EQ6 astro setup experiences

[mldee]

There's been a few threads recently on mount balancing and Side By Side (SBS) setups, so I thought I'd contribute my experiences in treading this path over the last year or so. I think I've found my preferred solution.

I have a C8 SCT, SW 8" Newt, and WO Megrez 80mm Triplet scopes, with the C8 being my main toy. I'm in the process of fitting it for Hyperstar and also have an Antares 6.3 Field reducer, this scope can have 3 different configurations to satisfy most of my DSO 'happy snaps' aspirations using my QHY8. The 1000mm f5 Newt and WO 80mm Triplet will find their respective niches as time goes by.

I bought an EQ6 and thought it would be nice to have two of the scopes available for use at the same time, so I put an SBS on the mount, planning on the C8 and the WO mainly residing there. Now I needed an extended counter weight shaft.......

Over some months, I found I was forever battling 3-axis balance, especially with the factors of both scopes being very rear-heavy and also offset from the axis of the EQ6 counter weights, thereby causing the top SBS assembly to want to rotate, depending on which side was heavier. It meant I had to fabricate a new front weight shaft above the EQ6 shaft to provide the necessary counter balance point. See Pic 1. This then meant additional weights on the bottom shaft. And so it went......Basically getting more and more complex, just so I could have the two scopes sitting on top, even though I really only used them one at a time.

The epiphany came a few weeks ago, when some threads revived the small "finder scope" guiding concept. I decided to give it a go and made up a simple DSI II + 8x50 guidescope, (Thanks Peter) which all up weighed about 350 grams and was easy to fit on a finder dovetail. It worked quite well.

So.....I looked at the mess I still had on my EQ6 (see first pic) and decided that one set of scopes had to go.:P

This let me move the remaining scope almost over the EQ6 counterweight axis while keeping the RHS SBS mount available for the little guidescope. See second pic. By moving it to the spare SBS plate, I was now able to change out the main scope from C8 to WO to Newt without upsetting my overall layout, and with only minimal rebalancing needed. It also reduced the counterweights from 3 to 2 and hopefully the overall EQ6 weight reduction would also improve tracking.:thumbsup:

I made up some rings for the little wide FOV finder OTA so that I could adjust it to point close by the C8 FOV. That worked out well and I was able to get a really good star pic on the screen so that I didn't have to use the optical finder still on the C8 at all. See pic 3.

Last night I then redid my drift alignment, as I noticed my stars had been moving without guiding on. I think I must have moved the mount azimuth when I accidentally bashed the extended counterweight shaft numerous times during previous months. Now I have the shorter shaft again, so hopefully that problem will also reduce. I also have no drift and much better guiding from PHD :)

Pic 4 shows the QHY8 setup on the back of the C8, with the Antares FR behind the Meade microfocuser followed by a T tube extender, to give the 105mm distance to the CCD. I may also try putting the FR in front of the focuser so that I can reduce the extender tube length. I'm unsure how much interraction using the focuser will incur. Anybody know?

The last pic is just to show my dodgy temporary attachment from the DSI to the threaded adaptor on the finderscope. I am going to replace the washers with some tubular spacers to level the clips with the flanges. My intent is to not damage the DSI but still have something easily removable. So far, so good.

Anyways, the point of the thread has been to pass on the lessons learnt with trying to pile too much gear on a mount, and the complexities that go with it. This approach may not be for others, especially those who also do astro viewing. My setup is purely photography based, and depends on using laptops for pretty well all viewing, imaging and control functions. I'm also not trying to outdo the Hubble for imaging quality, just having fun taking pretty snaps. I hope this will do the job.:D

[Bassnut]

Yes, you created a bit of nightmare there. Hate to say it, after youve spent so much money, but side-by-side ive found creates a differential flex hell, and you may find the extra weight of the mounting plates and weird counterbalances are half the total load.

If you just stripped the plates off and mounted the various tubes directly to the main OTA, youd save a lot of weight and reduce flexure.

The guide scope doesnt look stable all all on the stalk, hard mount it to the OTA, such a short FL will make it very sensitive to movement.

[mldee]

Perhaps you missed my comment that I've just removed the additional tubes and weights, not kept them!

The very lightwight guidescope assembly is actually quite solid and works well. It's not mounted on a 'stalk', but directly to the losmandy plate via the rings, which are probably a little sturdier than the standard finder dovetail arrangement, which also worked well.

As to money spent, I still have and use all that I've purchased, apart from some excess weights which I'm happy to pile in the corner, so can't see much waste there. Now my time, that's a different matter, but hey, it's just a hobby.

[Bassnut]

OK, sorry, I missidentified the guide cam. Left over plates are not waste ( ive attempted much as you have), you always get to use them in the end, with different configuations/purchases.

[bmitchell82]

Must admit that was a terrible mess, i would have thought you had a paramount under that load :)

I found the SBS bar a waste of time like fred said it introduces flexure and a whole kit of weight! I run the findger guider in its native state that is how you would pull it out of a box brand new. although i wish to make it like a set of adm rings, for a more "solid" mount but ill get to that, i still have a few things that i would like to sort out aka Rings ect ect.

I also want to get the weight as close to the mount head as possible, i use the extension bar on the EQ6, and although it works it tends to introduce more backlash. ill stick with the more weight senario close up to the top. I have already eyed off a 150mm solid steel bar sitting down in the prototype lab. so ill try and get a lump about 10kg. coupled with my remaining 2x 5.5 i should be able to balance the whole thing with a 10"+ED80+finderguider.

