0.00
...
·
 |
|---|
|
The postman brought me a 300mm m10 threaded rod counterweight bar today, but unfortunately I am still not happy (I know, not easy to be...): the mini pentax alt/az mount I intended to use as a DEC unit adds way too much moment arm and my 2.8/300 nikkor + camera needs a whopping 2kgs of counterweight to balance! and it indeed makes the mount slipping if I add less. Back to square one: ball heads... I had a medium sized stronger one, just broke recently. A small one that can hold the gear for a minute verified that the mount doesn't slip when i use it (far shorter moment arm). Also, there is this nice example with a gimbal head: https://clarkvision.com/articles/astrophotography-tracking.mounts/ Also, there are geared heads with the footprint of a large ball head with fine adjustment - costing an arm, leg and half a kidney! https://www.aliexpress.com/item/1005006442147941.html I really love the idea of a geared head, but it is simply uneconomical to add one to this kit, even a cheap one would bring the total mount cost to the level of a second hand GEM28. I am deciding between the large ball and the gimbal, both I'll be able to use for terrestrial photography. |
|
0.00
...
·
·
1
like
|
|---|
|
You can use a gimbal, carbon fiber one, say from Jobu, or you can use a ball head with a wimberly sidekick. I typically use a ball head wtih wimberly sidekick with my setup, it works well, especially when balanced. For a 300mm f/2.8, a gimbal may be a better option for overall clearance issues when looking north/northeast/zenith. Otherwise, sidekick works, but if you broke your ball head, a true gimbal might be the best bet. I don't think you'd want a geared head. Ball heads also slop and lose position when tightening. Gimbal is much less prone to this happening, and put less stress on the lighttrack ii when tracking at weird angles. Here's a video on the subject to (towards end of video): https://www.youtube.com/watch?v=pI47HvQ05PA |
1.20
...
·
|
|---|
| GTom, I tried ball heads, gimbals and geared heads with my lightrack ii and found problems with all of them. Find a used Fornax counterweight bar and a used Wiiliams optics wedge and it will be a very nice set up. I am attaching a link to a picture taken with that setup. https://www.astrobin.com/l8ivho/ If the link doesn't work, just click on my username and see the CA Nebula and M42. CS |
|
0.00
...
·
|
|---|
| The counterweight unit needs... counterweights. I'll try a gimbal with a familiar name: Innorel gh6. https://www.aliexpress.com/item/4000401496678.html |
|
0.00
...
·
|
|---|
GTom, I tried ball heads, gimbals and geared heads with my lightrack ii and found problems with all of them. Find a used Fornax counterweight bar and a used Wiiliams optics wedge and it will be a very nice set up. I am attaching a link to a picture taken with that setup. https://www.astrobin.com/l8ivho/ If the link doesn't work, just click on my username and see the CA Nebula and M42. CS Edit: My response wasn't in original post. There are folks out there that have reported similiar issues. A Fornax counterweight with a telescope is a very good solution. But the gimbal and sidekick with ball head balance very well most lens/camera combos in my experience, and most dual photographers already have a gimbal of some sort. The counterweight unit needs... counterweights. I'll try a gimbal with a familiar name: Innorel gh6. https://www.aliexpress.com/item/4000401496678.html Looks like a decent gimbal - I like that extension there for phone, could use to help find target and framing using stellarium app for example. |
|
0.00
...
·
|
|---|
| One question remains re gimbals: being a travel mount, how is Altitude balance when near the equator. Might need a mini wedge/90° cube with 3/8" crew/thread of some sort I guess. |
11.80
...
·
·
2
likes
|
|---|
| When I look at the various gimbal head options, I always wonder if they can be fully locked. They are not designed for astrophotography. Are the two knobs on the two axis supposed to fully lock the lens at any position? Or they are only supposed to provide some damping for smooth motion? |
|
0.00
...
·
·
1
like
|
|---|
One question remains re gimbals: being a travel mount, how is Altitude balance when near the equator. Might need a mini wedge/90° cube with 3/8" crew/thread of some sort I guess. If you watch that video, it can work but it is at steep angles. A mini wedge would reduce stress if you don’t add any weak points while doing so, but probably not required for travel situations given the heff of the mount. |
|
0.00
...
·
·
2
likes
|
|---|
Wei-Hao Wang: Yes, can be fullly locked down and maintain framing. Some better than others. Dampening and smoothness generally correlates with price. |
|
0.00
...
·
|
|---|
Wei-Hao Wang: *Yeah, my hope is that loading a stronger model at no more than 30% of its rated capacity will be good enough. I'll aim for 20kg+ models AND balance. |
|
0.00
...
·
|
|---|
Wei-Hao Wang: *Holding position under imbalanced load is of key importance and also shock/vibration resistance from e.g wind. |
