Only way I would want to use a Newt on Eq for visual would be with a very smooth set of rotating rings and the tube ballasted so the focuser remains at the correct angle at all times.
That plastic Telrad base seems out of place... They should made a nice aluminium version of it.
Agreed. I am not a fan of plastic anything - the plastic Takahashi 1.25" diagonal annoyed my sensibilities enough to purchase the 2" Tak diagonal as well.
The 1.25" works impeccably, just... well, plastic housing is not what I want
Leave plastic for caps and bahtinovs.
Now Phil, you COULD buy one of the Stromlo refractors...
Even though Planewave say the CDK is also a visual instrument I found my CDK17 to not give good views. I think it shows the seeing too much. So it would really require good seeing but the scope is more optimised for imaging with the relatively larger central obstruction as opposed to a Mewlon which has a very small secondary.
Sometimes Tak looks like they are still in the Stone Age. Can you imagine the thermal currents in that beast? The weight.
This is the age of carbon fibre with fans and thermal control for large scopes.
Greg.
It does have 3-4 fans behind the primary mirror. Since these are custom made scopes I would think a prospective buyer could enquire about the availability of a Carbon Fibre tube.
Been reviewing the options and think I will just stay with the Mewlon 300 for now considering the mounting/usability issues with a custom newt.
Any change to a new scope has to provide increased in optical performance and wider field without the prior mentioned drawbacks which looks like it will be hard to do unless I go to some sort of scope like dobsonian such as a SDM.
I don't particularly like the idea of climbing around on ladders just to get to the eyepiece !
Keep the Mewlon 300 for travel and get a 24" F3.3 dob for the home obsy Phil.
Newts on Eq mounts for visual were conceived by sadists and masochists !!!
The big tracking dob idea is a good one I think. IF you aren't into photography then I see no down side. Just get a good one with a good mirror set!
I would think big, no less than 24" and fast to keep it short.
Why not consider the corrector for the M300. This piece of optical wizardry from takahashi will convert the scope down to f10 with much less coma delivering your wider views. The corrector works brilliantly on the m250. Cheers. John
Been reviewing the options and think I will just stay with the Mewlon 300 for now considering the mounting/usability issues with a custom newt.
Any change to a new scope has to provide increased in optical performance and wider field without the prior mentioned drawbacks which looks like it will be hard to do unless I go to some sort of scope like dobsonian such as a SDM.
I don't particularly like the idea of climbing around on ladders just to get to the eyepiece !
Not such a bad thing having to 'settle' for Mewlon 300!!
Why not consider the corrector for the M300. This piece of optical wizardry from takahashi will convert the scope down to f10 with much less coma delivering your wider views. The corrector works brilliantly on the m250. Cheers. John
Thanks for the suggestion.
I actually had considered this and I know another Mewlon 300 owner who did the corrector upgrade.
Reality is that visually the coma is not noticeable in the Mewlon 300 so while the corrector would provide advantage to a larger format sensor the benefit is not that big for visual.
Will get a bit wider field but again did not seem compelling enough.
I suppose I could just do it anyway for the slight visual benefits as it would not represent any drawback or loss in the investment of the scope itself.
Only way I would want to use a Newt on Eq for visual would be with a very smooth set of rotating rings and the tube ballasted so the focuser remains at the correct angle at all times.
At Melbourne obs.,we have a 12" f7ish newt, the beauty of it is the rotating turret at the focused end, ep in wrong position, just slide it around..also useful for people of diff heights. It contains both the finder & secondary --I'm surprised you don't see more of them
Keep in mind that Dall Kirkhams and corrected Dall Kirkhams like the Planewave and Tak Mewlons have limitations and downsides as visual instruments. A high quality newtonian, properly set up, of equal aperture is going to outperform either of these scopes as a visual telescope, in several aspects of optical performance. While you might love your Mewlon 300, a high quality 12" newtonian, which has been properly set up by someone with the required know how will outperform it in most respects as a visual telescope. There is an abundance of literature available on why this is so. It is also supported by my practical experience. The above having been said there is also a downside to newtonians. It takes a bit of learning and know how to get a large aperture newtonian to perform at its best. I have looked through dozens and dozens of large aperture newtonians that were not properly set up and badly underperforming. What is sad is that most of the scope owners thought their scope was properly set up and they just didn't know any better. If you're not experienced in setting up a large aperture newtonian it is worth spending some time with someone who is and picking their brains
John, I think what makes Tak Cassegrains great (apart from the 1/20th wave optics) is how protected both the primary and secondary mirrors is from stray lights. If both scopes are properly set up, I still think the Tak will have an advantage over newtonian due to this, unless you observe from a very dark location.
Cheers,
Arief
Quote:
Originally Posted by ausastronomer
Hi Phil,
Keep in mind that Dall Kirkhams and corrected Dall Kirkhams like the Planewave and Tak Mewlons have limitations and downsides as visual instruments. A high quality newtonian, properly set up, of equal aperture is going to outperform either of these scopes as a visual telescope, in several aspects of optical performance. While you might love your Mewlon 300, a high quality 12" newtonian, which has been properly set up by someone with the required know how will outperform it in most respects as a visual telescope.
