Hola amigos, os escribo desde España y lo hago en español para que con el traductor me podais entender, ya que mi ingles es limitado. Tengo una Losmandy G11 y tubo parecido al tuyo Alfredo, y he estado probando con el guiado de PHD2 porque el de Ekos no me da muy buenos resultados posiblemente por las configuraciones. Las calibraciones las hace bien pero no obtengo guiados por debajo de 1,6RMS, por lo que tus guiados de 0,5 o 0,65 son sorprendentes. Mis tornillos bisinfin son de precision y creo que estan bien ajustados. Me podrias ayudar con los parametros de configuracion completos tanto en Ekos o PHD2, aunque preferiria utilizar Kstars para todo. Por otro lado la velocidad de guiado la tienes en 0,5 ??. Gracias Alfredo por tus aportes y ayuda.

Gracias por abrir este hilo, y lo seguire a diario . Un saludo

Hola Juanjo!

I never use PHD2 so I can't help with these settings. It is important to realize that without proper calibration you won't get good guiding results. I'm glad to hear your calibration is going well. Maybe you can post your calibration plot.

Yesterday evening I had another run with the internal guider. I was very pleased with Ekos' whole performance: Focusing, Calibrating, Guiding, taking subs, everything worked very well. Here are my guiding results and settings:











You're correct, guiding rate is 0,5. I had GPG turned OFF.

Seeing was ca. 1.1" which is outstanding for my place in Frankfurt. Guiding deteriorated a bit to around RMS 0,5-0,6 when the moon came up which is to be expected.

Yesterday I had "Remove DEC backlash in guide calibration" activated but I turned it off before I took the screen shots. That's why there is a white cross in the calibration plot. Probably my calibration settings are a bit extreme. You could go with 6x1000ms just as well. What is important IMO is you have to have overall movement of at least 10 pixels or so. You just can't calibrate within 2 or 3 pixels and expect good results.

HTH

Hola Alfred, muchas gracias por tu rapida respuesta. Veo que tu grafica de guiado es muy buena siempre dentro del segundo de arco, explendida yo diria con respecto a las que yo conseguia. En cuanto pueda voy a probar con tus datos de configuracion para ver si mi montura se comporta algo mejor de lo actual.

Entiendo entonces que la opcion de " Remove DEC backlash in guide calibration" debe de estar activada?.
Entiendo tambien que tu montura G11 tiene todos los engranajes y tornillos originales?.

Gracias por tu ayuda, si prefieres te escribo al privado para no cargar de mensajes el hilo del foro.

Saludos cordiales
Juanjo Herrera

De nada. Seeing limits what can be achieved by guiding. Yesterday's seeing was excellent, hence good guiding was possible.

The calibration plot shows whether or not the mechanical parts are in good working condition. If the calibration plot looks weird one should sort out mechanical issues first, by eliminating one possible cause after another before taking the next step experimenting with software settings.

I would recommend leaving DEC backlash elimination ON as it can lead to a better measurement. My G-11 was bought in the 2nd hand market several years ago and I didn't add any modifications, just tweaked worm block positions to eliminate backlash as well as possible.

Gracias Alfred. Yo tambien compre el año pasado mi Losmandy G11. He ajustado tambien los tornillos lo mejor posible, sobre todo el acople holdhan asi como la presion de los bloques del bisifin y la aproximacion del tornillo a la corona. En cuanto tenga buen tiempo hare una medicion de la calibracion para que puedas aconsejarme lo mejor posible.

Estoy hablando desde hace meses con un americano Hermann ,que recomienda cambiar los rodamientosy colocar unas juntas Bellevue aparte de otros cambios, pero nose si merece la pena ya que tus resultados son muy buenos.

Un saludo

Hi!
I'm coming a bit late to the party here, but anyway. I have a G11 that I've been using for about 10 years. RMS ca 0.7 is my standard, without too much tweaking.
What I have learned most from are guide logs. Do you have one to share? Preferably something like 20 mins unguided, and the same amount guided.

