Orion Optics CNC Rings & Plate for Mewlon-250CRS?

[AnakChan]

Hi all,
 
I'm looking for the lightest rings and plate I can find for my Mewlon 250CRS as the whole scope is going on an SXP which is rated at 16kg max (and the OTA is 12.3kg). I've narrowed down to Orion Optics UK's CNC Tube Rings :-
http://www.orionoptics.co.uk/ACCESSORIES/tuberingsa.html

Their sales has informed me that their 11" rings are 1kg in weight (for a pair?), and the baseplate will be 0.6kg. This makes it perfect as it'll put me 13.9kg leaving a little room for my diagonal & eyepiece - no AP planned so no worries there.
 
However the CNC rings do appear to be quite thin. It screws onto the baseplate via 3xM6 bolts per ring. Can anyone comment if it's a good idea to use the Orion Optics CNC tube rings for my Mewlon or is it too risky? I do see their rings being used on their on Astrographs, DKs, and Newtonians. Would you feel it's safe to so? Any concerns I should have or any other tips please?
 
 

 
Currently I'm using the Takahashi rings & plate which is 4.8kg on top of the 12.3kg 250CRS.

[libraryman]

I had opportunity to put my hands on a pair of OO CNC rings recently, they are thin and in my humble opinion; not good value.

However in terms of strength and rigidity, I'm sure they are quite good..it depends on the weight they have to carry.

Ray

[AnakChan]

I had opportunity to put my hands on a pair of OO CNC rings recently, they are thin and in my humble opinion; not good value.

However in terms of strength and rigidity, I'm sure they are quite good..it depends on the weight they have to carry.

Ray

Hi Ray,

Thank you very much for your prompt response. When you say not good value meaning that they're expensive? I was actually hoping to try the Burgess Optical CNC Ultralight or Light rings however I read some caution with Burgess Optical. This leaves the OO CNC rings left.

The weight was as mentioned, a Mewlon 250CRS that's 12.3kg (or maybe 13.3kg by the time I have my diagonal & eyepiece). Do you feel it's rigid enough to hold a 13.3kg OTA? The tube rings will hold onto the plate via 3xM6 bolts per ring. And I'll be bolting the plate onto the Vixen SXP mount instead of using dovetails.

Cheers,

Sean

[Peter Drew]

If you go for thin rings I would recommend you screw on an extra plate to join the tops of the rings together.    

[AnakChan]

Peter. Thank you. Point noted. I'll ask Orion Optics tonight. They seem confident their thin rings can hold the scope. I'm unfamiliar with them but I just want to check the audience here that this idea I have with their products will work.

[libraryman]

Yes, I feel that they are expensive, they are too thin for my taste, they do need the added plate on top to add rigidity though the central holes are very shallow!!

The clamp fingers are very short, with not enough meat on them, clamp tight and you will distort them. The clamp knob is well made with decent anodising, they are probably bought in, the rings were dull.

Talk to John before you commit, ask for your requirements!

Ray

[libraryman]

An afterthought....you might in the long run be better of looking for a heavier mount to hold that beautiful scope, and cut the risk of it falling, whilst keeping with the Takahashi original rings

Ray

[AnakChan]

Hi Ray,

Yes you're right about a more sturdy mount. It was a tactical retro on my part that I bought my SXP only 6 weeks ago thinking I was going for a certain sized scope then changed strategy & picked up the Mewlon 9 days ago. So for now and it's "retrofitting" what I have to work together.

If my Takahashi ring & plate set (total 18.1kg including OTA over the SXP's 16kg rated) will hold a little longer then I may look at other options than the Orion Optics. I heard Vixen is generally conservative in their ratings for max payload but I don't wanna push it too far.

[AnakChan]

6 weeks later, I finally got my Orion Optics CNC rings. I asked Barry/John to install the Altair CNC handle along with it. Overall I'm mostly pleased with the rings. Specs wise the total weight of the rings, base plate, and top plate+Altair handle is 2.3kg (as opposed to the Takahashi rings, base plate, & top plate at 5.4kg). The hinges of the OOUK CNC rings are somewhat quite sticky though. I'll have to see if they'll loosen in time. Anyhow, the rings have helped me reach my goal for now. Total weight of the OTA with diagonal/eyepiece, rings & plate total up to 15.6kg - 400g shy of the Vixen SXP's official 16kg limit. I'm banking that Vixen is conservative with that limit anyway.

