AZ3 too small?

[Ags]

This is the obvious sequel to my other thread about whether the HEQ5 was too big.

The AZ3 has a very nice price, but apparently it can't hold the ALT axis for larger scopes. I'm wondering whether it would be OK for a 150mm mak if it was upgraded with a counterweight bar - I've seen examples of the counterweight on the forum.

Obviously the AZ3 would be fine for the ST80 and as a camera mount. But I'm looking for a quick setup for grabbing views of planets at odd angles in my garden, and for something to put my Mak on while taking photos with my HEQ5.

[NGC 1502]

The idea of a counterweight is sound, the Vixen Custom D alt-az had one -

Two Fast and Useful Alt/Az Mounts: The Vixen Custom D Alt/Az Mount and Tele Vue Gibraltar Mount - Review

it was an upgrade of the more basic alt-az mount from Vixen.

Not sure if it would be good for a long focal length scope like a 150mm Mak, more suited to higher powers. Could be ok if you keep the magnification not too high.

Regards, Ed.

[John]

I've had a C5 5" SCT on an AZ-3 with no counterweight and it worked quite sweetly. I realise that the Mak 150 is heavier and has a longer focal length than a C5 though so it might be pushing things too much. The AZ-3 is certainly much better suited to short tube scopes like SCT's mak-cass's and fast refractors though.

[Ags]

Thanks. It sounds as if the AZ3 can cope with a c5 then it might cope with the mak if I add the counterweight.

[JamesF]

My AZ3 struggles with my 127 Mak (without a counterweight) as alt increases. I really should sort one out for it. The 150 Mak is another couple of kilos and then some compared with the 127. I wonder if the tripod legs are really up to carrying that sort of weight?

James

[JamesF]

Actually, looking at this page:

has | AZ-3 Mount Mod

The poster suggests that the AZ3 with counterweight will carry a scope, diagonal and ep weighing over 10lbs (about 4.5kg) so perhaps you'd be ok with the 150 Mak.

James

[SiriusB]

My mak127 works quite nicely on an az3, no counterweight mod.

The 127 weighs in about 5kg with finder & diag, i'm a bit reluctant to recommend this lightweight mount with anything much heavier,even with the counterweight mod i think you may be overtaxing the altitude pivot & end up with play in it after a bit of use.

( i'm on my second az3 if you get my drift. )

FWIW my feeling is a compact 5kg's about the limit.

How much does a mak 150 weigh BTW?

[JamesF]

I definitely struggle with both my 127 Mak and ST120 as the scope gets towards the zenith. I do have a 2" diagonal on my Mak, come to think of it. It's ok at lower angles.

I eventually found the OTA weights on the Skywatcher site. The 127 Mak OTA is claimed to be 3.4kg and the 150 is 5.6kg. The ST120 is 4kg, as near as makes no odds.

James

[SiriusB]

Here's a little tip for anyone suffering from a slipping altitude axis on the az3, or wanting to push the mount to the limit:

Replace the two m12 steel washers on the altitude shaft with m12 FORM C washers, which have a greater external diameter, & hence greater anti slippage properties.

Available here if you can't find a supplier:

A2A4 Fixings Ltd. Flat Stamped Washers Form C, A2

Well worth it IMO, you will need a new m12 nylock nut also, as once these have been loosened off they never seem to stay tight again??