Sharpsky Pro Focuser... A Luddites perspective!!

[acropolite]

My Sharpsky Pro focuser arrived this week from the UK.

The Sharpsky Pro is an evolution of a product that was initially offered as a Kit and which some IIS members have already built and use.

After seeing the proliferation of remote focusers at Astrofest I decided it was time to jump. Allan Gould had shown me his own kit built version of this focuser at Astrofest and after seeing a mention in another thread I couldn't resist the urge to hit the buy button....

The focuser arrived in perfect order (well packed) in just 8 days from order, a refreshing change from the often 40+ days or not at all for stuff from China. All hardware is beautifully built and easy (logical) to operate.

The Sharpsky Pro was developed by Dave Trewren in the UK. In it's present form it consists of a PC capable remote focus controller, manual control paddle, focus motor with encoders and an additional remote temperature sensor as well as cleverly designed 4 port dew controller.

Here is the package including a tape measure to give an idea of size. The cord on top of the main control unit is the additional temperature sensor, more about that later.

[acropolite]

The main controller is a double purpose interface with opposing sides having different functionality.
On one side is the focus section, consisting of a manual controller/sensor port, DB9 connector for the motor/sensor cable, USB and some indicator LEDS. The indicator LEDS indicate Rate, Focus IN Focus Out and USB connect. The USB connect has the option of indicating on or off for connection status, selectable via software, a nice touch if you don't want your mount looking like a christmas tree.

The focus motor has both an inbuilt encoder to track position and a temperature sensor which can be used for focus compensation as temps drop. The manual focus controller paddle allows several rates of adjustment selectable by pressing the focus knob in, the rate indicator show the rate selected by flashing momentarily 1 to 4 times. Manual focus and PC focus can be used at the same time, manual changes update the client software so your PC doesn't lose track of the focus position.

If you don't need/want to use the manual focus knob, there's an option to allow automatic temperature adjustment using the optional probe (included) on the first of the dew controller ports, or the optional sensor can be used in lieu of the one built in to the focus motor.

[acropolite]

The dew controller side of the unit consists of 4x RCA sockets, standard for dew straps, a 3 way toggle switch (spring loaded centre home position), LEDS and a power connection for 12V (centre positive).
The dew controller operates in a simple manner, pushing the toggle to the right selects a controller output, once an output is selected pushing left toggles the controller output to one of 4 preset levels or off. If there is no load, or your dew strap is open circuit, the level leds flash to indicat a fault. The 4 level presets are adjustable in software, e.g. level 1=10%, 2=25%, 3=50% , 4=100%. Once you set your preset levels they're set in non volatile memory, the unit then basically performs in stand alone mode.

Here's an image of the controller side, the silver button in the centre of the motor is the inbuilt temp sensor.

[acropolite]

I've yet to mount the focus motor on my ED80, included in the kit is a blank plate which needs to be drilled to fit the focuser shaft in my case Dave also included some spacers which he thinks may be needed for my SW focuser.
The focus motor attaches to the focuser shaft with a flexible coupler.

Here's the diagram of the focuser mount from the documentation, I'll add a couple of images once I get the beast mounted.

[acropolite]

The Sharpsky unit will run quite happily without any PC connection, a prerequisite for integration with your choice of controller software is installation of the Ascom platform (a free download). Ultimately I intend using Main Sequences' Sequence Generator Pro once I work out that can of worms.
I downloaded the latest Ascom 6 platform and installed, followed by the Sharpsky pro software which was included on a mini CD with the kit. The unit is firmware updateable so the disk also includes a firmware bootloader. At this stage I've run up SGP and tested the focus options.

Some screenshots of the various options available on the Sharpsky via the Ascom client.

Image 1 Ascom chooser showing the Sharpsky selected.
Image 2 Focus motor settings including range etc.
Image 3 Manual Paddle settings, including increment adjustment for all 4 focus step options.
Image 4 Temperature compensation options and temperature logging (a temperature log can be saved in the root directory of your HDD.
Image 5 Dew Controller output settings, note this sets the output level presets which are manually selectable via the toggle switch.

[Astroman]

Excellent write up Phil. I hope to get one of these in the future, very compact and looks great.. I hope you will provide some additional real-world reviews once you have it up and running and have used it.

