ED/APO for visual observations

[nightfisher]

funny how 2 achro`s can vary, a while back i had 2 100mm f10`s and the Tal beat the chinese by a huge margin

[Caldwell 14]

In astronomy, many £'s are spent by many people in pursuit of fairly small performance gains though

I think thats what I was getting at, perhaps

[MjrTom]

funny how 2 achro`s can vary, a while back i had 2 100mm f10`s and the Tal beat the chinese by a huge margin

I found the same when comparing my Japanese Vixen to a similar Chinese achromat.

The Vixen is pretty much identical to the Tal100RS of yours that I looked through at PSP2011.

[Caldwell 14]

I found the same when comparing my Japanese Vixen to a similar Chinese achromat.

The Vixen is pretty much identical to the Tal100RS of yours that I looked through at PSP2011.

The vixen is a very nice scope, lovely in fact. I often heard it said that the vixen and TAL had a very simular performance.

[Adz]

I haven't had much use with my new Tal 100rs, but visually it isn't as good as the 200p dob. I can now speak from experience as to have a bit of an idea how much aperture can make a a difference (and be king ).

But this is only when proper collimation is in place and the tal on an az4 is much easier to grab and go for me out of my back door for a quick session. So they both have their plus and minuses atm.

Question is, if you had £750 for a second hand Skywatcher 120ED or for a 12" GSO dobsonian, which would you choose? Just based upon visual performance, not portability or anything else.

[John]

Question is, if you had £750 for a second hand Skywatcher 120ED or for a 12" GSO dobsonian, which would you choose? Just based upon visual performance, not portability or anything else.

Ignoring the other scopes I own, I'd go for a Skywatcher 12" dobsonian rather than a GSO.

I was in more or less that position a few months back but I already had the 10" Orion Optics newtonian and I'd wanted an ED120 for years - so I went for the refractor on that occasion

[Adz]

Interesting John, why skywatcher over the new GSO one?

[michael.h.f.wilkinson]

My 80mm F/6 triplet gives outstanding wide-field views (up to 5.76 deg with 40mm Paragon, or 5.3 with the 31mm Nagler). Serious OMG territory. Much better than I ever got through an old 70mm F/10 achro. I have used Olly's TEC 140, and again, absolute WOW. For many objects I still rather prefer the large light buckets provided by reflectors (Sorry Olly, sir Isaac beats the TEC in my books;)).

[John]

Just based on previous experiences Adam.

I owned a Meade Lightbridge 12" for a while which had GSO mirrors and mirror cells in it - I believe GSO make the Lightbridge's for Meade. I also owned a Revelation 8" dobsonian for a while which was GSO made. The optics on both were not overcoated ( an issue that I have seen with other GSO made optics ) so the mirror coatings were suffering too early in the scopes life. I also felt the modifications needed to the primary cell of the 12", especially the support springs, should have been sorted during manufacture.

Optically, the Skywatcher dobs I have used are pretty much the same as the Meade / GSO's but they have seemed to me more ready for use "straight out of the box".

These are small details but enough to sway me towards the Skywatcher brand in this instance. It is possible that the latest GSO's have addressed these issues of course.

[dobbie]

hi cadwell, i have a stellavue 80ed and as you know now have the same set up as you ,tal 100rs az4 mount, the tal beats the 80ed on moon and planets, 100mm f10 vs 80mm ed f7 , for a quick grab n go / solar viewing the stellavue wins. for planets ,dso,doubles, the tal wins, i have also owned a ed100 celestron and from my personal point of view

and visual viewing it is not worth the extra expense on a ed ..

[dobbie]

I haven't had much use with my new Tal 100rs, but visually it isn't as good as the 200p dob. I can now speak from experience as to have a bit of an idea how much aperture can make a a difference (and be king ).

But this is only when proper collimation is in place and the tal on an az4 is much easier to grab and go for me out of my back door for a quick session. So they both have their plus and minuses atm.

Question is, if you had £750 for a second hand Skywatcher 120ED or for a 12" GSO dobsonian, which would you choose? Just based upon visual performance, not portability or anything else.

i own a sw 250px visually its the dogs danglers the views are to die for ,but grab n go nooooo

[NickK]

Having had a rather good visual session on saturday, the APO wins.

The Pentax is an SD air front doublet with an ED doublet at the back which also includes the field flattener. So the entire field is flat.

Looking at Jupiter with the Hyperion 31, 13 and 3.5mm gave exceptional views of the bands.

[johninderby]

When portability is the major concern then the APO wins because you can have good views with no or virtually no CA and sharp views in a compact and lightweight package that also doesn't need a big or heavy mount.

Recently I have been seduced by the long focal length achro. My Carton 100mm f/13 outperforms the FLT98 I had for visual on lunar/planetary (imaging would be another matter of course) with sharper more contrasty views and CA is so well controlled you can forget about it. Just sold my C8 SCT as I preferred the lunar/planetary views through the Carton. One downside of the Carton though is that there are 100mm APOs available for less money so it's not the cheapest option.

So for me the miniumum scope collection would consist of a smallish fast APO for portability and widefield. A quality long FL achro for lunar/planetary and a decent sized dob for DSOs etc.

Of course if I won the lottery then perhaps an APM 305 f/12.2 APO with obs might sneak in there.

John

[Mr Onions]

I have the little 60mm f/16.7 Carton in a Skylight tube and it is a superb lens,If I had my own garden I wouldn't hesitate to get a larger one.

[dobbie]

youre at it again mr onions , next you will be posting up them pics again:Envy:

[dobbie]

So for me the miniumum scope collection would consist of a smallish fast APO for portability and widefield. A quality long FL achro for lunar/planetary and a decent sized dob for DSOs etc.

John

wow thats my set up... apart from a 150p and binos ( i think i have to many scopes)..