Moonlite focuser on 300P

[mitchelln]

Hi.

I'm considering upgrading the focuser on my SW 300P GOTO Flextube to a Moonlite CR and have a few questions.

1) What length draw tube would people recommend? I do visual and photo work. Available lengths are 38,45,50 and 75mm. I was leaning toward 45mm. What are the issues if I get one with too much travel?

2) For the photo work a focus motor is indispensable. Moonlite offer a DC type and a full on stepper motor type. Whilst I take planetary photos, I'm not a serious astrophoto guy (especially with my mount!). So is the stepper motor version overkill for my setup?

I also considered the Baader Steeltrack, but the motor option on that seems silly money.

Any advice much appreciated!

[Tinker1947]

I did enquire about a motorized focuser for the Moonlight CR2 and the message then was its a factory fit and has to be used all the time, i brought my CR2 in Sept 2012 thing might have changed since then, i have the 50mm and it works ok with a DSLR and when i had one a CCD, the focuser as a focuser is worth having, while the Baader Steeltrack motor option is expensive it is detachable....

[catman161]

Hi I recently did this for my 200P. I chose the Moonlite CR2 and DC motor as I too am a planetary imager at present and the stepper motor definitely would have been surplus to my current requirements. Also I have trouble enough getting the capture software alone to work properly so adding into the mix the thought of controlling the stepper motor with computer software was too much for me!

I have since used the setup to great effect (see pic below) and do not regret going for the DC focuser.

The only thing I kind of regret was going for the 38mm draw tube as I have problems with back focus (not having enough) I wish I had gone for the 45mm version as this would make adding extensions to powermate/Barlow and being able to gain focus much more straightforward.

Also do not worry about not being able to focus by hand, you still can the DC motor has a small silver knurled knob that you turn to disengage the motor and you can use the focuser normally again. To use the motor again simply tighten (with fingers no tools required) the knob and off you go.

To conclude I highly recommend the moonlite focuser it's a great piece of kit and the DC motor is also brilliant and straighten forward to install.

Hope that helps

[mitchelln]

Thanks for the replies! Sounds like a 45mm draw tube and DC motor is the way to go then. You've saved me a lot of money The Moonlite motors do have clutches now, so I think a Baader setup is ruled out for cost reasons if nothing else.

That Jupiter shot is just breathtaking.

Sent from my GT-N7105 using Tapatalk

[Chris Rowland]

I've got two MoonLite focusers, the recent one has a clutch between the motor and the focuser so you can use the manual focus knob to focus, then the motor to touch up the focus.  These are all stepper motor focusers.  Don't know about draw tube length, I tend to add or subtract spacers.

Chris

[mitchelln]

I've been advised elsewhere to get the 38mm drawtube to bring any attached camera closer to the OTA. So now I'm a little confused.

Surely the length of the draw tube affects how far the focus point can be wound out, not how close to the OTA the draw tube being fully wound in will achieve. Or am I missing something fundamental here?

Thanks.

[Zakalwe]

Its pretty easy to make the adapter plates to fit a SW Autofocuser motor to the Baader focuser (and certainly a LOT cheaper than the outrageous amount that TS want for the kit). A couple of bits of ally flat bar, a HTC timing belt and pulley (both off Amazon).

Here's one cobbled together on my Lunt solarscope. I control it remotely using a Hitec DC motor controller.

Timing Belt: http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=321128923152

Pulley: http://www.amazon.co.uk/gp/product/B002T8T0MK/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

The pulley will need drilling to suit the motor shaft.

Here's a link to another way of doing the same thing: https://skydrive.live.com/view.aspx?resid=1779FF50C47508CF!342&app=WordPdf&wdo=2&authkey=!AHPsJrpwA6jnyzg

[mitchelln]

Oh wow. Thanks for that. I did briefly wonder if I could cobble something together as I have the SW auto focuser. Having photos and a list of parts is massively helpful. Thanks!

Is the focus pretty precise? I guess it is going onto the 10:1 reduction gear on the Baader, so it should be pretty good.

I guess I could also attach my SW motor to a Moonlite as well.

So question now is Moonlite vs Baader...

[mitchelln]

Just fitted a Moonlite CR2 to my 300P. I went for the 2" drawtube in the end and I'm glad I did. It gives much more focus travel than the standard focuser.  Plus due to the design, the tube does not impinge on the light path as much as the standard focuser when fully wound in either.

The difference is amazing. The standard SW Crayford has a lot of slop. I could literally rattle it about near the start of its travel and it couldn't really handle the weight of my DSLR.  The Moonlite, however, is as solid as a rock. The action is so much more refined as well and the shaft lock feature is invaluable. Yo can lock off the focuser without moving the drawtube at all unlike most other focusers.

The only fiddly bit was lining up the OTA holes with the holes in the block in the Universal installation kit. Top tip here is to use a head torch so you can see the holes when lining it up. Secondary needed re-aligning of course, but I was surprised to find that the focuser was completely square without the need to tweak the alignment screws.

Now I just have to come up with a bracket to attach my SW auto focuser motor to it...

[catman161]

Good stuff, great choice. Moonlite do a DC motor focuser for a modest price. I got mine from RVO.

[mitchelln]

Thanks for that. I was looking for a UK supplier.

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[catman161]

No probs

[mitchelln]

I got a Moonlite DC focus motor from Rother Valley Optics.

Fitting it was easy, the only thing that doesn't seem up to the usual MoonLite standard is they don't supply longer bolts for the attachment to the focuser. So you have to use the existing ones, which are only just long enough. I would like to have more bite on the threads.

It's also a shame that the bracket is handed, so you can only fit the motor on the left hand side of the focuser. So the motor is slightly proud of the top edge of the scope. Not a biggie though. If it really bothered me I'd knock up another bracket and swap the focuser knobs around.

Other than that, the build quality is great. It's a solid bit of kit. Best thing is the slip clutch. You can disengage the motor by just turning the knurled knob on the left. The only way to disconnect the motor on my SkyWatcher one was via a tiny allen screw. Something that proved fiddly at night. So the clutch on the MoonLite makes life a lot easier switching from manual to motor focus.

The handset sits nicely in the hand. It's a nice custom shaped box rather than an off the shelf ABS box. It can control 2 motors. Not sure why that would be needed, but hey! The controller has pots to set the speed, up/down buttons with a nice positive action and an on/off switch. It connects to the motor via a nice simple 3.5mm audio type cable.

The motor operation is smooth. On full whack it is much faster than the SW one, achieving full travel in a fraction of the time. At the finest setting it moves the focuser fractionally enough to get spot on focus.

Highly recommended!