Hi Russ, and all,
Hopefully not beating a dead horse...
To answer your question, when you are polar aligned, you?are polar aligned when at CWD. You?are also polar aligned at all other RA rotations too.
When you are polar aligned your?mount is aimed at NCP. If your mount were aimed directly at Polaris, you would be about 0.7 degree of arc off of NCP.
The Earth's rotation axis is moving slowly.... and Polaris itself and the Sun are moving relative to each other too.? Polaris is close enough to Earth ...about 330 light years (distance estimates vary too).? From Stellarium program calculations, Polaris appears to be moving closer to the actual NCP North Celestial Pole position.?? The movement of Polaris apparent distance from NCP was why the optical polar alignment scope needs a new glass reticule?produced every 10 years... to put the NCP position on the glass at the newer position of Polaris.
Today, Stellarium reports for Polaris this data: RA of Polaris using J2000:? 89deg 15 min 51.5 sec? ? so it was off by ~44.9 arc minutes in year 2000 RA of Polaris today's date: 89 deg 21 min 14.7 sec? ?so it is off by ~39.75 arc minutes today. ? For reference, the diameter of the full moon is about 30 arc minutes (varies with moon distance from Earth).? ?
(You can have fun with Stellarium... running the clock forward, Polaris gets as close as 89 deg, 31 min, 52.9 sec on Sept 23, 2086. ?That seems to be about the closest Stellarium predicts Polaris will be to NCP...about 28 arc minutes away from NCP, or about 1 full moon diameter away from NCP.?? ?Just wait 45 more years! )
This is also why the PoleMaster software uses many stars around Polaris to identify the correct location of NCP.? You?can't count on Polaris alone!
If you bump your tripod, or have an earthquake (a West Coast specialty), then... your mount might be again off of polar alignment.
Also be sure to check your tripod leg adjustment bolts.? I found one of my tripod legs slowly creeping shorter over time.? That mount is quite overloaded in weight, but I thought the legs would not slip... And check your AZ lock down bolts.? (There is a central bolt under the center of the mount head, where the mount top rotates around when you adjust AZ. )
in short, Murphy's Law likes?astronomy.? Plenty of things to go wrong at the worst possible time...
Stay well, Michael
Going to do some tests tonight with SharpCap and its Polar Alignment tool.? Just to be clear, when my G11G is at CWD (bubbles leveled) the scope should be polar aligned with the NCP.? Correct??
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Re: G11G and Polar Alignment
On 1/22/2021 1:20 PM, Chip Louie wrote: I have used the PoleMaster software with the mount powered on and off and can't see any difference in accuracy. Possibly because the PM software is a bit forgiving. But I swear that SharpCap's PAs are better. As long as the mount's altitude and/or azimuth does not change unexpectedly I see no way that having tracking running or disabled would affect anything that Polemaster uses to calculate the NCP. Until you are asked to adjust alt and az, all it is doing is rotationally matching the alignment stars to a template and then finding the center of rotation after a slew. Center of rotation calculation doesn't care if the mount is tracking or not because the star positions are recorded at the single instant when you click the box. FWIW, I don't even bother with finding center of rotation each session. I just use the previously calculated center of rotation unless I know I have disturbed the camera or mount adapter. Paul -- Paul Goelz Rochester Hills, MI USA pgoelz@... www.pgoelz.com
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1. When you restart the?mount, you always?restart from CWD position, correct?? I always park the mount at CWD whenever I finish for the night.??
2. Did you do a warm start or a warm restart?? ?Since I am in an observatory, I always do a Warm Restart to start off my nights activities (keeps modeling and site data).
3. Can you check your model terms and maybe snag a screen capture or write it down? Curious what that looks like. You can view them from HC main screen: Menu->Align->Model? ?I will get a screen capture tonight/tomorrow and upload here.
Thanks for everyones help!!!
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On Mon, Jan 18, 2021 at 05:49 PM, Russ wrote:
Thanks for the info.? I was able to get a break in the clouds tonight and using SharpCap and it Polar Alignment tool, adjust my PA to obtain excellent results and it only took a few minutes.? Will verify these results in a few days when it actually does get clear later this week.? Will do some drift alignment and other tests to see just how well the PA actually is.