Here's the µ-250CRS, rings & SXP.

[dweller25]

Hello AnakChan,

That is a superb scope but it looks very top heavy on that mount, and those tripod legs just look a bit marginal.

If I had a 250 Mewlon I would want to put the Tak rings back on and get a beefier mount.....

On a seperate note I would be very interested to know if you can put a carry handle across the Tak rings and how are the planetary views compared to say a 10" Newtonian ?

[AnakChan]

Hi David,

You're right. I originally had the VC200L & GP-DX and my upgrade was supposed to be the SXP so that I get GOTO (2nd hand Skysensor 2000's so hard to come by these days). Whilst doing the upgrade, I kept reading that the reason for the VC200L's low contrast was due to it's large 2ndary obstruction - i noticed the contrast compared to my friend's Dob last year too. So the hunt for the scope went after I purchased the SXP and settled for 3 - VMC260L, EdgeHD 9.25" (and later 11"), µ-250 and the sadly no used µ-250 in Japan, and a used VMC260L was being overhauled. All 3 options were pushing the SXP to it's official limits of which I heard that Vixen tends to be somewhat conservative.

No plans for AP so I think at least for visual, it will suffice. Should I do AP in the (distant?) future, I'll consider a mount upgrade. Meanwhile my AP is limited to just the Polarie & 14-24/24-70/70-200mm lenses on my D800E.

I've not taken my rig out for viewing yet - will have to plan a weekend holiday out of Tokyo for that. I'll check if the Altair can fit onto the Tak top plate when I get home tonight. But I'm actually planning on selling the Tak rings+base/top plates.

Cheers!

[dweller25]

Thanks......

[NickK]

Hmm I'd probably adjust the rings more towards the Tak ring positioning. It probably puts less strain on the bolts on the back ring (between the ring and the mount plate).

[AnakChan]

Hmm I'd probably adjust the rings more towards the Tak ring positioning. It probably puts less strain on the bolts on the back ring (between the ring and the mount plate).

Sorry, could you please clarify? Not certain of what you mean. This is my µ-250CRS with the original Takahashi rings :-

[NickK]

I see - the plate is bolted to the mount rather than on a sliding losmandy type. At the moment the centre point of force is around that back ring.. sliding the rings down to maintain the centre of gravity evens out the force between the two.

[AnakChan]

Okedoke, so bolt the plate to the mount closer to it's middle in between the rings. The only issue I may have with that is that I may not be able to get the OTA balanced as it's back/primary mirror heavy. Measuring right now, can slide the OTA further forward and the back ring will be completely flush to the mirror holder. That'll give me 6 cm to move the base plate closer to it's middle.

I'll give that a shot and will snap a pix to see if that's what you mean.

[Zhao]

^{Hi Chan}

^{You have a very nice setup indeed. Congratulation!}

^{Could you please talk a bit more about your experience with the Vixen SXP mount? I was interested in this mount, but could find few review of it on astro-forums. It seems that Vixen SX-series mounts are more popular in Asia (especially in Japan) than in other parts of the world.}

^{I appreciate if you could consider writing a review of SXP – about its e.g. tracking, goto precision, auto-guiding performance, starbook ten, etc. And I think many people will welcome such a review.}

^{Thanks, and merry Christmas!}

^Zhao

[Zhao]

Sorry, the previous text is too small. I don’t know how to edit it so I post it again. (It is my first time to speak in Stargazers Lounge)

Hi Chan

You have a very nice setup indeed. Congratulation!

Could you please talk a bit more about your experience with the Vixen SXP mount? I was interested in this mount, but could find few review of it on astro-forums. It seems that Vixen SX-series mounts are more popular in Asia (especially in Japan) than in other parts of the world.

I appreciate if you could consider writing a review of SXP – about its e.g. tracking, goto precision, auto-guiding performance, and starbook ten, etc. And I think many people will welcome such a review.

