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Fullerscopes Mark IV mount


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I  notice there are 2 Fullerscopes mark iv's in the for sale section, a bit like buses  you never see one and then 2 turn  up at once!

Seriously though I always wondered  what the weight capacity of those things were?  Any ideas, what would be the modern  equivalent

 

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Probably anything up to 50k.  The tracking won't be up to the same standard as a premium mount for astrophotography but for sheer carrying power, the best at the price.  I have one, but not for sale!   🙂

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Getting the worm/wormwheel adjustment just right is a real fiddle.
Mine found its limits with my 7" f/12 refractor. It had previously carried a 15" Newt!
The old MAINS synchronous motor drives and controller are bit out of date.
AWR[Tech]UK will do you a Goto ASCOM drive for a price.

 

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That's pretty cool, something I had always wondered. For a long time I  kept an eye open for a used one with the intention to add goto  etc (I think I have the know how and I had a mk III which I completely stripped,  cleaned and put back together so I appreciate the workmanship 🙂 ). 

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I bought one of them and had a wonderful Friday morning with the seller (Bodkin) - these old mk iv's are a joy and I've been after one for ages.  I'm planning to mount my old 12.5" Darkstar newt at some stage.  I would also like to add goto/tracking and have been looking at AWR or OnStep - or rmaybe a combination of AWR motors and mounts and OnStep software - I'd appreciate any thoughts as to which system would work best with guiding software.  Guy

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Posted (edited)
13 hours ago, GuySalkeld said:

I bought one of them and had a wonderful Friday morning with the seller (Bodkin) - these old mk iv's are a joy and I've been after one for ages.  I'm planning to mount my old 12.5" Darkstar newt at some stage.  I would also like to add goto/tracking and have been looking at AWR or OnStep - or rmaybe a combination of AWR motors and mounts and OnStep software - I'd appreciate any thoughts as to which system would work best with guiding software.  Guy

I know nothing about OnStep but: Let us know how you get on. I could do with a GOTO system which actually works as advertised. 

Several years after having paid lots of money for an AWR IH2 GOTO system I have never had a single GOTO find the sun! Nor anything else! Not even once in all that time! It can't even manage the short slew from horizontal, east facing parking position, to a low, rising sun in the East!

I have spent countless hours confirming the alignment of my mount using multiples methods. It tracks perfectly, once the sun is centered. [My main interest is Solar imaging] The telescope's shadows always end up as long ovals after EVERY "GOTO" slew. So the errors must be in the GOTO instructions. The observatory site is entered correctly and has been checked a hundred times. I also have to check the LST [Local Sidereal Time] time from an online service before every session.

The ASCOM[AWR] driver costs £50 a year for renewal. Even when it doesn't work.

AWR slews are glacially slow. Measured in minutes per 90°. Twice that to cross from EAST TO WEST.

ASCOM[AWR] routinely changes DEC drive direction from Negative to Positive. Which means the telescopes' noses end up on the observatory floor! You simply don't know which direction it will move unless you go into the IH2 menus at the start of every single session.

NEVER WALK AWAY FROM AN AWR SLEW! Not even back to the safe parking position which you have used for years. It may forget that it isn't allowed to go north of the pier to park! This has happened lots of times and the slew has to be quickly stopped. Nor do you have any idea where a slew will end! But at least you have plenty of time for it to get there. While you dash off into the shrubbery. I just hope your aim is better than AWR's! :wink2:

Edited by Rusted
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The OnStep solution sounds very good, but when you visit the forum you quickly get lost in the “nerdy “ opportunities and alternatives.

There doesn’t seem to be a OnStep solution available without getting involved in motor and mount parameters.

I’d love to give it a go on an old Carton (TV systems) fitted with GM8 motors, but where do you start?????

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Posted (edited)

Id recommend onstep using the CNC v3 board for a very low cost, easy to build system that will be cheap enough to test with. You need the right stepper motor driver chips, the tmc series (but should probably use the simpler drivers for a solder less solution ) and make some sensible stepper motor choices from motion products or elsewhere but you can get running very cheaply and the system is highly functional. 

Edited by skybadger
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To answer Ken's question, the wiki is a bit nerdy but with a few rereads it makes sense and it gets better all the time. The groups.io forum is also helpful and responsive. 

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If I went that route, I’d being using the existing GM8 stepper motors.

on the Losmandy site there is very little info on these motors.

I had assumed, probably incorrectly, that the OnStep software would interface with Cartes du Ciel in a similar manner to EQMod.

 

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11 hours ago, GuySalkeld said:

I bought one of them and had a wonderful Friday morning with the seller (Bodkin) - these old mk iv's are a joy and I've been after one for ages.  I'm planning to mount my old 12.5" Darkstar newt at some stage.  I would also like to add goto/tracking and have been looking at AWR or OnStep - or rmaybe a combination of AWR motors and mounts and OnStep software - I'd appreciate any thoughts as to which system would work best with guiding software.  Guy

It was great to meet you.  I am really happy that the mount is going to have a new life and get used as much as it deserves as well.

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I have been restoring my Fullerscope IV for a while now and have totally striped it down and added new motors, I just need to add a control board now to drive it. In my opinion it's a bit agricultural compared to the newer mounts, it takes a long time to set up the worm to wormwheel backlash adjustment, but on the other hand it does feel solid and takes a lot of weight.

Here is a video of mine.

 

 

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That reminds me. You need a turnbuckle for fine, PA altitude adjustment on the MkIV.
The tiny locking screws in the arcs have no holding power. So the PA slips in altitude.
I used a galvanized fencing turnbuckle. It makes adjustment effortless and it stays put.
The clamp on the end of the MkIV PA casting is from a car exhaust dealer.

Regarding the MkIV's original, matt black, wrinkle paint:
Try motorcycle customizers if you can't get the spray cans locally.
You'll need a heat gun to warm the paint to get a nice, even wrinkle.

Copy of IMG_0639 mk4 turnbuckle.JPG

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Some pictures of my restored MkIV. [Years ago now]
The bare mounting and on my welded pedestal stand.
7"Ø thick wall tube. Massive rectangular section "feet."
It is far too heavy to lift. After I welded it up I couldn't get it onto my car trailer.
Luckily a colleague came along and helped me.
The scope is a 6" f/8 Celestron. It suited the MkIV perfectly.
You could thump the OTA and the image stayed still!
I did a lot of handheld photography at the eyepiece back then.

fullerscopes MkIV rsz 500.jpg

__hr_Fullerscopes MkIV + CR150HD c.jpg

Plato 6in f8 on MkIV handheld snap.jpg

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  • 1 month later...
7 hours ago, HAsun said:

Hi Rusted, 

I have MK1v mount and I have bought a turnbuckle, but what is the exhaust part that you used called?

Thanks, Patrick

Hi Patrick,

It is just called an exhaust clamp.
Readily available in 1mm steps in diameter from car spares outlets.
You may even be able to find stainless steel clamps if you look around.
The ordinary electro plated clamps soon rust out of doors.
The turnbuckle is a very worthwhile mod for fine tuning PA altitude. :thumbsup:
 

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