I've literally spend many, many nights doing drift alignment due to the fact I can barely see Polaris due to the slope of my observatory roof getting in way.? Luckily with SharpCap, I only need to get close to obtain the initial image before I rotate the G11G, 90 degrees for secondary image.? If this indeed does work great, I will be thrilled!!!!!
Now if I can only fix my ROR issue, I will be set.? Roof seems to be 'twisting' during its opening/closing now.? May have to brace it using 2x4s and X pattern inside roof.
Can you put the Losmandy 4" pier extension under the mount and get a better shot at the NCP and surrounding stars?? ? -- Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
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Re: G11G and Polar Alignment
I have used the PoleMaster software with the mount powered on and off and can't see any difference in accuracy. Possibly because the PM software is a bit forgiving. But I swear that SharpCap's PAs are better.?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
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Hmm,
IME about 99.99% of cases like this when mysterious errors happen to a solo operator working from routine and memory where a system returns to normal functioning at some point later operator error is involved. This is why they invented run books and check lists.?My process is likely very different than yours being a portable user but you could document your startup procedure and keep it in the observatory for situations like this. Just saying I've been there and a run book resolves all procedural issues having to do with loose nuts and such leaving only true hardware/system errors when failures like these occur.? ??
--
Chip Louie Chief Daydreamer Imagination Hardware?
? ?Astropheric Weather Forecast - South Pasadena, CA?
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Hi Jim!!!
Yes!
I'm caught red handed!? ?
Yes.... Degrees.Minutes
On to make Rev 1!!!!!
Good thing I apologized in advance!
Very best to all, Michael
Michael, in your post, and thank your for it, you said:
Latitude and Longitude
?
These settings also use an unusual format (unusual for USA users).? There is a dot in the format that appears to be a decimal point.? It is not a decimal point.? Interpret the dot to be like a comma separator.? The format is Degrees.Seconds
Shouldn't that be Degrees.Minutes???
JIm
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Hi Russ
thanks for keeping us all up to date
Three quick things
1. When you restart the?mount, you always?restart from CWD position, correct?
2. Did you do a warm start or a warm restart??
3. Can you check your model terms and maybe snag a screen capture or write it down? Curious what that looks like. You can view them from HC main screen: Menu->Align->Model
If anything changes in the future, those model terms would be helpful to record and let us know
Brian
I should have noted that my system is in my ROR observatory.?
Summary: After my Polar Alignment with SharpCap, I decided to redo all my modeling thinking this would be a good idea after I nailed down my polar alignment.? I parked my system at CWD (bubbles leveled).? It was at this time I did the Cold Start (to erase everything in memory).? Once the system booted, I entered all my site info and then rebooted the system using Warm Restart (Since my system is in a fixed observatory).? I then tried to slew to Orion and that is when I noticed the slew was way off, and all my problems continued.
Update:? Last night was a clear night so I started all over again.? However; this time, after the data was entered and a Warm Restart was conducted, I told the system to slew to M42 and it slewed to almost dead on.? I then did the CWD park and initiated a model run using 5 stars each (East/West).? System appears to be running normal again.
Not sure why last night was different since the original problem earlier this week, I repeated the same steps as yesterday and still had the issues.? Really weird but as of right now, system is good and I don't think I will ever do another Cold Start again....LOL.
-- Brian?
Brian Valente portfolio
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Michael, in your post, and thank your for it, you said:
Latitude and Longitude
?
These settings also use an unusual format (unusual for USA users).? There is a dot in the format that appears to be a decimal point.? It is not a decimal point.? Interpret the dot to be like a comma separator.? The format is Degrees.Seconds
Shouldn't that be Degrees.Minutes???
JIm
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I should have noted that my system is in my ROR observatory.?
Summary: After my Polar Alignment with SharpCap, I decided to redo all my modeling thinking this would be a good idea after I nailed down my polar alignment.? I parked my system at CWD (bubbles leveled).? It was at this time I did the Cold Start (to erase everything in memory).? Once the system booted, I entered all my site info and then rebooted the system using Warm Restart (Since my system is in a fixed observatory).? I then tried to slew to Orion and that is when I noticed the slew was way off, and all my problems continued.
