Moonlite Focuser for a 30cm Orion Optics

[John]

I'm considering fitting a Moonlite CR2 focuser to my 30cm Orion Optics newtonian tube and I'm wondering which fitting kit would be the correct one ?.

The OO tube is 33cm / 13" in diameter which is narrower than the Skywatcher 12" tubes.

Has anyone fitted a Moonlite to a 30cm / 12" Orion Optics tube and, if so, which size kit works best ?

Moonlites standard kits are for 10" or 12" but nothing in between, as far as I can see. I'm trying to find out what diameter tube Moonlite assume when they talk of 12" and 10" mirrors.

Many thanks

[John]

Just a little correction - the Orion Optics tube is actually 326mm in diameter.

[Lorne]

John,

The Moonlite fitting plate on my SW 300 isn't a perfect fit - a good fit at the fixing ends but there is a space at the middle of the curve, not a big space but enough to see it would be a better fit with a slightly less circumference. I'll add a picture later, may explain it better!

L.

[faulksy]

hi john, flo sell the correct kits for the 00 as you say the tubes are smaller than the synta stuff, i bought one from flo when i had a moonlite. when i bought the feathertouch they just made one to suit for a couple of quid extra. theres a secondhand moonlite on abs at the moment

http://www.astrobuysell.com/uk/propview.php?view=102083

[John]

hi john, flo sell the correct kits for the 00 as you say the tubes are smaller than the synta stuff, i bought one from flo when i had a moonlite. when i bought the feathertouch they just made one to suit for a couple of quid extra. theres a secondhand moonlite on abs at the moment

http://www.astrobuysell.com/uk/propview.php?view=102083

Thats the one I'm interested in Mike

The difference in diameter between my OO tube and the one that this one has a fitting kit for is 4cm. Not much and I'd guess that it's better that way than the other ?

[faulksy]

Thats the one I'm interested in Mike

The difference in diameter between my OO tube and the one that this one has a fitting kit for is 4cm. Not much and I'd guess that it's better that way than the other ?

and reading lornes post he has a gap in the centre of the focuser base, suggesting it would fit a slightly small tube, sounds good john

[Lorne]

Picture of my base, slight gap showing but not enough to let any stray light in

Hope this helps.

L.

PS.... This base was the 12" kit bought from FLO 

[John]

and reading lornes post he has a gap in the centre of the focuser base, suggesting it would fit a slightly small tube, sounds good john

It's the other way around Mike. The one I'm looking at has a fitting kit for a 10". It looks like the 12" kit that Lorne has used would be the one I need

[faulksy]

It's the other way around Mike. The one I'm looking at has a fitting kit for a 10". It looks like the 12" kit that Lorne has used would be the one I need

yes just seen that john, thought the add was for a 12". sorry mate

[John]

yes just seen that john, thought the add was for a 12". sorry mate

No problem Mike.

I'm wondering whether to go with the Moonlite with the 10" kit on the basis that there will be a small gap between the base adapter and the tube which I could fill using black foam tape or similar ?. I've noticed from photos of scopes with aftermarket focusers fitted that quite a few have such gaps and still seem to work OK as long as light can't get into the optical path.

If it does not work out then I can always pick up the 12" kit and still not have spent as much as a new focuser + kit would cost.

[Lorne]

The 10" baseplate threaded fixing holes may end up at the wrong angle... ie, not at 90 degrees to the OTA due to the radius difference, but if you do have to buy the 12" kit I'm sure you could shift the 10" kit easily on the classifieds here or on AB&S.

[John]

The 10" baseplate threaded fixing holes may end up at the wrong angle... ie, not at 90 degrees to the OTA due to the radius difference, but if you do have to buy the 12" kit I'm sure you could shift the 10" kit easily on the classifieds here or on AB&S.

Ah, yes, I see that. The baseplate screws thread in from the bottom, from inside the tube don't they ?. I assume that once the base plate is in place the spacers and the focuser then bolt on from the outside - is that right ?

The Orion Optics tube is aluminium and quite flexible. I wonder if it would bend a little to accomodate the baseplate fixing screws as they were tighened up ?

[Uplooker]

John,

The Moonlite fitting plate on my SW 300 isn't a perfect fit - a good fit at the fixing ends but there is a space at the middle of the curve, not a big space but enough to see it would be a better fit with a slightly less circumference. I'll add a picture later, may explain it better!

L.

Hi John,

I have had similar experience to Lorne. I fitted a Moonlite focused with the 12 inch tube fitting kit to my SW 300PDS and have a small gap. It was easily fixed with tiny fillet of sealant.

