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Choosing a scope for EAA: Newt vs SCT vs APO

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#1 PowerM3

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Posted 12 February 2019 - 03:14 PM

Hi guys and gals, so I have been on a EAA scope binge and thought I would share some sample images and my experiences with choosing a scope for EAA between a Newt, SCT, and APO. I started down the road into EAA about a year ago and remember being so lost in selecting the equipment that would work well. I'm hoping that this might help the newer EAA adventurers out there like me:) I would also be very interested in hearing what choice of scope you came to and why!

 

I have this posted on my blog as its hard to upload decent resolution pictures on here directly.

 

 http://www.avt-astro...-eaa-comparison

 

Best, Vlad. 


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#2 shadowpdiggity

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Posted 12 February 2019 - 05:08 PM

Very nice read. I have an 8"sct and 6" newt. They both have their pluses and minuses. I prefer the sct as of now. I hope to get an apo soon so thus just helped me decide. Thanks for sharing.

#3 bobhen

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Posted 13 February 2019 - 07:53 AM

I did video astronomy for 15 years. It’s really hard to beat the value proposition of an SCT for EAA. They can be used from F2 to F20, have plenty of aperture, are reasonably priced, can be used on GE or Alt/Az mounts with GOTO, are compact and generally portable and are readily available.

 

Bob


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#4 Peter_-_

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Posted 13 February 2019 - 12:49 PM

Hi guys and gals, so I have been on a EAA scope binge and thought I would share some sample images and my experiences with choosing a scope for EAA between a Newt, SCT, and APO. I started down the road into EAA about a year ago and remember being so lost in selecting the equipment that would work well. I'm hoping that this might help the newer EAA adventurers out there like me:) I would also be very interested in hearing what choice of scope you came to and why!

 

I have this posted on my blog as its hard to upload decent resolution pictures on here directly.

 

 http://www.avt-astro...-eaa-comparison

 

Best, Vlad. 

Hi Vlad,

 

I've been learning the constellations and the brighter dso's for about a year too, but with binos; C12x60 and now a little pair of 8x40. I'm very surprised at the low quality of the unprocessed images produced by the SCT  and the Newt in comparison to the refractor.

 

What I really wanted to ask is if visual observations through those results in the same distorted images, and if the refractor is still miles ahead in pin sharp resolution ?



#5 PowerM3

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Posted 13 February 2019 - 02:15 PM

Hi Vlad,

 

I've been learning the constellations and the brighter dso's for about a year too, but with binos; C12x60 and now a little pair of 8x40. I'm very surprised at the low quality of the unprocessed images produced by the SCT  and the Newt in comparison to the refractor.

 

What I really wanted to ask is if visual observations through those results in the same distorted images, and if the refractor is still miles ahead in pin sharp resolution ?

Thanks everyone for the comment. As far as the refractor being sharper visually, for me this is the case at least 50% of the time. The seeing is not very good where I live and larger scopes get affected by seeing more than smaller ones. In general even in good seeing a refractor will produce tighter images especially of stars.



#6 Rickster

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Posted 13 February 2019 - 03:14 PM

Comparing the images is a bit tricky. The SCT and Newt have longer focal lengths and therefore provide magnified image scale. This makes their images appear less crisp than the APO. However, the Newt and the SCT are providing more detail, better resolution and deeper reach. Look closely at some of the fainter stars and details to see this. If the comparison had been performed using a camera having an 4/3 or APS-c sized sensor in the SCT and Newt, and then the images downsized to the same image scale as the 224/APO combination, the SCT and the Newt would have easily won the comparison. In a sense, the OP acknowledged this in his blog, by pointing out that he did not use focal reducers.

Having said that, I do think that this is a good comparison for a beginner to look at. I am only trying to provide clarification, not criticism. In that vein, a good lesson to take away from this comparison is that it is easier to get crisp images from a shorter focal length scope, especially a short APO. And therefore, a short APO is well suited to a beginner. Also, relatively inexpensive astro cams, commonly purchased by beginners, have relatively small sensors and pixels, which make them a nice match for relatively short focal length scope.

