But will it work???

[ollypenrice]

Turnbuckle - I was thinking more in terms of one at the front and one at the rear of the two bars to work against one another - once correctly aligned, you then fully tighten up the 'centre' mounting bolts on the two bars and hopefully you are in business.

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Gotcha. Thanks, Steve.

Olly

[ollypenrice]

OK, well first light was a nightmare! The track rod worked a treat, giving systematic incremental movemements in one axis. However, atttempts at shimming for dec alignment were totally non-systematic and impossible to control or learn from. Curses. We need one of these, a Cassady tilt-pan adjuster;

Indeed Yves has one here currently unused but the trouble is the weight, plus the amount it will raise one of the scopes, adding to the counterweight requirement. I'm sure it will take us too far over the payload on these mounts...

Pondering time...

Olly

[JamesF]

What are you trying to shim with, Olly? Do you have any feel for how much thickness you need? Or is it disturbing the fixings that causes the trouble?

James

[ollypenrice]

What are you trying to shim with, Olly? Do you have any feel for how much thickness you need? Or is it disturbing the fixings that causes the trouble?

James

I tried feeler gauges between tube rings and dovetail and also acetate packing between scope and rings. The problem is that the amount of mauling this entails changes everything, so a scope that needed raisng a tad sometimes needed raising a bit more after being raised and had also moved in RA.

Olly

[JamesF]

I thought that might be the case

James

[JamesF]

How about a push/pull collimation bolt style arrangement under the tube ring?

Retain the existing bolts that fasten the rings to the dovetail, but add another pair threaded into the dovetail that push up on the base of the tube ring mounting from below.

Having two bolts isn't an ideal arrangement -- it would be far better to have a metal block running on a couple of pins that could be raised or lowered with a single bolt, but that's more engineering work. If you turn the bolts by the same amount each I guess you should be reasonably ok. Perhaps add a locknut to each as you've done with the track rod.

James

[JCJC]

Hi Olly! Long time.

Looks like an awesome project and should get stunning results! I can't see how it could not reduce noise, did the guy on the French forum give a reason? It seems to me it doesn't matter if it's the same filter in both or different filters, either way you will get twice as much imaging time per session. As long as the correct calibration frames are used it's just like running the one camera for twice as much time. Surely?

All the best,

Jordan

[steppenwolf]

As you may have seen elsewhere, I too have tried shims with. My dual imaging rig also using a set of feeler gauges and although this certainly worked for me it was very fiddly to implement which is why I finally settled on the SW unit reviewed here. the extra height this imparted was not a particular concern for me as the ' scope I mounted on it was the smaller and lighter of the two. The joy of aligning using this adjustable system cannot be overstated but I am not sure that it would be suitable for your heavier and larger 'scope. A similar system by ADM may be more suitable in your case but I appreciate the additional counterbalance weight that this would entail through both the additional height and weight of the unit itself. Perhaps a lower profile unit would be suitable - the SW unit though excellently engineered is perhaps a little over-elaborate for the simple task it is required to perform. A custom fabricated unit with just two plates and simple bolts rather than beautifully crafted hand knobs would be a worthwhile project. This could be made very low profile as a very limited amount of adjustment would be required.

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[ollypenrice]

Hi Olly! Long time.

Looks like an awesome project and should get stunning results! I can't see how it could not reduce noise, did the guy on the French forum give a reason? It seems to me it doesn't matter if it's the same filter in both or different filters, either way you will get twice as much imaging time per session. As long as the correct calibration frames are used it's just like running the one camera for twice as much time. Surely?

All the best,

Jordan

Aha, Jordan, great to hear from you! In my opinion using two cameras should be a noise reducer because they capture the same signal but have different noise.

My problem here is the need to have my setup running for the next guests so I can't spend too long on this. I need to be sure the house setup is in perfect fettle. For the moment we'll just run the FSQs on two mounts. We can still combine data. It just means a bit more work at the capture stage.

As Steve says, a properly adjustable pan tilt like the Cassady, which we know can handle a heavy 7 inch Russian Mak, would be the answer. Bigger mount needed. It's been on the cards for a while anyway.

Many thanks for all the ideas, folks. At least my new Pizza oven works!!!

Olly

[steppenwolf]

Aaaaahhh new Pizza oven - nothing like food to bring us all down to ground level again. Currently sizzling two enormous pork chops on the barbecue watching the Sun go down - oh the joys of outdoor life!

Cloud on the horizon but clear overhead - maybe, just maybe, a few wide fields later?

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