120ED or OO VX6 ota

[Bender]

There has been a lot written about similar scope but I am looking for some input on these specific scopes.

I currently have a 80ED as small grab and go with solar wedge and couldn't resist when a 100ed popped up here. 

The 2 are quite close so I am thinking of replacing the 100ed with a 120ed for some extra light grasp. The main targets will be planets and moon from my light suburban garden. For the days when i only have an hour to pop out and my VX10  probably takes just as long to cool down.

Now i am wondering how the 00 vx6 would compare to the 120ed  on a alt az mount. It has a similar weight, is a bit shorter and cost new 2/3rds of a second hand 120ed.

(nothing wrong with the SW 150 pds, but considering that for the difference between VX6 and 150pds i get the OO version of the Baader steelstrack focuser and a certified 1/10th pv mirror, i think the price of the vx6 is not bad)

[dweller25]

At the eyepiece on the planets there will be very little difference in terms of contrast, the OO will have the edge on resolution and will have zero CA.

[Moonshane]

this is a tricky one. I agree with David's comments broadly. I have an old SW 120ED and a 6" f11 dob. both are excellent performers and thankfully I have no intention or need to be rid of either. I see them as very different scopes even though they do roughly the same thing. the views through the 6" f11 are probably just a little better of solar system objects and on a par on doubles etc, possibly better in the newt than the 120ED, albeit tighter stars in the 120ED.

the main reason I bought the 120ED was as an enhancement to the 120f5 achromat I was using for white light solar with a Herschel wedge. I wanted better night time views of grab and go sessions of moon, larger planets and double stars than the achromat could give me with the benefit of white light solar. in truth had the complication of solar come into my observing (Ha and white light) I would never have bought a refractor. 

so my recommendation is the newt if you are just considering night time solar system objects, or the frac if you are considering the same objects plus possibly solar in the future and doubles now.

[Caldwell14]

It depends if you can handle diffraction spikes, they still annoy me sadly. I'd buy the ED120

[moriniboy]

It depends if you can handle diffraction spikes, they still annoy me sadly. I'd buy the ED120

Curved spider vanes, I'm just about to convert my OO VX6L, no more diffraction spikes and a larger aperture!

[Luke]

If it was me I would stay frac but that's largely because of solar (for use with Herschel wedge for white light and Daystar Quark for h-alpha).

[spaceboy]

I find questions like this very difficult to answer. From my personal experience I have found the sky conditions to limit the observing capabilities of my scopes more so than any other factor.

Going off topic slightly, I remember a discussion some years ago about the effectiveness of filters. There was a crowd saying they make no difference what so ever then another crowd saying they wouldn't be with out them. My best guess is that when people answer these questions they are offering their genuine observations but never added to the conversation where they live or their average sky conditions (not that this is really practical to have to type this every time you reply to a thread). Needless to say it was eventually established that the filters had better effect for those under sodium St lighting.

It would be nice to see some sort of tick the scale template incorporated into the SGL personal settings so people can edit information on LP, Limiting magnitudes, types of St lights and if dimmed, built up area or rural etc, etc and it be automatically included similar to a signature in posts.

My experience has shown that under my skies anyway, that a 90mm to 130mm scope offers up sharper more settled images more of the time than scopes of 150mm and above. While the larger scopes compensate for this in brighter and better resolved views I find I am constantly chasing the fleeting moments when the object really shows it's full potential. Yes the pay off is there but you really have to compute the information quickly and then have to wait for the next patch of good seeing to confirm what you'd seen. Now the obvious thing is then to back off the magnification to reduce the effects from seeing and so get a more steady but obviously smaller image scale.  My argument could be that if I have the larger scope and have to back of the magnification am I not better using the smaller aperture and using the scope to it's full potential ??

Many members have pointed out that larger scopes see better detail on planets but they also amplify the effects of atmosphere. Similarly a smaller closed tube telescope is less effected by turbulence than an open tube design. There was a side by side in either 'Sky at night' or 'Astronomy now' where a Tal100RS was pitched against a Skyliner 150P. The results were that the Tal performed better on objects more of the time than the 150P but that the 150P on nights of good seeing out performed the Tal in details that could be seen.

Most of us have more than one scope because there is no silver bullet. In your case you have the 100ED that should in theory punch through the seeing and offer you up more observing mileage given the great skies we have in the UK but on the nights where everything comes together you have the VX10.

Just my 2p but hope it gives another perspective.

[nightfisher]

I find questions like this very difficult to answer. From my personal experience I have found the sky conditions to limit the observing capabilities of my scopes more so than any other factor.

Going off topic slightly, I remember a discussion some years ago about the effectiveness of filters. There was a crowd saying they make no difference what so ever then another crowd saying they wouldn't be with out them. My best guess is that when people answer these questions they are offering their genuine observations but never added to the conversation where they live or their average sky conditions (not that this is really practical to have to type this every time you reply to a thread). Needless to say it was eventually established that the filters had better effect for those under sodium St lighting.

It would be nice to see some sort of tick the scale template incorporated into the SGL personal settings so people can edit information on LP, Limiting magnitudes, types of St lights and if dimmed, built up area or rural etc, etc and it be automatically included similar to a signature in posts.

My experience has shown that under my skies anyway, that a 90mm to 130mm scope offers up sharper more settled images more of the time than scopes of 150mm and above. While the larger scopes compensate for this in brighter and better resolved views I find I am constantly chasing the fleeting moments when the object really shows it's full potential. Yes the pay off is there but you really have to compute the information quickly and then have to wait for the next patch of good seeing to confirm what you'd seen. Now the obvious thing is then to back off the magnification to reduce the effects from seeing and so get a more steady but obviously smaller image scale.  My argument could be that if I have the larger scope and have to back of the magnification am I not better using the smaller aperture and using the scope to it's full potential ??

Many members have pointed out that larger scopes see better detail on planets but they also amplify the effects of atmosphere. Similarly a smaller closed tube telescope is less effected by turbulence than an open tube design. There was a side by side in either 'Sky at night' or 'Astronomy now' where a Tal100RS was pitched against a Skyliner 150P. The results were that the Tal performed better on objects more of the time than the 150P but that the 150P on nights of good seeing out performed the Tal in details that could be seen.

Most of us have more than one scope because there is no silver bullet. In your case you have the 100ED that should in theory punch through the seeing and offer you up more observing mileage given the great skies we have in the UK but on the nights where everything comes together you have the VX10.

Just my 2p but hope it gives another perspective.

A very well constructed post from spaceboy, i tend to agree with the factor of slightly smaller scopes punching through the average seeing, if we had "Arizona desert" skies the aperture would win hands down, but we have soggy moisture laden skies 

[Bender]

Thanks everyone. I like my 100ed, perfect balance between light weight and halve decent aperture. Just feel sometimes that the image gets a bit to dim with 4mm eps on the moon. A little bit more aperture would be nice. However in this case I would prefer the smaller package of the vx6 over the 120ed.

Food for thought

I think I know what you mean with the steady views of smaller scopes. After short cool down my old tv102 would nearly always give me satisfying, albeit sometimes dim views. (Just sold it as I figured a sh tv102 can by you a new vx10 and a sh 100ed without giving up much on the views )