Skywatcher 16" EQ5/HEQ5 Extension Pillar.

[Franklin]

I have a question to ask all those who use the 16" extension pillar. Firstly my setup is for visual only, my scope is a 5" achromatic with a focal length of 1200mm, hence the extension. My mount is a Vixen GP2 which attaches to the top of the pillar via an adaptor with a ball bearing on the fixing screw, to enable azimuth movement of the mount head for polar alignment. The head and adaptor are then fixed to the top of the pillar via 3 bolts. Everything is fine with that. Its the fixing of the lower  end of the pillar onto the tripod base that concerns me. I have the 2" steel tubed field tripod which has an azimuth pin bolted to the top plate. The lower end adaptor supplied with the extension has a square hole cut out of it to fit over the azimuth pin when bolting the whole thing together. This hole is a good deal larger than the azimuth pin so there is potential for movement. Is there anything available from the manufactures such as some kind of metal sleeve adaptor that would slip over the azimuth pin and fill out the gap thus preventing any movement or a replacement azimuth pin that is larger or will I have to just make something myself? Has anyone else had problems with this and if so how did you sort it? Thanks.

[johninderby]

When I used one of the 16” extensions it just wasn’t a problem at all. Didn’t need to do anything about it as the pillar never shifted.

[Rob_UK_SE]

I have not had any issues with movement from the 16” extension pillar once the bolt is tightened from under the tripod (I am using a Berlebach uni 18). It feels very secure. As far as I am aware, the pin is mainly intended for lining up north on equatorial and/or motor driven mounts. It’s not really for added security. I would, however, check on the maximum load of your tripod as the extension pillar does add a considerable amount of weight. The positive of this is increased stability, but it will be much more demanding on your tripod. You also have to carry the mount fixed to the pillar (if you are moving it) which further increases the weight of your rig.

[Franklin]

Thanks John. Yes as long as the tripod bolt is tightened right up it appears to be stable. I'm probably just being over fussy! But I just wondered that as my tripod is older, it's from an old CG5 mount, the azimuth pin might be a different/smaller size than what should just plug into the base of the extension. 

[teoria_del_big_bang]

I did have the same problem even with a skywatcher tripod.

As you say the hole is larger than the pin which allows some movement.Normally for imaging it wasn't a big issue as it only moved when I transported the mount in and out of the garage. It relies on the bolt that goes in from below being super tight but even then could move during transport. But I had to polar align every time anyway so one placed on patio (or where ever I was) if the bolt from below was tight it did not move whilst imaging, or even really whilst adjusting the polar alignment screws.

I did however 3D print a sleeve as you suggest in plastic that stopped this movement.

Steve

 

 

[Franklin]

The tripod with the 2" tube legs is very solid and the whole setup is very heavy which is good. It probably weighs about 20-25kg all in. That is manageable for me. 

[Franklin]

That's exactly what I'm on about. Can you 3D print one for me, I'll pay you. 

ps. Led Zep are God.

[teoria_del_big_bang]

Buttering me up saying that won't work ha ha. 

If I can find the file I can print one for cost of postage - pm me your address.

Does your in look the same as mine in my tripod ?

Steve

[Franklin]

Yes, my setup looks exactly like your pic. No, I wasn't buttering you up, Led Zep are God! If you can find the file that would be great, I will pm you my address and pay you postage and a pint! Sound!

[Rob_UK_SE]

20 minutes ago, Franklin said:

The tripod with the 2" tube legs is very solid and the whole setup is very heavy which is good. It probably weighs about 20-25kg all in. That is manageable for me. 

I believe your tripod is rated for payloads of approximately 9kg. The pillar is 5kg and your GP2 is about 4kg (excluding counterweights). Not knowing your scope, I am assuming that it probably is around 8kg (calculated based on a Bresser 5” 1200mm or similar). Taking into account the counterweights too, I would say that you are right on the limit of your tripod’s payload with a 5” achro and would recommend being cautious about adding a pillar too.

As the legs on your tripod work on friction, it is slippage or leg failure you have to be mindful of. 

[Franklin]

Hi Rob, yes I think I am at the limit. My scope with all the kit on weighs in at 7.5kg which is bang on limit for the GP2 spec, although the EQ5/CG5/Mons2 which are all clones of the Vixen are given specs much higher than this. The CG5 tripod/mount was originally supplied by Celestron with 10kg worth of weights and a 6" frac on board. That seems a tad over the top. A 4" frac would be an ideal weight/size for my set up, although I used to have a SW120mm f8.3 that weighed around 5.5kg and it handled that well.

With the 127mm @7.5kg I tend not to extend the tripod at all, hence the pillar, it seems very stable. The small vibrations I do get are probably due to the boom arm effect of the long 1200mm tube, but for visual at sensible mags, it is usable.