Vixen dovetails stacked - yes or no? - Forums

Topic starter

Oct 30, 2024

Dear forum

I recently acquired MoonLite NiteCrawler WR35 and installed it on my (fairly new) Takahashi FSQ-106edx4. After I installed everything to my Vixen SXP2 mount I noticed I can't balance it (too much weight on focuser/camera side) and that the telescope + focusers are too close to my mount. I am sure a lot of people who got the monstrum of Moonlite WR35 got similar issues.

I solved it with stacking 3 vixen dovetails together (all of them are connected with 4 M6x12/M6x16 screws) and I wanted to ask here how did other people solve this issue. I am not sure if this is bullet proof solution with so many stacked parts (even-though I used a lot of screws). I would also like to get some feedback if people think, this is safe solution on a long run or whether I should find another, more tested, solution. With current setup I can balance the equipment and I can also see the rotator move all 360 degrees (see images attached)

Some pictures of assembly (even-though on some pictures not all screws are visible, all of them are screwed with 4 screws):

Helpful Engaging

Tony Gondola

Frequent contributor

Oct 30, 2024

Should be fine. I suspect the weak point is the mount saddle anyway.

Tom Boyd

Oct 30, 2024

Should work fine. I stacked two on my GT81 so the auto focuser would clear the saddle.

David Rosenthal

Oct 30, 2024 · Edited: Oct 30, 2024

I would be really afraid of the stresses placed on that small vixen saddle. That’s a heavy imaging setup and it is really far from (in 2 directions) the saddle. There may be varying flexure as the mount tracks the sky which may effect quiding and goto accuracy.

Is it possible to upgrade the saddle to D style for increased rigidity?

I too have a tail-heavy FSQ and had to shift mine further forward to be able to balance.

Helpful Insightful Respectful

Lynn K

Oct 30, 2024

I think the weak point is the out dated Vixen saddle with one small point of contact. I had a Sphinx DX . Your FSQ is probably at 45 to 50lbs. and putting the SXP2 at it's limit.
Lynn K.

andrea tasselli

Frequent contributor

Oct 30, 2024

Not enough bolts, you need at least one more per layer. Btw, how does your mount perform and is it used with NINA and if so how do you connect to it?

Engaging

Bob Lockwood

Oct 30, 2024 · Edited: Oct 30, 2024

Really bad idea as David, Lynn and Andrea have stated. If the Vixen style saddle is your only option, I would at least go with something like this.

Stellarvue - Riser Set with Vixen Rail (Metric) | Telescopes

I know this doesn't help you as it's all custom, but it gives you an idea of what I do with my setups.

David Rosenthal

Oct 30, 2024

Dangling well over 10,000USD worth of heavy imaging gear off that tinny saddle is just terrifying to me.

Well Written Engaging

Jure Menart

Topic starter

Oct 30, 2024

Lynn K:
I think the weak point is the out dated Vixen saddle with one small point of contact. I had a Sphinx DX . Your FSQ is probably at 45 to 50lbs. and putting the SXP2 at it's limit.
Lynn K.

Not sure where you got to this number from, I weighted equipment (before additional doveplates and screws) and it was around 11kg. Half what you are saying :o

Jure Menart

Topic starter

Oct 30, 2024

David Rosenthal:
Dangling well over 10,000USD worth of heavy imaging gear off that tinny saddle is just terrifying to me.

I think you emphasized that with your previous comment yes...

Jure Menart

Topic starter

Oct 30, 2024

Bob Lockwood:
Really bad idea as David, Lynn and Andrea have stated. If the Vixen style saddle is your only option, I would at least go with something like this.

Stellarvue - Riser Set with Vixen Rail (Metric) | Telescopes

That's good comment - I will look into it, thanks!

Jure Menart

Topic starter

Oct 30, 2024

andrea tasselli:
Not enough bolts, you need at least one more per layer. Btw, how does your mount perform and is it used with NINA and if so how do you connect to it?

Until now I had mini PC + Ekos/kstars coupled with phd2 and I had fairly good guiding numbers (<0.4 rms), but I had stock focuser on it.

I got good deal in 2nd hand Primalucelab Eagle 4 and on WR35 and decided to try NINA, but for now I am stuck only in lab...

Jure Menart

Topic starter

Oct 30, 2024

David Rosenthal:
I would be really afraid of the stresses placed on that small vixen saddle. That’s a heavy imaging setup and it is really far from (in 2 directions) the saddle. There may be varying flexure as the mount tracks the sky which may effect quiding and goto accuracy.

