Re: STUNNING image of M51


>> rounder stars.
>
> Oh, my! Of course they have rounder stars, they oversample the PSF!
> Even the very small amongst my stars have a FWHM of 2.8. The reduction,
> if any, is just due to the LR deconvolution.

You don't get it, stars should look round not pixelated. Oversampling is
not bad, SACD and DVD-A are all oversampled but higher resolution than
plain old CD's.



>> > Being well defined doesn't mean it needs to be oversampled. And
> even
>> > undersampled images can be restored, witness the Hubble.
>>
>> The Hubble had 2 waves of spherical abberation. The stars were
> bloated
>> and oversampled! Detail is lost where undersampled so why do it?
>
> Look. Do your homework a google search under the word "dithering" and
> "drizzle". You might learn something...
You didn't say that in the first place. Try to be on topic and precise in
your meaning.
Drizzle is fine for space imaging but on earth with the usual seeing and
pointing errors its not done. And 300% more exposure time to get 2x2 more
resolution, well in theory only -- not a happy tradoff.


>
> You don't know what you're talking about. Yes, they may visit WSP or
> TSP or whatever and may do some imaging but the core of their images is
> taken from where the hell they have permanently installed their
> instrumentation. I don't see Adam Block globetrotting the world around
> hauling the 20" RC and all the other stuff, do you?
Adam Block did happen to take M51 at Kitts Peak.
I do know a few serious astrophotograhers who go to better sites nearby
every clear new moon, and occasional vacation in Australia, Chile, etc.
They own apos and large SCT's for transportability. Some even take their
18" dob.


>>
>> It shouldn't be that hard to see the difference between a 6 Megapixel
>
>> image and a 1.4 Megapixel one.
>
> One is bigger than the other (more field of view). So what? And what's
> the connection with quality?
Your pixel size is not same since you used compressor.
Does a newpaper print and print from 120 film look the same to you if
same size and field of view?

>> > The point I'm trying to make is we don't know the details so how
> can we
>> > say who had the worst/best setup?
>>
>>
>> He posted that his scope is a RC AstroSib 10" f/8.
>
> Astrosib is the optics maker. The tube might be something entirely
> different.

Doesn't matter who made optics, sercondary size and baffle should be same
as in review.

>> We can see it has 40% obstruction here:
>> http://www.kasai-trading.jp/astrosib-rc.htm
>>
>> Off axis at 20mm the stars are bloated. The chip in the ST8E is
> offset by
>> a similiar amount.
>
> I can hardly belive it. In fact I think you are quite mistaken. His
> stars are as good at the corners as they are in the center. The
> onlyobjection one can possibly raise is that the colors aligment is not
> exactly right, maybe just a slightly different scale for each RGB
> plane.
No question a RC has worse off-axis than a Maksutov. That's why
Maksutov's exist.



>
> You are definitely going (selectively?) blind. Seek urgent medical
> help! The two pictures have about the same magnitude depth, maybe I go
> just a tad fainter than he does although I have no idea what the raw
> images he took might yield. But again, deeper magnitude means nothing
> and besides he had a bigger scope to start with.
>
>>
No more facts in your arguments Andrea? Just cheap shots.
I showed how you missed clearly stated facts, ST8E not ST8ME, 40%
obstruction as reviewed for his telescope.

And your posted image is still flipped.

You seem to show poor decision making, judgment, memory, spatial
orientation, thinking, reasoning, and verbal communication.

Now that sounds like dementia.

OK I let you back into your own little world.

Magnum

.

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