快將復活 -- 30cm F4 Newtonian

[Eddy So]

[LT]

To me, that is one of the most difficult part of re-building my DIY giant equatorial mount.

DEC_motor.jpg (325.1 KiB) 已瀏覽 23796 次

[Eddy So]

[BossKwan]

To me, that is one of the most difficult part of re-building my DIY giant equatorial mount.

From the shape of your motor, it should be a DC servo motor with encoder(the black part). Are you going to equip your new big mount with a Go-To system? That would involve rewriting the program of your original system if this motor comes from a small mount with smaller gear(I mean different number of teeths).
Out of curiosity, where did you get this motor?

[LT]

Yes, it is a DC servo goto motor, controlled by Vixen Skysensor 2000PC controller. This controller is very powerful. The motor can run at sidereal speed after inputting the correct gear ratio of the mount into the controller. No need to write any program. If the load doesn't exceed its limit, the max slewing speed can be up to 1200x.

As the worm wheels used in my DIY mount are 7.5" ones, I think it can work ok with a 12" Newtonian.

[BossKwan]

Yes, it is a DC servo goto motor, controlled by Vixen Skysensor 2000PC controller. This controller is very powerful. The motor can run at sidereal speed after inputting the correct gear ratio of the mount into the controller. No need to write any program. If the load doesn't exceed its limit, the max slewing speed can be up to 1200x.

As the worm wheels used in my DIY mount are 7.5" ones, I think it can work ok with a 12" Newtonian.

Unexpectedly, Skysensor really has such a great function that helps easily couple it with other mounts. 真係唔使頭痕!!

By the way, how many teeth your 7.5" worm wheel ?

[LT]

DEC: 360 teeth
RA: 359 teeth

[LT]

As no spec sheets coming with all the gears bought many years ago, I have used a vernier caliper to measure all the dimensions I need to know. If these measurement are correct, these pins can help me install the DEC gear wheel at the right position.

Supporting pin.jpg (371.46 KiB) 已瀏覽 23682 次

[BossKwan]

As no spec sheets coming with all the gears bought many years ago, I have used a vernier caliper to measure all the dimensions I need to know. If these measurement are correct, these pins can help me install the DEC gear wheel at the right position.

Supporting pin.jpg

Like a Radio Knob, can't get any idea of its usage.
Where are those pins installed to ?

[LT]

As no spec sheets coming with all the gears bought many years ago, I have used a vernier caliper to measure all the dimensions I need to know. If these measurement are correct, these pins can help me install the DEC gear wheel at the right position.

Supporting pin.jpg

Like a Radio Knob, can't get any idea of its usage.
Where are those pins installed to ?

They are used for keeping the correct distance of the worm wheel from the bottom end of DEC housing, and will be removed after the wheel installed.

[LT]

DEC axis, almost done

DEC_body.jpg (475.91 KiB) 已瀏覽 23619 次

[Eddy So]

[littleming]

[BossKwan]

DEC axis, almost done

A good finished !

Your Declination housing looks machined from a piece of solid aluminium cylinder. Veiwing throught its polarscope hole, I can see, the wall of the housing seems remain certain thickness, I prefer reducing the thickness a bit for having the piece a more light weight, but still remains its strength. However, your whole declination are finished very nice.

Let me share my DIY history, thirtysome years ago, I finished the declination (my 2nd DIY mount) in a way of using sand-casting which means whole piece of the declination can be formed. In those years, Hong Kong still had a few small factory providing metal casting service(they are called foundry 鑄造廠 ). It is no doubt a good way to make some mechinical parts in whole piece design and also save many machining time. another great advantage is that you can get a number of pieces or more at the same time. ( Photo below )

Truly, your on going project really aroused my interest. If I were ten years younger, I am sure, I would start up my project for a new generation mount.

[LT]

Thanks for your sharing Mr. Kwan. DIY is fun no matter what age you are, and just do it if you want to start it again.

Yes, that was made from a solid cylinder. Because that is a permant setup, weight may not be a concern. I left the wall so thick because of less cost involved. That housing was not finished by me. So sad it is seemed all the aluminum alloy foundries had been moved to the Mainland.