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Considering a 1 metre Optiques Fullum folded newtonian. Please debate pros/cons.

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#51 clivemilne

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Posted 29 January 2021 - 01:04 AM

I’m pretty sure the stig is a result of putting the cellular mirror in a sling. Tong insists that is the issue

 

Tom Dey made a ladder sling for his 36" Fullum cellular mirror.

 

His scope does not suffer from any meaningful amount of astigmatism.



#52 Augustus

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Posted 29 January 2021 - 01:27 AM

Tom Dey made a ladder sling for his 36" Fullum cellular mirror.

His scope does not suffer from any meaningful amount of astigmatism.


Ladder sling /=/ regular sling

#53 clivemilne

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Posted 29 January 2021 - 10:08 PM

Also:

 

Hubble Cellular ≠ Fullum Cellular


Edited by clivemilne, 29 January 2021 - 10:09 PM.

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#54 Ittaku

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Posted 16 February 2021 - 09:44 PM

Ordered the 50" F/3.


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#55 ntph

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Posted 16 February 2021 - 10:55 PM

ATTABOY!


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#56 Pierre Lemay

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Posted 16 February 2021 - 10:55 PM

Ordered the 50" F/3.

Wow, congratulations. I will have to drop by Normand's shop to see your mirror being made this summer, when Covid subsides.

 

In the mean time, to wet your appetite, here is a picture I took of another 50 inch mirror Mr. Fullum was working on about two years ago:

 

Normand Fullum devant 50 pouces et polisseuse.jpg


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#57 Ittaku

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Posted 16 February 2021 - 11:05 PM

Wow, congratulations. I will have to drop by Normand's shop to see your mirror being made this summer, when Covid subsides.

Awesome, I'll welcome any pictures of it in progress! I'm hoping restrictions worldwide will have eased in ~10 months so that Hugo can personally come over to help commission my scope and we can share a beer or six.


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#58 starzonesteve

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Posted 19 February 2021 - 03:14 AM

Ordered the 50" F/3.

This sounds epic! Hoping you will keep us abreast of the project as it unfolds.

 

Steve


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#59 Ittaku

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Posted 19 February 2021 - 03:39 AM

This sounds epic! Hoping you will keep us abreast of the project as it unfolds.

Sure, will do :)
 


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#60 Ittaku

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Posted 21 February 2021 - 01:08 AM

First few comments since commissioning its build. Here is a photo of Hugo with a 40" blank to give an idea of scale. Hopefully he'll send me a photo soon of the 50" blank he'll be using for mine.

 

40 inch blank

 

Contrary to what others have been designing for their scopes of this size, I will NOT be creating a roll-off-roof observatory. I am planning a roll-in roll-out scope designed to sit on a specially modified all terrain pallet jack. The building of an ROR comes with significant risks and complexities that I'm not willing to face, even though it offers certain advantages.

 

All terrain pallet jack
 

This alternative approach I'll be using will allow me to use virtually any builder to create my storage shed for it, and I plan to create a little courtyard outside the shed where I'll roll the scope out into instead. There will be a path to a round patch of concrete I'll roll it onto, but a timber platform around it about 50cm high that will allow me to stand at all times whilst viewing, which will also avoid the heat issues of using lots of concrete. I was inspired by something like this for the step:

 

PXL 20210217 085314541
 
Finally I plan to put a little fence around the courtyard, low enough to not block viewing down to about 15 degrees, but high enough to provide some wind and weather protection to the scope when it's in place. I haven't done the numbers yet to know approximately how high or how far out to build it, but I'm guessing around 900 or 1200mm (a couple of standard sizes.)
 
More as the plan unfolds.

Edited by Ittaku, 21 February 2021 - 01:10 AM.

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#61 Allan Wade

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Posted 21 February 2021 - 06:55 AM

Having walls around the scope is very nice for protection. The side walls in my observatory are 900mm high and I can see almost down to the horizon. I think you could go 1200mm. With my dob horizontal, I left a 500mm gap between dob and wall on the sides which are east and west. On the north and south ends the gap is more like 1.5m because I like to have more versatility observing in that direction of the sky.

 

How heavy is the scope? I'm guessing around 300kg. Something to consider. You could use a ride on mower to tow it out. I do really like having my dob fixed though because you can optimise the pointing accuracy.


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#62 Ittaku

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Posted 21 February 2021 - 07:03 AM

Having walls around the scope is very nice for protection. The side walls in my observatory are 900mm high and I can see almost down to the horizon. I think you could go 1200mm. With my dob horizontal, I left a 500mm gap between dob and wall on the sides which are east and west. On the north and south ends the gap is more like 1.5m because I like to have more versatility observing in that direction of the sky.

 

How heavy is the scope? I'm guessing around 300kg. Something to consider. You could use a ride on mower to tow it out. I do really like having my dob fixed though because you can optimise the pointing accuracy.

It is indeed 300kg. They've (Fullum have) used this setup with the one person operated jack before and it's a simple move when attached to the base. The appeal of pointing accuracy of an immobile setup is strong, but alas I can't really find the expertise to do an ROR for me whereas any builder can make what I'm compromising on, and rapidly. The ROR designs I've read about online look like a heck of a lot more work and complexity. It'll also be in a bushfire prone area and on a local's recommendation I'm planning to put some water tanks and pump that can be used to douse the garage/shed remotely in case of emergency.


