HitecAstro DC Focus Controller

[Thalestris24]

Hi Louise

Yes,  followed it all as per your comments and the video. Did have a moment today when 1 of the little O rings fell inside the scope body, moments of panic when it couldn't be seen, then managed to turn scope on end and it fell out - phew! Yes I have the black coupling as not required for the 80ED. I haven't drilled out any extra holes, but elongated 2 of them in the bracket that came with the motor so that the 2 grub screws to adjust the level of the neoprene washer on the focuser shaft. The bracket that came with the motor is not for the 80ED and the holes don't align, see 15.50 minutes frames in the video.

I am interested to know from anyone who has taken off the knurled coupling (with black grub screw) next to the motor, see my image above, as to what is inside it. Without undoing the grub screw that holds it onto the motor shaft,  it appears to be some sort of flexible coupling? I am reluctant to take it off to have a look as the producer of the video warns against its removal as its very difficult to refit!

Regards

Alec

Hiya

Yeah those O-rings are pesky little things!

"The bracket that came with the motor is not for the 80ED and the holes don't align, see 15.50 minutes frames in the video." Huh? The holes should align if you adjust as demonstrated - you definitely shouldn't need to enlarge any of the holes in the plate...

I previously removed the autofocuser from my 150pds in order to pit it on an ST80. I left the silver coupler attached to the 150pds crayford. It does seem to have some flexibility.  

Louise

[alcol620]

Hiya

Yeah those O-rings are pesky little things!

"The bracket that came with the motor is not for the 80ED and the holes don't align, see 15.50 minutes frames in the video." Huh? The holes should align if you adjust as demonstrated - you definitely shouldn't need to enlarge any of the holes in the plate...

I previously removed the autofocuser from my 150pds in order to pit it on an ST80. I left the silver coupler attached to the 150pds crayford. It does seem to have some flexibility.  

Louise

I think it may be so flexible that it will allow the motor to turn without the shaft of the focuser being turned if the shaft is loaded. That's why I'm interested in what is inside the silver knurled coupler.

Alec

[Thalestris24]

I think it may be so flexible that it will allow the motor to turn without the shaft of the focuser being turned if the shaft is loaded. That's why I'm interested in what is inside the silver knurled coupler.

Alec

I'm not sure it does that though the motor can make the focuser drawtube go too far in or out but I don't know for sure what effect that has on the motor turning. The black coupler I have on the ST80 has grub screws on the R+P shaft and on the motor shaft so that would seem to cause a stall in the motor if the limits are exceeded. I guess with only a 9v pp3 powering it, there is little chance of the motor burning out or anything. The motor gears do seem to provide quite a bit of torque though.

Did you see how the holes in the plate align?

Louise

[Starlight 1]

The silver one only fits the fine Focus , the silver one in three parts, once you slacken the grub screw the inner part unscrews from the outer inside is a little Black 0 ring

that push over the shaft . So the inter part screw in to compress the 0 ring on the shaft motor end.

[alcol620]

The silver one only fits the fine Focus , the silver one in three parts, once you slacken the grub screw the inner part unscrews from the outer inside is a little Black 0 ring

that push over the shaft . So the inter part screw in to compress the 0 ring on the shaft motor end.

If the grub screw is loosened and the coupling taken to pieces is it easy to reassemble? What is the purpose of the O ring?

[Starlight 1]

The 0 ring is there so you still move the focus my hand ? so you can fit a 20mm ep move the focus my hand till you get a Star, then fit your camera and the focus will be close just a mm or 2 in or out. so if you are useing a program like SG PRO it will to the fine focus for you . so all the little 0 ring is for so you can move focus my hand without try to turn the motor at the same time.

[Thalestris24]

They are DC motors so 0v across them except when being actively adjusted. On my ST80 with the black coupler, and using the hand controller, if I move the focuser in as far as possible, the motor still makes a noise but the motor shaft doesn't appear to turn. Now, at some point, I managed to 'break' the motor! It stopped driving the shaft... I'm not sure if that was caused by trying to move the focus tube beyond it's limits or from manually turning it. I think what happens is that one of the gears jumps out... So I had to undo the motor (fiddly) and make sure all the gears were mating as expected. Seems to be working again now . Still, there's a warning there and something to be aware of, lol.

Here's what the motor looks like inside:

Edit: I think the large metal gear is on the wrong way round in the photo

Hope that's of use

Louise

[alcol620]

Thanks folks. Still not sure if I would get the pieces back together again if I undid the grub screw and took the flexible o ring out of the knurled coupling.