[multiweb]

Good stuff Phil. Mine is in the mail. Can't wait. Pretty neat kit hey? Thanks for the break down post. I'll revisit when time comes to setup. :thumbsup:

[acropolite]

I'll post some more once I get the motor mounted and software sorted.

Dave's support is second to none, we had exchanged several emails before I even pushed the buy button, Dave gave helpful suggestions without being asked, the quality of the hardware is exceptional and the package complete, no add ons to buy!

Sharpsky website if you want to browse the manuals etc. http://www.sharpsky.net/

I have no affiliation with Dave or Sharpsky BTW,

[acropolite]

Here's a cut and paste from the temperature log file created by the device, the temps are sitting on the kitchen table, from the last 2 entries you can see where I moved the focus motor.


Temperature = 26.25 * Position = 29467 * Motor Sensor * 14/09/2013 10:10:39 AM
Temperature = 26.31 * Position = 29467 * Motor Sensor * 14/09/2013 10:10:52 AM
Temperature = 26.31 * Position = 29467 * Motor Sensor * 14/09/2013 10:11:12 AM
Temperature = 26.31 * Position = 29467 * Motor Sensor * 14/09/2013 10:11:25 AM
Temperature = 26.44 * Position = 29467 * Motor Sensor * 14/09/2013 10:11:38 AM
Temperature = 26.56 * Position = 29467 * Motor Sensor * 14/09/2013 10:11:51 AM
Temperature = 26.69 * Position = 29467 * Motor Sensor * 14/09/2013 10:12:04 AM
Temperature = 26.81 * Position = 29467 * Motor Sensor * 14/09/2013 10:12:17 AM
Temperature = 26.81 * Position = 29467 * Motor Sensor * 14/09/2013 10:12:29 AM
Temperature = 26.88 * Position = 29467 * Motor Sensor * 14/09/2013 10:12:42 AM
Temperature = 26.81 * Position = 29492 * Motor Sensor * 14/09/2013 10:12:55 AM
Temperature = 26.75 * Position = 29482 * Motor Sensor * 14/09/2013 10:13:08 AM

[jwoody]

Good write up Phil. It really looks the business and very well made. I built one the focus kits when Dave was doing them and I am very happy with it...although I could upgrade?:question:
Look forward to your first use report and maybe some piccies with it on your ED80.
Cheers
Jeremy

[allan gould]

Excellent write up Phil and I trust you will get a whole lot of use out of it. Dave is excellent in communication re his device and Im sure it will do well.
Allan

[acropolite]

Dave has also written a (free) simple client app to allow access to the various Sharpsky modules, he mentioned it as an alternative in an earlier email to me but I'd forgotten. Just tried it out, it's nice and simple, I'll probably use it until I get my head around SGP.

The Sharpsky client can be downloaded at http://www.dt-space.co.uk/SharpSkyClient

[dtrewren]

Morning Phil et al,

I am very pleased you are happy with the SharpSky Pro focuser. Many thanks for the excellent and very positive report. It makes all the time & effort worth while when guys post up such positive feedback. One of the motivations for developing the SharpSky Pro equipment was the amount of interest and positive feedback I received from imagers in Australia and elsewhere 'down under' following the SharpSky kit version. I was sad to have to stop producing the kit but unfortunately there are only so many hours in the day.

I have been doing quite a bit of testing with Sequence Generator Pro in the last few days. This client seems to be very popular in Australia. I personally have had a very positive experience with the tool and the level of support from the development team is second to none. The SGP guys were very helpful and have even provided me with a license so I can carry out long term SharpSky testing and support.

As Phil mentioned in his report I have written a very simple client which is handy to get a feel for automated focusing. Once you get into it something like SGP is definitely the way forward.

Again, many thanks Phil and I look forward to hearing how you get on using SharpSky Pro in anger on those lovely southern skies (envy :))

Cheers & clear skies,

Dave

SharpSky Innovations
Bristol UK

[acropolite]

Nice to see you pop out of the aether Dave, did you learn that trick from Gary Kopf (of Argonavis fame)....:P

I've had a bit of a fiddle with the focuser option on SGP. One nice feature in SGP that isn't available on the freebie Sharpsky client is the ability to directly enter a step position and go to.

