience.?
I understand your request - at this moment the resources and approaches that are available are all pretty well laid out in this thread
Brian
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Re: G11 Exploded View... unavailable.
>>> This might be why the standing recommendation is to put them back in the same order you took them off.
yep
[AMD Official Use Only - Internal Distribution Only]
>we've already done this with our mount cleaning/greasing video??
I believe fetoma said earlier that the video did not go deep enough. Not sure about specifics though.
Would something like the following help ?
That said, there seem to be a couple of different opinions re: what the best (as opposed to "right") sequence is:
This might be why the standing recommendation is to put them back in the same order you took them off.
Thanks,
John
-- Brian?
Brian Valente portfolio
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Re: G11 Exploded View... unavailable.
There are only two photos in that .pdf.
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Re: G11 Exploded View... unavailable.
The fifth photo in the sequence, with its caption, pretty much does it. ?Except that it’s different than the sequence that Scott gives in the cleaning & greasing video. ?“Put it back the way it was” doesn’t quite work for me, because it might’ve been mixed up in a previous re-assembly. ?I’d rather have a definitive statement from someone who knows what they’re talking about (e.g., Losmandy) on what the arrangement should be.
Brian, you’re right, the video has the info. ?Often, though, it’s nice to have things like the assembly order in a simple reference document. ?Having watched the video, I’ll remember how to do the cleaning, but want to have the specifics of the order at hand when I’m actually doing the assembly. ?I just cobbled together the attached from the video.
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[AMD Official Use Only - Internal Distribution Only]
>we've already done this with our mount cleaning/greasing video??
I believe fetoma said earlier that the video did not go deep enough. Not sure about specifics though.
Would something like the following help ?
That said, there seem to be a couple of different opinions re: what the best (as opposed to "right") sequence is:
This might be why the standing recommendation is to put them back in the same order you took them off.
Thanks, John
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Re: G11 Exploded View... unavailable.
[AMD Official Use Only - Internal Distribution Only]
>we've already done this with our mount cleaning/greasing video??
I believe fetoma said earlier that the video did not go deep enough. Not sure about specifics though.
Would something like the following help ?
That said, there seem to be a couple of different opinions re: what the best (as opposed to "right") sequence is:
This might be why the standing recommendation is to put them back in the same order you took them off.
Thanks,
John
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Re: G11 Exploded View... unavailable.
Then how does Losmandy build the mounts without assembly instructions? Not trying to be a smart ass here, but when most manufacturers build something, there are usually diagrams and instructions on how to assemble, especially when they train new employees.
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Re: G11 Exploded View... unavailable.
Les
>>> take the knob off and pull the various washers, bearings, etc. apart enough to identify them, and/or lay them out on the table?in front of the axis, in the proper order — would be great.?
we've already done this with our mount cleaning/greasing video??
On Thu, Apr 29, 2021 at 12:24 PM Les Niles < les@...> wrote: A textual description of the official order of assembly, together with a couple of photos — I’m thinking, take the knob off and pull the various washers, bearings, etc. apart enough to identify them, and/or lay them out on the table?in front of the axis, in the proper order — would be great.? Any chance you could find time to put together something like that?? It would be a great reference to print out and use in the shop when I’m messing with the mount. ?
On 29 Apr 2021, at 8:27, Brian Valente < bvalente@...> wrote:
guys
We don't have an exploded diagram like you are requesting. If we did, I would have posted it long ago.
I'm not sure the reason why, but as I mentioned before you can always write to support with any specific questions.
Brian On Thu, Apr 29, 2021 at 8:01 AM fetoma < fetoma@...> wrote: I would think Brian Valente could help here. He linked a video in my other post, but that re-greasing video doesn't go deep enough into the mount. If someone wanted to copy the mount abroad, all they would have to do is buy one to do that. Don't know what the big secret is here. I'm going to take mine apart for the first time to clean, re-grease, install new clutch discs and install new bearings on the worms and the belleville washer mod, both which I got from you. I was hoping someone could provide the stack up order for the worm wheel, bearings, and the degree wheels in case I get interrupted and have to walk away from it for a few days. I'll just be careful.
-- Brian?
Brian Valente portfolio
-- Brian?
Brian Valente portfolio
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Re: G11 Exploded View... unavailable.
A textual description of the official order of assembly, together with a couple of photos — I’m thinking, take the knob off and pull the various washers, bearings, etc. apart enough to identify them, and/or lay them out on the table?in front of the axis, in the proper order — would be great. ?Any chance you could find time to put together something like that? ?It would be a great reference to print out and use in the shop when I’m messing with the mount. ?
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On 29 Apr 2021, at 8:27, Brian Valente < bvalente@...> wrote:
guys
We don't have an exploded diagram like you are requesting. If we did, I would have posted it long ago.
I'm not sure the reason why, but as I mentioned before you can always write to support with any specific questions.
Brian On Thu, Apr 29, 2021 at 8:01 AM fetoma < fetoma@...> wrote: I would think Brian Valente could help here. He linked a video in my other post, but that re-greasing video doesn't go deep enough into the mount. If someone wanted to copy the mount abroad, all they would have to do is buy one to do that. Don't know what the big secret is here. I'm going to take mine apart for the first time to clean, re-grease, install new clutch discs and install new bearings on the worms and the belleville washer mod, both which I got from you. I was hoping someone could provide the stack up order for the worm wheel, bearings, and the degree wheels in case I get interrupted and have to walk away from it for a few days. I'll just be careful.
-- Brian?
Brian Valente portfolio
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Carl
Wow. Are you sure that picture of your telescope wasn't originally an ion drive for a spacecraft? Well done cable management
Chuck On Thursday, April 29, 2021, 09:44:10 AM PDT, Carl Bj?rk <carl.bjork@...> wrote:
Absolutely wonderful!
I have 3d printed many many parts for my mount, computer, weather box, OAG caps to prevent light leaks, tightening knobs, and oh probably best of all a plug holder.
May I ask what mill you have?
Cheers,
Carl
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Paul Kanevsky
Pete
David C. Partridge