MN190 Vs new 5 element 120

[Freddie]

Hi,

Would welcome peoples thoughts on best scope for DSO ccd imaging (no plans to use for visual) between the Skywatcher MN190 and the new 5 element 120 soon to be released by SW. Scope would be on NEQ6 mount. Thoughts on advantages/disadvantages of each would be appreciated. Thanks Freddie.

[shaunster]

until we see some tests with the 120 its hard to speculate what it will be like

But i see it like this

MN190 pro's

- Proven optics

- Cheap (for what it is)

- fast focal ratio (f/5.3?)

Cons

- Requires collimation

- Bulky and heavy

- requires carefull balancing

120 speculation

- slower focal ratio f/7 not ideal - Possibly use a reducer?

- easy to use - refractor is plug and play

MN190 is a lot of scope for the money

Unless you have a permanent setup imaging with a frac will be a lot easier IMO

[Whippy]

until we see some tests with the 120 its hard to speculate what it will be like

+1. One thing that will be interesting to see will be if Synta have mastered the consistancy for the production of scopes like the forthcoming 120 with it's lens groupings. Petzvals and the like (which I'm guessing this will be like) are notoriously difficult to make and to mass produce them will require some tight production. I hope they do it but we'll see I guess.

FWIW, I use an ED120 and it's a nice scope, it'll be interesting to see how the new models stack up against the current range.

Tony..

[Deneb]

Is anyone thinking about - How much they would Cost !

it'll be interesting to see how the new models stack up against the current range.

That would be very interesting Tony...

Nadeem.

[Freddie]

Thanks for the comments. Some interesting points here. Nadeem, are you able to comment on the cons (collimation, bulk, balancing) of the MN190 as you have one on the NEQ6 mount. If you set up each time or have a permanent set up would also be useful to know.

Thanks Freddie

[ollypenrice]

Very intersting thread. I image with a TEC140, a dream refractor about as good as they get. It is a lovely scope, very forgiving with tight optics and excellent colour correction plus a mechanical side to die for. Plug and play is the word.

But it is F7 and that is not fast... The Mn 190 is nearly twice as fast and that is a lot. On a night when everything was going the 190s way (good collimation, no wind, the mount handling the bulk perfectly) I think the the MN would win. If the camera were uncooled and so limited as to exposure time I think it would certainly win, but I use CCD. I have used 15 and 20 minute Luminance subs in the TEC with excellent results.

I really hope to have a shoot out one day but as yet no 190 has appeared here.

And how's that for a refractor buff eating humbe pie??

Olly

[Freddie]

Although I would use CCD, having FR of 5.3 Vs 7 looks like a big advantage. There are a few people with the 190 and guide scope on the NEQ6 mount with no reported weight issues. Lots of people imaging with refractors and newts out there but the 190 appears to be a bit overlooked for a scope that tends to get very positive reviews.

[Whippy]

Although I would use CCD, having FR of 5.3 Vs 7 looks like a big advantage. There are a few people with the 190 and guide scope on the NEQ6 mount with no reported weight issues. Lots of people imaging with refractors and newts out there but the 190 appears to be a bit overlooked for a scope that tends to get very positive reviews.

Overlooked? Not really, the Skywatcher Mak-Newts haven't been around that long and IMO, there's a fair few around. The big problem with them is that weight and size. It has to have an EQ6 mount minimum and even then, if I wanted one, I'd have it permanently mounted in an observatory to shield it away from any potential gusts of wind. I'd also go with an OAG over using a guidescope to keep away from any balance issues. It's a great scope undoubtedly but it's not perfect nor a one scope solution for imaging either.

Tony..

[Freddie]

Hi Tony,

Fair comments there. When you say not a one scope solution for imaging do you mean not planetary as well as DSO?

Freddie

[Whippy]

It's primarily designed as a scope for DSO imaging but I would imagine you could put a Barlow in the optical train so you could get the focal length needed for planetary imaging.