Concerning calibration: I was struck when you wrote that you do NOT have backlash. To the best of my knowledge, there is always backlash in a G11. If you do NOT have any, might you have tightened it too much, so you get sticktion and stuff like that? Anyway, that is visible in a guide log.
If you post a log, I'd be happy to have a look.

Magnus

Hi Magnus,

IMO my latest calibration plot shows there is no backlash in RA as the green and white dots overlap. I did not notice stiction but I haven't been guiding a lot since I last tweaked the blocks two weeks ago.

DEC is another story. When I got this mount, I noticed the RA bearings were a bit worn out and rough so I swapped RA and DEC blocks and bearings. Obviously there is much more wear on RA bearings as they move all the time whereas DEC bearings don't, so no surprise here. Now the rough bearings are in DEC which occasionally leads to spikes in my DEC guiding. These spikes became worse and more frequent recently so I am about to replace the bearings soon. Until then Ekos takes care of these spikes by aborting affected subs via the "Abort if guide deviation >" feature.

I don't have guide logs but I will record some next time.

Hi!

Post logs when you can, that is the golden material for diagnosing guiding problems.

There are a lot of things involved in this, I would advice you not to change too much but to try and isolate one thing at the time. I still believe the "no backlash" sounds spooky, and wonder if you have not tigntened the worm against the ring too much - which leads to spikes and all sorts of things.

More importantly: you say "rough bearings". How did you diagnose that? The feeling when rotating them (and in that case, was there anything else involved, mechanically?), or how? Bearings can be a culprit, I have changed mine several times - and it makes a world of difference if you use high quality or not. It is not easy to find the right dimensions of high quality in Europe, I've had an astronomer in the US buy some for me, last time...

Magnus

The mount was guiding wonderfully last time I tried. I'd assume a RMS of 0,4" rules out serious issues like stiction. I could feel and hear the bearings were rough when I did move the worm by hand years ago (motor and gearbox detached). During guiding, DEC moves just a tiny fraction of a turn so most of the time the DEC bearings don't play any role. I did a search for bearings that fit the bill (as far as I understand it) and came out with either a "R4-2Z" shielded, stainless steel precision bearing (ABEC-5) or its ABEC-7 sibling which is 3x more expensive. (You can search for "r4-2z" at www.mcmaster.com) Somewhere I read ABEC-5 bearings were much better than the original ones already. On one hand ABEC-7 probably is overkill, on the other hand I wouldn't mind a few bucks extra too much. From what you said I conclude I should go with the highest precision possible?

Hi!

For bearings: go with the best you can, McMasters are good (but do not sell to Europe, AFAIK). Ask on the Losmandy list for precise recommendations, they are the real experts

Dec bearings do play a role of they are not smooth.. even small movements can disrupt guiding. But of course, much more happens in RA. And with good PA, you can disable Dec guiding and see how it works with just RA, might be informative (I can usually guide for several minutes like that, if my PA is good).

Magnus

Hola de nuevo Alfred. Veo que si que le has echo mejoras a la parte mecanica de la montura. Los rodamientos y las juntas bellevie son indispensables para obtener buenos seguimientos y resultados en la autoguia. Michael Herman me dio este enlace para los rodamientos: www.bocabearings.com/search?w=R4zZ+ABEC-7. Estos son los mejores.

Si estais interesados , el me paso una serie de archivos en PDF y fotos, de las modificaciones y ajustes que se deben de hacer a estas monturas para que funcionen muchismo mejor de lo que lo hacen ahora. Por eso me extrañaba que tuvieras esos datos de guiado, si esta noche me lo permiten las nubes hare yo unas pruebas con tus datos de calibracion y veremos que resultados salen.
Por otro lado he puesto en un hilo del foro que tengo problemas con la funcion park en Ekos. Vosotros no teneis problemas al mandar la orden de park??.

Un saludo
Juanjo