Not sure if I need a new mount for this?

[stafford_stargazer]

Just arrived today the skywatcher 150PL.

I am hoping this will be descent now for serious planetary viewing.

It's on my porta II az mount, all's good but not sure if I need something better.

Maybe even an eq3-2 or something.

What you all reckon to this setup?

Thanks Gary 

 

[CraigT82]

Best thing to do is just get out with it next clear night and see how well it works. Observe something at the highest magnifications you’re likely to use and see how easy it is to track the object, and how badly the view wobbles when you touch the focuser. 
 

If either of those things are going to be a chore you may need a larger mount.

[stafford_stargazer]

3 minutes ago, CraigT82 said:

Best thing to do is just get out with it next clear night and see how well it works. Observe something at the highest magnifications you’re likely to use and see how easy it is to track the object, and how badly the view wobbles when you touch the focuser. 
 

If either of those things are going to be a chore you may need a larger mount.

Sounds a sensible way of doing it, yes I'll do that. Because of the legs I reckon it could be a slight wobbly, I don't have them right up though, just half way for stability.

Thanks for reply.👍

[CraigT82]

If you can get away with fully retracting then legs that will be best in terms of stability (seated observing?).

You could also try using an accessory tray on the spreader to stiffen that, or the time honoured method of hanging weight from the tripod to improve stability. 

If the mount head is easy to move at high mags and you can track things easily, but the view shakes too much when you focus, you could try the skywatcher motor focuser. Be cheaper than a new mount.

[Zermelo]

FLO do sell the 150PL on an EQ3-2, so it's obviously not an unreasonable match.

The performance of increasingly heavy OTAs on a specific mount does not have a sharp transition from "OK" to "not OK", it's a gradual decline. I couldn't see a weight on FLO for the 150PL, but elsewhere it's quoted as 5.9kg. The stated max for the EQ3-2 is 5kg, so it's pushing it. And that's before you start adding a Telrad, better optical finder, heavier eyepieces, etc.

The other factor with the 150PL is its length. It has a greater moment of inertia than a shorter OTA of the same weight, which affects its stability on a borderline mount. It also makes it more vulnerable to disturbance from wind.

Obviously you just need to try it on your mount first a few times, especially in a breeze. A 6" F/8 is a classic configuration and a good all-rounder, and for visual only, you may find it works for you. If you need to get a heavier mount, you might be better off looking for a second hand EQ5.

[Mr Spock]

Given the length of the tube I'd suggest an EQ5 as the minimum you'll need. 

[Franklin]

EQ5, GP, CG5, EXOS2 will all make great mounts for an F/8 6" reflector, easy to add an RA drive for planetary tracking at a later date.

[stafford_stargazer]

23 minutes ago, Franklin said:

EQ5, GP, CG5, EXOS2 will all make great mounts for an F/8 6" reflector, easy to add an RA drive for planetary tracking at a later date.

Thanks Tim, I'm on the lookout.😁

[stafford_stargazer]

1 hour ago, Zermelo said:

FLO do sell the 150PL on an EQ3-2, so it's obviously not an unreasonable match.

The performance of increasingly heavy OTAs on a specific mount does not have a sharp transition from "OK" to "not OK", it's a gradual decline. I couldn't see a weight on FLO for the 150PL, but elsewhere it's quoted as 5.9kg. The stated max for the EQ3-2 is 5kg, so it's pushing it. And that's before you start adding a Telrad, better optical finder, heavier eyepieces, etc.

The other factor with the 150PL is its length. It has a greater moment of inertia than a shorter OTA of the same weight, which affects its stability on a borderline mount. It also makes it more vulnerable to disturbance from wind.

Obviously you just need to try it on your mount first a few times, especially in a breeze. A 6" F/8 is a classic configuration and a good all-rounder, and for visual only, you may find it works for you. If you need to get a heavier mount, you might be better off looking for a second hand EQ5.

Thanks for reply, I do agree with all you say, yes 5.9kg tube. I've balanced it well so it doesn't end up being heavy at one end, but I'm on the lookout now.😁.

Thanks Gary 

[RobertI]

Ive used my 150PL very successfully on my CG5 and Skytee 2, both on the hefty 2” tripod, and they were rock solid, even in light breezes. I’ve also tried it on my AZ4 on a 1.75” tripod, which I would say is closer to your Porta II setup, but the results were not so good, with wobble at medium to higher powers. Another problem is focusing can induce huge wobble, as it’s a fairly stiff single speed focuser at the end of a long tube, again a solid mount helps reduce this. Focus induced wobble can be infuriating when trying to fine focus on planets and doubles at very high power. I have thought about a cheap skywatcher remote focuser, but so far have not been able to remove either of the focuser knobs to do this. 

Edited March 8, 2023 by RobertI

[stafford_stargazer]

1 hour ago, RobertI said:

Ive used my 150PL very successfully on my CG5 and Skytee 2, both on the hefty 2” tripod, and they were rock solid, even in light breezes. I’ve also tried it on my AZ4 on a 1.75” tripod, which I would say is closer to your Porta II setup, but the results were not so good, with wobble at medium to higher powers. Another problem is focusing can induce huge wobble, as it’s a fairly stiff single speed focuser at the end of a long tube, again a solid mount helps reduce this. Focus induced wobble can be infuriating when trying to fine focus on planets and doubles at very high power. I have thought about a cheap skywatcher remote focuser, but so far have not been able to remove either of the focuser knobs to do this. 

Thanks Rob appreciate your input, yes the focuser it quite stiff like you say soni can imagine what a pain it will be.. I'm on the lookout for something 👍

[RobertI]

1 hour ago, stafford_stargazer said:

Thanks Rob appreciate your input, yes the focuser it quite stiff like you say soni can imagine what a pain it will be.. I'm on the lookout for something 👍

I did manage to make the focuser a bit less stiff with a bit of fiddling but really needs a new two speed focuser or motorized focuser. Let me know how you get on.