GSO RC8 or MN190 or something else?

[swag72]

@ Kirkster - Ian King Imaging (IKI) sells them

[kirkster501]

@ Kirkster - Ian King Imaging (IKI) sells them

Great thanks for the heads up Sara. Not getting one yet - will see how I get on with collimation without it first. Most just use a cheshire and a calibrated standard laser collimator.

[philming]

On an RC, a laser wont do any good. I'm pretty sur about the results of the taka, and the other day, I double checked with a laser (a Baader one), and it the result wasnt good.

Use a sheshire if possible, but a Taka will be far more precise.

[philming]

And thanx for your comment about my shoots :-)

[kirkster501]

On an RC, a laser wont do any good. I'm pretty sur about the results of the taka, and the other day, I double checked with a laser (a Baader one), and it the result wasnt good.

Use a sheshire if possible, but a Taka will be far more precise.

.... and expensive! Thing is, I have the deluxe Carbon Fibre 8 inch with the upgraded focuser - that's £1700 worth brand new. I will try to get it right with a Cheshire first. But in the great scheme of things if the Takahashi turns it from a good scope to a great one then its not that much in the great scheme of things.

[Ibbo!]

Ian King has them on his website

not cheap

I likewise am using an F8 with the reducer, but am waiting for a clear spell to go back to F8 for the galaxy season.

Steve

[Ibbo!]

I used a Tak coli then had to tweak using an actual star.

The coli scope is fine but assumes everything is lined up

Steve

[philming]

Well it actually HELPS lining up things...

[Ibbo!]

yes if the secondary mirror is properly spotted and that the support is round etc

star test every time for final sorting out IMO

Steve

[philming]

Oh and I forgot. The weight !

The MN190 is allmost 10kg. The RC8 is about half that weight.

[tonedeaf]

(i want to edit my posts, therefore i´ll try to reach the 250 posts )

now as above said there are many pros and cons...

the weight is one...

...as now written with a FR the RC would get faster...and then i also have the greater flexibility to use the greater FL...

good to know that i have to wait till next year

inbetween i´ll try to build an obsy first

[michael.h.f.wilkinson]

Just like you can put a reducer in the RC8, you can put a Barlow in the MN190. The latter will have the larger FOV, but that is only relevant for big chips.

[Gina]

Yep, a 2x Barlow in the 190 will give you 2m FL and f10.7

[perfrej]

One more point in favour of the cheapo 190MN is the fact that it is a lot easier to collimate than the RCs. Maybe CDK is a better choice than RC, simply because collimation gets easier the closer to the sweet spot you get rather than the other way around with the RC.

Well, well...

Oh, on a side note, the Lepus reducer at 0.62x for the EdgeHD 925 wasn't that expensive.

/per

[ollypenrice]

The ODK certainly wasn't hard to collimate and hasn't been touched since it arrived 15 months ago. Quite a relief!

The MN190 has such a convincing set of optics that it strikes me as odd and a shame that nobody makes a rather more lavish one, lavish from the engineering point of view. Double the price, improve the enigneering, and you still have an affordable scope which could beat the very expensive metre FL apochromats at less than half the price. It would take some doing to get a big apo down to F5.3.

Olly

[perfrej]

Yes, ODK is fine with collimation. It is the RC design that gets more sensitive to error the closer to collimation you get. CDK, ODK - fine, they're the opposite.

As for better and bigger Maksutov-Newtons, well, they are available. The meniscuous corrector, apparently, is a very expensive pice of glass and as the size goes up, so does the price - exponentially!

Just check out the good old Intes MN-scopes (APM Telescopes). A 10" MN is €11000, a 14" is €22000. Both are f/4 I am pretty convinced that those are darn good scopes! And what happens with another two inches of aperture? Yes, you guessed correctly: €40000...

/per