New Hemy V2 on the field.

[nicomor2]

Hi,
I finally got to test my Hemy last night.
The full setup weighs around 8 kg (SkyWatcher 150/750, SVBony 585 camera, MaxField corrector with filter drawer, Gemini Mini Hub V2, and guiding with a 60/240). I’m using the Proxisky base with an adapter to mount everything on my EQ5 tripod.

Polar alignment wasn’t that easy, and I suspect there’s still a bit of instability somewhere. Below are some pictures inside of the mount, as well as the PHD2 calibration.

I followed the recommendations after running the guiding assistant. I tried changing a few parameters, and I noticed improvements when I increased the image frequency to 0.5 s. I haven’t tested other DEC algorithms yet.

For the test target, I chose M31 (something simple to start with). At best I managed 0.39" RMS, but on average it was between 0.5" and 0.7" over the course of an hour. I also got a few peaks, but I don’t know yet what caused them. In any case, it’s already far better than my old EQ5, which I could never guide properly with this setup.

I still need to learn more about OnStep. Toward the end of the session, I reached the limit and the mount stopped guiding—I don’t yet understand why.

As for improvements,like Polar-Bear, I find that the screws to fix the scope to the mount don’t provide enough grip for the hands, so I might 3D-print something for that.

Also about the PCB, the smaller PCB, I used AWG18 for the power cable and AWG20 for the USB. Since I’m not very good at soldering, it wasn’t easy to attach the cables to the PCB. I even broke a ground pad, so I had to bypass it with a wire.

[polar-beard]

Heck yeah, nice setup! And also the write-up. I was also imaging Andromeda on the recent new moon as one of my first targets. Thankfully, using a 344mm focal length results in being very forgiving of my guiding, which I still haven't yet figured out completely. Your graph looks way better than mine already!

When slewing at 2.5 deg/s, I hear a small tapping or clicking sound from inside the HEMY consistently every couple of seconds. Maybe one of my belts are rubbing on the side of their gear...

Here's the simple knob I used with an M6x40mm hex head screw, if you choose to save the hassle of designing your own. Git will only let me attach it as a zip file. M6 knurled knob 28mm.zip

[polvinc]

Thank you for sharing your experience in such detail! Great first light for your HEMY. The guiding is consistent with what I'm getting on my end.
Regarding the Losemandy mounting screws, polar-bear's solution is indeed an interesting one. For my part, I found other knob screws with better grip: https://www.amazon.fr/dp/B07ZQ9FH6P
But it's so complicated to use the Aliexpress search engine that I gave up trying to find them on that site and bought them from Amazon instead!

[nicomor2]

Hi,

On ali, i have these options in 25mm :

https://nl.aliexpress.com/item/1005008088950649.html

Or this one in 18mm:

https://nl.aliexpress.com/item/1005009240072394.html

[polvinc]

I have edited your post so that the links are clickable.

[lukewas]

Fantastic! I would like to build it...could you help me with this?

[polvinc]

Read this repo carefully, there is a lot of information available to help you. Then join the Discord server if you need help with specific points.