Update:? Last night was a clear night so I started all over again.? However; this time, after the data was entered and a Warm Restart was conducted, I told the system to slew to M42 and it slewed to almost dead on.? I then did the CWD park and initiated a model run using 5 stars each (East/West).? System appears to be running normal again.
Not sure why last night was different since the original problem earlier this week, I repeated the same steps as yesterday and still had the issues.? Really weird but as of right now, system is good and I don't think I will ever do another Cold Start again....LOL.
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Marc,
That's incredible!? I love to see shots from the southern hemisphere.?
Matt
Thanks Brian. Here's another field I did on Carina last Tuesday (34x300s). Packed up now the moon is up and temperature is getting in the low 40c until mid next week.
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On Thu, Jan 21, 2021 at 10:29 AM, bbillp wrote:
Potential camera CRASH is not appreciated. ?
That made me LOL, Bill. Potential crash is there anytime we start our car, too. ;^) All, I always cold start. Because I always dismantle my mount and bring it in. I have never settled for night to night carry over of yesterdays settings. To say the least, the Earth we live on has moved around the Sun since yesterday. So in view of that, I like to Polar Align fresh, then cold start and do a fresh Modeling build. (Usually a 12 star Model) Since getting SharpCap to work with my Atik Infiniky camera, and doing my elongated Model build, I've been getting some very satisfying bullseyes on my slewing through Stellarium. If I don't, it's usually because I bumped the PA off. I used to check all the settings, every time. But now, eh, as above. Every night is a new night for me. 8^) ? -- SonnyE (I suggest viewed in full screen)
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Thanks Brian. Here's another field I did on Carina last Tuesday (34x300s). Packed up now the moon is up and temperature is getting in the low 40c until mid next week.
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Re: G11G and Polar Alignment
>>>
I did have it on once, and I got no warning from SharpCap that my mount couldn't be found, so that nag screen was nice to pass on.
It won't complain
given your relatively widefield telescope, it probably won't make a difference for you. i'm talking more in the 1000mm+ range of focal length
Good to know Brian.
Since I love to tinker, and "Push buttons to see what happens", I'm going to start trying with my mount on during Polar Alignment.
I did have it on once, and I got no warning from SharpCap that my mount couldn't be found, so that nag screen was nice to pass on.
But... I expect to see a wash. Because I use a wide field telescope, and do Deep Space Imaging.
My understanding is we are trying to get the RA axis aimed at the North Celestial Pole. That imaginary pivot point of zero movement in space.
Maybe with the mount ON, it will solve even faster than what I'm seeing now.
But I think it will be interesting to try. I know it is working with my mount off. So maybe I can slide because of my 80 mm telescope.
But Ima gonna try both. ;^)
(Of course, we are going into Brush Growing Season, so clouds and rain. :^(? )
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
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Re: G11G and Polar Alignment
Good to know Brian.
Since I love to tinker, and "Push buttons to see what happens", I'm going to start trying with my mount on during Polar Alignment.
I did have it on once, and I got no warning from SharpCap that my mount couldn't be found, so that nag screen was nice to pass on.
But... I expect to see a wash. Because I use a wide field telescope, and do Deep Space Imaging.
My understanding is we are trying to get the RA axis aimed at the North Celestial Pole. That imaginary pivot point of zero movement in space.
Maybe with the mount ON, it will solve even faster than what I'm seeing now.
But I think it will be interesting to try. I know it is working with my mount off. So maybe I can slide because of my 80 mm telescope.
But Ima gonna try both. ;^)
(Of course, we are going into Brush Growing Season, so clouds and rain. :^(? )
--
SonnyE
(I suggest viewed in full screen)
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Russ tried to skip some important steps like setting setting CWD then power up to do a Cold Start Immediately ?followed by Modeling. ?These steps cannot be overlooked.?
My new Gemini-2 HC went crazy the other night just like so many others have already described . Potential camera CRASH is not appreciated. ? ?
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The plot thickens? Here are some thoughts ...things to try.