Thanks, and merry Christmas!

Zhao

[AnakChan]

Hi @NickK, I tried mounting the base plate in the middle and pushed the OTA as far forward as possible. Unfortunately with the diagonal & eyepiece in place, it's still back heavy.So if I continue with this integration I will need to mount the base plate at the end as originally shown before. Alternatively I may bite the bullet and have a Losmandy-styled plate & clamp. That'll mean adding an extra 500g->1kg but I think the SXP will be able to handle it.

@Zhao, I can talk about the SXP but not in reference to any modern mounts. My former setup was the Vixen VC200L & GP-DX and I didn't have any GOTO computer (never got around to buying the SkySensor 2000). I had the VC200L/GP-DX setup for about 18 years and no experience of other mounts during that time. Before that I had a Meade DS-10a.

This past weekend however I had first light for my µ-250CRS and Vixen SXP however and spent the whole night out with it (with some friends). Polar alignment with the northern hemisphere is still somewhat new to me. Although I had no problems finding Polaris positioning it appropriately in the polar scope was something that I needed more practice on. However, alignment correction on the SXP and Starbook Ten is quite easy. I think the SXP allows up to 20 alignments but after about 5, GOTO seems to be accurate enough to put the object into field of view of an eyepiece of about 83x (LV30mm on my µ-250CRS so FoV approx 43.2'??). That's accurate enough for me. Thereafter tracking was also quite accurate despite poor alignment. I had as high as 532x (yes don't laugh, it's just for test and not practical for use. I've owned a Meade UW 4000 4.7mm from my old Meade DS-10a days) and left it for a few minutes and Jupiter was till within the FoV with little drift.

The Starbook Ten has a small learning curve but that's easily learnt. Overall operation is very intuitive. It has Cross Over Meridian warnings which is cool (standard on other mounts?? Don't know). I've not used all the features of the Starbook Ten yet as the past weekend was almost exclusively a visual exercise and the SXP worked well for that.

The slewing was fast and smooth. I thought the motor was loud until my friend with his SkyWatcher 8" Dob slewed with this and mentioned mine was rather quiet. I was pushing the SXP close to it's official limit of 16kg. My OTA/rings/diagonal/eyepiece came up to approx 15.6kg. However in researching with the folks in the forums, Vixen is somewhat conservative with their ratings usually; and previously I did try my OTA with the Takahashi rings (which is 3kg more than my current Orion Optics CNC Rings). As mentioned to NickK, I may consider using a Losmandy or ADM-styled plate and clamp. The clamp will be an extra weight but I think the SXP will be able to handle it. I'm thinking of this option 'cos currently I risk scratching/dropping my OTA more having to remove it from it's rings so that I can mount the plate to the mount. It's probably better and easier to just have the rings permanently on the OTA and sliding it onto the mount whenever I assemble/disassemble the setup.

On a side note about the µ-250CRS, it's a great scope. I love it. I've never seen so many objects in a single night in my life and I've been doing amateur astronomy since the early 80's. The GOTO helps a lot, the large aperture allowed me to see faint DSOs brighter than my friend's 8" (despite his Dob having a smaller 2ndary obstruction). Best of all, come to think of it I've not thought about cool down or dew at all till now, way after my viewing night. The scope spent the day in my office, then 3 hrs in my car back seat, and when I took it out of the car it was approx 2-3°C. The area we were at wasn't as dark as I've seen but pretty good for being an hr out of Tokyo. We were next to a dam, and it was somewhat windy with skyglow till approx 25° from the horizon from nearby villages/towns.

[Zhao]

Hi @NickK, I tried mounting the base plate in the middle and pushed the OTA as far forward as possible. Unfortunately with the diagonal & eyepiece in place, it's still back heavy.So if I continue with this integration I will need to mount the base plate at the end as originally shown before. Alternatively I may bite the bullet and have a Losmandy-styled plate & clamp. That'll mean adding an extra 500g->1kg but I think the SXP will be able to handle it.

@Zhao, I can talk about the SXP but not in reference to any modern mounts. My former setup was the Vixen VC200L & GP-DX and I didn't have any GOTO computer (never got around to buying the SkySensor 2000). I had the VC200L/GP-DX setup for about 18 years and no experience of other mounts during that time. Before that I had a Meade DS-10a.