What I meant is that imaging at 1 metre (which is the native focal length of the MN190) is for me, a 'half-way house' length to image at. It's not really long enough for the smaller galaxies but not short enough to image the bigger objects either. My ED120 has a focal length of 900mm and with my Atik camera I get a FOV of 25 x 35 arcmins so it's great for M51, M106 and the like but imaging anything smaller like M57 needs more focal length. Conversely the FOV isn't big enough for M33 or the Rosette Nebula. Obviously if you had a different camera, that FOV would be different, a DSLR's FOV is much bigger than that!

If I had to have one scope out of my current crop, it'd be the ED80 because the shorter focal length (600mm) makes it more versatile, it's less subsceptable to sky conditions and wind because it's smaller and lighter and it's easier to guide with so it gets more use than the 120. But, if I had an observatory it'd be a much different story!

Tony..

[ollypenrice]

I agree with Tony that a metre is a bit of a halfway house on FL. Around 500mm and around 1.5 metres targets abound. If you have a huge chip then maybe not but I use 15mm square chips. I had to 'semi mosaic' M33, for instance, by taking offset images. It took a lomng time!

Olly

[Catanonia]

Ok I have owned the existing Skywatcher ED120 Diamond and now have a MN190.

The MN190 is twice as fast when you put in size and speed in comparison to the refractor.

It is massive and heavy and DOES need a EQ6 minumum to handle it.

Collimation and cool down are a pain, but you get used to it.

The field is lovely and flat with the MN190, better than the ED120

The refractor is much easier to use, setup and learn on. But the MN190 is a much better scope for roughly same money and focal range.

BUT and a BIG but, I wouldn't have one if I didn't have an observatory to keep it setup. It is huge, heavy and the associated pier for it is too.

[Freddie]

Thanks for the comments everyone. It's usually a refractor Vs Newt debate but this has got some ineresting comparisons and comments going. Size and weight appear to be an issue with some but others are OK with it. I haven't seen a bad picture from one yet though !!

[ollypenrice]

Thanks for the comments everyone. It's usually a refractor Vs Newt debate but this has got some ineresting comparisons and comments going. Size and weight appear to be an issue with some but others are OK with it. I haven't seen a bad picture from one yet though !!

True, me neither. However, the thing about relatively difficult big scopes is that people don't post if they don't image...

This whole debate has no one solution.

Olly

[Catanonia]

Thanks for the comments everyone. It's usually a refractor Vs Newt debate but this has got some ineresting comparisons and comments going. Size and weight appear to be an issue with some but others are OK with it. I haven't seen a bad picture from one yet though !!

When they are setup (not to difficult) they do produce some cracking images. So much so, I do not miss the ED120 Pro refractor one bit.

[nightvision]

............

If I had to have one scope out of my current crop, it'd be the ED80 because the shorter focal length (600mm) makes it more versatile, it's less subsceptable to sky conditions and wind because it's smaller and lighter and it's easier to guide with so it gets more use than the 120. But, if I had an observatory it'd be a much different story!

Tony..

Really interesting thread for someone setting out on the rocky road to imaging.

Hi Tony, can you elaborate on the ED80 being '...less susceptible to sky conditions'?

Curious... If you had an obs what would the story be?

Tony.

[Whippy]

A scope with a longer focal length can be limited by the seeing, much less so with smaller, shoter scopes. They're also likely to be affected by wind too.

As an example, I only use my ED120 when the seeing is pretty steady and the wind is low to non-existant. Conversely, the ED80 or ZS66 can be used almost anytime, I've had a couple of sessions with the ED80 in near gale force winds and got 10 minute subs with no hassle .

If I had an obs? Realistically (budget-wise) I'd like to have 3 scopes. Something like the Edge11 with a reducer for long f/l work, probably a MN190, Intes Micro MN84 or Intes Micro 6" f6 'photo' Mak for that mid-range and a 80mm f/6 'frac with the LOMO lens or FLT98 for the wider fields. Still not cheap though!

Tony..