Skywatcher 190mn pro or Equinox 120 APO?

[Herrman]

Hi,

I have been giving some thought into investing in a Skywatcher EQ 120 APO, however I have just read the May 2009 report in Astonomy Now on the Skywatcher 190MN Pro, which states ".... what equates to almost an 8" triplet apochromat". That's a pretty impressive credential in my book. Should I be swayed by this review and opt for the MN instead of the EQ120? Also, I should say that my mount is a HEQ5, would it cope with the MN, especially if I piggybacked an EQ 80 as a guidescope? I realise that the MN is a faster scope, which is beneficial for my primary interest- astrophotography, but apart from this, I am finding it hard to make a choice.

I would be really interested to hear your opinions.

All the best, Herrman.

[dweller25]

There is no way a 7.5" mak newt with a central obstruction is going to match an 8" APO - it's just the laws of physics.

The 190MN might push a 6" APO though, which is a bigger scope than the 120ED you mention.

Just my two penneth.

[Whippy]

It depends on what you want from the scopes. The ED120 has enough aperure to be a good all-round observing scope and imaging scope. The MN190 also has the credientials but the big downside is that it's heavy. The cliche with MN's is that a Mak-Newt is the equal to an apochromat with an inch less of aperture (ie: a 7.5" MN is the equal of a 6.5" APO). I would suspect it wouldn't be comfortable on a HEQ5 even for visual and certainly a non-starter for imaging. An EQ6 would be the minimum there.

Tony..

[Beyond_Vision]

I agree with Tony's comments it would need an EQ6 for imaging. The only other point would be that the MN190 is going to have a flatter field than most refractors. You would have to use a field flattner with most refractors to approach the MN190's performance. Only the more expensive refractors like a Tak FSQ106 or Pentax would have a flat field like it out of the box and they cost around £3,000

Regards

Kevin

[Herrman]

Hi All,

Very many thanks for your valuable advice. It sounds like the real disadvantage of the MN is its weight. I don't think I will be able to upgrade to a HEQ6 for a while yet, so I will probably opt for the refractor.

Again, many thanks for you thoughts.

All the best, Herrman.