The BBC micro was used to teach everyone computer skills - via schools and television - in an era when computers was unfamiliar. It had unique features: there was no huge operating system to act as a barrier - just a BBC BASIC interpreter chip; its inner workings were fully explained, particularly in the “Advanced User Guide”; it had a multitude of ports and timers to explore. Our APT used the Printer Port to control the stepper motors; the User Port for the Button Box; and the 1 MHz Bus for controlling and taking readings from the (photon) counting board. Before this, I can remember programming a BBC Buggy to follow a dark-line course. My father suggested building an automatic photometric telescope controlled by stepper motors. He told me that I could do the programming. When I expressed my lack of confidence, he said, “You can do it!” Please let me have your questions and comments!
Many thanks! If you look at the reference Part II: Hardware (Given in the description), you'll find full information (pp. 26-27) about its construction and testing. Details of the stepper motor electrics (the interface with the BBC micro) are given on pp. 28-29. How did you come across the video? Was it through one of the hashtags? Thanks once again. Peter
Thank you for making this video. I was especially intrigued by the friction roller drive system and the algorithms used for positioning the star in the pinhole, etc. I'm sorry you lost your father only two years after first light. He was obviously a great dad.
@gregben: Many thanks for this! Se my reply to @d.ericanderson1984 for more details about the rollers. For more detail about centring, see APT Part III Software (in the description; pp. 31-31).
Thanks for the great video. It is amazing that your father was able to combine a telescope drive system, photometry system, and computer to complete an automated variable star observing system in the 1980s. I also wanted to try photometry of celestial objects at that time, and experimented with photodiodes because I did not have a PMT and a high-voltage power supply, but I was limited to measuring stars as bright as Jupiter. I finally managed to build a practical drive system for the telescope recently, using a home-built computer with a 6502 CPU, the same as the BBC Micro. I believe that the basic hardware-software exploration was easier with the concept computers of that time than with today's state-of-the-art computers.
Many thanks for this. I watched your video "Telescope Mount Controller using homemade 6502 computer PERSEUS-9" with great interest. I would have to study it in more detail to see how you managed to get such a large difference between tracking and slewing using stepper motors. This wasn't needed for our application: In differential photometry, all the targets (stars and sky) are within a few degrees of one another. I've got a couple of comments about your system: (1). The knob that switches between fast and fine slewing is on the MCT-6 Control Unit. It would be convenient if this could be controlled from your hand controller. (2). On your associated web page, you write, "The self-built mount system obtained a slewing speed of up to 1024 times faster than the tracking speed and a positional accuracy of about 1% with respect to the amount of movement." We had problems combining tracking and slewing due to these pulses occasionally being sent too close together to be carried out by the RA stepper motor. The way we solved this is described in Part III: Software (pp. 30-31). (See the description above. (3). You are right about the BBC Micro. See my first (pinned) comment. Thanks once again. I've subscribed to your channel.🤎
@@peterells1720 Thanks for your comment. The following is how my system was able to slew 1024x. The R-motion stage I used consists of a 200 p/r stepper motor and 90:1 worm gear, so 18,000 p/r. The microstep driver further divides this by 128, so 2304000 p/r. If I drive this number of pulses in 23h56m04s, I get 26.74 pulse/sec, a frequency at which my telescope does not vibrate in tracking. This is increased to 1024 times the speed, the frequency for a slewing is 27 k pulse/sec, just barely a frequency at which the motor does not step out. (1) The reason why there is no speed switch knob on the hand controller side is because I am currently using a simple hand controller that I made by myself 10 years ago. This is sometimes inconvenient in operation, but it is easier to perform trial experiments on the circuit. (2) I have read the paper for your software. In my case, the way to prevent errors in tracking and slewing is that both RA and DEC can be driven independently and simultaneously, and that the RA's counting on slewing is subtracted by a pulse corresponding to the sidereal time. The error during slewing is mainly due to the installation accuracy of the polar axis. Thanks once again.
