120ED on a AZ4?

[Woking]

Hi

What's the advisable minimum mount set-up for a SW 120ED Evostar, purely for visual use?

I want to move away from GEM as I'm only visual and happy with out GOTO or motorised tracking. Also want to upgrade to a 120ED as it's the biggest able frac in my budget.

Really like the look of the steel legged AZ4, which would already be perfect for my 100ED so easy to use and very portable. Have seen some feedback that a 120ED might be too much for higher mag stuff on moon and planets etc so want to check before I buy really.

Oh and would anyone recommend the 20mm jump to the 120ED, I'm thinking it will be worth it with the extra detail on both solar and DSOs but don't want to be disappointed!

thanks!

[John]

I have an ED120 and a Vixen ED102. I've owned an ED100 in the past too. There is a noticeable difference in the views of both DSO's and lunar / planets. Not mind blowing, of course, but it's there. The 120 will show a touch more CA than your ED100 does so be prepared for that. It also seems to need a little more cooling time on these cold nights.

I have used my ED120 on my AZ-4 mount and it works pretty well for short sessions up to 150x or so. My main mount for the 120 is a Giro-type alt-az on a 2" CG5 tripod with 16" pillar extension to raise the eyepiece if I'm viewing near the zenith. That's a rock solid mount with that scope.

Overall I love my ED120 (mine is one of the older gold tube versions) and use it more than my other two scopes by a fair margin

[Caldwell 14]

I have an AZ 4 for my TAL 100RS, again I use mine up to 150x. I'm sure about the differences in length or weight but I do know others on here have used EVO 120's on AZ 4 mounts.

[Woking]

cheers

John, which Giro mount is it that you use? I might go down that route too.

There seems to be a gap in the market for heavy duty AZs

[John]

It's a mount in the Giro style made by a small UK engineering company called Ambermille. They are not in the astro business any more I believe.

Alternative HD alt-az mounts would be the Skywatcher Skytee II, with the dovetail clamps upgraded, that will carry an ED120 with ease or the Bresser Giro which can carry scopes up to 20kg:

Bresser Giro Mount + Tripod

My Ambermille alt-az looks very like the Bresser Giro.

[spaceboy]

I can vouch for there being some improvement between the 100 & 120mm. I gave up an EVO120 Achro as I felt the CA was too distracted and went with a 100ED. Despite there being no false colour in the ED I miss the EVO 120. Not really a deep sky scope but surprising what DSO's you can see with a 4.75" refractor.

[Woking]

Thanks John, the Bresser is also a cheaper option to the Skytee (I've heard about the issues with the dovetail clamps).

It's a tricky one as it appears only dual mounts are available for heavy duty AZs, so leads me back to GEMs but I really don't want to go down the GOTO/motorised/power supply route which these mounts are primarily aimed at.

Thanks Spaceboy, backs up my thinking. I've not been disappointed with DSO performance in the 100ED when acknowledging that it's a 4" frac it's still pretty good. But I do have the opportunity to share the view through scopes of fellow observers so don't really miss out on the faint stuff with some of the fantastic dobs and reflectors in our little group.

[John]

How about a GEM used in alt-azimuth mode ?

This article covers the Vixen Super Polaris but I think it can be done with the EQ5 / CG5 as well:

Astromart Reviews - The Super Polaris Mount in Alt-Az Configuration

[Woking]

Cheers, funny enough I nearly did that to my eq3-2 last week!

I'm going to have a browse on the web and weigh up all the options. Best thing is that there's no rush as the 100ED is still a great frac.

[jam1e1]

Will bring 120 up next time so can compare. On note about mount, eq5 is sturdy so no wobbling, a lightweight mount could put u off, welcome to mount it on your eq3 to test

[MjrTom]

I use a Giro type mount for my 102mm f/10 Achro and its pretty stable upto 200x.

Ideally I need to get a 2" Steel tripod.

John where did you get yours? I can only source the smaller 1.75 inch steel legged ones designed for the EQ5.....