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I may sound stupid, but im slowly learning!

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#1 Luke Speed - Turner

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Posted 06 August 2022 - 08:55 AM

Okay so im wondering do you need a field flattener for a dedicated astrophotgraphy camera or is it just needed for dslr astrophotgraphy. Im not sure if i have to buy a field flattener for my ZWO camera.

Many thanks.

#2 daveco2

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Posted 06 August 2022 - 09:15 AM

A field flattener is (may be) required to correct for the field curvature out of the telescope, no matter what type of camera follows it. 



#3 Midnight Dan

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Posted 06 August 2022 - 09:15 AM

A field flattener has nothing to do with the camera.  It corrects the field for the telescope.

 

Most refractor telecscopes produce a in-focus field which is not flat.  Since the camera sensor is flat, that means only part of the field will be in focus on the sensor.  Usually, you focus on the center and the outer areas are soft.  So a flattener must be designed to work for your type of scope (not your camera), to flatten that field and give you sharp stars across the sensor.

 

-Dan


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#4 idclimber

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Posted 06 August 2022 - 09:30 AM

I don't normally like piling on but.... the above is correct, the flattener is matched to the scope. 

 

Welcome to Cloudy Nights. NEVER feel stupid for asking questions here and NO you don't sound that way. This forum is our designated safe space for asking anything about imaging. We have complete novices here daily asking essentially identical questions. 

 

Please use this site and the collective knowledge here to assist you in this wonderfully rewarding endeavor. 


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#5 KTAZ

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Posted 06 August 2022 - 09:43 AM

NOW...If you had asked whether you need a chip curver, THAT would have been stupid!

 

Like @id said, slowly learning is the name of the game with AP. There is no stupid question, and if you try to learn too quickly, you will probably just get frustrated. So much has to be experienced in a tactile way, before many of us truly comprehend what we are doing.

 

As a newcomer, welcome! PLEASE do use the forums, and PLEASE make sure you end threads with whatever solution you may have discovered. It seems a lot of newcomers will just drop a thread when they have realized that they made a "stupid" mistake; but posting back what you discovered can still help many others that will, almost certainly, make that same mistake.


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#6 Notdarkenough

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Posted 06 August 2022 - 09:58 AM

NOW...If you had asked whether you need a chip curver, THAT would have been stupid!

 

Great, now the internet will be flooded with " Sensor Chip Curvers"!



#7 idclimber

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Posted 06 August 2022 - 05:13 PM

I admit that I was once young and naive enough to go on a search for the left handed smoke bender. Like 50 years ago. 


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#8 Spaceman 56

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Posted 06 August 2022 - 06:42 PM

for people starting with imaging a field flattener may not be required.

 

when I shoot an image about 30% of the outside of target gets cropped out anyway, so any curvature or bending at the very 

outside edge is irrelevant anyway. its gone once I crop.

 

but a Flattener/reducer brings down imaging time slightly, which has a value.

 

but for someone starting out, flatteners are not essential IMHO.

 

I took this without a flattener or reducer. processed by Acrh2.

 

Spaceman

 

Alnitak 23rd Feb.

 

 

and this.

 

Rosette Nebulae
 
best wishes Spaceman

Edited by Spaceman 56, 06 August 2022 - 06:43 PM.

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#9 marter

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Posted 06 August 2022 - 08:52 PM

Okay so im wondering do you need a field flattener for a dedicated astrophotgraphy camera or is it just needed for dslr astrophotgraphy. Im not sure if i have to buy a field flattener for my ZWO camera.

Many thanks.

Not all refractors require a field flattener; some have them built in. They are generally known as astrographs and are dedicated to imaging only, vs. imaging or visual. My Askar FRA400 is a Petzval astrograph with a buit-in flattener. Other astrographs include the William Optics RedCat 71. Look for the word astrograph or Petzval. Or call one of the shops and ask them.

 

Good luck on your search.


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#10 Sacred Heart

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Posted 06 August 2022 - 10:24 PM

Okay so im wondering do you need a field flattener for a dedicated astrophotgraphy camera or is it just needed for dslr astrophotgraphy. Im not sure if i have to buy a field flattener for my ZWO camera.

Many thanks.

Okay, field flatteners do flatten the curve of the refractor lens.  That being said, you need to find out the size of the flat circle you are imaging through.  Is the image curved on the edges, look funny??  Your scope lens may be big enough so that your camera sensor is small enough to look through the lens and does not come close to the curved edges.   A field flattener specification should tell you how big the flat circle is.  Not all flatteners give the same size circle of flatness.

 

Take a few pictures and see how the field is.  If it looks flat, the same, side to side and top to bottom - you are good.  If not, get a flattener for you scope and check the size of the flattened circle.  Make sure it is large enough for your camera sensor.

 

Joe



#11 Alex McConahay

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Posted 07 August 2022 - 12:45 AM

By the way—-on the “chip curver” issue

A Schmidt camera is a telescope with a curved sensor. It held the film in a curve matched to the aberration of the telescope.

Alex
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