Note that the Sharpsky Pro menus aren't available from the focus control in SGP but are available if you go in to SGP setup and disconnect from the focuser temporarily. It's no real bother as once the initial setup is done other than to change the dew heater % settings there's no real need to access the menus.

Screenshots from the focuser control, temperature compensation and the section where you access the Sharpsky menus if necessary.

[dtrewren]

Hi Phil,

Adding a direct step go to entry input on my SharpSky client is not a problem and I will have a look at implementing this shortly - not sure why it is not present at the moment ....

Interestingly, I was only speaking to the SGP developers on Friday evening regarding making setting changes to the driver when connected. As you correctly pointed out when SGP connects to an ASCOM device you lose the ability to pop open the settings dialog window. This is a client specific author choice as I an not aware of any ASCOM standard directive regarding this operation.

So some clients, (eg MaxIm) allow the user to open the settings dialog window when connected and some (SGP) do not. As the SGP developers point out there is no driver property indicating whether it is 'safe' to make changes when connected and so they have decided to air on the side of caution and prevent the operation.

In the case of SharpSky Pro any driver setup window changes are noted and on connection committed to driver persistent storage and if necessary transmitted to the control box for commitment to non volatile memory. The driver also pops up a courtesy message just to let you know you are making a change in a non connected state.

So as you correctly mention when using SGP it is necessary to first disconnect make any required setup window changes and then re-connect.
Safe and effective :)

Cheers & clear skies,

Dave

[LewisM]

Dave,

A question on the focuserspindle size - If I am reading it right, the mtor adapter collar has a 3mm spindle clamp. Is this so? Can you make them larger? The focuser spindle shaft on my astrograph is a 6mm shaft, and wanted to try your gear. I won't modify the stock focuser apart from removing the knob

[dtrewren]

Morning Lewis,

As standard the flexible shaft coupler has a 3mm diameter hole at the focuser side (the motor is 5mm). Both sides of the coupler have a clamp but in addition I drill and tap both ends and fit with 3mm grub screws. I fit two grub screws the focuser side and one on the motor side. The motor shaft has a flat so only one grub screw is required whereas the focuser side is generally a round shaft and so two grub screw are a better idea.

A focuser with a 6mm shaft is not a problem. I can drill out the 3mm hole to 6mm on my lathe. It's worth checking as accurately as possible - as my old metalwork teacher used to say 'taking metal off is much easier than adding it back in' :)

Cheers & clear skies,

Dave

[dtrewren]

Evening Phil et al,

Following a suggestion from Phil I have added a 'Goto' feature to my simple client application.

When the application is invoked the Goto value is populated with the current absolute position. This initial value can be modified either by typing a new value or using the up/down input. The focuser will then adopt this new absolute position when the Goto button is pressed.

The new version V1.15 is now live on the website for download :
www.dt-space.co.uk/SharpSkyClient/

Cheers & clear skies,

Dave

[acropolite]

Thanks Dave, That was quick! I'll hopefully be mounting my focus motor at the weekend, pics to follow.

[LewisM]

Dave, I'll check all dimensions, then I will send you an email with my order. Your offering is JUST the ticket in many ways for what I need to do (and NOT alter my existing scope in any way apart from removing one focus knob).

[dtrewren]

Hi Phil,

No problem :)

Looking forward to seeing the fruits of your labor !

It would be fantastic to have a 'one size fits all' bracket but alas this seems to be unachievable due to the range and diversity of different focusers on the market. The closest I could get was making the bracket adjustable in length. Personally, I found fitting the bracket much more straight forward with this length adjustment.

I will be very interested to see how you get on. Never ceases to amaze me how ingenious guys get coupling the motor to their particular setup :)

Cheers,

Dave

[dtrewren]

Afternoon everyone,

I have just had an email from the developers at SGP. The have been looking into the reason why SGP disables the option to open a setup window when a focuser (or other ASCOM hardware) is connected. This was raised by Phil earlier in the thread. I also noticed the feature during SharpSky testing and raised it with the SGP guys.

Being the proactive sort of chaps they are ... they have come to the conclusion there is no real reason and so have removed the restriction. This modification is due for release in V2.2.11

Good job :)

Dave

[acropolite]

I reloaded SGP and it looks like change has already been patched in to the existing current release. :)

[acropolite]

Dave has, after my suggestion, again modded the sharpsky client allowing positions to be saved against profiles, which in my case allows me to save and go to the focus positions for my SSAG and 5D when swapping for polar alignment. (or different cameras for example) :thumbsup:

Download the updated client at http://www.dt-space.co.uk/SharpSkyClient

With the new Laptop up and running, I've also got the Sharpsky running without issues on Win8 pro64 and on USB3 ports.