[Thalestris24]

Thanks folks. Still not sure if I would get the pieces back together again if I undid the grub screw and took the flexible o ring out of the knurled coupling.

Hi Alec

Um, why would you want or need to?

Louise

[alcol620]

Hi Louise

Only thinking ahead to the time if the assembly starts to slip again, with the motor rotor turning but the focuser shaft not turning.

Regards

Alec

[Thalestris24]

Hi Louise

Only thinking ahead to the time if the assembly starts to slip again, with the motor rotor turning but the focuser shaft not turning.

Regards

Alec

Mind you haven't done what I did above! (#32) Once the gears jump out you'll hear the motor rotating but there's no drive and the focus mechanism goes sloppy. I think it highly unlikely there would be a problem with the silver coupler...

Louise

[alcol620]

Hi Louise

Thanks again for all your inputs, much appreciated.

Best regards

Alec

[Starlight 1]

The silver one is just fine it's made to work that way if you removed your 0 ring you will not get any drive, the only problem I could possibly see if you had a heavy camera ect check focus every 30 mins.

[alcol620]

Thanks Starlight

I have an Atik 383 and a Skywatcher 5 x 2" filter wheel, plus a reducer/flattener hanging on, so quite weighty.

Regards

Alwc

[Vox45]

Nice thread focusing is becoming a big issue for me with the cold weather we have here right now

So, looking at HitecAstro DC Focus + SkyWatcher Auto Focuser

I use to have a JMI motofocus on my C6 but for some reason, the price seems to have skyrocketed !! 154£ for a motofocus now... used to be much cheaper

As I plan to upgrade the stock focuser in the future I just hope the SkyWatcher Auto Focuser can be adapted to a Baader Diamond Steeltrack ... but I doubt it :/

[StevieDvd]

There is/was a kit for the older version of the focuser here if the screw positions/sizes are the same it should fit.

[Vox45]

I finally got the HitecAstro DC Focus + SkyWatcher Auto Focuser

It's working great and after adjusting the stock focuser on my 80ED, everything is much tighter... Let's just say that the urge of upgrading my focuser has gone for now. I can start spending $$$ on other bits that suddenly became more important to get

I am now officially fully 'remote' ! I can control everything from the comfort of my bed using a 5m USB extension cable.

Now I'd like to find a replacement cable for the coiled cable that goes from the focuser control box to the motor... I wrote to Hitecastro to ask if I could use a simple flat phone cable or crimp it myself as I find the coiled one a bit annoying on the cable management side of things ...

[Thalestris24]

3 hours ago, Vox45 said:

I finally got the HitecAstro DC Focus + SkyWatcher Auto Focuser

It's working great and after adjusting the stock focuser on my 80ED, everything is much tighter... Let's just say that the urge of upgrading my focuser has gone for now. I can start spending $$$ on other bits that suddenly became more important to get

I am now officially fully 'remote' ! I can control everything from the comfort of my bed using a 5m USB extension cable.

Now I'd like to find a replacement cable for the coiled cable that goes from the focuser control box to the motor... I wrote to Hitecastro to ask if I could use a simple flat phone cable or crimp it myself as I find the coiled one a bit annoying on the cable management side of things ...

Yeah, the coiled style cable is too springy - I think any flat equivalent RJ11 cable will do - it only uses two pins for the + and - DC connection.

Louise

[Vox45]

17 hours ago, Thalestris24 said:

Yeah, the coiled style cable is too springy - I think any flat equivalent RJ11 cable will do - it only uses two pins for the + and - DC connection.

Louise

No answer yet from Hitecastro. Thanks Louise, I'm sure I have a phone cable somewhere... I'll test this tonight

[Thalestris24]

Actually, the flat cable RJ9/10/22 cables seem quite hard to come by! I've searched all the obviously places but couldn't find an off the shelf uk source (why didn't they use RJ11???). Making one would be easy if you had the crimp tool but not worth buying one just for that... Fortunately, I only refocus occasionally so it's not a big deal.

Louise 

[Vox45]

On 27/2/2016 at 17:42, Thalestris24 said:

Actually, the flat cable RJ9/10/22 cables seem quite hard to come by! I've searched all the obviously places but couldn't find an off the shelf uk source (why didn't they use RJ11???). Making one would be easy if you had the crimp tool but not worth buying one just for that... Fortunately, I only refocus occasionally so it's not a big deal.

Louise 

Yes I have a crimp tool and access to loads of connectors ... I'll try that when I get the chance. No answer from Hitecastro as of today :/