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buying advice for first planetary camera for C8

astrophotography beginner Celestron equipment planet SCT
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#1 Dave 123

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Posted 27 September 2020 - 12:07 AM

Hi All,

 

I was recommended to buy the ASI178MC to use with my C8 based on fact that it had the highest resolution (6.4MB) when compared to ASI224MC (1.2) and ASI462MC (2.1).

 

However, using astronomy.tools/calculators/field_of_view/ it seems like the smaller sensors will "zoom" in more on planets than the ASI178MC sensor will using my C8.

 

But the ASI178MC may allow me to capture some DSO's with my reducer.

 

Any advice? Can I crop in with my ASI178MC when capturing the image or afterwards?

 

Thanks in advance,

Dave

Attached Thumbnails

  • C8 x 178 & 224 & 462 Jupiter astronomy_tools_fov.png

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#2 bobzeq25

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Posted 27 September 2020 - 12:56 AM

Buying advice.

 

For DSOs you definitely want a cooled camera, you don't need it for planetary.   There is no cooled 178.

 

You don't "zoom in" and megapixels are unimportant.  Resolution is set by your skies (seeing) mostly, scope aperture (and quality), and pixel size.

 

For planets you don't use the whole chip, just the Region of Interest you need.  That speeds up downloads, and speed is very important for quality.  This is not "zooming in".

 

The larger chip on the 178 is mostly good for lunar.


Edited by bobzeq25, 27 September 2020 - 12:57 AM.

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#3 spereira

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Posted 27 September 2020 - 07:17 AM

Moving to Solar System I&P ...

 

smp



#4 audioengr

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Posted 27 September 2020 - 11:18 AM

I like having more resolution on the planetary camera, as in megapixels, because with a 3X or 4X Barlow, you get a large planet in the frame.  These are bright objects, even with Barlows, particularly if you have a large aperture like 8" or more.  If you are lucky enough to live in low Bortle zone, I think you will pick up more detail on a larger image.  I would go for the 462, which is said to be a perfect planetary camera.  It has very low noise too.  QHY has a very nice version with filters.


Edited by audioengr, 27 September 2020 - 11:19 AM.

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#5 Tulloch

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Posted 27 September 2020 - 08:25 PM

The optimal focal ratio for planetary is around 5x the pixel size of the camera - more pixels is not required for planetary, a 224MC (at f/20) or 462MC (at f/15) is more than sufficient. Cooling is not required for planetary imaging either as the shutter speeds are so low.

 

The only reasons for going to a larger sensor camera is for lunar imaging, capturing all the Jovian moons in a single shot (which is rarely required), or for using the same camera for DSO imaging, in which case you will want a cooled camera.

 

Have a look at these tutorial videos to learn more.

http://planetaryimagingtutorials.com/

 

Andrew


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#6 KTAZ

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Posted 27 September 2020 - 08:33 PM

The optimal focal ratio for planetary is around 5x the pixel size of the camera - more pixels is not required for planetary, a 224MC (at f/20) or 462MC (at f/15) is more than sufficient. Cooling is not required for planetary imaging either as the shutter speeds are so low.

 

The only reasons for going to a larger sensor camera is for lunar imaging, capturing all the Jovian moons in a single shot (which is rarely required), or for using the same camera for DSO imaging, in which case you will want a cooled camera.

 

Have a look at these tutorial videos to learn more.

http://planetaryimagingtutorials.com/

 

Andrew

Hey Andrew;

 

With respect to the 5x pixel size guideline, is that 5x minimum or maximum? KiwiPaul said it is 5x minimum and I thought I’d ask you to confirm. Seems like minimum is logical to ensure the image is large enough to not get pixelated, yes?

 

EDIT: And kudos to the OP for actually doing the research to see what the actual FOV would be on the cameras you are considering. Something so simple to do but rarely done by folks.


Edited by KTAZ, 27 September 2020 - 08:34 PM.

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#7 Tulloch

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Posted 27 September 2020 - 08:45 PM

The 5x is the recommended maximum, above which there is no increase in resolution possible - here's the maths (not worked out by me, btw).

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  • Focal ratio 5x pixel size proof.jpg

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