A couple of notes.

With W8 there seems to be a quirk with the Ascom chooser in that the first time you choose connect to the focuser nothing happens until you check the properties of the focuser (which you can access from the chooser window).

You can select the Sharpsky focuser, but until the properties option is entered then OK'd you can't connect. This appears to be a problem with Ascom and W8 and has been passed on to the Ascom team. (The same thing happens if you choose the focus simulator)

It's no real problem as once the properties have been selected for the first time subsequent connections occur without issues and without having to revisit the properties.

SGP also runs the Sharpsky without issues on W8.

[multiweb]

Here's my sahrpsky pro installed. Did a lot of cutting, drilling, tapping and painting this week-end. Now I can move the motor from my newt to the C11 really quick and easy. Next I have to do my refractor. Then learn how to use it.

[acropolite]

Neat job Marc, I'm waiting on some longer brass standoffs for mine, Dave supplies additional motors BTW, from memory they're £80 (around $140 at current exchange rates) including shipping. I was thinking some sort quick release would be useful if swapping.

There's really nothing to learn, if you download Dave's client, it's dead easy to use.

[multiweb]

That's what I did. I have two screws to take off to swap it over to the newt back and forth. So I actually tapped the thin plates. No more nuts and bolts. My fingers are too thick (or maybe it's me)for all this small stuff + washers. Drives me nuts. :lol:

[dtrewren]

Morning (well it is here) guys,

Excellent job Marc, really looks the business with your bracket assembly. Yes indeed I can source additional motors that's not a problem but if you have a swap mechanism that works then happy days. Generally I tend to find I use one scope for several weeks if not an entire season so swapping would not be an issue in reality.

Many thanks for the positive feedback on Win8 Phil. I have a machine set up here now and have been running SharpSky through its paces without an issue.

It's always really nice to see photographs of the design being used in anger so thumbs up for the postings :)

Cheers & clear skies,

Dave

[multiweb]

Unless you image with two telescopes at the same time it's more efficient to move the motor around I reckon.

[LewisM]

Any updates about actual use etc yet?

[multiweb]

Yeah it works great. I tested the temperature compensation. Cool stuff. Software/drivers, all run as advertised. HP notebook Win7 home 64bit 8GB RAM. No problem at all.

[LewisM]

IS the max travel (start pos'n, end pos'n} automatically calculated for your drawtube, or?

[multiweb]

I haven't used this. Don't think so. I reckon you'd set that explicitly. The motor records an absolute position. So first time you get focus you lock it in. It knows temperature at the time of focus and will save this as the focus point at T temperature. When you start again a T+/-n temperature it will move the motor and refocus based on your temperature compensation and motor steps. I don't think you'll ever go near the limit. This is just a fail safe. I haven't read the doc that far. David might chip in or you can download and read the PDF manual. Then you tell me :P

[acropolite]

You can set the "Zero" position from Dave's tool, You can also save presets, Dave incorporated that feature in the app, very handy when polar aligning, if you're like me your guidecam will have vastly different focus points to your main camera.
The log can be used to save focus position against time and Temp, from that you can calculate (and enter) any necessary offset.

[LewisM]

Dave posted mine today, so I'll let you all know in about 8 days :) VERY excited, because focusing my f/5 astrograph manually is NOT fun.

[dtrewren]

Hello Marc, Phil et al,

Apologies for not chipping in - for some reason I wasn't getting emails from the thread so didn't realise things were being posted until logging in .... software :P

SharpSky defaults to an arbitrary position of 25000 out of the box. In the driver you can set a minimum & maximum step value that the driver prevents you from exceeding in either direction - defaults min/max are 0 & 150,000 respectively which is a lot of travel. If you want to change to another position but not physically move the focuser you can use the 'Initial focuser position' and 'set position' feature on the setup window.

Temperature compensation has a 'Compensation resume' feature. Say you are imaging one night using temperature compensation to track. The last temperature & position used before disconnection is stored by the driver. On a subsequent night one may wish to continue with the same target but the temperature may be very different. By using the resume feature the focuser will automatically make a step movement to the new temperature based position getting you very close to focus before you start the second session.