But, to be clear, that does not mean that an 80mm APO is a better EAA scope than an 8" SCT or Newt. For example, take a look at some of the work that Astro Jedi, Gofish and Roelb have done with 8" SCTs and Newts and small sensor cameras. And for examples of what can be done with a 8" Newt and an APS-C sensor, take a look at Howie1's youtube videos (under the name "Carl Smith").

Edited by Rickster, 13 February 2019 - 03:16 PM.


#7 Peter_-_

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Posted 13 February 2019 - 07:04 PM

Comparing the images is a bit tricky. The SCT and Newt have longer focal lengths and therefore provide magnified image scale. This makes their images appear less crisp than the APO. However, the Newt and the SCT are providing more detail, better resolution and deeper reach. Look closely at some of the fainter stars and details to see this. If the comparison had been performed using a camera having an 4/3 or APS-c sized sensor in the SCT and Newt, and then the images downsized to the same image scale as the 224/APO combination, the SCT and the Newt would have easily won the comparison. In a sense, the OP acknowledged this in his blog, by pointing out that he did not use focal reducers.

Having said that, I do think that this is a good comparison for a beginner to look at. I am only trying to provide clarification, not criticism. In that vein, a good lesson to take away from this comparison is that it is easier to get crisp images from a shorter focal length scope, especially a short APO. And therefore, a short APO is well suited to a beginner. Also, relatively inexpensive astro cams, commonly purchased by beginners, have relatively small sensors and pixels, which make them a nice match for relatively short focal length scope.

But, to be clear, that does not mean that an 80mm APO is a better EAA scope than an 8" SCT or Newt. For example, take a look at some of the work that Astro Jedi, Gofish and Roelb have done with 8" SCTs and Newts and small sensor cameras. And for examples of what can be done with a 8" Newt and an APS-C sensor, take a look at Howie1's youtube videos (under the name "Carl Smith").

Thanks for clarifying an important point that I had not fully grasped. Evaluating equipment is a very complex issue: a lot more complex than I at first thought. :)


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#8 PowerM3

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Posted 14 February 2019 - 02:53 AM

Comparing the images is a bit tricky. The SCT and Newt have longer focal lengths and therefore provide magnified image scale. This makes their images appear less crisp than the APO. However, the Newt and the SCT are providing more detail, better resolution and deeper reach. Look closely at some of the fainter stars and details to see this. If the comparison had been performed using a camera having an 4/3 or APS-c sized sensor in the SCT and Newt, and then the images downsized to the same image scale as the 224/APO combination, the SCT and the Newt would have easily won the comparison. In a sense, the OP acknowledged this in his blog, by pointing out that he did not use focal reducers.

Having said that, I do think that this is a good comparison for a beginner to look at. I am only trying to provide clarification, not criticism. In that vein, a good lesson to take away from this comparison is that it is easier to get crisp images from a shorter focal length scope, especially a short APO. And therefore, a short APO is well suited to a beginner. Also, relatively inexpensive astro cams, commonly purchased by beginners, have relatively small sensors and pixels, which make them a nice match for relatively short focal length scope.

But, to be clear, that does not mean that an 80mm APO is a better EAA scope than an 8" SCT or Newt. For example, take a look at some of the work that Astro Jedi, Gofish and Roelb have done with 8" SCTs and Newts and small sensor cameras. And for examples of what can be done with a 8" Newt and an APS-C sensor, take a look at Howie1's youtube videos (under the name "Carl Smith").

Thank you for this additional info, I think this is a great clarification. I agree 100% with you in that an APO is not a better instrument 100% of the time in all cases. I guess I just wanted to make it as simple as possible for a 100% noob to compare what they can expect from each kind of instrument with in entry level camera. I totally agree that an advanced EAA'er can get great images from any scope:)



#9 Anduin

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Posted 14 February 2019 - 12:37 PM

I have a SCT9.25, C6, hyperstar and an 71mm apo f4.9 under heavy light pollution.

In my opinion, nothing beats the fun of the 71mm refractor with an electronic filter wheel and sharpcap.

