20 replies to this topic

[Lord Beowulf]

So a while back I posted about trying to decide on the AT60EDP and Mike pointed out that it was only designed for astrophotography and wouldn't be suitable for what was my main reason for getting it, which was to give me a wider field of view with my DayStar Gemini Quark.  From that standpoint, the AT60ED didn't disappoint, and I now can get the entire Sun in view in the eyepiece.  I also bought the focal reducer/flattener for it and a bunch of spacers to get the sensor spacing just right, and generally I've been pretty happy with the flatness of the field to the corners of my APS-C sensor in the QHY-247C.  I was able to design a 3D printed focus motor assembly for it similar to what I had on my AT80LE that worked fine as well. 

 

 

 

That said, there have been several disappointments with this scope as well.  First off was a speck of dust inside or behind the objective lens.  Mike at Astronomics thinks it's just inside the cell and can be blown out, but I haven't disassembled it to try yet.  

 

 

 

However, while that is hopefully just a manufacturing issue that only affects my scope, the bigger issue is with the weak mount ring provided with the OTA.  It was obvious as soon as I hung my QHY247C off the back of the focal reducer that the unit was flexing badly, but after having it installed for a while, it turned out to be completely bent when I took it off to start setting up for solar observing for the eclipse.  I wasn't sure initially if it was the mount or the OTA itself, but removing the mount and installing it backwards reversed the tilt on the OTA.  Putting the mount on a square, it was bent by about a sixteenth of an inch.  I bent it back as close to straight as I could get, and it took an incredibly small amount of force to do so, so I don't expect it to hold its shape for any length of time.  I'm hoping Mike can get with his supplier and get them to revise this with a beefier mount.  (Of course, I'd appreciate receiving one if you fix it!)  Until they do, I certainly wouldn't recommend this scope for anything more than visual observing with light weight eyepieces.  It definitely is not up to holding a cooled camera off the end of the focal reducer/flattener.  That whole assembly weighs considerably more than the OTA, and when focused is longer as well!

 

<More pictures in the next post>

 

Beo

Edited by Lord Beowulf, 27 March 2024 - 10:11 PM.

[Lord Beowulf]

Here it is with the mount turned around, so it's leaning forward, but not as much as it would be if the weight of the filter and eyepiece weren't pulling it back.

 

 

You'll have to click on the picture to look at the full sized image to see the gap.

 

 

And straightened.

 

 

After straightening, it's not too far off, but not perfect, and it still sags under the load of the filter and eyepiece.

 

 

Beo

[Lord Beowulf]

Here's an unprocessed single frame from the QHY247C.  In the bottom center, hanging off the edge of the print, you'll see an overlaid tiny image from my QHY183C on the C11 that this is piggybacked on, illustrating just how much sag I'm getting with the AT60ED mount.

 

I guide with the C11 and was getting drift in my wide field images, even with my solidly mounted AT80LE, so I went and designed a new focus motor for my old Zhumell SCT focuser, bought a new thin OAG to replace my monster Taurus Tracker, and locked down the mirror to eliminate any possibility of mirror flop.  So with a now rock solid C11 OTA, I went and did an unguided drift test for several hours to see how things faired.  Boy, was that a disappointment!  There is of course some drift in the SCT, presumably because my polar alignment needs work, but it's relatively straight and the cogging of the RA motor and the jumping of the OTA is clearly visible.

 

 

Again, overlaying the above picture on the AT60ED, you can clearly see the flexure rolling over as the direction of gravity changes from down to sideways.

 

 

So much for the pinpoint guiding I can get off the C11 OTA!

 

Beo

Edited by Lord Beowulf, 27 March 2024 - 10:26 PM.

[wrvond]

Rather than disassemble the OTA to go after a speck of dust, I think I'd try blowing air up from the focuser end first. 

 

The foot on my AT60EDP is substantial - it also doesn't hurt it's attached to a 'D' rail.

 

[attachment=2551058:Screenshot 2024-03-27 234319.jpg]

 

Assuming the diameter of the two optical tubes are the same, this should be an easy fix.

[bobzeq25]

For you, personally, I'd recommend getting rid of the foot and mounting the scope with two rings.  It may be unaesthetic to have to discard the foot, but I think it would be worth it to you.  You've wasted more than enough time on this.

 

You have the power to do that.  Waiting for the manufacturer to redesign the foot is likely to be a long wait.  <smile> 

 

wrvond's idea could also work, but changing a single mounting point to two is powerful, perhaps moreso than your intuition thinks.  The buzzphase is "triangulating the load" and it's a very basic engineering move to stiffen something up.  Another possibility is getting a ring that mounts just forward of the foot.

Edited by bobzeq25, 28 March 2024 - 01:06 AM.

[Lord Beowulf]

Thanks to both of you.  Wrvond, yes, that AT60EDP mount is much better that the rinky-dink ring on the AT60ED!  That makes much more sense for imaging, but given that they're selling the flattener for the AT60ED, that implies it can be used for imaging too, so they need to fix this.  Otherwise, this is like Celestron selling the wedge for the NexStar 8se.  I still have that brick in a box somewhere!  

 

Bobzeq25, I do have a (big) set of rings that I was debating doing just that when I go back to the imaging rig.  However, my concern there is that I don't get the impression that the OTA tube is that substantial or well attached to the focuser.  That impression may just be due to the flexure of the mounting clamp, but I don't know.  The existing clamp actually clamps to a small band on the focuser just behind the white tube (didn't take a picture while it was off).  I'm afraid if I try holding that by the tube, the adjustment screws are just going to dent the tube or the focuser is going to fall off the back.  Hopefully, if one ring clamps where the band is, the other is just balancing it, but we'll see.  The normal arrangement for the rings is with a single screw on top, which means that with the OTA back-loaded, it will be that one screw pushing down getting all the force, at least when the OTA is sitting on top of the mount.  