If have attempted to explain this in the manual but if there are questions or ambiguities please fire away and I will try and clarify :)

Cheers, hope your skies are clearer than here !

Dave

[multiweb]

Hi David, the initial focusing is done by hand. In the future would the SharpSky client support a FWHM detection from a looped imager or can it work with a program that would already do it. I'm thinking to get the best focus by the number like RoboFocus. Nebulosity detects FWHM. I assume Maxim DL would too?

[Logieberra]

Dave, is Mac support in the pipeline?

How about a native X2 driver for TheSkyX? I'm no developer, but I hear the X2 toolkit goes a long way to supporting new products ease into TSX.

[dtrewren]

Hi Guys,

SharpSky works really well with MaxIm and FocusMax. Several chaps have used FocusMax (which is free) with MaxIm and have achieved really good repeatable results. Other chaps have also used FocusMax with CCDSoft but the general opinion seems to be that the MaxIm interface is better. MaxIm can also perform autofocus itself but again I think the reference seems to be FocusMax - at the end of the day it a personal choice I think the end result will be much the same whichever route is taken, maybe some routes a bit faster than others.

I hadn't planned on enhancing the client. The client was really something I designed up for myself and to have a crack at writing a client application to compliment the driver. Also it allows anyone who purchases a SharpSky focuser to get up and running immediately without having to spend any more money on software. Then once you get into remote focusing and get a feel for it the decision on more sophisticated software becomes clearer IMO.

I have found with many pieces of expensive commercial software there is a software 'arms race' going on with dozens of features being included to differentiate one product from the next. This then pushes up the price and makes the software much more difficult to test. You then end up paying money for many features that are nice but not really essential - my opinion obviously. That was my motivation for writing the client to just include a few features I thought were useful to me.

However, including a camera capture option which could work in conjunction with FocusMax is a nice idea :) I am surprised FocusMax can't capture it's own images making it stand alone ?

I don't have any plans to support Mac at the moment. To be honest only one or two people have mentioned Mac so it is a bit difficult to justify the time without the demand.

Cheers & clear skies,

Dave

[Logieberra]

Thanks Dave. A niche project. I wish you well :)

[multiweb]

Thanks David. FocusMax sounds very good. I have Maxim DL so I'll look into it for initial focus. I have a few ideas as well to focus M prime Pentax lenses with your system when imaging at 150mm and longer.

[dtrewren]

Hi Marc,

I don't think you will be disappointed with FocusMax and MaxIm they make an excellent combination.

I'll be interested to see how you get on with the Pentax lens. I did something similar with a Nikkor 180mm ED f/2.8

Here are some photo of my widefield setup :)

http://www.dt-space.co.uk/WF_project

Cheers,

Dave

[multiweb]

I think I've worked it out now. Very cool. :thumbsup: Trying tonight on a real star. I like your tensioning belt system. Did you use bearings for the rollers or just straight shaft in the alu blocks?
PS: If you've got the part# for the cogs and width of the belts. There's a lot of this stuff on eBay but not sure on your dimensions. 11mm?

[multiweb]

Here's a graph a mate of mine did from a demo. The steps were set to 500 counts and I was holding the external temperature probe in my hands. Perfect linearity.

[dtrewren]

Morning Marc et al,

Hope you had a good first light motor focusing ?

Pleased you like the WF rig, I really like WF imaging as you end up seeing all sorts of interesting objects that are generally not imaged individually.

With reference to the WF rig setup :
I used pillow bearing blocks to carry the drive shaft. The blocks have little ball races embedded into them. The drive shafts are made from 3mm stainless steel with 3mm pillow bearings to match. The same arrangement was used for the drive and idler block. I made the aluminium spacers used to raise the drive axis to the mid point of the lens.

With the belt wrapping around the lens it's analogous to gripping the lens with your hand an rotating exerting almost no lateral force only rotational.

The belt used was a HTD timing belt with 140 teeth. It just so happened that the tooth pitch on the belt exactly matched that of the rubber grip on the lens so there is absolutely no danger of slip. The pulleys are 12 tooth HTD aluminium with a 3mm drive shaft aperture.

