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Best scope option for Planetary visual and imaging?

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#1 bluesilver

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Posted 18 May 2021 - 05:55 PM

Hi,  Sorry if i have got this in the wring section,  couldn't really find the correct section as it refers to a few different types of scope.

 

So first off i want to move into a completely dedicated scope for use on only Planetary visual and planetary imaging.

 

I currently have a Skywatcher 16" Dobsonian that is on a goto mount.

From my location and i think i have it collimated pretty good,  i can usually use a 100 eyepiece to view Jupiter / Saturn,  and smaller eye piece tends to make the planets start to get a bit fuzzy,  this work out to a magnification of around 180x

 

I was looking to move into something like either the Skywatcher 180/2700 mak,  of a Celestron C14,  two very large price gaps differences i know.

 

Now i have been playing around with the stronomy.tools calculator to find out the difference fields of view that the different scope produce with certain lens.

 

I am hoping some on here might be able to offer a bit of advise on what might be the best way to go.

 

Going from my 16" Dobsonian and working of 180X as the highest magnification available at my site, ( i could be wrong on all this though )

The Skywatcher 180 / 270 mak with a 15mm eye piece give around 180X and a much closer view of Jupiter

The Celestron C14 with a 20mm eye piece give you roughly 195X magnification and a slightly less closer view of Jupiter.

 

Now when i put in the planetary imaging camera  ( ZWO  asi224mc )

the Celestron C14 give the closer image, then the 180/270 mak flowed by the Dobsonian.

 

So i was hoping i might be able to get some advise on what would be the best option to go with there.

A lot say the Dobsonian is a great scope,  bit from what i am seeing is that both the Skywatcher 180/270 mak and the Celestron C14 will give much closer views both through a eyepiece and also via the planetary camera.

 

After all that,  then you come to barlows to get the f-number up to what i believe to be the sweet spot at around f 20.

For the Dobsonian that would be around an 5x barlow and i an thinking for the other two a 2X barlow.

 

Any advice would be greatly appreciated.

Thanks.


Edited by bluesilver, 18 May 2021 - 06:04 PM.


#2 Tulloch

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Posted 18 May 2021 - 06:12 PM

Hi there, the 16" Dob should be a real planet killer, both for viewing and imaging. Going to a smaller diameter is not what you want here, especially reducing down to a 180/270 Mak. The C14 is a fine scope, but if there's nothing wrong with the optics on your current Dob, I wouldn't spend that much money on the C14.

 

For imaging especially, the optimal focal ratio to use is 5x the pixel size of your camera. Assuming your native f/num is around f/5, if you were to get a 3x Barlow and pair it with an ASI462MC then you would be working at a focal length of 5400 mm and achieve excellent resolution. For the ASI224MC you would want to ramp it up to f/20.

 

Here's a sample of what's possible with a 16" (Newt)

https://www.cloudyni...ing-mars-102720

https://www.cloudyni...jupiter-images/

 

If you've never done planetary imaging before, have a look at these tutorial videos.

http://planetaryimagingtutorials.com/

 

Hope this helps,

 

Andrew


Edited by Tulloch, 18 May 2021 - 06:19 PM.

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#3 Jethro7

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Posted 18 May 2021 - 07:34 PM

Hello Bluesilver,

I can add nothing  but a plus 1 for Andrew's post #2. The Dobsonian fits your criteria for what you want to accomplish. Unless you just want another scope and that's as good excuse as any to buy another scope. It has worked for me. 

 

HAPPY SKIES AND KEEP LOOKING UP Jethro



#4 bluesilver

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Posted 18 May 2021 - 09:45 PM

Thanks for the replies,  appreciated.

I really do like the Dobsonian,  I was just trying to work out how to get it to work with Fire Capture though.

My other scopes and mounts that i have all run of Ascom and run of a laptop.

The Dobsonian being goto doesn't really have this option for FireCapture to move the mount to keep the image in the center.

 

I was hoping to use FireCaputure as it is a good program for this type of work.

 

Can the Dobsonian work with FireCaputure for this,  if so you are correct,  it would be the pick of the bunch.

 

Sorry for these basic questions.



#5 Tulloch

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Posted 18 May 2021 - 10:13 PM

I (like most planetary imagers) use FireCapture exclusively for planetary imaging. Track the planet with the goto mount, control the camera with FC. It's that easy. Firecapture even has a mode where it will keep the target in the center of the ROI (region of interest), all you need to do the nudge the scope every now and then to keep it on the sensor.

 

Watch the tutorial videos mentioned above, they will help :).



#6 bluesilver

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Posted 18 May 2021 - 11:06 PM

Thanks again for the reply,  I will check out the tutorials again.

I am use to the Ascom driving the mount rather than manually.

I have always been using a Refractor to image with,  ( planets and DSO )

But it is worth giving it a try with the Dobsonian,  just for some weird reason i haven't tried it with FireCapture 

I see that fireCapture keeps the target in the center of the ROI,  i have always had the mount moving with FireCapture.

 

But appreciate the advice for sure,  if it can be done with a Dobsonian on a goto mount,  that will be the way to go for sure.




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