Building a telescope mount and have some questions

[Braumin]

Hello everyone.

I'm finishing up my diploma in Computer Engineering Technology, and it is time to start thinking of final projects. Basically we have to build something that incorporates a microcontroller and we can do pretty much anything we want. I have decided to build an equatorial telescope mount for my reflector telescope, and have it do star tracking as well as a "go to" feature from a database of likely just the Messier objects.

I have a few questions that I really need to find some clear answers on before I can decide on what type of stepper motors etc that I will need to buy.

Should I do a Pulse Width Modulation motor for a constant speed for tracking or would a stepper motor work? How many degrees per second (or fractions of degrees) does the mount have to move to track stars? This is likely the most important question so I can get to work on finding a drive system for my mount.

Also, can anyone point me to some good websites explaining sidreal time? Google has not turned up anything that does a really good job of explaining this to me. I was thinking of just having a real time clock chip on my PCB that I could set to my local sidreal time and just have a simple way to program it if I needed to change sites. I was thinking of just having one of the big dipper stars as HOME and I could set the scope to that star and just press a button to set up my sidreal time. Would this work?

Any input is appreciated!

 

[Labguy]

Hello everyone.

I'm finishing up my diploma in Computer Engineering Technology, and it is time to start thinking of final projects. Basically we have to build something that incorporates a microcontroller and we can do pretty much anything we want. I have decided to build an equatorial telescope mount for my reflector telescope, and have it do star tracking as well as a "go to" feature from a database of likely just the Messier objects.

I have a few questions that I really need to find some clear answers on before I can decide on what type of stepper motors etc that I will need to buy.

Should I do a Pulse Width Modulation motor for a constant speed for tracking or would a stepper motor work? How many degrees per second (or fractions of degrees) does the mount have to move to track stars? This is likely the most important question so I can get to work on finding a drive system for my mount.

Also, can anyone point me to some good websites explaining sidreal time? Google has not turned up anything that does a really good job of explaining this to me. I was thinking of just having a real time clock chip on my PCB that I could set to my local sidreal time and just have a simple way to program it if I needed to change sites. I was thinking of just having one of the big dipper stars as HOME and I could set the scope to that star and just press a button to set up my sidreal time. Would this work?

Any input is appreciated!

Mel Bartels knows more about this stuff than about anyone in the US. From his site you can link to just about anything you would ever need to know about mounts, motors, tracking, etc, etc.

http://www.bbastrodesigns.com/cot/cot.html#DOWNLOAD

 

[Chronos]

Yep, that's an excellent source by Labguy. The gears, not the motor are the tough part. You want the thing to make one revolution every 24 hours [ok, that's not 100% correct, but close enough]. Typically the gear system starts with a worm screw.

 

[hypatia]

Thats a fantastic site..lol..it will take me days to look through it all.

 

[Braumin]

Thanks for the link I'll start looking through that right away!