Homemade DIY Equatorial GEM Telescope Mount Slewing
Category: Homemade Telescope Mount
Posted by: Tom How
After lots of construction work over the last couple of weekends, I've got some Meade DS motors rigged up on the homemade equatorial telescope mount. Using Meade Autostar I can slew in both directions - right ascension and declination. Read more for the video.
The Meade DS motor kit is a favourite with homemade telescope mounts. Although these motors are small, they come in nice housings that are relatively straightforward to attach to your mount project. My telescope mount has 7 inch 360 tooth worm wheels, so the slew rate is rather slow, but acceptable. I do not visit large numbers of objects in one night - I tend to image only one or two objects per night, so if it takes a couple of minutes to slew to a target, I am not too bothered - I'm going to be collecting 4 hours of data.
The nice thing about the Meade Autostar controller is that it lets you adjust the "ratio" values used by the motors to calculate how fast they need to do. This means you can adjust the values to suit any gear system. The lower the gearing, the slower it goes, but in principle even a heavy system can be driven by these tiny motors, albeit rather slowly. Of course, the Autostar controller can be connected to a computer and used to control the telescope remotely.
I apologise for the quality of this video - the mount is now rather heavy and a great hassle to move around. Therefore shifting it into the part of the house with a more neutral background is hard work! You can see me driving the scope in both directions - the hand controller is out of shot.
I have also made some rough test of the GOTO indoors by slewing to various stars and making sure that the mount points the scope in roughly the correct direction. The next step is to attached an eyepeice to the small scope and test the GOTO more accurately outside.
The grey tape is holding on a 5 kilo diving weight. This mount is deisgned for a much heavier telescope (20-30lbs at least) and you need some weight up the scope end of the declination axis to counter balance the weight of the gears on the other end. Soon I will have to attach a counterweight bar to balance the scope when I have more hefty equipment on it.
The other problem of course is the sound. These motors make a loud annoying noise when operating at high speed. This would be very annoying at a Star Party where you were slewing to many different objects, however, this for use in my observatory, and only visiting a small number of objects, it is not a problem. If I open a window I can hear the mount slewing, so I know it is working!
The Meade DS motor kit is a favourite with homemade telescope mounts. Although these motors are small, they come in nice housings that are relatively straightforward to attach to your mount project. My telescope mount has 7 inch 360 tooth worm wheels, so the slew rate is rather slow, but acceptable. I do not visit large numbers of objects in one night - I tend to image only one or two objects per night, so if it takes a couple of minutes to slew to a target, I am not too bothered - I'm going to be collecting 4 hours of data.
The nice thing about the Meade Autostar controller is that it lets you adjust the "ratio" values used by the motors to calculate how fast they need to do. This means you can adjust the values to suit any gear system. The lower the gearing, the slower it goes, but in principle even a heavy system can be driven by these tiny motors, albeit rather slowly. Of course, the Autostar controller can be connected to a computer and used to control the telescope remotely.
I apologise for the quality of this video - the mount is now rather heavy and a great hassle to move around. Therefore shifting it into the part of the house with a more neutral background is hard work! You can see me driving the scope in both directions - the hand controller is out of shot.
I have also made some rough test of the GOTO indoors by slewing to various stars and making sure that the mount points the scope in roughly the correct direction. The next step is to attached an eyepeice to the small scope and test the GOTO more accurately outside.
The grey tape is holding on a 5 kilo diving weight. This mount is deisgned for a much heavier telescope (20-30lbs at least) and you need some weight up the scope end of the declination axis to counter balance the weight of the gears on the other end. Soon I will have to attach a counterweight bar to balance the scope when I have more hefty equipment on it.
The other problem of course is the sound. These motors make a loud annoying noise when operating at high speed. This would be very annoying at a Star Party where you were slewing to many different objects, however, this for use in my observatory, and only visiting a small number of objects, it is not a problem. If I open a window I can hear the mount slewing, so I know it is working!