Sent from my Fone

[John]

Thanks very much for all the advice and feedback folks - I've decided to go for the Moonlite

My dob deserves a pressie - it's given me so much enjoyment !

[John]

Just a quick update to this thread.

My Moolite CR2 focuser has just arrived (it's beautiful - thanks James  ) and the 10" fitting kit that came with it fits the radius of the tube of my 30cm Orion Optics just about perfectly. 

Just in case anyone else is contemplating this focuser for the same scope.

I'm hoping the mounting of the focuser will be a straighforward operation. I can't see any reason why it should not be.

[John]

Well the base plate is a really nice fit around the radus of the tube but, despite 9 positions to choose from, there are no threaded screw holes that match those in the tube of my Orion Optics 30cm newt. So I guess I'm going to have to elongate the holes that are in the tube to allow enough "wiggle room" for the screws to find suitable matching holes in the Moonlite base plate. A job for another time I think - don't want to hurry that ! I think I'll make a paper mask of the 4 holes and the drawtube aperture so that I can experiment before getting the metal file out.

It's turned out to be a clear night while I've had the focuser off the scope - typical

If anyone has any smarter way to match the holes in the Moonlite base plate than what I'm proposing above, I'll be pleased to hear them

I'm sure I'm not the 1st person to fit a Moonlite focuser to a 30cm Orion Optics newtonian.

[jambouk]

That is a pain, it did sound like it was going to fit perfectly.

I would avoid making new holes or making the existing ones bigger in the first instance. I'd try to ascertain if a fitting kit for a 12" newt would make everything line up perfectly. Maybe ask MoonLite directly, or FLO. If they think it will, I'd be tempted to get the correct fitting kit, and see if they can do a part exchange for the one you have. i'm sorry it's not straight forwards.

James

[John]

Hi James,

Thanks for the advice. The focuser is great - it's just getting that base plate mounted that is proving a small challenge but I sort of expected that.

I'll get in touch with FLO and ask their advice. They have helped at least one member on here fit the same focuser to a 30cm Orion Optics scope so they will probably know the knack. The base plate you supplied is spot on the right radius for my tube so I'd like to use it if possible. The nearest holes in the base are only a couple of mm out from matching those in my scope tube so there is not much of a difference to overcome.

I'm sure I'll get this sorted very soon - thanks for taking an interest

[Stu]

Sounds like the most important element is correct John ie the base plate being the correct radius. Hopefully you won't have too much trouble adjusting the holes to fit.

[ChrisLX200]

If I was going to DIY this job, I would attach the base-plate to the Moonlite focuser, then use a length of 2" bar that passed through both focussers (with the bases facing each other in the middle). Spot through the OO focuser with a suitable sized drill to mark the centre positions of the new holes (or extended holes) on the Moonlight's base-plate. Remove the base-plate and drill new holes. If the holes do overlap (so you're only making them oval) I would use a small slot drill to cut the new hole - this won't be deflected like a drill would due to it cutting less than full diameter.

ChrisH

[John]

Thanks for the suggestion Chris

I'll see what FLO come up with. The Moonlite baseplate is pre-drilled and threaded in 9 locations (x4 corners) so it's a bit of bad luck that at least one set of holes don't match those in the tube wall. 

Maybe they do and I'm not going about it the right way ?

I guess if I do choose to drill the tube I can pick to match the new holes with a set in the base plate that are far enough away from the ones already in the tube to allow nice clean new holes with no overlap. With Orion Optics the tube is aluminum so dead easy to drill !

[Moonshane]

I'd go for it John. I doubt you will sell the scope. Another set of (hidden) holes is a small price to pay for such a top focuser

[John]

I'd go for it John. I doubt you will sell the scope. Another set of (hidden) holes is a small price to pay for such a top focuser

Cheers Shane - I suspect some new holes in the tube will be the best way forward.

What type of drill bit is best for making a neat job in aluminum tube wall ?. I have a decent set of HSS ones - will they do ?

[ChrisLX200]

Cheers Shane - I suspect some new holes in the tube will be the best way forward.

What type of drill bit is best for making a neat job in aluminum tube wall ?. I have a decent set of HSS ones - will they do ?

If they're sharp then yes, but they will tend to skip/drift away from where you intend the hole to be without support (e.g. if you can tape the baseplate in place to use as a template and pass the drill through that), otherwise I would drill very small pilot holes to start with, that will stop the full size going off line.

ChrisH

[jambouk]

I'd wait for FLO to get back to you before drilling holes. What is another 36 hours compared to a tube with excessive holes in and potentially a focuser which flops around all over the place... I just don't want you to knacker up your tube!

James