![The most beautiful equation in math, explained visually [Euler’s Formula]](/img/n.gif)
The BBC micro was used to teach everyone computer skills - via schools and television - in an era when computers was unfamiliar. It had unique features: there was no huge operating system to act as a barrier - just a BBC BASIC interpreter chip; its inner workings were fully explained, particularly in the “Advanced User Guide”; it had a multitude of ports and timers to explore.
Our APT used the Printer Port to control the stepper motors; the User Port for the Button Box; and the 1 MHz Bus for controlling and taking readings from the (photon) counting board.
Before this, I can remember programming a BBC Buggy to follow a dark-line course. My father suggested building an automatic photometric telescope controlled by stepper motors. He told me that I could do the programming. When I expressed my lack of confidence, he said, “You can do it!”
Please let me have your questions and comments!
Inspiring story of an effective “small team” project. Thanks for making the video. I especially appreciated the rollers.
Many thanks! If you look at the reference Part II: Hardware (Given in the description), you'll find full information (pp. 26-27) about its construction and testing. Details of the stepper motor electrics (the interface with the BBC micro) are given on pp. 28-29.
How did you come across the video? Was it through one of the hashtags? Thanks once again. Peter
Thank you for making this video. I was especially intrigued by the friction roller drive system and the algorithms used for positioning the star in the pinhole, etc. I'm sorry you lost your father only two years after first light. He was obviously a great dad.
@gregben: Many thanks for this! Se my reply to @d.ericanderson1984 for more details about the rollers. For more detail about centring, see APT Part III Software (in the description; pp. 31-31).
Thanks for the great video. It is amazing that your father was able to combine a telescope drive system, photometry system, and computer to complete an automated variable star observing system in the 1980s.
I also wanted to try photometry of celestial objects at that time, and experimented with photodiodes because I did not have a PMT and a high-voltage power supply, but I was limited to measuring stars as bright as Jupiter.
I finally managed to build a practical drive system for the telescope recently, using a home-built computer with a 6502 CPU, the same as the BBC Micro. I believe that the basic hardware-software exploration was easier with the concept computers of that time than with today's state-of-the-art computers.
Many thanks for this. I watched your video "Telescope Mount Controller using homemade 6502 computer PERSEUS-9" with great interest. I would have to study it in more detail to see how you managed to get such a large difference between tracking and slewing using stepper motors. This wasn't needed for our application: In differential photometry, all the targets (stars and sky) are within a few degrees of one another. I've got a couple of comments about your system:
(1). The knob that switches between fast and fine slewing is on the MCT-6 Control Unit. It would be convenient if this could be controlled from your hand controller.
(2). On your associated web page, you write, "The self-built mount system obtained a slewing speed of up to 1024 times faster than the tracking speed and a positional accuracy of about 1% with respect to the amount of movement." We had problems combining tracking and slewing due to these pulses occasionally being sent too close together to be carried out by the RA stepper motor. The way we solved this is described in Part III: Software (pp. 30-31). (See the description above.
(3). You are right about the BBC Micro. See my first (pinned) comment.
Thanks once again. I've subscribed to your channel.🤎
@@peterells1720 Thanks for your comment. The following is how my system was able to slew 1024x. The R-motion stage I used consists of a 200 p/r stepper motor and 90:1 worm gear, so 18,000 p/r. The microstep driver further divides this by 128, so 2304000 p/r. If I drive this number of pulses in 23h56m04s, I get 26.74 pulse/sec, a frequency at which my telescope does not vibrate in tracking. This is increased to 1024 times the speed, the frequency for a slewing is 27 k pulse/sec, just barely a frequency at which the motor does not step out.
(1) The reason why there is no speed switch knob on the hand controller side is because I am currently using a simple hand controller that I made by myself 10 years ago. This is sometimes inconvenient in operation, but it is easier to perform trial experiments on the circuit.
(2) I have read the paper for your software. In my case, the way to prevent errors in tracking and slewing is that both RA and DEC can be driven independently and simultaneously, and that the RA's counting on slewing is subtracted by a pulse corresponding to the sidereal time. The error during slewing is mainly due to the installation accuracy of the polar axis. Thanks once again.