This past weekend however I had first light for my µ-250CRS and Vixen SXP however and spent the whole night out with it (with some friends). Polar alignment with the northern hemisphere is still somewhat new to me. Although I had no problems finding Polaris positioning it appropriately in the polar scope was something that I needed more practice on. However, alignment correction on the SXP and Starbook Ten is quite easy. I think the SXP allows up to 20 alignments but after about 5, GOTO seems to be accurate enough to put the object into field of view of an eyepiece of about 83x (LV30mm on my µ-250CRS so FoV approx 43.2'??). That's accurate enough for me. Thereafter tracking was also quite accurate despite poor alignment. I had as high as 532x (yes don't laugh, it's just for test and not practical for use. I've owned a Meade UW 4000 4.7mm from my old Meade DS-10a days) and left it for a few minutes and Jupiter was till within the FoV with little drift.

The Starbook Ten has a small learning curve but that's easily learnt. Overall operation is very intuitive. It has Cross Over Meridian warnings which is cool (standard on other mounts?? Don't know). I've not used all the features of the Starbook Ten yet as the past weekend was almost exclusively a visual exercise and the SXP worked well for that.

The slewing was fast and smooth. I thought the motor was loud until my friend with his SkyWatcher 8" Dob slewed with this and mentioned mine was rather quiet. I was pushing the SXP close to it's official limit of 16kg. My OTA/rings/diagonal/eyepiece came up to approx 15.6kg. However in researching with the folks in the forums, Vixen is somewhat conservative with their ratings usually; and previously I did try my OTA with the Takahashi rings (which is 3kg more than my current Orion Optics CNC Rings). As mentioned to NickK, I may consider using a Losmandy or ADM-styled plate and clamp. The clamp will be an extra weight but I think the SXP will be able to handle it. I'm thinking of this option 'cos currently I risk scratching/dropping my OTA more having to remove it from it's rings so that I can mount the plate to the mount. It's probably better and easier to just have the rings permanently on the OTA and sliding it onto the mount whenever I assemble/disassemble the setup.

On a side note about the µ-250CRS, it's a great scope. I love it. I've never seen so many objects in a single night in my life and I've been doing amateur astronomy since the early 80's. The GOTO helps a lot, the large aperture allowed me to see faint DSOs brighter than my friend's 8" (despite his Dob having a smaller 2ndary obstruction). Best of all, come to think of it I've not thought about cool down or dew at all till now, way after my viewing night. The scope spent the day in my office, then 3 hrs in my car back seat, and when I took it out of the car it was approx 2-3°C. The area we were at wasn't as dark as I've seen but pretty good for being an hr out of Tokyo. We were next to a dam, and it was somewhat windy with skyglow till approx 25° from the horizon from nearby villages/towns.

Hi Chan

Thanks very much for your detailed review! And sorry for this very late reply.

It looks that Vixen SXP is a very good mount. Many people said that SXP is a competitor to Tak EM200 – both of them have a 16kg payload. I will upgrade my whole set up within this year. I may go for toa130f, but am doubt if SXP can bear it. While EM200 can load up an 11.4kg TOA130f with accessories (almost 16kg in total), many people mentioned that SXP + toa130f can’t work as stable and solid as EM200. But I feel confident when seeing SXP works well with your heavy µ-250CRS. At least SXP + TOA130 is far more enough for simple visual use.

Cheers!

[AnakChan]

In my honest opinion, I've really pushed my SXP close to its limits but I don't know if I'd recommend others to do the same. Last weekend I went out with a friend (this is his pix actually as such the blurring of the faces), and it was windy. I had a hard time having a still view as the OTA was quivering due to the winds. Admittedly I did prop up my scope a little too high & should have lowered it closer to the ground for a little more stability.

It worked much better after the winds had died down but but bottom line, a sturdier mount would have performed better...something like the AXD or EM400.

Also if you still so decide on the SXP + TOA130NFB you're leaving no room for any astrophotographic equipment to mount on it.

That's my 2 yen worth anyway.