Is it possible to upgrade the saddle to D style for increased rigidity?

I too have a tail-heavy FSQ and had to shift mine further forward to be able to balance.

Hi David, yeah I think D style saddle is a way to go forward, appreciate the comment.

Habib Sekha

Oct 30, 2024

I’ve used 3 cm spacers from PrimaLuceLab.9

Lynn K

Oct 30, 2024

Hi Jure. I was estimating the weight of your FSQ based off of my FSQ106ED with camera, dovetail and focuser motor. I was assuming the NiteCrawler would equal that weight. My set up with two D size dovetail, QHY268M, Filter wheel, Starlight focuser motor and AP/Baader guide scope takes two 14 lbs and two 9 lbs weight to ballance. However, I do push the weights up close to the RA axis on a Mack1.

Can't you remove the the Vixen saddle and replace it with a D size saddle? I thought Vixen offered that option on the SXP.

Lynn K.

Helpful

andrea tasselli

Frequent contributor

Oct 30, 2024

Jure Menart:
Until now I had mini PC + Ekos/kstars coupled with phd2 and I had fairly good guiding numbers (<0.4 rms), but I had stock focuser on it.

I got good deal in 2nd hand Primalucelab Eagle 4 and on WR35 and decided to try NINA, but for now I am stuck only in lab...

Thanks for the feedback. Are you connecting the mount via Ethernet jack?

Well Written Respectful

David Rosenthal

Oct 30, 2024

mine is quite heavy and I have it mounted like this. Robin Cassidy saddle and long, thick D Plate. The length of the plate lets me balance and the tube holder has the height offset built in. Super secure and rock solid.

apennine104

Oct 30, 2024 · Edited: Oct 30, 2024

Like @Habib Sekha said, I think thePrimaLuceLab risersare the best bet. Stellarvue stuff is mainly in US units, I doubt they would fit with your rings, to allow for two fasteners per ring (I haven't checked though

Jure Menart

Topic starter

Oct 31, 2024

andrea tasselli:
Jure Menart:
Until now I had mini PC + Ekos/kstars coupled with phd2 and I had fairly good guiding numbers (<0.4 rms), but I had stock focuser on it.

I got good deal in 2nd hand Primalucelab Eagle 4 and on WR35 and decided to try NINA, but for now I am stuck only in lab...

Thanks for the feedback. Are you connecting the mount via Ethernet jack?

Hi Andrea

Yeah I am connecting it via Ethernet cable (I did it previously on mini PC and I plan to do it now with Eagle 4).

Jure Menart

Topic starter

Oct 31, 2024

Lynn K:
Hi Jure. I was estimating the weight of your FSQ based off of my FSQ106ED with camera, dovetail and focuser motor. I was assuming the NiteCrawler would equal that weight. My set up with two D size dovetail, QHY268M, Filter wheel, Starlight focuser motor and AP/Baader guide scope takes two 14 lbs and two 9 lbs weight to ballance. However, I do push the weights up close to the RA axis on a Mack1.

Can't you remove the the Vixen saddle and replace it with a D size saddle? I thought Vixen offered that option on the SXP.

Lynn K.

I weighted it again now and I measure half of this (it's true without cables, but cables will not add 10 kilos

). I was a little bit worried about this though, but right now I should still be fine and I am also having really good experience with this mount - it's really good, so I don't think I will have problems. But let's see once I am out on the field... maybe I will just need to spend more $$$

this is the nature of the hobby it seems

Jure Menart

Topic starter

Oct 31, 2024

Like @Habib Sekha said, I think thePrimaLuceLab risersare the best bet. Stellarvue stuff is mainly in US units, I doubt they would fit with your rings, to allow for two fasteners per ring (I haven't checked though ).

Thanks I will check either the risers or probably even better switch to D style saddle. Thanks for the input again, really appreciated

Jure Menart

Topic starter

Oct 31, 2024

David Rosenthal:

mine is quite heavy and I have it mounted like this. Robin Cassidy saddle and long, thick D Plate. The length of the plate lets me balance and the tube holder has the height offset built in. Super secure and rock solid.

Very nice setup David

I send around emails to check which Losmandy dovetail I could use. I agree it seems a little bit more stable. Which one are you using on your Takahashi mount? I think Vixen & Takahashi have quite similar heads.