astronobob
03-07-2013, 09:29 PM
There are many ways, infact, probably closer to two never the same, and that is in the mounting of a simple motor focuser onto a telescope !
I have used this type of design for all my scopes, including Reflectors & refractors, from Mak 150's and C8's to my ED refractors, & my newtonians.
I thought to show this one I built & fabricated yesterday for my recent 10" BD Newtonian to give an idea to those who may be considering a similar homemade modification and dont have the means in purchasing expensive PC controlled Motor focusers.
The main assistance this type of focuser gives is that one can sit at the Lappy in the field/obs etc and adjust focus without handling the scope and by looking at the Live view on the Lappy using the motor focuser cable remote controller :thumbsup:
The 2nd positive in this design is that the motor focuser is addapted in a way that gives an approximate extra 5:1 accuracy ratio which is dominately related to the strong drive band from the motor focuser to the scope focus wheel. I have used a 10mm Diameter, 25mm length, brass Rod (drilled and Modded to suit) on the motor focus shaft which needs to turn approx 5 times to rotate the scopes focus wheel once :thumbsup: This will vary apon what you use for the motor focuser rod and size of your particular focus wheel
These bands can be purchased from your local RC (Remote Control) Store, eg, remote cars trucks, planes etc for $2-3 a piece, the ones I have used are the smallest they have and suits these applications perfectly, and applying a little tension when designing the motor location will provide a Non-Slip operation and actually add support to the focus wheels as so they dont move as much, if at all (under weight, camera etc) when the band is in place :thumbsup:
In Pics : The Aluminium Angle is 125mm x 50mm x 3mm thin. I picked up a 1meter length for approx $15-20 two yr ago from a local alluminium supplier !
As you can see, in this case, I have Jigsawed a semi-round out of one side as to have it hugg the focuser and look neat. From there you just need a couple of small bolts, a drill and Ive chose some wing nuts for easy removal and attachment of the motor focuser as it is the only one I have :P and all my other scopes have a piece of alluminium bracket secured in a similar fashion, and I just move the motor from one scope to the other when needed, easy :thumbsup:
I also needed to find (in my small workshop) two slightly longer bolts to replace the oridginal scope focuser mount bolts as these were Not long enough to secure the alluminium angle in place ! I then drill two more appropriately size holes in the allu angle to secure the oridginal scope focusing bolts so as to Not lose them if decide to sell later :thumbsup:
From here, I'll let the attached pics do some talking and hope this may be a useful idea or example of a simple modification to any who are contemplating similar :thumbsup:
I have used this type of design for all my scopes, including Reflectors & refractors, from Mak 150's and C8's to my ED refractors, & my newtonians.
I thought to show this one I built & fabricated yesterday for my recent 10" BD Newtonian to give an idea to those who may be considering a similar homemade modification and dont have the means in purchasing expensive PC controlled Motor focusers.
The main assistance this type of focuser gives is that one can sit at the Lappy in the field/obs etc and adjust focus without handling the scope and by looking at the Live view on the Lappy using the motor focuser cable remote controller :thumbsup:
The 2nd positive in this design is that the motor focuser is addapted in a way that gives an approximate extra 5:1 accuracy ratio which is dominately related to the strong drive band from the motor focuser to the scope focus wheel. I have used a 10mm Diameter, 25mm length, brass Rod (drilled and Modded to suit) on the motor focus shaft which needs to turn approx 5 times to rotate the scopes focus wheel once :thumbsup: This will vary apon what you use for the motor focuser rod and size of your particular focus wheel
These bands can be purchased from your local RC (Remote Control) Store, eg, remote cars trucks, planes etc for $2-3 a piece, the ones I have used are the smallest they have and suits these applications perfectly, and applying a little tension when designing the motor location will provide a Non-Slip operation and actually add support to the focus wheels as so they dont move as much, if at all (under weight, camera etc) when the band is in place :thumbsup:
In Pics : The Aluminium Angle is 125mm x 50mm x 3mm thin. I picked up a 1meter length for approx $15-20 two yr ago from a local alluminium supplier !
As you can see, in this case, I have Jigsawed a semi-round out of one side as to have it hugg the focuser and look neat. From there you just need a couple of small bolts, a drill and Ive chose some wing nuts for easy removal and attachment of the motor focuser as it is the only one I have :P and all my other scopes have a piece of alluminium bracket secured in a similar fashion, and I just move the motor from one scope to the other when needed, easy :thumbsup:
I also needed to find (in my small workshop) two slightly longer bolts to replace the oridginal scope focuser mount bolts as these were Not long enough to secure the alluminium angle in place ! I then drill two more appropriately size holes in the allu angle to secure the oridginal scope focusing bolts so as to Not lose them if decide to sell later :thumbsup:
From here, I'll let the attached pics do some talking and hope this may be a useful idea or example of a simple modification to any who are contemplating similar :thumbsup: