Maksutov-Newtonian or newtonian for astrophotography and visual astronomy

[Mark Jo]

I am considering to buy a Sky-Watcher Explorer 190MN DS-PRO Maksutov-Newtonian or a newtonian OTA for about 50 / 50 use though that may change with time. I dont have a fixed choice on the newtonian but thinking of an aperture of 200mm. I should have an Skywatcher eq6 mount soon and should be sufficient for what i get.

think that the  Maksutov-Newtonian will give better images but not sure how it is for visual?

i have heard that the Maksutov-Newtonian is difficult to collminate compared with newtonians also that the dept h of focus is very shallow.

does anyone have experience of using Sky-Watcher Explorer 190MN DS-PRO, would like to see what pros and cons  that i need to consider

 

[wimvb]

The MN190 isn’t any more difficult than an ordinary newtonian and it holds collimation well. Just, whatever you do, don’t mess with the secondary offset. I use a barlowed laser for collimation, and after I collimated my scope yesterday, it was spot on according to my cheshire. The primary only needed a tiny bit of tweeking. And that was after I accidentily bumped the rear part in a door post when carrying it from summer storage to my obsy. (A mild bump with no damage to either scope nor door post.)

The tube is heavy for a Newtonian, but not compared to a refractor. Your eq6 should have no trouble carrying it.

At f/5.3, the maknewt is no more critical to focus than any other scope of that ”speed”. The low profile focuser works well, once you fix the included extension. On my scope, there was some play in the extension, but it was easily fixed with a strip of aluminium tape between this extension and the draw tube.

I have heard rumours that Skywatcher is discontinuing the MN190, so grab one while you can.

Edited September 9, 2020 by wimvb

[almcl]

Plus 1 for what Wim said.

I recently added a SW 190 MN to my collection and it is a much nicer scope for imaging than my SW 200p.  I spent a couple of days getting to grips with collimation - in some respects it's easier as there's no spider with microscopically thin support vanes to muck up secondary mirror centralisation - but there is an extra step of getting the centre circle on the secondary centered under the eyepiece, not difficult if taken steadily.  In just over a month, I haven't had to touch the collimation screws.  And the image is flat and distortion free across the whole of my Canon 700d's sensor with no coma corrector needed. I've been getting better FWHM figures, as well.

I was told it would take a month for mine to come from China, but it was actually quicker than that.

 

[nfotis]

From what I remember, the MN190 is a rare breed. Quite heavy for a HEQ5 mount, it has its own niche.

I wouldn't expect a new model of this type.

N.F.

 

[Erling G-P]

On 10/09/2020 at 01:01, almcl said:

Plus 1 for what Wim said.

I recently added a SW 190 MN to my collection and it is a much nicer scope for imaging than my SW 200p.  I spent a couple of days getting to grips with collimation - in some respects it's easier as there's no spider with microscopically thin support vanes to muck up secondary mirror centralisation - but there is an extra step of getting the centre circle on the secondary centered under the eyepiece, not difficult if taken steadily.  In just over a month, I haven't had to touch the collimation screws.  And the image is flat and distortion free across the whole of my Canon 700d's sensor with no coma corrector needed. I've been getting better FWHM figures, as well.

I was told it would take a month for mine to come from China, but it was actually quicker than that.

 

As you have both the 190 MN and a 200P, can you tell me how much heavier the 190 is?

Am imaging with a 200PDS on a HEQ5 presently, but have always drooled over the 190. Fear though that it would be too much for a HEQ5, but really don't want to carry something as heavy as the EQ6, so that's kept me off the 190 up til now.  If it's indeed being discontinued, I do have to reconsider after all.

[almcl]

My 200p weighs in at about 7.5 kg without finder guider or scope rings. 

The 190MN is a bit over 11 kg but I find it rather more awkward to get hold of as the mirror end has a flush fitting plate and the eyepiece end has a cover with nothing to grip.  It is noticeably more of an effort to carry out of storage to put on the mount, although I wouldn't describe it as  difficult.

I saw the rumour that the 190 MN was being discontinued, but FLO rather poured scorn on that idea when I enquired and ordered me one which had to come from China.  Three weeks later it arrived, so as of late July they still had stock. 

[Erling G-P]

Thanks for the info   That is a fair bit more for the 190MN - are the 11 kg for it also without tube rings etc. ?

[almcl]

That's with the finder and tube rings.  I have an aluminium bar on top of the rings which serves as a handle for lifting the OTA out of its box.

[Erling G-P]

Thanks for the info again; definitely food for thought

[Mark Jo]

Thanks for the comments, they have helped.

Only concern is the weight 🙁.

Is there any case or bag that can be used to transport it?

[wimvb]

24 minutes ago, Mark Jo said:

 

Is there any case or bag that can be used to transport it?

A sizeable sports bag probably.

Or as already mentioned, a dovetail on top to act as a carrying handle.