Refractor vs Reflector

[Fedele]

On the same morning ( today - 05.06.21), I alternatively used the Skywatcher 120ED (kicked out 10 minutes earlier), the Mewlon 180c (stayed out all night) initially with UV&IR Cut filter, then, with the progress of dawn and early morning light, with Astronomik IR PASS 742 (used only with mewlon).
The analysis of the frames carried out by Astrosurface is illustrated. What emerges is what is also found visually. The 120ED offered very still images compared to the Mewlon with Barlow TV2x. obviously the smaller diameter is less affected by the effects of air turbulence. The Mewlon in moments of calm returns an APO level image with a diameter greater than the first obviously, but the images of the refractor are usable all the time.
The video analysis graph reveals a very high percentage (well over 50% and we can say almost up to 80% and more) of excellent, good or sufficiently good frames).
In the mirror telescope the percentage is considerably reduced, settling on average much below 50%. Wanting to limit ourselves to only really good frames, we should stay on percentages below 10% (my initial imaging experience is leading me to always prefer the fewest possible number of excellent frames to be included in the cauldron of Staking algorithms).
This percentage increases with the use of selective filters capable of limiting the effects of seeing, since they select certain bands of the spectrum.
Here the percentages up to a more than sufficient level of sharpness are selected with the horizontal slide only

Edited June 5, 2021 by Fedele

[JeremyS]

Fascinating result @Fedele !
Can you comment on the detail you saw in each telescope when the conditions were good?

[Fedele]

Practically i use Mewlon quite only for imaging planets. I prefer to look at the sky through the lenses

Edited June 5, 2021 by Fedele

[Fedele]

120ED is good but not like i want. 

I have understand this: 

reflector to be really usefull for DSO  but also  resolution for imaging , must be more than 25 cm. Visual DSO serius start from there. 

what a around 20 cm mirros can do, is best made and more often best, from a Lens from 120/150 mm

(for like i want to see). 

120Ed is good but not like i want.

So this is my actual dilemma..... 

- Protability and quality and Bino  with FC100DZ? 3200 euro

- more power (?) and resolution (?) with TSA120?  5000 euro

- huge power and diameter and quality (???)   with APM 140 SD?   3000 euro