WO Megrez 72 -SOOOOOO FRUSTRATING!

[steve2310]

Before I begin my rant I just want to point out that I love this little scope - I really, really do.

I use it far more than my Equinox 120ed but now I have changed my guiding (from dual bar to OAG) the Megrez 72 is really starting to cause me some problems.

In order to better balance the Megrez I can no longer get away with the "L-Type Bracket" that sits underneath the scope, but will need some way to mount the scope, preferably mounting/tube rings?

The things is I just cannot find tube rings for it anywhere! I believe the diameter of the 72 is 87mm so can I get away with 90mm tube rings?

Anyone who has had a similar problem with megrez 72 I would really love to know how this problem was resolved.

Any help would be really appreciated.

Steve

[StevieDvd]

I use a 'Deluxe Vixen Style Photo Dovetail' from Modern Astronomy with my Meg 72. I would check that it now comes with two screws instead of one as that makes it more stable and it can be a pain to find the correct bolts.

[steve2310]

Thanks for that Steve. Yeah, I did come across them earlier, it's just a shame that they are not a bit longer. My concern is hanging a CCD/filter wheel etc of the back and trying to make that all balance in DEC.

It's an option though......

[Merlin66]

I have a similar problem with the "non-standard" size of the Genesis tube.

I ended up getting the next size up and fitting cork spacers ( three per ring) to "clamp" the tube.

Been using it that way for the last five years... no problems....

[steve2310]

Thanks for that info Merlin. During my 'googling' this morning I did come across a few WO 72 owners who were considering this in order to overcome the '72 problem'.

I think the 72 has a diameter of 87mm so 90mm tube rings might do the job?

I wonder of the L bracket will get in the way and if it's removable?

My concern with the "cork solution" is of course movement as the whole point of going OAG is to try and eliminate flexure. Dont want to re-introduce it if possible but you sound confident if you have used it that way for a few years now.

MMM......

[steve2310]

My other option is to buy another WO that DOES have standard sizing but of course I want the same FOV. Also, the other half will just KILL me! (Tempting though!)

[Merlin66]

The wide cork spacers I used seriously work very well....

BTW when you have an OAG set-up guiding it would correct for any movement as there's only one optical axis involved!

( I now use a pellicle beamsplitter rather than the pick-off prism - I can see ALL the FOV and only lose 4% of the light to the guider....)

[steve2310]

I'm pretty new to all this so not heard of the 'pellicle beamsplitter' before..whill google shortly! Sounds expensive.

Being new I thought the mount would have to balanced in RA AND DEC but you say that this is corrected? I'm just concerned about hanging an oag/fw/camera off the back of the little 72 so want to try and balance it out as best I can.

As an aside, (another stupid question coming up), where do you buy the wide cork spacers?

[steve2310]

Interesting to see you are in Belgium Merlin. The other half is from Belgium and originates from Ingulmunster (spelling??)

I just LOVE Belgium.

[Merlin66]

Edmund Optics do the 1" Pellicle beamsplitters.....

Yes, the scope has still to be balanced, but remember with the OAG there's no "relative" movements.

The cork gasket material originally came from a trade shop, but I'm sure you'll find similar in B&Q - it's used behind pictures and on the bottom of vases etc.

[steve2310]

Thanks Merlin for all the help and guidance. I'm currently looking around FLO at dovetails and tube rings. Looks like the way to go.

Thanks again.

[Earl]

The ADM Rings should do the trick, I use them on my 80mm Stellavue, I went for 100mm rings

[steve2310]

Thanks Earl.....are you referring to ADM guide rings? If so, I have those already but dont want to use them as I just dont think that they are sturdy enough and dont trust them to hold the Megrez.

Thanks though ......

[Earl]

Thanks Earl.....are you referring to ADM guide rings? If so, I have those already but dont want to use them as I just dont think that they are sturdy enough and dont trust them to hold the Megrez.

Thanks though ......

Should be fine. my scope is larger and solid as a rock.

[ollypenrice]

All I would do is bolt the shoe of the 72 to a length of Vixen/Synta rail and bolt a Vixen rail clamp as sold by Baader to the side by side plate or whatever. These are the things with the black and red knobs on this page;

Schwalbenschwanzsystem Vixen, Celestron Typ V bei Baader Planetarium, Zubehoer - Sektion 03

They are incredibly uiseful if you have them all over your sytem. I can put the solarscope on where the guidescope goes in a second, or swap guidescopes or camera lens setups just as easily, etc etc.

Olly

[steve2310]

It might be worth a try while I decide what to do and before I spend more money.

[steve2310]

Thanks for that Olly - just trying to get my head around what you are saying and the german website but thanks! You dont happen to know if 'teleskope' german supplier do them?

[hunterknox]

If you're not that bothered what angle the focuser ends up at the Altair Astro dovetails fit underneath the standard shoe and are plenty long enough.

[Star Gazer]

I use 90 mm rings. I have them packed out with one layer of sticky back cork and one layer of black Fablon. This works fine for me, but I not guiding. For guiding something less compressible might be better. May be 1.5 mm PVC sheeting or similar cut into strips and stuck in place with carpet tape?

[Rossco72]

Ii removed the L Shoe from my WO 66 and used the bolts to bolt on an ADM dovetail Bar in it's place. Absolutely rock solid and no problems at all.

[steve2310]

Thanks Stuart and Star Gazer - a few options to consider (many thanks).

[htj]

You could also get a couple of rings custom made the scope. Not as expensive as one might think:

Multiplex tube ring pair - customized - for 40...100 mm tube di