When you use "Warm Boot" , the Gemini uses it's previously stored position information...of its encoders and distances (motor rotations) to get to sky objects .? These remembered values can be (in your case are!) way off.??
If the girls are way off, you must perform a first "Align to Bright Star" to get the Gemini to know it's initial encoder position.? And that first Align can send your mount off into space, as you report.? Below I'll explain what to do.?
I think you wrote that you made some new entries (or revised entries, or Sharpcap made entries...who knows!). Then...you say you did a Warm Start.
I think the Warm Start is the culprit.? Instead try this:
Loosen your clutches, in case you need to grab the scope.? Tell the mount "Park at CWD".? See if it actually goes there and be ready to grab the scope if it goes haywire.? When the Park at CWD stops, put your scope physically at the CWD position.
Then shut off the power.
Then retighten the clutches.
Then boot up and choose Cold Boot!
Verify these are correct in the Gemini:
_____
UTC time must be the correct format.
UTC time must follow this unique format: YYMM.DD HH:MM:SS YY is the year like 21. (we are in 2021) MM is the month. 01 DD is the day in Greenwich England.? It may be a day ahead of your local date.
HH is the 24 hour clock time in Greenwich England, of course.? MM the minute, SS the second.
Get your UTC time from this website for example:
So would be for a UTC time on Jan 13, 2021 at 06:15:25 am you'd take 21 as the last 2 digits from 2021, the 01 is January, ...: 2101.13 06:15:25
For time after noon like 14:00 = 2pm enter like 2101.13 14:15:25
___
Mount type:
When Gemini loses its memory, it also resets it's mount type.? It might default to Titan type.? The different mounts have different gear ratios.? Your pointing will go haywire if your mount type is set wrong.?? ____
Latitude and Longitude
These settings also use an unusual format (unusual for USA users).? There is a dot in the format that appears to be a decimal point.? It is not a decimal point.? Interpret the dot to be like a comma separator.? The format is Degrees.Seconds?
For East of the Greenwich Prime Meridian, Longitudes are entered with a + sign.? For Western longitude like USA, you enter a - sign.? The strange thing is that when Gemini displays the longitude, it shows a W for west (not the - sign you entered!) or an E for East (for a positive Longitude).?? ___
There is a nice way to see these entries if your Gemini is connected to a PC.? You can use the ASCOM Gemini.net applet.?
?When you use this PC applet, you must first click a "Read from Gemini" button in the Applet.??
Use the Advanced Panel and press "Read from Gemini" to see Mount type.? You can then use the Gemini.net Telescope Panel to see the UTC time and Latitude and Longitude.??
Always press the button Read from Gemini, else you are only seeing the PC copy of the values (Yes... the PC has a set of Gemini values it keeps in a local file, and the Gemini unit has its values.? These two sets of values are not automatically synched!? When you change a PC value in Gemini.net, the Gemini unit won't receive it until you press a button "Send to Gemini". )
Now try to Align to Bright Star and see if you are back to normal operation.
? The mount will go back to normal.... normally!??
But on very rare occasions, a Gemini-1 EPROM can lose data, or the SRAM or CPU chips become damaged.? That will cause GoTos or other behavior to go haywire.? I make/reprogram these Eproms, and repair G-1 units.
?If your Gemini-1 always exhibits strange display symbols, either its SRAM chip, or its CPU chip, or its EPROM chip have gone bad.? Send me your unit and I'll evaluate it and repair it.? (I'm in the US, Brendan Smith is in Australia, and David Partridge is in the UK).??
All the best,? Stay well and safe, Michael
Thanks all for the comments, I really appreciate it.?
-? I have not switched the RA/DEC cables since I initially installed the system back in Oct when everything was working correctly.? I did make sure the cable were fully in last night.
-? Time settings and zone is correct for my location in PA; -5 hours.
-? This issue started after I used SharpCap to get a 'perfect' Polar Alignment (that was verified the 2nd night when I reran SharpCap).? I decided to delete my model runs and start new models with an Excellent polar alignment.
-? It was then I decided to do a Cold Start and reentered all my Site Lat/Long/Time into the handheld.? I tripled all the inputed data to make sure it was correct (including the appropriate - signs).