To support the lens I used 100mm guide rings, one of which I had to turn down in order that it fitted the rear of the lens correctly.

I bought all my stuff from :
www.motionco.co.uk

I expect you have similar places down under or as you say ebay is rice in such components :)

Any questions please fire at will.

Clear skies,

Dave

[multiweb]

Awesome. :thumbsup: Thanks for the clarification and links. Time to go shopping now. :D

[LewisM]

Mine still have not arrived. Impatiently waiting (11 days in transit so far)

[multiweb]

Unusual - got mine in 3 days. :question:

[LewisM]

Don't stress me any more than needed Marc :)

[LewisM]

At least I have had time to design the convoluted mounting bracket (since my focuser is NOT a regular type in any way)

[multiweb]

Got to try Focusmax with the SharpSky Pro last night. Connected the QHY9 via MAXIM DL as an ASCOM camera. The mount connected with Gemini.net ASCOM Driver as well. Then fired up Focusmax and connected to the SharpSky Pro focuser. Clicked 'new wizard' and sat and watched whilte the V-Curve generation happened. 5min later I had an absolute position and it was focused. Pretty cool. :)

Tonight I'm going to try again the temperature compensation as I have a couple of logs now to get a good step value. Seeing was terrible. I got a FWHM of 4 to 4.5 but in normal conditions without focusing aid I would have got 5 or more.

[LewisM]

Mine arrived just now! To say I am overwhelmingly impressed is an understatement!!!

Of course, it's cloudy and windy...

[multiweb]

Plenty to do indoors before going live. You can also use the ASCOM simulators to test everything.

[dtrewren]

Morning guys,

All very good to hear on a Friday morning :)

Marc, I thought you might enjoy the FocusMax/Maxim combination. Several chaps up here top side are using it and have been getting really nice repeatable results - certainly as good and more often better than using a mask and once the V-curves are done very quick/repeatable.

Hi Lewis .... yes your wait of eleven days is a little excessive and unusual. Maybe your unit was subject to a customs spot check ? This has caused delivery delays in the past. Generally delivery from the UK down under takes about seven working days.

Very pleased you like the equipment and am looking forward to seeing an image or two of the fitted solution :)

Talking of images here are a couple of links to a Ha images taken with the Nikkor 180mm ED f/2.8 lens and WF rig posted earlier :

The Rosette
www.dt-space.co.uk/AstroImages/Rosette_widefield.html

Heart & Soul
www.dt-space.co.uk/AstroImages/Heart_Soul.html

Clear skies,

Dave

[h0ughy]

i bought a GSO two speed focuser for the saxon ED80 i have, my problem is not knowing how to attach the sharpsky. I bought this new from a member here on IIS, he got it only a few weeks ago, but there are a few bolts short of the full quid which i will have to get, that's not the problem. it is how i attach it to the focuser? see the pic of the new focuser.

[acropolite]

Dave I have mine on the genuine SW 10:1, mainly because it takes the SW focal reducer. If I get a chance at the weekend I'll have a look at the GSO focusser, I took one off my ED80 and still have it around somewhere.

[h0ughy]

thanks Phil. I think a bag of nuts an bolts went missing - the three that connect the plate to the other plate that connects to the sharpsky. but how i connect to the focuser and keep it solid?

[acropolite]

Dave, my best guess is to make a curved and slightly offset bracket on the top of the focusser, shouldn't be too difficult with a piece of Aluminium, a drill and some filing (MacGyver one up....:D). Imagine a flattened out question mark.

On the other side of the focusser, a little forward of the focus mechanism and before the flange, there are two small Allen grub screws that are just blanking mounting holes for findersope mounts. On my focuser you can see the dome headed screws I bought to replace them. They're a commonly available thread (may even be the same as some used on the Meade stuff), I took one of the grubscrews out and in to my local Nuts & Bolts shop and matched with some stainless dome head screws.

Make sure you don't get them too long as the drawtube will hit them if they're too long. The countersunk screws hold the roller mechanisms that the drawtube rolls against, I don't think they adjust so you may also be able to use them with the right length screws. If you're going down that route it may be worth taking the drawtube out and doing some fine tuning, mine is way too smooth and the focusser slipped easily.



If you need some small bolts to join the bracket to the Sharpsky, I have plenty, complete with locknuts that should fit, just holler and I'll send some up.

