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20948 tdk I mean. The documentation is awful. The dmp on 6050 was awesome so I had high hopes for dmp3

Added to the description. Random visitor of my channel might be out of context - this video is less about image quality and more about the accuracy of tracking of the DIY GOTO system I've put on my Dob (I've posted a series of videos on how to do that)

Hi, did you have any luck with the configuration spreadsheet?

@@PeterTakac I did but I amended the design quite a bit... I used the same size belt for the alt, but the az I went a different approach and used a slightly smaller MDF disc with a belt around it ..

the nuts can be sourced on on e-bay by searching for "M6x10x10 nut" www.ebay.com/itm/185952833397 to get the nuts inside you have to unscrew the bearing assembly from inside the tube using Philips screwdriver. I recommend to remove main mirror cell. This way you get the shortest and unobstructed access to the screws. Keep your scope horizontally not to accidentally drop any screws onto secondary mirror.

Thanks man. Your friction drive idea made implementation of this project very easy. However for these who travel with their tube often it It has a major disadvantage - after re-assembly of the scope the friction drive ratio changes slightly (variability of pressure in compliant mechanism and its positioning) I have to fine tune for more accurate tracking in OnStep app. But I usually don't bother, I seems found a perfect ratio where the object stays in the FOV for about 2 min. Which is good enough for visual. Dobs are not used for DSO astro-photo anyway and 2 min is good enough for planetary photography

DLP (D2 Photon) is not "galvo". When somebody talks about "galvo" in the optical scanning system it is usually one ray (or line of rays) delectated on varying angle in a scanning pattern with a brushless motor. DLP is an array of tiny mirrors flipped in a binary way (just two discrete angles - on/off). Don't waste your time on any "galvo" ideas in DIY project. Specifically complex part is a change of focal distance through working area - a ray deflected by galvo-mirror in to the center of your working area will have a shorter travel path than a ray deflected onto the edge of working area. Thus any galvo system should also adopt automatic focus adjustment based on deflection angle. Alternatively you may forget about Z and just mount a laser on long distance form working area (e.g. 3x longer than the size of working area). This way gaussian beam of the laser will have much longer depth of focus, making "defocusing" error negligible through the whole working area. The larger the ratio - the more negligible the error. But it is still there, so quality of cut on the edge is not the same as in the center. Almost all desktop galvo engravers are usually using this principle - their working area is much smaller then the height of the device. And the taller models are performing better. None of them accommodates automatic focus adjustment because its very complex to do at high speeds.

@@alexm7056 okay. I was aware they called it a DMD array for the photon because it is a series of mirrors pivoting rapidly to make the lines. It would more aptly be called hundreds of galvos then? Because as far as I'm aware a galvo is axis controlled mirrors reflecting light and that's what a DMD is but hundreds of them. You are probably right when it comes to jargon, but boiling it down to understanding for building I think I am more correct. Correct me if I'm wrong though. I found jargon nigh blasphemous. Keep it simply stupid.

Just open eBay and search for "300 LPI ink jet encoder strip". I've also printed few more of these few weeks ago but did not have time to post it on eBay.

ruclips.net/video/2oASeJlPFI0/видео.html

Bonjour je voudrai faire la même chose sur mon dobson skywatcher 254 /1200 peux t on utiliser une carte fysetc s6 pour le faire merci

@@louloulouloy4978 Sure it will work. Controller type/model does not matter much. The hardest part is to do mechanics right. Your telescope has a bit different design of an altitude bearing. So the timing wheel design will not be as easy.

What software were you using to control it?

Warning label says 400~460, I don't have a spectrometer to measure exact value. Its a typical blue laser of eBay. Not an extreme UV

frankly - there is no alternative, it is not about a motor - these are pretty com m on NEMA17 steppers you can find as low as $10 a piece of eBay used in decent codition. It is about the gearbox they come with - it is high precision gearbox with a very small backlash. It may work with cheaper gearboxes, you may have to play around with backlash config settings in OnStep onstep.groups.io/g/main/wiki/20943 You need any NEMA17 stepper with gearbox with at least 1:50 ratio

Did not have time to get to it yet. Sometimes work takes priority of home pet projects. THey will do the job for visual for sure. Its just not a great enough quality and to large pitch for astrophoto.

Unfortunately the answer is "No, it won't". The advantage of the dob I have is a nice thrust bearing design of altitude bearings in CNC body. Which allows to fit this large timing belt wheel on it very nicely and very centered without drilling any holes in the telescope tube. It is however possible to design something for your specific scope model, but installation of these mechanisms won't be as easy.

Yes, absolutely. Its essentially the same scope, just slightly larger size. Two things to take care of: 1. the belt length you need. 2. modify the geometry of the motor mount. Because the geometry of 10" mount base is slightly different (distance and angle from vertical wall to the circumference of the base). As for that large timing wheel (altitude) - you can just print out my design, it must fit.

@@alexm7056 thanks sir but the stepper motor link is invalid. Where can I get these same engines?

@@khattab9612 www.omc-stepperonline.com/nema-17-stepper-motor-l-39mm-gear-ratio-100-1-high-precision-planetary-gearbox-17hs15-1684s-hg100

@@alexm7056 thanks. Where can I find an onstep motor controller?

@@khattab9612 you have to make it yourself. The cheapest way is WeMos R2 + CNC shield (which I actually use in this project) onstep.groups.io/g/main/wiki/19670 You do need to have certain "Arduino-level" skills to make it work. Instructiions may looks way to technical for the newbies, but don't hesitate to ask a question in group discussion.