 

Either way, I think Mike needs to take a closer look at what he's selling in this scope and make some adjustments.

 

Thanks,

 

Beo

[largelenses]

I have the AT60ED too and I like it... except for that mounting shoe that needs to find it's way into a dumpster.

[Challenger75]

One clamping ring has always reared it's ugly head for an otherwise excellent telescope.

[Lord Beowulf]

With the sunny day yesterday, I went back and aligned the AT60ED to the C11 OTA that it's piggybacked on.  Years ago (just before the 2017 eclipse) I 3D printed a fixture that allowed me to adjust the piggyback rail to perfectly align my AT80LE with its dual ring clamp, and that has worked fine since.  However, with the sag and bending of this mount, I had to move the rail a massive amount.  Hopefully it will stay stable for the next week at least.  Still, pretty disappointing.  

 

 

 

 

[wrvond]

If you've got a 3D printer, why not make your own ring that mounts in front of the existing ring and attaches to that foot?

[firemachine69]

There's no way that 3d printed part and flimsy rail isn't going to induce some flex.

[Lord Beowulf]

There's no way that 3d printed part and flimsy rail isn't going to induce some flex.

My 3D printed parts are actually a lot tougher than the lousy ring that comes with this scope.  However, before I'd confirmed that the ring was bent, I had tried switching to an all metal rail clamp with no improvement.  I do need to tweak the design on that push/pull block though as it has a weak spot at the bottom where it has a notch for the ridge at the base of the Vixen rail and tends to crack.  The wedge still holds the rail in compression, but given this much correction, there's room to beef up the portion between the rail and OTA.  And if you look at the original picture of the imaging setup, you'll see that's on a Losmandy rail, not the Vixen.  The sag is in the scope/ring, not the rail or clamp.

 

Beo

Edited by Lord Beowulf, 03 April 2024 - 11:17 PM.

[Lord Beowulf]

If you've got a 3D printer, why not make your own ring that mounts in front of the existing ring and attaches to that foot?

Actually, I've been considering the alternative, which was to create a part that would wedge in under the focuser and take up that back-load.  However, there's not a lot of room there before stuff gets in the way.

 

Beo

[Astronomics]

So, the foot is not a vixen shoe and should be mounted to a vixen dovetail of some sort or attached to a plate using a 1/4" 20 thread screw.

 

I can easily add a set of rings and dovetail, and raise the price another $50 or so at least.  However, that price point isn't sustainable for that scope.

 

We have sold thousands of the 60s and haven't had any real issue with the mounting ring. 

[Andrea Salati]

I am not complaining because I still love my AT60ED but the first time I tried to open that ring I found out the thread was stripped. I was trying to see if I could improve things, I ended up discovering that now that is was open there was no way to close it again, the screw just had no way to grip to the threads. I bought a set of 79mm tube rings (here), added some "padding" and moved on.
The foot has been sitting in a drawer since then.
If you want me to send it back to you to perform a "post-mortem" I can do that. I agree with both assessments that have been made here, i.e. that that foot is virtually worthless and the only way to replace it with something more functional implies raising the price significantly.

[wpvan01]

Hi, I have the AstroTech 60mm doublet too and solved the poor mounting ring shoe issue by buying this part from SkyRover on AliExpress…the Sky Rover 60mm is the same scope rebranded. Solves any mount flex issues completely with a two piece ring solution.

https://www.aliexpre...2812956555.html

 

[chvvkumar]

Got my AT60ED last month for Okie-Tex. Unfortunately the reducer or the flattener was not in stock in time for the star party so I used it natively. Given, my sensors are tiny, but I am quite happy with my purchase. I was debating between this and the EDP version but the lack of a reducer steered me to the ED as I needed a shorter focal length below 300mm.

 

I put mine on a Losmandy rail using the stock foot, but I have these Agena tube rings ordered to switch over to.

 

https://agenaastro.c...e-ring-2-9.html

 

 

 

[Lord Beowulf]

I finally got around to designing and printing my new clamp a couple of months ago.  Nice and solid, but unfortunately I haven't had the chance to test it out due to a problem with my roll-off drive motor!

 

Beo

 

 

[maniack]

I had considered this scope but ended up with a smaller 50mm scope. I might one day find myself with one of these still. A 3D printed clamp would be first on my list of modifications to do. The stock ring looks like it would be difficult to balance with without adding a dovetail. A 3D printed clamshell and built-in rail would be a cheap and lightweight solution, and when printed with enough shells/walls can be very rigid. I ended up doing that for my 50mm scope.

[Tbob32]

I finally got around to designing and printing my new clamp a couple of months ago.  Nice and solid, but unfortunately I haven't had the chance to test it out due to a problem with my roll-off drive motor!

 

Beo

 

 

Would you be able to share the STL file you used to print this?

 

Thanks,

Bob

Edited by Tbob32, 24 March 2025 - 10:28 AM.

[kmparsons]

I use the AT60ED for purely visual. Had it out the other night and was amazed at what this mighty mite can do. I mount it on an L-bracket which is mounted on a Porta II head or the UA Dwarf Star mounted on a heavy-duty photo tripod. Problem solved!