Newtonian on Alt-az / Giro

[pavel_s]

When it comes to Newtonian scopes, usually people mean Dobsonians.

I always wonder why Newtonian scopes are not so popular on tripods with Alt-az / Giro-style mounts.

Why do people prefer Dobson mount over tripod+alt-az? Is it because the tube could hit the leg when observing near zenith? That could be solved with an extension. What are other reasons?

[Zermelo]

I use a 6" Newtonian on a conventional tripod+alt-az mount. The reason that Dobs tend to dominate on larger sizes is cost. To mount a 10" Newtonian on a tripod alt-az as steadily as a on a Dob base would cost a lot more. With a Dob, you are maximising the aperture you can get for your outlay.

[PeterC65]

I also use a 6" Newtonian on an AZ tripod mount and have just upgraded my mount, partly so that I could use an 8" Newtonian.

Newtonians are very big. Even the 6" is quite a thing to handle. My new mount (Sky-Watcher AZ-EQ5) can handle the 8" OK but I wouldn't go bigger than that. I think you do find people putting 6" and 8" Newtonians on AZ and EQ tripod mounts, but only rarely do people do this with 10" and above Newtonians. With scopes that big a Dobsonian mount is much more practical and cost effective. With their lower centre of mass they also keep the eyepiece at a more sensible height from the ground.

With my 8" Newtonian on the AZ-EQ5 in AZ mode without a tripod extension I can get to 80 degrees without the scope hitting the tripod by the way.

 

[Captain Scarlet]

I quite happily mount my 12” Newtonian on an AZ-EQ6 in alt-az mode. Although mine is now lighter than it used to be at around 21kg, my much heavier 300p came in at 27kg with finders eyepiece etc, and that was ok too, for visual only I should add. The Rowan AZ100 would be fine too I think.

Magnus 

 

[Mutley]

Bit off topic but as you're here @Captain Scarlet, is that a Berlebach Planet? Does it have a removable azimuth pin - just wondering if I got a Planet with an EQ6 fitting, would it also do for an AZ-100,?

 

 

[Captain Scarlet]

58 minutes ago, Mutley said:

Bit off topic but as you're here @Captain Scarlet, is that a Berlebach Planet? Does it have a removable azimuth pin - just wondering if I got a Planet with an EQ6 fitting, would it also do for an AZ-100,?

 

 

Yes it is a Planet, and I’ve just checked the az pin is removable. I believe @Stu has an AZ100 on a Planet.

[Louis D]

I use a GSO 6" f/5 on a DSV-2B alt-az mount without any major issues.  However, anything bigger, and I would prefer a Dob mount.

One issue I have with my alt-az mount is that if I move my rig to a different spot in the yard to dodge sky obstructions, any bit of being out of perfectly level and the azimuth axis swings around to the low side.  This pretty much does not happen with Dobsonian mounts unless you've got a really heavy load in the focuser.  Having to relevel a mount in the dark is a pain, so there's a win for the Dob.

[The60mmKid]

I think it works well with smaller OTAs. I like using a pier.

The advantage of the dob mount is that it allows a much larger OTA to be conveniently mounted. (They're also usually less expensive, which is nice, too.) In my opinion, it might not be that people prefer dob mounts but, rather, that people like using larger OTAs (which is easier to do with a dob mount).

[Alan White]

@The60mmKid looking through the site and seen your pier mounted newt, is that a mark newt and what is it.

Just being curios really.

[The60mmKid]

1 hour ago, Alan White said:

@The60mmKid looking through the site and seen your pier mounted newt, is that a mark newt and what is it.

Just being curios really.

Hi Alan 😊

Yes: It's a Ceravolo HD-145 (6" f/6) mak-newt 🦁

[Alan White]

3 minutes ago, The60mmKid said:

Hi Alan 😊

Yes: It's a Ceravolo HD-145 (6" f/6) mak-newt 🦁

Nice, not heard of these before, presume this was acquired while you were in the US.
Looks a great set up on your SW pier with the APZ.