Easier to polar alignment (with sharpcap), easier to plate solve, easier to change filters and I do that a lot in one night, between skyglow, halpha, and no filter. No colllimation issues. You can’t beat overall image quality and easy to use of a the small refractor for eaa. With my asi1600mm I have a 3 degree fov.

Of course for small targets, I have to use longer focal lenghts, than the sct is my choice. By small I mean bellow 20’ of size. Above that I stick to the refractor and zoom the image.

Sculptor galaxy 27’ size with the 71mm apo, skyglow filter, asi1600mm. 15s exposures. 50% zoom on the fly.

fd8ec1f11b65c647947c2f051d45a785.jpg



Enviado do meu iPhone usando Tapatalk

Edited by Anduin, 14 February 2019 - 12:48 PM.

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#10 Rickster

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Posted 14 February 2019 - 01:54 PM

I am impressed with what you can do with that 71mm and the ASI1600.

#11 GaryShaw

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Posted 15 February 2019 - 06:52 PM

Nice images David. What were the basic settings and how much post processing was done on these images? Is this EAA or AP?

best,

Gary



#12 Peter_-_

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Posted 16 February 2019 - 06:07 AM

Nice images David. What were the basic settings and how much post processing was done on these images? Is this EAA or AP?

best,

Gary

 

I think those are really lovely images, and I would very much like to have the skill and technical ability to produce them. smile.gif But you do raise an interesting question: should AP really be called Astro-Photo-Shop , and how much difference is there between those altered photos and just electronically  enhanced images?


Edited by Peter_-_, 16 February 2019 - 06:34 AM.


#13 DSO_Viewer

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Posted 16 February 2019 - 11:54 AM

I think those are really lovely images, and I would very much like to have the skill and technical ability to produce them. smile.gif But you do raise an interesting question: should AP really be called Astro-Photo-Shop , and how much difference is there between those altered photos and just electronically  enhanced images?

I think that once an image is saved to a storage (hard drive, disc, etc) for post-processing then it becomes AP. If the image is live or current as a single or stacked image and adjusted it is still EAA.

 

Steve



#14 DSO_Viewer

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Posted 16 February 2019 - 12:37 PM

Hmmm, Then we need to change the title of Astro Video Image Gallery because then we are all violating the rules of the forum, because we are now taking screen captures of our DSO images and with that statement that once we do a screen capture of a Live Stacked image and calling it AP, we are all in violation. So, taking an iphone pic of your stacked image or doing a screen capture, then we are all essentially doing AP, right?

David I do not know if your quote is from my statement and if it is I will say this " I am talking only post-processing and NOT screen captures unless you are going to process them afterwards".

 

Steve


Edited by DSO_Viewer, 16 February 2019 - 12:38 PM.


#15 roelb

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Posted 16 February 2019 - 07:29 PM

Hi guys and gals, so I have been on a EAA scope binge and thought I would share some sample images and my experiences with choosing a scope for EAA between a Newt, SCT, and APO. I started down the road into EAA about a year ago and remember being so lost in selecting the equipment that would work well. I'm hoping that this might help the newer EAA adventurers out there like me:) I would also be very interested in hearing what choice of scope you came to and why!

 

I have this posted on my blog as its hard to upload decent resolution pictures on here directly.

 

 http://www.avt-astro...-eaa-comparison

 

Best, Vlad. 

I could be wrong but the "SCT-images" look not sharp to me due to bad focusing?



#16 mikenoname

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Posted 16 February 2019 - 09:53 PM

That was my thought as well. It looks to me like the SCT was the only scope in the lineup that did not achieve proper focus.



#17 PowerM3

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Posted 16 February 2019 - 11:15 PM

I could be wrong but the "SCT-images" look not sharp to me due to bad focusing?

Its possible that the focus was a bit off in the SCT. I focused each scope the best I could using SharpCap. Best, Vlad.


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#18 mikenoname

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Posted 16 February 2019 - 11:55 PM

That's why I love my Bahtinov mask. Dirt cheap to buy and perfect focus every session. :)


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