Weight bearing

[wookie1965]

Hello all you knowledgeable people I want to pick your brains. 

I have a EQ5 Pro on a EQ6 Tripod with adapter, had a bit of trouble with the mount not hitting targets I found the RA axis brass screw was loose. I have since put ptfe tape on which has helped but I am going to line the hole with some aluminium I have been recommended from a gentleman who has stripped and rebuilt a mount on here perhaps you have read it. 

Now I was reading another thread about which mount and it mentions weight capacity and should not put too much weight on. 

Now what is too much weight according to Skywatcher the EQ5 can take 9kgs visual now my Meade 127mm F9. 3 weighs 18lbs is this too much weight. 

I am saving for a Ioptron AZ Pro with pier extension hoping with the extension it will take the longer frac. 

If not I don't know what to do the 127mm it owes me £300 with the Skywatcher dual speed focuser and adapter plate I had made. 

I am never going to get anything like that so selling the 5* is out of the question. 

I struggle now with my mount so getting a HEQ5 or a EQ6 I am going to struggle even worse or not get out at all. 

Have any of you got any ideas and Imput on the weight issue please 

Paul 

 

 

Edited August 18, 2021 by wookie1965

[Franklin]

This is a very confusing situation which I had myself. EQ5 =9kg, EXOS2=12kg, CG5=10kg and yet all these mounts and I'm sure there's more out there, are essentially the same. All clones of the Vixen GP which has a 7kg payload. In the end I just gave up believing what any of the retailers say about their products. They sell 6" refractors on these mounts??? I know from trying it that it just won't work. Sure at low powers it might but at higher powers you might as well mount your scope on a jelly. 

10kg will not break an EQ5 grade mount but the scope won't be able to be used to it's full potential. I have had an EQ5, a CG5 (kept the 2" tripod from that) and now have a GP2 on the 2" steel tubed tripod and 16" extension. I have had 6", 5" and now 4" refractors. That is the size refractor I would put on this grade of mount, 4" weighing around 5-6kg with all the kit on. At that level the scope can be used to it's true potential, the mount handles it fine, there is no stress.

If you're going to keep the 127mm achro and you should because they are great scopes, I would suggest either a Skytee II or shell out for the HEQ5.

My advice is to halve whatever the specs say and I mean for visual only. Imaging is another story, I've seen guys with tiny ED fracs on EQ6 mounts and I think they are correct to do that.

Edited August 17, 2021 by Franklin
grammer

[wookie1965]

Thank you Franklin for that very concise reply you have answered everything I had asked. 

I wonder if the Ioptron will take the longer frac with the pier extension. 

I have two 4" fracs which will do very well on the EQ5 so it's just the 5" now I will price up a skytee ll or a HEQ5. 

Paul 

[Franklin]

Don't know much about all the new modern goto alt-taz mounts but the Ioptron AZ Pro with 15kg payload looks the business. Still wouldn't put more than 7/8kg on it. The saddle plate looks better than the standard EQ5. ADM two bolt vice types make a big difference with longer tubes.

My 4" is at f11 and even though it only weighs around 5kg the sheer length of it causes instability with the stock saddle on the GP2 especially if there's a breeze. I've now got it on a 400mm bar and have upgraded to an ADM puck and saddle. The difference is VERY noticable.  Before I would have to give it a sec or two to settle down after focusing but now it's solid. I also adjusted the lateral tension on the Ra and Dec worms which helped as well.

[wookie1965]

I have got new tube rings well new to me and a longer dovetail bar, being on the EQ6 Tripod it's really solid even at higher powers I just don't want to break the mount or thrash the gears. 

I can easily use my 4" scopes and see about either a Ioptron or a Skywatcher HEQ5 or EQ6 next August. 

Thank you Franklin much appreciated. 

Paul 

[Rusted]

The term for long telescopes causing major, mounting distress is moment.
Mass x distance from the axis.
A refractor has to be balanced, is usually quite long  and has heavy bits on each end.
Which often means twice the moment, or much more.

I put a 7" f/12 refractor on my Fullerscopes MkIV and found it exceeded its comfortable limits.
Yet it had been used by an astro club with a 15" Newtonian before me.

If you don't need an equatorial then I might suggest making a plywood "Richard Berry" style, offset fork.
It is like a Dobsonian, as far as the box and bearings go, but raised on a post, pier or solid tripod.

For a couple of pounds in materials you can be the envy of all refractor owners everywhere.
Silky soft movement in all directions. 
Lest thee scoff at such money saving:
There are some very posh APOs mounted on a "couple of bits of plywood" out there.

Google for: Richard Berry offset fork mounting.
[I made one from scrap materials back in the '80s.]