Beginners naiveté? - 10" on a LXD75

[Kirkus (Kirk)]

I'm sure this is me being a beginner, and many of you will chuckle at the idea, but I'm going to ask anyway.

I have my 10" Dob reflector and I've just purchased a used Meade 6" SN on an LXD75. I'm falling in love with the tracking ability of the LXD75 but totally missing the views of the 10" reflector.

What are the reasons that I can't mount the 10" reflector onto the LXD75 mount and have the best of both worlds?

I'm thinking so long as I have the thing balanced well, the drain on the motors shouldn't be bad, and if I keep it low to the ground the tripod shouldn't have trouble supporting the extra weight.

Feel free to point and laugh.

Seriously, though. Does this sound feasible?

[wasyoungonce (Brendan)]

Fair enough question.

The LDX 75 mount will generally not be stable enough to hold your 10 inch scope steady. Sure, you can get tube rings for the 10 inch scope, balance the whole assembly on the LDX75 and it will slew and track if balanced well,
but, the all up mass will cause the mount to wobble un-acceptably.

You will need a more heavy duty mount. I have a C8 on an EQ5 (a similar mount) and it has too much wobble on the tripod. I'm soon to try a pier but I feel this may be an exercise in tail chasing.

Anyway my suggestion is that for a 10 inch scope you will need a HEQ6 mount...commonly called the "Atlas EQ-G" mount in USA:

http://www.telescope.com/control/pro...oduct_id=24338

[Kirkus (Kirk)]

Well, after going round and round with myself for more than a month, I decided to give this a go. Tube rings for this set up are pretty expensive just to try, so I made my own just to see if it would be worth buying the actual tube rings. I also cheated on the extra weights for my test.

All in all, I'm pretty happy with how it turned out and will be spending the extra money now to do it right.

The Saturn photo is from the first night out under medium seeing conditions. About 250 frames out of 2,000. Prime focus using a cheap 2x Barlow.

Now, where's that credit card?

[wasyoungonce (Brendan)]

Your not a beginner...I see another scope in the background

Well done on your set-up you proved me wrong.

How is the stability and vibrations?

[chris lewis]

Good luck ! it does loook like the LXD75 is at its 'limits'. The LXD75 has a load capacity of about 10Kgs.[22Lbs.] Some reviewers and observers say 13 Klg [30lb. ] but that is really pushing it. Nice shot of Saturn still.

[Kirkus (Kirk)]

Originally Posted by wasyoungonce

Your not a beginner...I see another scope in the background

Well done on your set-up you proved me wrong.

How is the stability and vibrations?

The scope in the background is the 6" SN that came with the mount.

I took your advise to heart. It took me several weeks just to try this. The first time I attempted it, the clamps were the only thing attaching the scope to the dove-tail. The scope never made it to the LXD75. I was too afraid of it all crashing to the ground.

Then, after several more weeks I decided to give the metal "bed" a try attaching it directly to the dove-tail mount, then the clamps around the whole thing. I felt more comfortable giving this a go.

It's actually steadier than I thought it would be. Not having the tripod legs extended at all (except to level it) helps a lot I think.

Originally Posted by chris lewis

Good luck ! it does loook like the LXD75 is at its 'limits'. The LXD75 has a load capacity of about 10Kgs.[22Lbs.] Some reviewers and observers say 13 Klg [30lb. ] but that is really pushing it. Nice shot of Saturn still.

I read several reviews that rated the LXD75 for 54 lbs! I'm just below that. So now I'm freaking out again reading your post. Money's definitely an issue for me and I don't want to ruin my small investment by burning out the motors. I spent a long time making sure the balance was as close to perfect as possible, but now I wonder.

I'm sure many of you are thinking, "wow, what a goof ball". But when I got Saturn on my laptop and actually saw a little bit of detail, I almost jumped for joy (I didn't want to wake my wife up, so I held back).

[Kirkus (Kirk)]

I'm just curious. When "load capacity" is stated, does this include both the OTA and counter-weights or just the OTA?

[chris lewis]

I dont think any one thinks you area goof ball ! its good to experiment. The concern is as you have mentioned that while it may work now the potential to burnt out the motors is increased. Balance is a key thing and you have appeared to have got that sorted. But you do have a load on there.

[wasyoungonce (Brendan)]

Originally Posted by Kirkus

Money's definitely an issue for me and I don't want to ruin my small investment by burning out the motors.

Money is an issue for us all and being prepared to give it a go yourself makes your dollar go further.

As long as the setup is balanced you won't burn out the motors. Watch out for putting accessories on the OTA that may necessitate re-balancing. The only trouble I can see is the mount not being able to dampen out vibrations and wobble at an acceptable rate. Time will tell! But I must say...well done

[Kirkus (Kirk)]

My sincere thanks to you all for your encouragement and experience.

Correction: Not sure where I got 54 lbs. from (maybe a dream I had one night). This is from Telescopes.com:

The sturdy German equatorial mount is both accurate and precise. RA and Dec axes move effortlessly on four high-precision stainless steel ball bearings. High-Precision worm gears also provide smooth tracking and slewing. Capacity is 47 pounds.

Obviously I take that with a grain/bag of salt. But I'm at 48 lbs. with the OTA and counter-weights. That's a risk I'm willing to take.

Also, it was kind of rude of me to say "Money's definitely an issue for me", like all other members at IIS have money trees in their back yards and just throw money around. Sorry about that.

Anyway, thanks again to you all.

[Brian W (Brian)]

Actually I do have a money tree it just never seems to blossom. But all the same congratulations on some very impressive tinkering.
Brian

[Fox]

Hi Kirkus, well done! At the other end of the spectrum, my LXD75 drives my 5kg Genesis. The LXD75/Autostar is a great performer for the price and what is offers, overall rather crude, but amazing compared to what the same amount of money would buy 10-15 years ago before Goto came of age. I've certainly been tempted to go the next level up, Vixen etc. but I think I'll wait until my LXD75 burns out or whatever. I treat my Genesis and EPs like gold, but my LXD75 gets bashed around like crazy. Hey, I really wonder if Meade stays put, and eventually makes an improved "LXD75 sequel" - what will it be like, mechanically better but still keep Austostar ? Cheers, Fox

[xelasnave]

You may find if you are worrying about the weight use the 6 inch for imaging..it wont cut it for planets but should be reasonable for deep sky...the wider field with the 6 inch will "cover"some mount problems and just running less weight will make the mount perform better...
Iuse the same 6 inch for imaging but it is on a eq6 mount now... the eq6 will take a lot more no doubt but when imaging its the limits of the mount that are more relevant than the scope used.
I any event you have grabbed a great image there... but if myself and others journeys are anything to go by start thinking of a bigger better mount before you ever think of another bigger scope.
Keep the thing perfectly balanced..what may be balanced in one position may not be balanced in another...
the other uplifting thing I will say...there is a 200 inch scope on this planet that can be driven by either a one quarter horse power or one horse power motor..and yes it is fairly well balanced.

Thanks for sharing the experience ...the wives often do not understand..er even friends do not understand...but dont let that put you off you are doing very well and I congratulate you.
alex

[Kirkus (Kirk)]

Thanks again for all the encouragement and words of wisdome. I'm really quite excited!