New mount for LONG refractor

[Ad Astra]

Hi folks,

I have a very long refractor - 133 mm f/12 Apomax 'Super Planetary'. It is a lovely beast, but very long and heavy at a bit over 20 kg - and 85% of the mass is at the very ends with a large, heavy 4-element objective and a 4"/2"/1.25" focuser. All this makes for a real pain to mount, but absolutely gorgeous to look through machine.

I've been suffering with a borrowed Celestron CGEM mount, but this scope is way too much for it. I have about 5K saved up, and hoped to go all the way for an Astro-Physics or Losmandy Titan mount - but the price is too much for me.... and in this economy, I don't think I'll be able to save faster than prices are rising just now!

So I've pretty much decided to pull the trigger and go with a Celestron CGE-PRO mount I can afford. My local dealer has one that was a display at a show (open box) and is offering a great deal for cash (under $4600 out the door) which leaves me enough to buy a nice scope dolly to roll it in and out of the garage on.

So far - so good.... but am I making the wrong call? Obviously, the worst case scenario would be to actually spend 5K, then realize that the darn thing didn't actually do what you needed it to do. So the BIG QUESTION is....

Have any of you some experience with a long refractor and a CGE-PRO? Alternatively, do you have a suggestion for a mount in this price class that will do a better job?

Just looking for thoughts... ideas.... hand holding..... (It's a LOT of money for me... several years of saving!)

Dan

[Peter Drew]

Hello Dan.

Can I recommend a "Hargreaves strut", this is a length of rigid material like a piece of T shape aluminium strip that is connected to as near to the front of the scope as possible and also to the end of the declination axis. This forms a triangle between the scope and the mount and greatly improves the stability and dampens vibrations.

[Ad Astra]

Thanks, Peter!

The idea seems sound, I'll do some research on that!

Dan

[LMC]

Sounds like a beautiful monster!

You could try the ISTAR and D&G user's groups on Yahoo for mount advice.

Both brands of scopes are typically long and heavy.

There is one bloke in Singapore who has an ISTAR 8" refractor that's approx. 6ft long successfully mounted on a G11 which has about the same capacity as a CGE.

Good luck and I'd love to see a picture of your setup!!

[JamesM]

Hi Dan, most impressed by this beast you've got chained up there - as requested above, you've got to post some photos! On cloudy nights, they've got a great gallery of refractors that people own, some bought, some DIY builds of all sizes. I've still to work if looking at these galleries is such a good thing in quenching aperture fever or whether it makes it worse.

I current own a little beastie of my own (152mm F12) which is about 7 feet long but I was careful to note the weight which allows me to put it on an HEQ6 Pro as it's less than 18kg. Your tube is just over that so you're in to another league there. It is the only thing stopping me getting hold of a bigger size of tube/glass because including the cost of big enough mount creates a very big jump in costs. Of course there was talk of the new EQ7 that was to come out which would have been a cheaper option for you and fills that capacity gap between my mount and the CGEM without having to pay as much as the Celestron Mount. The Hargreaves Strut is a good idea and another consideration is the tube rings and more importantly the plate that supports them, what are you using or what ideas do you have? The D&G rings look great and aren't too expensive as you live in the U.S. I use some metalwork by ADM which is robust enough and can provide it in decent lengths.

Clear skies and look forward to some pictures!

James

[ollypenrice]

Skywatcher have a big mount on the way, well up on the EQ6 and not likely to be over you budget bearing in mind their present product prices. The new mount has been seen at various trade shows and might be exactly what you need when it becomes available.

Olly

[Ad Astra]

Hi Dan, most impressed by this beast you've got chained up there - as requested above, you've got to post some photos! On cloudy nights, they've got a great gallery of refractors that people own, some bought, some DIY builds of all sizes. I've still to work if looking at these galleries is such a good thing in quenching aperture fever or whether it makes it worse.

I current own a little beastie of my own (152mm F12) which is about 7 feet long but I was careful to note the weight which allows me to put it on an HEQ6 Pro as it's less than 18kg. Your tube is just over that so you're in to another league there. It is the only thing stopping me getting hold of a bigger size of tube/glass because including the cost of big enough mount creates a very big jump in costs. Of course there was talk of the new EQ7 that was to come out which would have been a cheaper option for you and fills that capacity gap between my mount and the CGEM without having to pay as much as the Celestron Mount. The Hargreaves Strut is a good idea and another consideration is the tube rings and more importantly the plate that supports them, what are you using or what ideas do you have? The D&G rings look great and aren't too expensive as you live in the U.S. I use some metalwork by ADM which is robust enough and can provide it in decent lengths.

Clear skies and look forward to some pictures!

James

Hello James,

Thanks! Your scope sounds wonderful, too! I get lots of looks when I'm out with the scope, but I've had it for 13 years and it has very little viewing time because of the mounting problem. I got the OTA very reasonably and "couldn't afford not to buy it!" back in the 90's. Figured I'd have a mount in a few months - but the big, long, heavy tube has given me a real education on mounting scopes!

I'll be leaving for the dealer in an hour or so - I'll post some photos when I get back! Photo below is the scope on a CGEM.

Dan

[Doc]

I would try the Hargreaves strutt first as it's pretty cheap to manufacture and set up.

How much weight does the G11 take, I would have thought it would take a 133mm F12.

[Rossco72]

Looks a cracking scope and the CGE Pro does get ok reviews.

I have a CGE and it's a fair step up from an EQ6 but it did have some teething problems which were supposed to be resolved in the CGE Pro