Skywatcher 190MN

[CraigD1986]

I currently have on loan a Skywatcher 190MN with the option to buy. It’s a used scope that was donated to my local astronomy club and has been sat on the shelf for a couple of years. I’ve had a few sessions with it and really enjoy the longer focal length so I’m thinking of buying off the club. Does anyone have an experience with this scope and can offer any advice as to what I should look out for with it? I’ll be using it on my EQ6-R Pro and so far, the weight hasn’t been a problem.

 

Thanks in advance

[GalaxyGael]

The mak newt is fantastic, and rarely will you find a focal length of a meter at f/5.3, and without requiring any correctors. The law of conservation of benefits has balance though😊. Collimation is not like a Newtonian, as much as you will read. Principles are similar but a mak newt has one golden rule that newts dont need to satisfy in perfect Collimation: the front corrector and the primary mirror must remain parallel to each other while being centered with the eyepiece.

That means limiting tilt of the primary, never moving the secondary up and down the tube and using only focuser lateral movement (mak newts allow for this) to sort out the offset and centering. In a perfect mak newt, tilting of the mirrors is not needed, just focuser offset and secondary rotation. Anyway, the butt of this is to make sure whoever had this scope did not use classical newtonian approaches to collimate and that they did not move the secondary up and down the tube. If not and alignment is close and optics look good, it's a great scope of you can handle the size and weight.

 

This method clearly outlines the crux of the mak newt needs compared to a newt, in case it's needed. 

 

https://www.cloudynights.com/articles/cat/articles/collimating-a-maksutov-newtonian-with-a-howie-glatter-laser-collimator-r3377

 

[CraigD1986]

Thanks for your response.

It sounds like this scope is pretty decent and I'm enjoying it so far so all looks good. Coming from a Skywatcher 72ED (refractor), I don't have any experience with collimation but I've been told that the 190MN holds it's collimation really well. I would also imagine that the person who originally owned this knew what they were doing. At £1300, it's not exactly an entry level scope.

I have the option to buy this scope if I want to keep it but I'm not sure what a fair price would be. Any thoughts?

[Stu]

I’ve bought and sold a good example for £700 before. One up on ABS for a similar amount so it seems about right.

https://www.astrobuysell.com/uk/propview.php?view=198965

[GalaxyGael]

1 hour ago, CraigD1986 said:

Thanks for your response.

It sounds like this scope is pretty decent and I'm enjoying it so far so all looks good. Coming from a Skywatcher 72ED (refractor), I don't have any experience with collimation but I've been told that the 190MN holds it's collimation really well. I would also imagine that the person who originally owned this knew what they were doing. At £1300, it's not exactly an entry level scope.

I have the option to buy this scope if I want to keep it but I'm not sure what a fair price would be. Any thoughts?

Well, you can get one brand new for 1750-1800 EUR, so with conversion you can see how well 1300 GBP is. Sounds a bit steep to me (maybe?) unless it is in near perfect condition. Imaging versions can often be well loved since they are biggish and most I known keep them in the lonely cold in personal observatories (depends on climate too though). Does it have any upgrades, like a change to the focuser? No need to change that for visual use though really. It does hold collimation well. Visual or imaging for yourself?

[CraigD1986]

4 hours ago, GalaxyGael said:

Well, you can get one brand new for 1750-1800 EUR, so with conversion you can see how well 1300 GBP is. Sounds a bit steep to me (maybe?) unless it is in near perfect condition. Imaging versions can often be well loved since they are biggish and most I known keep them in the lonely cold in personal observatories (depends on climate too though). Does it have any upgrades, like a change to the focuser? No need to change that for visual use though really. It does hold collimation well. Visual or imaging for yourself?

Sorry, I think you misunderstood me. The price of the scope new is about £1300 so I was meaning that whoever purchased it new must have been serious.

I'm not sure what a reasonable amount would be to offer for the scope used. The guide scope wasn't original (An Altair white scope of some description with an eyepiece) but I removed this immediately to fit my guide scope and camera. The focuser is original and had a little bit of play in it so it would be a good idea to replace this, although I don't really know what with. I'll be using the scope for deep sky imaging with my ASI533MC Pro.

[GalaxyGael]

Ah, I did misunderstand or misread, apologies. Maybe recent sales on astromart or astro buy sell might give you an indication on the likely price for a similar state 190MN. Likely a few historicals on ebay also as in indication.

[wimvb]

2 hours ago, CraigD1986 said:

The focuser is original and had a little bit of play in it so it would be a good idea to replace this,

It is probably the built in extension tube that shows play. You can fix this by tightening the thumb screw as much as possible, without resorting to tools.

You can replace the stock focuser with either a MoonLite or a FeatherTouch. Both have adapters that fit. If you decide for a FeatherTouch, I hope you have a lot of patience. I ordered one last august, and so far it hasn't materialised.

[Stu]

9 hours ago, Stu said:

I’ve bought and sold a good example for £700 before. One up on ABS for a similar amount so it seems about right.

https://www.astrobuysell.com/uk/propview.php?view=198965

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