Skywatcher PDS200/HEQ5 Pro balance

[Guest]

I can only just about balance this scope but only by putting the counterbalance weight right at the very end of the counterbalance bar. This is with the bare scope plus, eyepiece and finder scope.

I checked the weight of the OTA which came out at 8.3 kg. The skywatcher website quotes 8.75 kg. The maximum payload capacity is quoted as 13.7kg so I thought I'd be well in.

I've checked that the counterbalance bar is fully extended.

I thought perhaps it might be because it's an 8 inch scope that the centre of gravity would be a bit further out than say a refractor of the same weight. Could it be that?

I suppose I could add extra weight to the bar but I didn't want to do that until I knew why it wouldn't balance.

Cheers

Steve

 

[almcl]

Can you confirm that you have two 5 kg counterweights, as it will need both of them to balance.

[Skyline]

For this scope which I had in a past life 😀, your very much on the limit with this mount.  My 200PDS was mounted on an eq6.

I would not put anything above 8kg for dso imaging on an heq5 pro. Even though I'm sure others would disagree. 

For planetary or visual you should be fine, just balance it properly, might I suggest another 5kg counterweight so you are using 2x 5 kg counterweights.

N.

Edited November 24, 2019 by Skyline

[Tomatobro]

The pro came with two weights and I could get balance when I had my SW200, Altair guide scope and guide camera and Atik 314L OSC camera but it was on the limit. When I went to a Atik 383 mono and 7 position filter wheel together with a mount clamp upgrade which pushed the scope further away from the mount head I had to use a CW extension bar to balance. Even at this I could image ok.

Sample picture posted

Edited November 24, 2019 by Tomatobro
update

[Guest]

Quote

 

Yes I have the two weights on. I haven't weighed them but they look pretty much as per your photo.

I'm dismayed about what you say about the 200pds on the heq5 pro mount. It was bought very recently from Rother Valley as a package (scope plus mount) and promoted as ideal for astro photography. In fact they also sell the same scope with the EQ5 pro mount. The EQ5 Pro mount has a payload of 9.10kg and the HEQ5 has a payload capacity of 13.7kg so I thought I was playing safe.

[Guest]

Thanks, I'll check again that I haven't done something stupid.

 

[CloudMagnet]

I don't think you have done anything stupid. I use the 200p on an EQ5 with a DSLR, finderscope and telrad and I have never had a problem balancing in RA using the two 5kg counterweights and have (some) room to spare on the counterweight bar.

Could be worth balancing the scope in declination first just to make sure that isn't throwing up any problems and also checking the counterweights are the correct mass.

[Tomatobro]

Attached is a sample image taken with the setup I described and the Atik314l OSC so you should be ok

[Skyline]

A picture paints a thousand words, good picture that, your guiding must be good.

[Whistlin Bob]

I'm using a 200p on an HEQ5 Pro with a lump of a home cooled DSLR and a finder guider. All up it's just under 10kgs. I need a counterweight extension bar to balance it. So long as I do this it's ok, although the guiding seems more susceptible to bad seeing than with the 130pds. M13 included for evidence. 😁

[dannybgoode]

Does the mount have an extension bar for the counterweights. Mine does - it screws into the end of the bar on the mount just about doubling the length of it. 
 

This allows you to put the weights further away from the mount thus making it easier to balance due to the extra leverage. 

[Guest]

Thanks everyone. The mount doesn't have an extension bar. I'm thinking this is just me getting over-anxious about a new scope. 

I even weighed the counter weights and they are 5.3 kg each.  I did some measurements and worked out that should be ample to balance the tube with some to spare. But I think the balance is affected by the position of the DEC axis. 

I found you can get an extra inch on the counterbalances by putting the larger diameter hole in the weights downwards and then the screw that goes on the end of the bar slips inside the hole.

Anyway, I think I'll stop worrying about it for now.  

Thanks 

Steve

 

[Erling G-P]

I have the same scope & mount, and have had problems too, with a fairly heavy DSLR attached (and putting a heavy ADM saddle on didn't help either).  One neat trick that does help however, is rotating the OTA so that the eyepiece or camera is on the 'inside', towards the mount - that moves the center of gravity closer to the mount and was enough to solve the problem in my case.

Cheers,

Erling G-P