[h0ughy]

wont say no to those Phil - thanks. making a bracket will be interesting and i can see what you are talking about

[h0ughy]

what i have to work with, what i got in the care package ;) AND THE FOCUSER

I am wondering if araldite and or velcro will work?

[h0ughy]

Dave,

I also am looking at upgrading the moonlite focus motor. Will your setup be able to couple with this?

[dtrewren]

Hello David,

Coupling the SharpSky motor, or any other motor, depends on several factors. Obviously, the scope focuser design and how handy you happen to be mechanically. If you are considering the upgrade but not too sure about the mechanical aspects I can send you a SharpSky bracket as fitted to the motor.

The bracket is adjustable length ways so once a suitable mounting point has been identified aligning the motor drive with the respective focuser drive shaft should prove relatively straight forward.

Looking at your focuser you appear to have a couple of mounting screw points either side of the knurled lock/tension adjustment. You also have a large flat surface (the blue face) which could be used as a fixing point.

If you would like a bracket in the flesh, so to speak, please let me know :)

Shaft diameter :
If you let me know the diameter of the focuser drive shaft I can customize the flexible aluminium coupler to any shaft
size equal to or in excess of 3mm.

Cheers & clear skies (wall to wall cloud here),

Dave

[h0ughy]

that is true but i have no idea how the existing focus motor works - not sure if the second part is a gearbox? not that mechanically minded but i can hack and break anything ;)

[dtrewren]

Hi David,

Yes, I suspect you are correct and there is a gear box between the motor and the drive shaft.

Are there any mounting points on the ML focuser, specifically on the black aluminium body of the focuser ? I have seen images of motors bolted to this part of the focuser body.

I will try and get hold of the ML focuser and have a look for a suitable solution.

Cheers,

Dave

[acropolite]

If I get some time over the next few of days, I'll knock something up as a trial, the top mounting option is the way to go IMO.

[dtrewren]

Hi Phil et al,

Yes I think you are correct with the top mount idea. As you have pointed out the GSO style focuser has the two grub screws which are just present to stop dust & muck getting into the focuser barrel. Once removed will provide a very secure anchoring point for a top bracket.

The top bracket could either be curved or flat mounted into two small aluminum blocks which have been profiled to sit flush onto the curved barrel - custom stand-offs if you like.

I think I have a GSO style focuser on an old Newt so will see if mine has similar anchor points.

Cheers & clear skies,

Dave

[acropolite]

OK Dave's H and T, Solution at hand, I will post more shortly. Dave H, I will make you a bracket and procure the correct screws if you can wait.

[dtrewren]

Good job Phil !

I meant to mention (I'm sure you already know Phil) the SharpSky Pro bracket is bolted to the base of the motor enclosure using M3 bolts. The Aluminium case is tapped M3 to receive said bolts. Therefore, you can remove the bracket - nothing is going to fall off inside the motor enclosure.

Cheers,

Dave

[acropolite]

Ok here goes, a few images and explanation. It's actually easier (and a better job) than on the standard Synta 10:1

The sharpsky focuser connects to the fine focus shaft which is 2.5mm in diameter.

At 2.5mm the fine focus shaft is a little undersized for the sharpsky coupler, this makes the flexible coupler a little loose but there are special adjusting screws on the coupler that can be used to correct OR better still you can have some of Phil's "Steampunk" (© Fred = bassnut) brass tubing for an almost perfect shim.

You'll need a 2mm allen key to remove the black knob from the fine focus shaft and a good quality philips head screwdriver of the correct size to remove the "bearing sled" (let's call it that) mounting screws (they were quite tight on mine); I'd remove one screw at a time and make sure there is some pressure on the drawtube from the fucusser to ensure the "sled' stays aligned correctly.

Pic 1 shows the Sharpsky fit to the shaft, note that for the purpose of illustration that the orientation of the sharpsky is 90 degrees out.

Pic 2 shows the correct orientation and the standard sharpsky brackets.

Pic 3 shows the one of the two screws that hold the "bearing sled" and the perfect orientation with the centreline of the sharpsky bracket.

Pic 4 Phil's fickle finger of fate points to the right mounting (looking from the rear) screw.

Pic 5 shows the LHS screw.

pic 6 shows a rough approximation of how the bracket needs to be bent. Bunnings should have some suitable flat aluminium.

