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Sidereal vs King rate


 

So which choice is better for imaging? Or are there situations where one is better than the other??

Jamie


 

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For most solar system objects, neither rate is correct so it doesn¡¯t much matter which you use.?

If you¡¯re shooting short subs, it won¡¯t matter because the rates are very close, and aligning the subs will compensate for differences due to refraction.?

If you¡¯re shooting long subs, you should be auto guiding, so it won¡¯t matter which you use for the base tracking rate. ?

If you¡¯re using a 492 digital drive, its King rate is just an average refraction compensation, not particularly accurate for most positions. ?King rate should be marginally better, but really you want to either shoot short subs or auto guide. ?Or both. ?

I don¡¯t know if the Gemini implements position-dependent King rate; if so, it would in principle be better for unguided imaging with subs on the order of a minute or longer. ?In any case, if the mount is properly set up, King rate shouldn¡¯t be any worse than sidereal for objects outside the solar system. ?

? -Les



On 12 Jul 2020, at 22:20, Jamie Amendolagine <jamie.amendolagine@...> wrote:

So which choice is better for imaging? Or are there situations where one is better than the other??

Jamie


 

Hi Jamie

it's kind of six of one, half dozen of another

generally most folks use sidereal. King Rate accounts for atmospheric refraction but isn't terribly helpful if you are imaging higher in the sky (>30 degrees?)?

Guiding usually takes care of any changes in apparent star motion as well

On Sun, Jul 12, 2020 at 10:21 PM Jamie Amendolagine <jamie.amendolagine@...> wrote:
So which choice is better for imaging? Or are there situations where one is better than the other??

Jamie



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Brian?



Brian Valente
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Sonny Edmonds
 

Since I live in a democracy, I stay away from King rate.
I think it is Imperialistic...

But, I could be wrong. ;^)

--
SonnyE


(I suggest viewed in full screen)


 

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Sonny,

You can live in a democracy and still have a King or a Queen for that matter, they are not mutually exclusive :)

Paul




On 14 Jul 2020, at 6:02:27 am, Sonny Edmonds <sonnyedmonds@...> wrote:

Since I live in a democracy, I stay away from King rate.
I think it is Imperialistic...

But, I could be wrong. ;^)

--
SonnyE


(I suggest viewed in full screen)