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Re: Dec vernier old Celestron G11
Dr Puzzleworth I have that "CG11" mount, perhaps even a photo somewhere of the Dec markings.? I'm on travel, but when I get home will send that or take a picture for you.? In practice,? if you have a Gemini for GoTos, you really will just want to mark where "CWD" is...and for that, putting on two white label maker triangles as arrows works well for me.?? Best, Michael? On Nov 12, 2017 1:14 PM, "puzzlewuzzle.dr@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Re: Pointing issues
Paul, I understand and the openness of Gemini.net is of great value.? ?Your authorship and maintenance and improvements of that are also a fabulous benefit. The Orion Atlas/Synta EQ6 group has a PC interface program called EQMOD that is so good, people sell off their hand controllers completely and just use that.? ?In their EQMOD pointing model method, they do model cone error and some other parameters, but as importantly, they triangulate in the region between known "align" stars, so each portion of the sky can have a unique "pointing model" for its part of the sky? (actually each star ).? Then any other object is just interpolated.? Extrapolation is used outside "align" points but that is a less certain region.? You add align stars across the sky as the need arises for new targets, which you just interpolate position.?? The Atlas mount itself is not as rigid a platform as the G11, or maybe not even as solid as the GM8.? The tripod is weak, the mount head is inadequately coupled to the tripod, the AZ and elevation adjustments are weak.? PE is worse.? But still the Atlas GoTos are rarely if ever far from their target.? There is just a conceptual difference in how the sky and mount and scope are modeled between the EQMOD and the Gemini. So...my question is:? Do you think there could be a way to do that multiple star triangulation and interpolation, using the Gemini model system.? That is, keep all the Gemini parameters zero, yet get its encoder tick positions, and then map the GoTo sky chart location to the Gemini through a PC program like EQMOD is doing? Anyway...not a short term project for sure... Best, Michael?? On Nov 12, 2017 12:20 PM, "'Derek C Breit' breit_ideas@... [Losmandy_users]" <Losmandy_users@yahoogroups.
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Re: Pointing issues
HI Derek, I try my best...but since I've repeated that list a few times this year...yes...it's time to make a PDF and just point to that.? I can add screen shots too... another benefit.?? I rely wish I had access to the source code so I could remedy or at least understand the causes of these strange pointing errors.? But...it is locked up.? Gemini2 code might be open but...I don't have one! Michael? On Nov 12, 2017 11:10 AM, "'Derek C Breit' breit_ideas@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Re: Pointing issues
typo: "" is wrong... is correct...sorry for that! Michael? On Nov 12, 2017 7:36 AM, "Michael Herman" <mherman346@...> wrote:
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Re: Pointing issues
Hi Doc, I find it valuable to do these steps if my pointing goes haywire.?? I am using a Gemini 1, not a Gemini 2.? They differ in hardware, but I'm not aware of any difference between the two in software algorithms.?? So try these steps to diagnose what's going on. (I use Gemini.net to more easily get to internal pointing model values.? You get that and basic ASCOM software from the ASCOM website.) 1. Using the Gemink.net Advanced window, download the internal parameters ("Read from Gemini".) Write down the existing pointing model parameter values.? I think there are about 9 of these, and they are explained in the Gemini manual.? ?Later, you will? compare the values to those of a good model.?? 2. Store the existing pointing model in a file, and name that file "Nov 12 2017 bad pointing" or something like that.?? 3. In Gemini.net, on the Advanced window,? uncheck the tick box "Synch performs additional Align ". Also inchecjk the box "PC sends to Gemini on connect" to make sure your PC, that may have bad values in its default file, does not send those to the handset. 4. Exit Gemini.net (software disconnect the Gemini from the PC...the cable can still be there.) 5. From the handset, perform a Cold Boot.? This sets all internal model values to zero. 6. Reconnect Gemini to the PC.? Use Gemini.net to Read the Mount values.? Ensure they are all zero still.? Also look at the Latitude, Longitude, Elevation, UTC date and time.? (There is a tickbox for having Gemini.net send the correct PC known date and time to the Gemini when it connects.? I do use that. )? 7. Start a sky chart on the PC that links to Gemini.net.? For that, I use both Stellarium-scope? (from Dragon-Welch computing website I think is ) and the sky chart itself Stellarium from? Stellarium.org.? ?You run Stellarium first to set its location to your site, then Save configuration, then exit.? Second, start Stellarium-scope, then select mount Gemini.net, then start Stellarium (a button on Stellarium-scope can do that).? Your Stellarium should show "scope" pointed at Polaris, if you are in positive latitude.? (You can minimize the Stellarium-scope window...just don't kill the program as it nicely links Stellarium and the Gemini.net together.? ) 8. From the handset,? use Align Telescope to go to a bright star in its list.? Sometimes, this initial point is accurate, and sometimes, for unknown reason, it will be way off.?? (I never know if this is due to old Daylight savings time change dates internal to the Gemini1 code, or why this happens... but it does even for a cold boot.? It's the weirdest thing because the mount correctly knows CWD...and time and location...how can it be so far far off in 1st star point?! ) 9. When you have centered your first Alignment star, complete handset alignment pressing the buttons that requires.? 10. Look at the Model parameters using Gemini.net.? ?They will all still be zero.? What changed?? The settings for RA and DEC offset encoder counts.?? 11. Look at the skychart.? It should show the "scope" right atop the star you aligned to. 12. Back to Gemini.net, advanced page.? Now check the tick box for "Synch performs additional Align".? That allows the Sky chart software to not only Synch the existing (all zero) model, but allows Gemini to calculate new parameter values.? ? 13. Back to the Sky chart.? Use your mouse to select a new star... (important!:) on the same side of the meridian as the first star.? (Press the spacebar to center and track that star on Stellarium.? ?) That means keep the 2nd ( and 3rd ) stars East of the meridian if the 1st star was East.? Or stars 2 and 3 must be West if the first star was West.? Use the (Control-1 in Stellarium) issue a goto from the sky chart to move the scope, then center the star on your scope with your handset.? Then on the sky chart do a Synch (Control-3 from Stellarium). Do that again for a 3rd star also same side of meridian as 1st star. 11. Now use Gemini.net "advanced" page,? Read from Gemini, and look at the model pointing parameters again.? You should see a few non-zero values.? You can save that data in a file with some name..."Model with 3 stars Nov 12 2017" etc. 12. Now use the sky chart to pick 3 stars on the opposite side of meridian.? Synch (and "Synch performs additional Align" is checked in Gemini.net) and Align to those from the sky chart.? ?Download and look at the parameter list and see more values change.?? 14. At this point,? I stop and save the model as full model for the? date.? ?Your system should accurately point to new objects around the sky.? I also Un-check the box "Synch performs additional Align " because I don't want added star's data to somehow mess up the calculations (which are a black- box to me).?? 15.? Now examine the model values.? ?How do your original "bad" model values compare? Let us know what you find....? I hope all these steps get you to a good and repeatable solution, and more enjoyment of your system. - Michael Herman? On Nov 11, 2017 6:11 PM, "lfbqtuqvokrxwkk24m2de6zj23io2kfpm5qcqt2w@... [Losmandy_users]" <Losmandy_users@...> wrote:
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Michael Herman
Paul Kanevsky
Bill Krosney