Good thread! new players take heed :D

[mch62]

And yet I didn't have any problems with a side by side set up as long as you respect the fact it is only an EQ6 with a claimed capacity of 18kgs which would be visual so imaging will need to be reduced some what.
(depends on whos specs you read) .:question:
The 10"newtonian comes in at 10kg the wo66 a couple more plus cameras and guide cams ect and the side by sides. I did how ever put one larger weight at the bottom of the counter weight shaft reducing the need for extra smaller counter weights over taxing the thin shaft.
With just two scopes balacing was not an issue.
I originally had the guide scope piggy backed on the Newt and required an extra counter weight over what you see , so dispite the side by side weight it saved me a counter weight.
Mark

[mldee]

Brendan, Thanks for the very pertinent comments.

Yep, the first photo shows a rather crowded EQ6, although I must admit that was worst case, including still having my original 80mm guidescope piggybacked on the WO. If I'd have tried to piggyback them on the C8, it would have looked really impressive! Until it all fell over :)

So my real accomplishment (for me) has been to reduce the total mounted weight by elimination of the two refractors, remove the need for the 80mm guidescope thanks to yours and others posts on finderguiders, fix the balance problem and still have an easily-mountable setup for my three scopes, using the LHS plate.

Since all my scopes have a top vixen rail, I can piggy back easily-removable lightweight things there, such as widefield cameras, etc, while still having the guiding via the lightweight finderguider sitting fixed on the RHS panel. I suspect it's ~400g total weight would hardly cause any SBS flexure problems there, especially with the main scope over the EQ6 axis.

Anyway, it looks much neater, far more accessible, is easily balanced, guides well, and accomodates all my scopes. What more can I say?

[mldee]

Hi Mark, you've done a good job with the 10" and WO finder there, I presume you can use the WO for either guiding or semiwidefield unguided stuff via the flip mirror if you wished. Selling the obs so you can get bigger one to fit the 20" Hmmmm?

My major problme in trying do the same sort of thing was the excessive rear weight of the SCT and WO triplet scopes, there was no way I could get the SBS to balance when the EQ6 was horizontal. It just wanted to rotate vertical depending on which scope was weighted the heavier. That's when I kludged the top counterweight over the axis. Fixed the balance problem but introduced vibration and flexure aspects and needed another weight on the bottom! Time for a total rethink, he said.

Dump the big guidescope, put the finderguider on the RHS, and add scopes as needed to the LHS. Ahhh, that's better.

Next stop is the threatened Hyperstar install, which, with the alternative 6.3FR option, will hopefully give me a good range of FL's from the SCT. It may turn out that the 8" 1000mm Newt + MPCC is overkill, we'll see. It's all good fun.

[bmitchell82]

just keep your eye on the balance of the scope when you run the finder on one side, sure its only 400g, but it does make a difference. I recently posted that i had to rotate the OTA to put the focuser/guider under the tube inline with the axis to stop getting the rotation and my balance came good.

Also do remember to offset your balance to bias one side or the other. If you are imaging in the East bias the Dec down, same goes for RA, bais it to one side. The rational behind this is to keep the motors loaded at all times and reduce backlash considerably. thats what i do and my standard shot is 10 min each which i get round stars with the 10" as long as the wind isn't around, and easy 10 min with the ed 80. i could well go into the 20 and 30 min subs for the ed 80 with no fear of guiding issues.

Some food for thought

[mldee]

Yep, setting some bias is on the agenda, my view is from SW to NE, so I'll leave a bit of weight on the Scope side. Can't notice any particular abnormal rotation tendencies around the EQ6 shaft axis now, just the normal Dec and RA balancing to consider.

It's clouds again here, so I want to do a few dry runs when the clouds clear and see how thing look.

[RobF]

Thanks for posting your experiences Mike. This is what IIS is about after all - countless people will eventually digest and learn from your experiences.

I always thought SBS setups looks so professional, so interesting to hear of strengths/weaknesses.

Brendan, if you read this, I would have thought you'd put your main focuser and camera assembly down toward the ground in Park position. Did you mean you've rotated the OTA to get average of focuser and finder vertical, or is the finder truely the one pointing down now?

[mldee]

Thanks Rob, It's just what I feel most comfortable at contributing. Most of my photos so far have been rather jarring even to my eyes, so not worth subjecting IIS to them until I can at least say 'This is the best I can do'.

I guess my inner feeling is that if you want to see some really nice astro pics, go look at the Hubble site, so I won't subject you to my eggies and blurry seagulls just yet:)

[bmitchell82]

hahaha rob you make me laugh, :) fat lot of good that will do pointing the finder to the ground! :) it is like you suggest that it is on the underside of the OTA with the focuser inline with the virtical plane running North - South.

[RobF]

:thumbsup:

Just making sure I hadn't misunderstood.
Thanks Brendan

[mldee]

Chapter 2....Have completed my initial EQ6 and mount trials and as I'm about to do the Hyperstar conversion, I moved the C8 off the mount and installed the Newt.

All up, it took less than 15 minutes, including rebalancing and camera install....plus another 30 minutes beforehand to remove the Newt primary mirror and give it a good clean with Isopropyl alcohol then a recollimation check. All OK for tonight. QHY & Mirror is cooling down as I write. Couple of happy snaps below.

Last night with the C8 + 6.3FR, guiding was great, never missed a beat, even with high level clouds scudding across for a couple of hours. Easy to see them on the guider PHD screen too! I imaged on some smaller DSO's (NGC 3576 & Co) up around Carina, for > 30 minutes each time. The finderguider seems like a neat weapon. Galaxy night tonight!

After a few nights of Newt, it will be time to try the WO refractor on the LHS for some wider-field images.

This setup is just so trouble free and easy to reconfigure.:D

[bmitchell82]

im glad that its all working out, looks nice and neat which is the killer so to speak. less cable drag, better guidnig more efficiency! run a PE graph and see how its working :)