This friction drive cannot be tuned precisely enough to do long exposure DSO. My main goal of this "invention" was a quick disassembly and set-up to use my dob as a travel scope.. Every time I mount the drive module the friction radius is slightly different. So drift varies and needs adjustment, but it's good enough for visual so I don't bother with readjusting. The solution to this would be gluing a GT2 belt around the base. So you would have a fixed tooth count. Here is the example: ruclips.net/video/vPDEvH8jAW0/видео.html

Nope, any plastic will have a lot more flex than metal

onstep.groups.io/g/main/wiki/4464

cad.onshape.com/help/Content/exporting-files.htm

IMU device calibrates itself all the time. On Invensense you have to read these settings when you consider the device have been rotated enough in all directions and save them into flash memory. Then load them into IMU on next startup. On Invensense driver these are inv_icm20948_get_bias and inv_icm20948_set_bias functions. BNO device has its own non-volatile memory, so you can call sh2_saveDcdNow function to make it remember the settings (it will re-apply them on power-cycle) and sh2_clearDcdAndReset to clean them up (when you want to re-calibrate the device from its factory settings).

@@alexm7056 мой вопрос возник откуда, на BNO055 после калибрации нужно было гдето сохронять offset данные в ручную и потом применять их(все в ручную). А тут тоесть просто делаю ДИНАМИЧЕСКУЮ(А НЕ СТАТИЧЕСКУЮ) КАЛИБРАЦИЮ, сохроняю его с помощью той функции и все? Второй вопрос: сенсор считаеться откалиброванным когда AQURRACY LEVEL = 3 да? допустим в случае кода нужен только rotation vector(quaternions). И третий вопрос: тут нету статической калибрации да? Спасибо.

@@emmetray9703К сожелению на все эти вопросы я ответов ужене знаю, этим проектом уже давно не занимался и много чего подзабыл. В моем коде статической калибровкой (если там и есть такая) не пользовался. "Динамическая" скорее всего иммется ввиду что фюжен-фильтр сам себя каллибрирует когда видит разницу в показателях от разных сенсоров в рантайме (например по гироскопу видим поворот на 90 градусов, а по компасу на 45, значит компас сбит). Насчет того насколько сам модуль уверен в калибровке - я бы этому параметру не доверял. Даже перемещение модуля между включениями в другю комнату может сбить калибровку компаса, так как рябом может изменится кол-во металическиг предметов (напрмер жестяная плита на кухне или стол с метлическими ножками может повлять на показатели если все очень близко).Жалетельно процедуру калибровки встроить в интерфейс прибора по месту его использования.

@@alexm7056 вы можете показать исходники вашего кода?

Gear box is 1:100, belt drive is 1:9. With a motor of 200 steps/turn and a driver with 32x micro-stepping it results into 16000 micro-steps per degree, or roughly 4 micro-steps per arc second.

~$350, most of the cost is take by geared steppers and hardware, around $100 for 3D printing plastic. At this cost it is more reasonable to look for mildly used CG5 AS GT.

@@alexm7056 thanks for that feed back!

Я выложил линки на детали в Thigiverse. Если нет 3D принтера - то можно заказать пластиковые детали онлайн за небольшую сумму - остальные компоненты можно заказать с AliExpress.

@@alexm7056 Благодарю!

small disk is a disadvantage, you need a leverage of large radius to pull the tube by a small motor with a good precision also is minimum transfer ratio which comes into play with OnStep

It is 8" (200 mm) Ritchey Cretien (Malincam VRC8, the same as AT8RC). Almost 10 kg with diagonal and large eypiece.

I did one planetary visual observation only. Tracking is OK, but I did not measure it with PHD2 just yet. It will not do well for long-exposure astro-photo The main reason are direct belt connection to the axles. Belt is stretchy, tension will not help here. So for wind it wiggles like a spring. Recommendation is to replace belt drive with worm-gear: www.aliexpress.com/item/3256803968510991.html Again - as per my calculations a better investment of money would be to acquire a used CG5 or AVX for around $300...$400. This was "just for fun" experiment which is only applicable for visual and short-exposure astro-photography (under 60 sec).

@@alexm7056 ​ So, I got funding from a local company to build this, as it would be my final project in HS. If I replace the nylon with carbon fibre filament and upgrade the belt to worm drive and add guiding do you think I could do some real astrophotography with an 8” 11kg telescope? Im aiming for 30-60 second exposures.

@@MatijaSircelj during calm weather (no wind) this mount will handle 60 second exposure with no issues. Even without warm drive. I am just learning how to use PHD2, waiting for clear skies to test out RMS.

@@alexm7056 You see the problem is that I'm making this mount out of aluminum and the belt probably wont be enough. Or perhaps it will?

@@MatijaSircelj belt will pull it, but - with a problem of wind. Belt is springy - like a rubber. So with a wind gust a telescope starts to wiggle. Some may say that the belt tensioner will solve the problem - but NOT! Over-tensioning the belt makes it worse. It is possible to increase the tension of the belt by putting shims of thin plastic or sheet metal between the motor mounting bracket and axle block (which is 3D printed in my case). High belt tension puts too much load on the axle bearings and motor gearbox bearings. The tracking becomes "jerky" or "sticky". It becomes impossible to use the mount even for visual use. Axle rotation vibrates like it has Alzheimer's . I will post a video of this later. So you cannot overtighten the belts to solve a wind problem and improve positional accuracy. With normal tension - mount works in a calm weather and tracks smoothly. But positioning accuracy is affected by balancing of your setup. E.g. swapping to a heavier eyepiece starts stretching the belt due to off balance, and your target on a sky shifts slightly. I recommend you to redesign the axle drive to worm gear.