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Motorize Your Focuser with a Tasco 1603EF

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#1 actionhac

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Posted 19 April 2011 - 11:24 AM

I purchased this focus motor to test on a few telescopes. Mainly those with feeble mounting and the annoying shimmy that accompanies this. My Sears 6345 is a prime example and my OC Discoverer is guilty also.
Telescope Warehouse has the 1603EF for $19.95:
http://stores.ebay.c...sid=p4340.l2563

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#2 actionhac

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Posted 19 April 2011 - 11:28 AM

Test subject is a 1970's after market Japanese focuser found on a lot of our classics.

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#3 actionhac

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Posted 19 April 2011 - 11:33 AM

The mount is universal and adjustable for a variety of focusers. This application was a no-brain. Some may require modifying the bracket.

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#4 actionhac

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Posted 19 April 2011 - 11:36 AM

You can see how it clamps to the pinion block.

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#5 actionhac

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Posted 19 April 2011 - 11:39 AM

I removed a knob and replaced it with a sheet metal U to couple with the 1603EF's U. This works well with 0 backlash.

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#6 actionhac

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Posted 19 April 2011 - 11:47 AM

This unit has a clutch if you wish to focus manually.
A little zippy for focal ratios f6 and faster, requiring tapping the controller buttons but much more precise than manual especially if you are under mounted. I feel it's more suited to f10-15 with their greater depth of focus but still it is very nice to focus "hands off". A person could add a potentiometer to have the 3V AA battery supply voltage variable. I thought I would see how the unit acts as the batteries become depleted and decide.
If you've never used an electric focuser before this would be a very good introduction. I find after using them I'm spoiled. I have a much more expensive Meade version on a scope and this little cheapy ain't much different in function.

Robert

#7 eric_zeiner

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Posted 19 April 2011 - 12:18 PM

Nice

#8 actionhac

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Posted 19 April 2011 - 04:57 PM

I thought since I've completely finished the installation I should read the instructions and noticed the copyright is 1993 which could mean these are no longer made and TW has some new old stock. These are new but no box. No sign of being returns or refurbished, at least my example.

Robert

#9 albert1

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Posted 19 April 2011 - 08:04 PM

I thought since I've completely finished the installation I should read the instructions


:lol:

Thanks for the photos Robert. Think I'm gonna try one. Nice idea with the U joint.

#10 actionhac

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Posted 19 April 2011 - 09:37 PM

It's a very good deal. I'm having a great time with it on my newt, never have I had such a luxury before on a scope that I like to use all the time, I usually prefer the stripped-down models.
The "U" driver on the 1603EF is meant to engage slots in some of the Tasco scope knobs, after you pry off the decorative cover. The mating sheet metal U works great especially if a good fit. Or I have seen others use a square wood driven knob.

Robert

#11 bob midiri

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Posted 27 April 2011 - 10:22 AM

Robert I may be slow, but how did you make that reverse U joint. I bought two of these focusers and want to use one on my Sears 6344 76mm refractor OTA. One fit perfectly on my classic Tasco 11TR, obviously made for that scope. But the Sears has metal focuser wheels. Thanks Bob

#12 actionhac

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Posted 27 April 2011 - 11:05 AM

Hi Bob,
I removed a knob from the focuser and replaced it with a sheet metal "U" that I bent to fit inside the "U" of the motor and drilled a hole exactly in the center to mount to the focuser shaft. I replaced the knob screw with one better suited to hold the flat sheet metal, the knob screw is a countersink head.
If you prefer using wood you can make a square hardwood knob to replace the original focuser knob that will fit inside the Tasco motor "U" and if made the same thickness the original screw can be used.
In this photo you can see the brass "U" inside the chrome motor "U". Just a strip the same width bent to shape with pliers. I backed it up with a washer because it is bearing against the end of the tapered focuser shaft. The chrome half of the U joint comes with the 1603EF.

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#13 actionhac

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Posted 27 April 2011 - 12:12 PM

I've been using the motor focuser for a week now viewing Saturn which is a very demanding job for the focuser and it works beautifully.
To slow down it's movement if your focuser has a tension/lock screw you can tighten it or tighten the pinion block screws to increase drag on the focus, the 1603EF has sufficient torque to keep working but at a slower speed. Tightening up the focuser to a level that would be unbearable manually also removes all play and absolutely no image shift, and the motor doesn't seem to mind.
The U joint coupler must be a tight connection, any slop would mean poor response when moving between Forward and Reverse, you want zero backlash. The 1603EF has no backlash in it's gear train and actually a well made unit.
It's surprisingly easy to hit best focus and make small precise corrections with the R and F buttons.