Pic 7 shows a Stainless cap screw that will replace the couuntersunk item(s) and attach the bracket.

Dave H, PM me with your address and I'll send you a kit, bracket and screws.

Remind me never to get stuck on a desert island with you....:P

[h0ughy]

for the GSO i will wait phil, your the main man:D

while i can use the moonlite now manually i will be upgrading that soon. maybe a late santa gift ?

[h0ughy]

oh the shim sounds great - cant thank you enough Phil (and Dave) will this be Phil's secret GSO fit up kit? mechanically not there but you know i would have a trailer load of spares ;)

[h0ughy]

I will take some more photos soon of the focuser. be good to see the other focuser mountings:question:

[dtrewren]

Hi David,

Sorry for the delay, work keep asking me to do things while I'm trying to think about important astro-stuff ..... really is most inconvenient :)

Here is a image of a ML focuser showing some possible mounting points - do they exist on the model you have ?

[h0ughy]

yes i know what that is like:lol:;) this is some more of the moonlite i have - i don't seem to have those "holes" the two holes you do see for one of the two focus brackets was stripped when the scope fell off my mount not long after i fitted the focuser. snapped it straight off and there is a bit of bolt still in one hole - scope is fine ;) - wow that was a few years ago now at ISSAC?

[dtrewren]

Ouch, that's is a nightmare accident :(

Shame, because if you could use the two holes and the flat that would give you a nice solid mounting point.

Can you remove the bolt from the inside, or drill it out and re-tap the holes ?

This is always the headache with brackets, there are so many focusers and variants on the market it's impossible to come up with a one bracket fits all solution. Making the SharpSky bracket adjustable does make things much easier but it still takes a bit of head scratching.

Probably the simplest focusers are the SkyWatcher models as they generally have a flat surface base and four fixing bolts that can be replaced with hex stand-off bolts the bracket being attached to the female side of the stand-off.

Cheers,

Dave

[acropolite]

OK Dave h0ugh, here is your bracket (shortly to be in the mail) and fitting instructions.

The bracket isn't entirely flex free, but I'd say its as solid as the stock brackets and so should be OK.


1. Remove existing sharpsky bracket from focus motor, note that there are 4 washers underneath the bracket, take it off somewhere safe in case the washers try to run away and hide (as mine did)...:P

2. Fit the new bracket to the motor, re-use the washers between the motor and bracket. Leave the screws loose until after the bracket is fastened to the focusser. Note the screws have a very fine thread and are easily cross threaded or stripped so be careful. @ Dave T, it wouldn't hurt to use slightly bigger screws, I can't see the threads lasting if motors are transferred between mounts in this manner.

3. Remove the fine focus wheel, if you have some of the "Steampunk" tubing (© Fred) to shim the shaft now is the time to use it.

4. Take out the two countersunk screws holding the bearing assemblyon the focuser, make sure there is some pressure on the focusser so that the assembly doesn't move.

5. Slide the focus motor on to the shaft, allowing a little clearance between the coupler and the coarse focus wheel. Using the 2 dome headed screws secure the bracket which should be close to perfectly aligned, if not you may need to make some small bendy type adjustments. After the two bolts are tightened on the focusser, you can then carefully tighten the screws on the motor, not too much pressure as mentioned before. Once you're satisfied with the alignment tighten the coupler screws, there is one black allen bolt and 2 grubscrews).

[h0ughy]

:thumbsup: :thanx: :cool::cool::cool::cool: :2thumbs::2thumbs: :prey: :prey: :prey: :eyepop: :D:D:D:astron: :astron: :sunny: :sunny: :stargaze: :stargaze: :prey2: :prey2: :prey2: :prey2: :party2: :party2: :thanks: :thanks: :thanks: :jump: :jump: :jump::D:D

[dtrewren]

Fantastic job Phil, good work !

It is this sort of sharing of skills and helping guys out that makes this hobby and these forums so rewarding ...

Hope everyone had a great Christmas.

Cheers & clear skies,

Dave

[h0ughy]

only just having a go at fitting this now Phil. have mounted the bracket and I did try the shim but it kept slipping.

[h0ughy]

getting there, thank you so much Phil!!!

[dtrewren]

Looking good David and nice job on the bracket Phil :)

Cheers,

Dave