200pds f/5 with coma corrector or mn190 f5.3?

[Starblazer]

Seeing as people are loving the mn190 as of late and I am trying to work out the pro's n con's of certain setups.

What would the difference be, cost/image quality between both but with the added coma corrector for f/5 scopes from skywatcher to even the field, so to speak.

Does the glass at the front of the MN190 and the size of the secondary reduce the light gathering capabilities, all be it maybe small, when compared to the 200pds?

Would there be a noticeable amount of detail difference in the image between the 2, other than a slightly different field of view?

Does the cost justify the benefit? I'm really curious mainly because those differences, other than the corrector plate on the mn190, seem like mods that could be done yourself for little to nothing?

And please don't think this is an attempt to slag off the scope or those who can and do use them. I am only trying to work out what the cost/benefit is between the 2, even as standard, without mods, other than the coma corrector for the 200pds.

Then decide if its time to sell my scopes to fund one haha.

[angusb1]

MN190 will probably hold collimation better but will take longer to cool down.

[Starblazer]

Surely that alone is not worth the £650 extra?

[Penfold]

Good question.. It would be interesting to see the results if someone had both.

[Starblazer]

It probably sounds like a silly comparison to most who are in the know, but for someone like myself and anyone else who isn't aware of the importance of the differences between the 2 and to what degree it would benefit you over the cheaper option with added bits.

And i'm not talking about being a cheapskate either, this is more to see if the cost out weighs the benefits.

[Penfold]

Either everyone who's bought a mn190 are thinking... "Why didn't I think of that" or no one has tested it.

To me you seem to be onto a cheaper way of perhaps getting someway towards the mn190.

[Starblazer]

No doubt there are some very good reasons for picking the MN190 over the 200pds, wish there were a few of the users who could comment on this.

I've had a nose at the specs and it isn't overly dissimilar to the 200pds, I know the glass at the front is probably amazing, but i've seen some very flat fields using the skywatcher corrector which costs £98.

Is there a great deal of difference between baffling and flocking?

It's often said that cheap stuff is rubbish and the more you spend the better the results. I'm just curious as to just how much better these results are.

Now I know sellers maybe wouldn't want to do such a comparison as it may end up with them losing out in the long run, but then if it proved a significant benefit, then people could stop throwing money away tryin to botch the job together and invest in a tried tested and proven piece of equipment.

Would be great to see a side by side comparison of both using same subject, conditions, temps, camera, the whole shabang lol.

[Starblazer]

Either everyone who's bought a mn190 are thinking... "Why didn't I think of that" or no one has tested it.

To me you seem to be onto a cheaper way of perhaps getting someway towards the mn190.

The are probably thinking...what does this noob know about imaging...well nothing tbh, i've done a little and instead of just getting out there and taking some half decent images, i'm waiting to get my setup sorted tidy and i'll go from there.

[brantuk]

I think this thread may help here:

http://stargazerslounge.com/sponsor-announcements-offers/68722-skywatcher-190mm-maksutov-newtonian-astrograph-4.html and this one:

http://www.firstlightoptics.com/proddetail.php?prod=skywatcher_mak_newt_astograph

[Starblazer]

Cheers for the link. The images taken do indeed look lovely, but there is no real side by side comparison of the 2.

The added time required to cool the scope down, the requirement for dew heaters...added cost and time lost possibly?

Are the benefits still weighing in on the mn190 or could the 200pds do the same with some bits for cheaper?

[Whippy]

Imaging-wise, there's no diffraction spikes with the MN190, collimation can be a bit trickier with a MN but it has a much thicker tube so flexture isn't so much of an issue. Not that I've tried it, but I can imagine using a coma corrector might be a bit fiddly with a CCD if you have a filterwheel or other bits and pieces in the optical train, getting the spacing right could be a pain. I know Yfronto and Steppenwolf both use newts with correctors and they get great results so it's far from impossible.

Saying that, I can't imagine seeing a huge amount of difference between the two in a side by side test if they're both setup properly, after all the only real difference is that the corrector on the MN is at the front while it's in the focuser with the newt.

I can't say about observing as I've only had the briefest of looks through a MN190.

Tony..

[Starblazer]

Thank's for the input Whippy, this is more of what I was looking for with regards to debate and other people's views.

Diffraction spikes are one of those things, you either love them or hate them. I wonder how many with diffractionless scopes add in spikes later?

There seems to me to be the same amount of glass in the imaging train and as you mention, having to use a corrector could cause focusing issues, but surely there have been solutions to these issues already done by others to the point that it is not detrimental to the final image.

[Whippy]

I don't think there'd be focusing issues in regards to using a corrector (although there might be due to lack of focus travel in the newtonian design), it'd be getting the spacing right between the camera and the corrector. It's the same as using a field flattener/reducer, if you don't get the spacing right then it doesn't work properly.

FWIW, I don't get spikes as I image with refractors and I don't add them in when processing .

Tony..

[markarian]

Can't compare with the MN190, but I have a 200P and Baader MPCC. The difference the corrector made was staggering. So I can recommend that setup - but can't compare - sorry.

Mark

[Starblazer]

Cheers for Chiming in Mark

[Starblazer]

Any more MN190 or 200pds users want to chime in?

[Deneb]

yes I want to chime in, I have had both !

You can't really compare the two, as they the MN190 is in a league of it's own.

If your on a budget, then go for a SW200P DS+SW coma corrector, you'll get very good images from it. But bear in mind you might have to change the focuser on it. Also you can mount it on a HEQ5 mount, you have to take in account the MN190 being around 10kg in weight, you will have to mount it on a EQ6 Pro hence more money to spend...

ps. I think i'll have to buy something like a takahashi or something next time, MN190's are becoming a norm !

Nadeem.

[Starblazer]

Could you post some comparison images from both to show field width difference, field flatness (with corrector on 200pds) and general reasons why the MN190 is worth it?

Is the dual speed crayford different from the one on the mn190?

I'm not really concerned with budget as i'm not planning on buying any new scopes for a while lol....well, i hope not to buy any more scopes for a while

Would you honestly say that the difference in imaging quality is worth the extra?

To someone who already has an EQ6. Would you say, if you have the money, this scope will give you a marked improvement on overall image quality and clarity without being more hassle for only a small improvement.

[Deneb]

Could you post some comparison images from both to show field width difference, field flatness (with corrector on 200pds) and general reasons why the MN190 is worth it?

Is the dual speed crayford different from the one on the mn190?

I'm not really concerned with budget as i'm not planning on buying any new scopes for a while lol....well, i hope not to buy any more scopes for a while

Would you honestly say that the difference in imaging quality is worth the extra?

To someone who already has an EQ6. Would you say, if you have the money, this scope will give you a marked improvement on overall image quality and clarity without being more hassle for only a small improvement.

If money is of no consequence, then by the MN190, I would say there is a lot of difference in imaging quality. The two albums (one is mine & TJ'S)show what can be achieved with this scope using dslr & ccd cameras. BTW apart from a couple of images in my album, they were done unguided...

Stargazers Lounge - Deneb's Album: Skywatcher MN190

Stargazers Lounge - TJ's Album: Mak-Newt 190 Pictures

There's only one pic I have done with the 200PDS with the coma corrector & that was this one:

http://www.backyardscope.org.uk/images/gallery/dso/Clusters/M48.jpg

Im sure you could find others if you use the search facility..

Regarding the focuser on the MN190, it's pretty good, strong, has a pull up 50mm ext. tube built into it & of course can take the weight of a ccd camera, filter wheel & off axis guider...

Nadeem.