-? Once this data was entered, I changed the handheld to start at warm reset and powered off the system, waited 30 seconds and powered on.? I verified the site and time info still correct.
That is when I tried to slew to Orion (in SE sky) and mount slewed to SW part of sky.
This when I tried the Gemini Software (Which I have used in the past and configured with my site info).? I noticed now that it will not let me input my Site info in the software (either with mount powered on or off).? Not sure what is going on with it.
Brian:? Have not had a chance to read your notes but will look at them today (had cataract surgery yesterday so seeing slightly off right now...lol)
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Re: G11G and Polar Alignment
I want to add some clarification to this
when polar aligning, the optics are pointing at north pole, so the amount of rotation is pretty minimal
for a widefield optic like the polemaster, tracking on or off may not be that important because there isn't that much rotation in that direction, and you are doing polar alignment in a relatively short time
With Sharpcap, it's the same situation but you are potentially using a much longer focal length (your telescope) and sharpcap is platesolving, so having pinpoint stars is important for accuracy there.?
So overall I'd say tracking on is less important for polemaster, and more important for sharpcap polar align
On Wed, Jan 20, 2021 at 11:17 PM, Paul Homer wrote:
Sonny,
?
I should point out that turning off the mount does not stop the Earth from turning :)
That's true. But my mount, on or off, is riding this mud ball. Just like everybody else's.
?
--
SonnyE
(I suggest viewed in full screen)
-- Brian?
Brian Valente portfolio
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>>>
I changed the handheld to start at warm reset and powered off the system,?
warm restart?
that basically leaves the model in place and assumes you are starting from non-cwd position
it's better at this point if you cold start
Thanks all for the comments, I really appreciate it.?
-? I have not switched the RA/DEC cables since I initially installed the system back in Oct when everything was working correctly.? I did make sure the cable were fully in last night.
-? Time settings and zone is correct for my location in PA; -5 hours.
-? This issue started after I used SharpCap to get a 'perfect' Polar Alignment (that was verified the 2nd night when I reran SharpCap).? I decided to delete my model runs and start new models with an Excellent polar alignment.
-? It was then I decided to do a Cold Start and reentered all my Site Lat/Long/Time into the handheld.? I tripled all the inputed data to make sure it was correct (including the appropriate - signs).
-? Once this data was entered, I changed the handheld to start at warm reset and powered off the system, waited 30 seconds and powered on.? I verified the site and time info still correct.
That is when I tried to slew to Orion (in SE sky) and mount slewed to SW part of sky.
This when I tried the Gemini Software (Which I have used in the past and configured with my site info).? I noticed now that it will not let me input my Site info in the software (either with mount powered on or off).? Not sure what is going on with it.
Brian:? Have not had a chance to read your notes but will look at them today (had cataract surgery yesterday so seeing slightly off right now...lol)
-- Brian?
Brian Valente portfolio
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Thanks all for the comments, I really appreciate it.?
-? I have not switched the RA/DEC cables since I initially installed the system back in Oct when everything was working correctly.? I did make sure the cable were fully in last night.
-? Time settings and zone is correct for my location in PA; -5 hours.
-? This issue started after I used SharpCap to get a 'perfect' Polar Alignment (that was verified the 2nd night when I reran SharpCap).? I decided to delete my model runs and start new models with an Excellent polar alignment.
-? It was then I decided to do a Cold Start and then reentered all my Site Lat/Long/Time into the handheld.??
-? Once this data was entered, I changed the handheld to start at warm reset and powered off the system, waited 30 seconds and powered on.? I verified the site and time info still correct including the appropriate - signs.
That is when I tried to slew to Orion (in SE sky) and mount slewed to SW part of sky.
This when I tried the Gemini Software (Which I have used in the past and configured with my site info).? I noticed now that it will not let me input my Site info in the software (either with mount powered on or off).? Not sure what is going on with it.
Brian:? Have not had a chance to read your notes but will look at them today (had cataract surgery yesterday so seeing slightly off right now...lol)
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Michael Herman
Chip Louie
Bill P.