Edited by Ittaku, 21 February 2021 - 07:03 AM.


#63 Ittaku

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Posted 21 February 2021 - 07:06 AM

Oh yeah and I've seen your build, looks very nice indeed :)



#64 Allan Wade

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Posted 21 February 2021 - 07:31 AM

It is indeed 300kg. They've (Fullum have) used this setup with the one person operated jack before and it's a simple move when attached to the base. The appeal of pointing accuracy of an immobile setup is strong, but alas I can't really find the expertise to do an ROR for me whereas any builder can make what I'm compromising on, and rapidly. The ROR designs I've read about online look like a heck of a lot more work and complexity. It'll also be in a bushfire prone area and on a local's recommendation I'm planning to put some water tanks and pump that can be used to douse the garage/shed remotely in case of emergency.

That’s very understandable. I built a 6 bedroom, 2 story house and I can tell you when I built the ROR observatory it wasn’t much less complicated to do. There’s not really anyone in Australia who builds ROR obs, and the ones I’ve seen have all been built by their owners with widely varying levels of success. A standard shed to house it in is certainly a far easier path to take.


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#65 eyeoftexas

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Posted 21 February 2021 - 09:13 PM

I'm sure you've gone through every angle, but did you consider a modified version of this:

 

http://astroclosets....onomy-platform/

 

Rather than roll out the scope, you would slide the closet away from it on tracks.  You would avoid having to move with it with that hand truck.

 

Good luck!


Edited by eyeoftexas, 21 February 2021 - 09:13 PM.

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#66 Ittaku

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Posted 21 February 2021 - 09:15 PM

I'm sure you've gone through every angle, but did you consider a modified version of this:

 

http://astroclosets....onomy-platform/

 

Rather than roll out the scope, you would slide the closet away from it on tracks.  You would avoid having to move with it with that hand truck.

No I haven't, but I will do some reading and see if it can fit something as big as I need, thanks!


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#67 eyeoftexas

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Posted 21 February 2021 - 09:35 PM

No I haven't, but I will do some reading and see if it can fit something as big as I need, thanks!

I doubt the astrocloset as advertised could fit yours, but you might find a small shed/closet that could slide off.  It would just be a matter of getting the floor rails.

 

Clear Skies!



#68 Pierre Lemay

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Posted 21 February 2021 - 10:58 PM

I doubt the astrocloset as advertised could fit yours, but you might find a small shed/closet that could slide off.  It would just be a matter of getting the floor rails.

 

I custom built something similar for my 20 inch except mine hinges up and to the back. A sliding shelter like the astrocloset would be useless, or very frustrating to use half the year here in Montreal due to snow and ice in the tracks. That’s why I designed the shelter shown in the picture below. Click on the website in my signature block below for more details on how I built it. 

 

3C1FFC4D-5C06-4496-9BE2-F208503B0229.jpeg


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#69 Ittaku

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Posted 18 March 2021 - 03:06 AM

Preparing of the columns that will be fusing both plates of the mirror. They are all diamond cut and diamond sanded to size, all 300+ of them! about a week long process.

 

Fullum001
Fullum002

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#70 Mirzam

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Posted 18 March 2021 - 08:11 AM

I also like the idea of a roll off building as opposed to moving such a massive telescope.  Keep in mind that the collimation of such a fast Newtonian is extremely critical.  Much more likely to stay close to good collimation if it is not bumped around every time you try to use it.

 

JimC



#71 Ittaku

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Posted 18 March 2021 - 04:16 PM

I also like the idea of a roll off building as opposed to moving such a massive telescope.  Keep in mind that the collimation of such a fast Newtonian is extremely critical.  Much more likely to stay close to good collimation if it is not bumped around every time you try to use it.

Yes I would love to do that. I'm limited by practicality constraints of time and capability of doing it myself, and I've gone searching and can't find any local expertise to contract out to do it. Everyone who's got one that I've contacted did it themselves, and it took far longer than they'd hoped. I plan to be up and running by the start of next year.



#72 clivemilne

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Posted 19 March 2021 - 05:34 AM

Ordered the 50" F/3.

  Bravo !!!


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#73 dave brock

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Posted 20 March 2021 - 05:17 AM

I'm having trouble visualising moving with a pallet jack in combination with the 500mm raised platform.

Will there be an area left without the platform?



#74 Ittaku

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Posted 20 March 2021 - 05:28 AM

I'm having trouble visualising moving with a pallet jack in combination with the 500mm raised platform.

Will there be an area left without the platform?

I'll remove the pallet jack and have a wedge of movable platform that I can move into place to complete the circle.



#75 Bob4BVM

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Posted 20 March 2021 - 12:31 PM

Sounds like there are time constrains on how long in to the future you will be able to observe.

In that case I'd recommend that you look into the observing from different angle - Renting a observatory. I am not sure if it is even possible in Australia but here in the US you can rent the whole observatory at several locations. While I was waiting for my DOB to be made, I have rented the 20" observatory at Kitt Peak, Arizona for overnight observing - twice. And Once I will reach the limit of my 22" Dob then my plan is to rent the 30" at Mount Lemon observatory.... And Hopefully, one day I will go all the way to Mt.Wilsons 60" and 100" telescopes. If money is not the issue (which seems to be the case here) then there are great benefits of renting an observatory. Just my 2c.

This is a fascinating option if you have it available down there !

Does anyone know the specifics of renting the Wilson 60"  ?




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