Another question on Mounts and Weight limits

[Droogie 2001]

Sorry to post another thread about weight limits on mounts but as there a lot of different setups out there I guess this is inevitable.

After having some success with basic Astrophotography on a Alt Azimuth mount it is now come to the time to get a more suitable mount for my Celestron 8 SE.

I have been looking at the  Skywatcher HEQ 5 Pro Synscan and Celestron AVX mount.
In helping me decide on which to go for and whether these will be sufficiently capable to allow future upgrades I need to calculate the weights / limits.

On reading the Celestron manual it reports that the 8SE weighs 24 Lbs (I assume US?) which is just under 11Kg which seems to be very high for just a tube? Are they accounting the Single Fork Alt AZ arm into this as of course I won’t need this when mounting on to an EQ dove tail?
I can weigh the tube when I get home but was just curious as cannot see any more info on this at the moment.

Also what is the recommended maximum weight to load onto these mounts for Astrophotography?
Again tried searching but get mixed results. I also find references with the HEQ 5 mount which is less able to deal with the same weight if I am interpreting correctly?

I realise that going for the EQ6 mount would probably solved this issue but aside from costs it’s bulkier and less portable.

Once accounting for the tube I would add a DSLR which is around 0.5Kg, a focal reducer (not sure on weight but small) . Going forward I would like a guide scope and a better focuser and so this will again add extra weight.

I have no plans to upgrade tube yet (famous last words…)

Can anyone help or have experience with this on a similar setup such as the Celestron C8?

Many Thanks

[Cornelius Varley]

The C8 ota weighs about  5.67kg http://www.firstlightoptics.com/optical-tube-assemblies/celestron-c8-xlt-optical-tube-assembly.html . The HEQ5 pro has a recommended payload capacity of 11kg for imaging and 15kg for visual use (the imaging payload is usually about 2/3 the visual capacity) . The AVX seems to have a visual capacity of 30lbs (13.6kg)  http://www.optcorp.com/celestron-advanced-vx-equatorial-mount-91519.html  so will have a correspondingly lower imaging capacity.

[Droogie 2001]

Thanks for the quick response Peter.

So the HEQ 5 Pro has 11Kg for imaging then I should be ok with the Tube, DSLR and extras like guide scope and focuser in the future?

With the Tube and DSLR it works out to be about 6.5Kg so with this against 11kg is 57% load which is well under the 75% mark. At least this leaves room for extras like guide scope and a  focuser which on rough calculation should keep it to under the  recommended 75% load.

I am trying to  think of any missing or obvious elements that will be needed for DSO AP. Do I need to consider counter weights into my calculations? (sorry if this is a stupid question but EQ's are still a bit of a mystery / scary to me)

[Cornelius Varley]

Counterweights aren't considered part of the payload, only items attached via the dovetail or to the telescope are.