What eyepiece do you have at 10mm? I find for planetary, it depends more on the magnification use than the eyepiece. A difference of 50x can mean the planet looking sharp or blur and less contrast.
At exactly 10mm, I've only had an Orion Sirius Plossl.
However, the night before, I was swapping between a 13mm Hyperion, 11mm UWA, 9mm ortho and TV 8 plossl.
I find the 10XW gave better views so I don't think it's the magnification or exit pupil since the views at both lower and higher mag could not compare with the 10XW. Atmospheric conditions were also similar for the 2 nights of testing.
That is why is it not accurate to compare an eyepiece with different focal length and different exit pupil especially on higher magnification where the atmosphere and exit pupil plays a big role.
The FL of the M180 is 2160mm and the C8 is ~2032 so the magnification is 216x & 203x and exit pupil is 1.2mm & 1 mm respectively - the difference is not big enough to make a significant difference.
There are many options available that is cheaper and will provide as good or better especially specialized orthos for on-axis performance. I would say the difference is real slight. On axis the volcano top ortho does not beat in sharpness and planetary contrast to the Type 6 Nagler in anyway and off axis, the Nagler just beat it well. However the ortho is simply much cheaper.
I've got orthos from 4mm to 9mm (except 8mm which doesn't exist) and several BO/TMBs. These are what many consider the "cheaper but as good" options. I've also tried using a range of different EPs when viewing Jupiter last year at a star party.
I don't know what it is, the 10XW still gives me the most pleasing views so far.
Let me justify by saying that the statement is made according to the conditions last night - non-tracking mount (large FOV helped alot), specific scope type &atmopspheric conditions(the 200x magnification and 1mm exit pupil on this scope, obviously it'll give a different mag on a diff. scope), and most importantly, my eyes.
Another example was when viewing Jupiter last year at another starparty, I had a tracking mount and the atmospheric conditions were very different (it was much less windy and I think seeing was better). We borrowed and tried a range of diff EPs including the Nagler 3-6 zoom, orthos from 5 to 9mm, and a 9T6. In the end, guess which EP gave the most pleasing views to me ..... a Pentax 8XP.
It had a subtle colour tint that made the planet look just so much sweeter and of course it was really sharp!
Of course, this was cos I had a tracking mount. If I were to put an 8XP in last night on e astroslew, I'm not sure it would be the best EP then. I know some guys can and like to track manually at high powers but I personally just like larger FOVs and let the planet drift.
Anyway, after spending lots of time reading, buying, selling EPs, I think it's more cost effective and saves time just to buy the EP "at the end of the road" instead of buying a whole bunch of EPs now just to try and sell them later.
(I think you gave me similar advice before eh? hee hee ..
)
Let me say though that I still love orthos and plossls and I think they give pretty views, just that I don't have a tracking mount all the time and for me, without a tracking mount, orthos are uncomfortable to use.
I'm still gonna get a couple more TV plossls and orthos. Like I told rlow before, sometimes the smaller FOVs just give a different perspective on things and the view on the same object can be very different.
Once again, your mileage may vary.
Cheers!
I have told myself not to buy any astro things but so far I have not stopped! Oh Oh. Better control! 