Telescope alignment system - help wanted
We are looking for people who can help with the development of a simple telescope alignment system. The goal is to design a portable system powered from a car battery that does not use a PC. Two motors - one to track right ascension (RA), the other to correct declination - with proper speed control should do the trick.
We are looking for people who can help with the development of a simple telescope alignment system. The goal is to design a portable system powered from a car battery that does not use a PC. Two motors - one to track right ascension (RA), the other to correct declination - with proper speed control should do the trick. Anyone out there has some tips on offer or built such a system and wants to share it with us? Thanks for reading, Clemens
Here is the original request, translated from French:
Hello!
I do not speak English that's why I write in French. This was originally my project. I am looking for a simple celestial body tracker without PC and without programming. Without PC because it is difficult to power it all night out in the field. Without programming because I do not know how to program. The circuit from June 2012 uses a PC. Also I do not know a lot about electronics, just the basic stuff. I know how to solder but not how to design.
Currently I use a Dobson Lightbrige 305 that weighs about 40kg and my project is to build a portable horseshoe frame. I hope that the total weight will be not more than 50kg. I added a photograph of a similar project done by a German guy but I don’t have any information about the electronics. I just bought on the internet an SAA1027 stepper motor driver chip. If the circuit could use this, that would be great.
Thanks,
Eric
Discussie (5 opmerking(en))
SteveH 11 jaar geleden
Hi Clemens,
this looks like a very interesting and useful project. It does raise a few questions in my mind.
1) Why do you not want to use a microcontroller ?
2) When you talk about an algnment system, and 2-axis driven control, what form of control input from the user do you envisage?
I've been building (and rebuilding) a system for many years now. It is very simple and has 2 drive motors that are pwm speed controlled. They are well geared down (parts of an old Olivetti teletype for some gearing, other bits home-made). I get the object of interest in general view, then trim the speed of the motors to keep it in the field of view. I want to eventually automate some of it, probably with LCD imaging, and some software to automatically track objects, but all this is subject to time and resources. Still ideas are easier.
3) Do you want to locate specific objects ? Hence also :-
4) What form of user input/control do you have in mind ?
Joystick control was something I originally wanted to use, but I still needed to follow objects in the field of view (and they move pretty quickly, faster with higher magnification...). I settled on a simple pot/pwm speed control on motors. I cut down on much movement on one axis by making the telescope mount polar, so that axis is aligned fairly roughly with the Earths axis of rotation, thus that drive is only slowly driven if at all. The other axis does all the main drive.
A further point is the need for controlled slow drive on each axis, and, faster drive/manual input to get roughly/quickly to the approximate area of interest. On my crude gearbox I have a sliding shaft that disengages the motors/worm reduction drives. Probably need a mechanical engineer on-board to design a suitable system. I'm now considering an automotive differential drive system (where the driven wheels can rotate at different speeds when cornering.....use this in reverse and drive with two different motors/gear ratios, and take the output from where the input would go...)
5) How do the astronomers do it ?
I've seen mention of systems by the likes of Meade and others. I think you line-up the scope with some know objects to calibrate the system first. So it depends on the level of control and pointing detail you would like. (I think this ultimately depends upon whether or not you can leave the telescope in place from one night to the next, or if it has to be stowed away from bad weather etc. (in which case, some kind of locating system is useful if you can use the same location each time. Eg pointed jacking screws into conical cups set into a solid concrete base..
So, just a few thoughts which no doubt others have got some sophisticated solutions for. I know it is easiest to buy a system, but there is nothing like brewing your own (and I find I learn a lot more along the way).
Very best wishes, and every success with your project
Steve
SteveH 12 jaar geleden
ClemensValens 12 jaar geleden
chatbleu54 11 jaar geleden
Hello!
I do not speak English that's why I write in French. This was originally my project. I am looking for a simple celestial body tracker without PC and without programming. Without PC because it is difficult to power it all night out in the field. Without programming because I do not know how to program. The circuit from June 2012 uses a PC. Also I do not know a lot about electronics, just the basic stuff. I know how to solder but not how to design.
Currently I use a Dobson Lightbrige 305 that weighs about 40kg and my project is to build a portable horseshoe frame. I hope that the total weight will be not more than 50kg. I added a photograph of a similar project done by a German guy but I don’t have any information about the electronics. I just bought on the internet an SAA1027 stepper motor driver chip. If the circuit could use this, that would be great.
Thanks,
Eric
Original message:
Bonjour !
Je ne suis pas anglophone c'est pourquoi j'écris en français. Ceci, à la base, est mon projet. Ma demande est un suivi des étoiles simple, sans ordinateur et sans programation ! Sans ordinateur car il est dificile de l'alimenter toute une nuit dans la campagne et sans programation car je n'y connais rien. Le montage de juin 2012 utilise un ordinateur. je n'y connais rien non plus en électronique ou simplement la base! Je suis électricien et je sais donc souder des composants mais pas créer des montages.
Pour l'instant j'ai un Dobson Lightbrige de 305 qui pèse environ 40 kg et mon projet est de faire une monture en fer à cheval transportable. Donc le poids ne devrai pas trop dépasser les 50 kg, enfin je l'espère. J'ai mis une photo d'un projet identique qui a été réalisé par un allemand, mais je n'ai aucun détail sur l'électronique. Je viens d'acheter sur internet un circuit SAA 1027 , un driver de moteur pas à pas. Si le montage pouvait fonctionner avec , se serait magnifique.
Merci Eric
SteveH 12 jaar geleden
chatbleu54 12 jaar geleden
NECV20 12 jaar geleden
NECV20 11 jaar geleden
Consider the heliostat of Elektor june 2012. It can follow the sun, and by speeding up the internal 'clock' from 24 hours to 23h56m for a 360 degrees turn it can track stars. You have to experiment with the amount of weight you can put on the heliostat.
In practise most ready made mounts use steppermotors. So again look in Elektor june 2012. The more steps per rotation the motor has, the less gearboxes you have to use.
NECV20 11 jaar geleden
First, sorry I misplaced my contribution as a comment.
So now I joined the project, here is what I wrote earlier.
'Me too. So I use a Celestron 102SLT refractor and motorized GT mount. I extended the basic configuration with RS232 interface (USB / RS232) on a netbook running Cartes de Ciel.
I also bought a Celestron CCD camera (deprized at 100 euro) an built myself a motorfocuser using a servo.
I can now operate the telescope from a nice distance of 10 meters (in a warm and comfortable room).
But building a mount myself without a microcontroller? It can be done if you decide to switch from RA + dec. motors to parallactic (one axis is set up parallel to the earth N-S axis) mount (with counterweight). In that case there is only one motor to control.
With RA and dec. motors you get hopelessly confused in implementing sinus en cosinus functions (wherefore you need a microcontroller).
Are you at least willing to consider to connect to a laptop/netbook/tablet to do the arithmetic?
There is one more problem for people interested in electronics; transmission and gearboxes.
I am interested if you are experienced with that topic. And I like to know what weight the telescope will have that you would like to align. '
Thijs Beckers 11 jaar geleden
I'm always interested in looking at the sky and the stars!
NECV20 12 jaar geleden