Re: Hubble vs C14


thefamily90 Phillips
 

Perfectly said Roland. Poor quality optics or large central obstructions decrease the contrast, however, if imaging, the contrast can be increased via computer software. I was a strictly visual observer for 35 years then became a strict lunar and planetary imager for almost 20 years and am now doing more and more visual observing with minimal imaging. 
I paid the big bucks to get the best instruments possible for visual observing decades ago. Large AP and LZOS apochromatic refractors along with a fair number of nights of very good/excellent seeing each year have provided me with superb views of the Moon and planets using a Binoviewer and TMB monocentrics.

If I wanted to just image the planets I probably should’ve gotten a C 14.

JimP 


From: main@ap-ug.groups.io <main@ap-ug.groups.io> on behalf of Roland Christen via groups.io <chris1011@...>
Sent: Tuesday, November 23, 2021 10:13:37 PM
To: main@ap-ug.groups.io <main@ap-ug.groups.io>
Subject: Re: [ap-ug] Hubble vs C14
 
The amount of resolution and detail that can be achieved with lucky imaging is not scope dependent. A scope can have very poor contrast, which would make it a poor visual instrument, but when you combine thousands of very short exposures with lucky imaging techniques, you can achieve the theoretical resolution of that aperture. Low contrast becomes meaningless because you can enhance that with filtering techniques (wavelets and other sharpening). Aperture and good seeing are of prime importance for imaging planets.

Therefore, for imaging of planets, aperture is always going to be king. I have seen even higher resolution images of Jupiter taken with an amateur instrument (36" i believe) on a mountain top in Chile at Cerro Tololo. Marj and I spent a week at Cerro Tololo a number of years ago and I can tell you that the seeing there is second to none.

For visual, the human eye/brain does not have the luxury of enhancing contrast or stacking many thousands of video frames. Therefore a good optical system will need high contrast. That means excellent polish and figure, and a very small secondary obstruction. I have pointed my 10" Mak-Cass (23% obstruction) at Jupiter right next to my 17" Cassegrain (34% secondary obstruction). Almost always the 10" presents a cleaner and more contrasty image and will show more fleeting detail. The local seeing does not support the 17" aperture except for very rare nights that occur maybe once in a blue moon. The 10" is a much more satisfying scope to use visually. A C14 at our location is not any better than my 17" for visual planetary observations. The 10" beats them both by a mile.

Rolando

-----Original Message-----
From: Christopher M <mirfak@...>
To: main@ap-ug.groups.io
Sent: Tue, Nov 23, 2021 8:46 pm
Subject: Re: [ap-ug] Hubble vs C14

Nicely done.  I can't wait to see what you would do with one of Roland's Maksutov's or any other better telescope.
C

--
Jim Phillips

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