Robert

#14 bob midiri

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Posted 27 April 2011 - 12:47 PM

Robert thanks so much. Now I see what you did. Bob

#15 Geo.

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Posted 27 April 2011 - 06:16 PM

Yes, I saw these and wondered. However, I went for the Tasco 1606 RA drive for $50. These are made for use on the Vixen Polaris mounts that Tasco Sold in the '80s.

#16 pjac

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Posted 22 December 2012 - 04:28 PM

I just got one partly encouraged by this thread, and I'm pleased to say the Tasco 1603EF appears to need no modification at all to use with the SkyWatcher Explorer 130M (also known as the SK1309EQ2), so thank you for sharing those images.

Here's my blog post with photos of the Tasco 1603EF - I'm looking forward to trying it out :)

#17 desertrefugee

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Posted 22 December 2012 - 07:47 PM

I must be crackin' up. Pjac comes in (welcome by the way!), digs up an old thread and has me saying, "Why not?"

Yeah, I ordered one. I think I'll put it to good use doing some lunar photography.

Thanks pjac. :)

#18 tim53

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Posted 22 December 2012 - 08:01 PM

I put one of these on the 14F about a year or so ago. Mine had a broken solder connection on it, so initially it didn't work. When I fixed that, though, it's been great. Next thing I need to do is figure out how to stiffen those metal legs. I hate em!

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-Tim.

#19 pjac

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Posted 22 December 2012 - 09:19 PM

... The U joint coupler must be a tight connection, any slop would mean poor response when moving between Forward and Reverse, you want zero backlash. The 1603EF has no backlash in it's gear train and actually a well made unit.
It's surprisingly easy to hit best focus and make small precise corrections with the R and F buttons.

Robert

That's the only thing I'm considering tweaking for using the 1603EF motor on my SkyWatcher - the spokes on my focus knob give a couple of millimetre's slack meaning fine control F/R suffers from a delay when switching direction. That's what you meant by "slop" I assume Robert? When it stops raining, I'll try it as is, but a tighter fit shouldn't be too hard to improvise...

Update: Putting a bit of blu-tack into the focus wheel slots where the U-piece inserts seems to have done the job.

#20 pjac

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Posted 22 December 2012 - 09:20 PM

I must be crackin' up. Pjac comes in (welcome by the way!), digs up an old thread and has me saying, "Why not?"

Yeah, I ordered one. I think I'll put it to good use doing some lunar photography.

Thanks pjac. :)

Enjoy :grin: - I think my own thought process when ordering this was quite similar ;)

Update: It was a bit windy tonight making wobble more of a problem than usual, and incoming cloud cut short my viewing session of Jupiter and the moon - but my first impressions are very favourable. At high magnification (eg with a Barlow) even when using an eyepiece focusing via the motor was convenient to avoid wobble, but I found this really payed off when used with my webcam.

#21 actionhac

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Posted 22 December 2012 - 11:40 PM

... The U joint coupler must be a tight connection, any slop would mean poor response when moving between Forward and Reverse, you want zero backlash. The 1603EF has no backlash in it's gear train and actually a well made unit.
It's surprisingly easy to hit best focus and make small precise corrections with the R and F buttons.

Robert

That's the only thing I'm considering tweaking for using the 1603EF motor on my SkyWatcher - the spokes on my focus knob give a couple of millimetre's slack meaning fine control F/R suffers from a delay when switching direction. That's what you meant by "slop" I assume Robert? When it stops raining, I'll try it as is, but a tighter fit shouldn't be too hard to improvise...


Yes no slop. Because you are shifting forward and backward hunting for a sharp focus. You will overshoot and back up sometimes and you will find slop is intolerable. Once you get the hang of it you can zoom on in and nail it first try, and that's a great feeling, especially at extreme high power.
The motor's tines, where they to plug into the focuser knob should be coupled tightly. Possibly silicon tubing on the "U" tines where they plug into the knob recesses, so everything is tight.

Robert

#22 dgreyson

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Posted 23 December 2012 - 02:25 AM

Ive seen those focusers for sale before but alwats wondered if they were worth the bother.

#23 Karl Fabian

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Posted 28 December 2012 - 05:37 PM

Adapted one of those Tasco 1603 units to my Meade DS2090AT-TC about a year ago. Before the mod focusing at anything over 100x was hit or miss. I simply replaced the focus knob with rectangular flat stock and remounted the entire assembly on aluminum bar stock to line things up.

#24 Karl Fabian

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Posted 28 December 2012 - 05:55 PM

Here it is mounted up.

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#25 Karl Fabian

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Posted 28 December 2012 - 06:03 PM

The square plate to take the place of focus knob.

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