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getting ready to pull trigger on first osc ... what you think

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#1 1hander

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Posted 12 August 2020 - 04:03 PM

hello guys

i finally have gotten around to it and im gettin ready to pull the trigger on a an asi183mc pro 

to go with my WO gt71 with no reducer 

astronomy tools says that im

1.18 pixel scale 

which puts me in good shape for ok seeing of .67-2

but just over the max for good seeing  of .33 to 1 

 

if i could find a camera with 2 micron pixel size it would be perfect.. if you guys got suggestions, please share them.. 

 



#2 Jim Waters

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Posted 12 August 2020 - 04:33 PM

IMO its a waytogo.gif



#3 Peregrinatum

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Posted 12 August 2020 - 04:35 PM

sounds good, do you need a flattener?



#4 cal1mero

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Posted 12 August 2020 - 04:38 PM

I just recently got a similar system : WO GT71 with 0.8x reducer flattener. I also have the asi183MC pro with a ASI290MM mini for guide.
Here is my first try with the system (... and any system) from last weekend of NGC7000. This was taken with a Optolong L-enhanced and quickly processed with DSS and photoshop. This is about 60  2min subs.

 

Please keep in mind that this is my very first astro imaging. I need to learn about astro specific processing as I am a complete newbie. .. but I am quite satisfied with the camera. Sure there are better cameras such as the ASI071 and ASI2600 but they are way more expensive. The ASI183MC has amp-glow quite visible on the darks but this was mostly mitigated by getting enough exposure time and using the darks during the stacking process.

 

For this system I am at 1.48 pixel scale.

 

Hope this will help in your choice. If you can afford you can also look at the ASI294, ASI071 (which would have been my choice for a more money).

 

By the way, I would advise you to get the flattener. My stars are round from edges to edges and it provides you with a slightly larger field of view.

 

NGC7000

 

 


Edited by cal1mero, 12 August 2020 - 04:48 PM.

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#5 Der_Pit

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Posted 13 August 2020 - 06:40 PM

Hehe, I also couldn't resist and had ordered one 5 days ago :D

 

Even smaller pixels would give you substantially smaller full well, i.e., reduce the dynamic range.

 

Don't forget that your 71mm aperture only gives you a 1.45" resolution (or less, depending what formula you use), so I'd rather look at that, than at the seeing, if yours is usually around or better than that.

Seeing better than an arc sec wouldn't give you sharper stars



#6 1hander

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Posted 14 August 2020 - 12:14 AM

The flattener im currently using has no reduction that i can see or find

sounds good, do you need a flattener?



#7 1hander

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Posted 14 August 2020 - 12:16 AM

I just recently got a similar system : WO GT71 with 0.8x reducer flattener. I also have the asi183MC pro with a ASI290MM mini for guide.
Here is my first try with the system (... and any system) from last weekend of NGC7000. This was taken with a Optolong L-enhanced and quickly processed with DSS and photoshop. This is about 60 2min subs.

Please keep in mind that this is my very first astro imaging. I need to learn about astro specific processing as I am a complete newbie. .. but I am quite satisfied with the camera. Sure there are better cameras such as the ASI071 and ASI2600 but they are way more expensive. The ASI183MC has amp-glow quite visible on the darks but this was mostly mitigated by getting enough exposure time and using the darks during the stacking process.

For this system I am at 1.48 pixel scale.

Hope this will help in your choice. If you can afford you can also look at the ASI294, ASI071 (which would have been my choice for a more money).

By the way, I would advise you to get the flattener. My stars are round from edges to edges and it provides you with a slightly larger field of view.


Fing ..awesome ..i hope my first try is half as good as that ..i still need some dewheaters and to finish up power distribution box im designing

#8 1hander

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Posted 14 August 2020 - 12:17 AM

Hehe, I also couldn't resist and had ordered one 5 days ago :D

Even smaller pixels would give you substantially smaller full well, i.e., reduce the dynamic range.

Don't forget that your 71mm aperture only gives you a 1.45" resolution (or less, depending what formula you use), so I'd rather look at that, than at the seeing, if yours is usually around or better than that.
Seeing better than an arc sec wouldn't give you sharper stars


1 day I will understand wat you just said 😌

#9 Der_Pit

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Posted 14 August 2020 - 02:51 AM

1 day I will understand wat you just said

:D

 

  1. Resolution:  Not only seeing limits the resolution of your image, but also the aperture of the optics.  The smaller the aperture, the larger the image it creates from a point source.  So even without any distortion from the atmosphere you aperture (71mm) will create star images of roughly 1.5".  So this is the number you should base your pixel scale computation on....
  2. Full well:  The smaller a pixel 'bucket' is, the less electrons it can hold (the sensor 'converts' light into electrons, and counts those).  Dynamic range is the factor between the brightest and the darkest feature you can measure, so it is something in the order of log(<full well>).  Also, the noise in your image (just from light intensity) is square root of the measured electrons, so the signal-to-noise ratio (SNR) is 1/sqrt(FW) and decreases with less counted photons -> small pixel sensors are noisier and need more sophisticated postprocessing treatment.

Maybe helps making 'one day' being sooner wink.gif


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