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New scope for the Mars opposition.

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#51 t.r.

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Posted 26 June 2020 - 07:40 AM

Your experiences are your experiences. Don't sell yourself short. You are the ONLY expert in your experiences and no one can really refute what you experience. Why I was saying mine are in the opposite realm so the true answer obviously exists on a continuum that swings from your aperture always gives you a better experience to mine that aperture does not give a better experience especially in ease of use and for rock steady views. So it is good for others to have both viewpoints, both just as valid. Lets everyone know that there is no one answer and it just depends as a host of variables involved that we will all weight differently per our preferences.

FWIW a 152 Apo can be either a beast or just a husky, all depends on how the observers goes about things. If they must have a triplet and can only deal with gotos and tracking to observe, then yes, what they put together will be a beast for sure. But if they are visual only then a Doublet is sufficient and if they can star hop then an alt-az is fine. In that configuration the entire rig is not heavy at all, maybe 35-40 lbs tops. I lift and carry it mounted so not a big deal. But if I had it on a GEM or something, would be too much of a hassle for me and likely not to observe much with it. Convenience really has a big impact on the observing habit.


This is why I read everything Bill posts...he values others experiences and doesn’t try to argue over who’s got it right!
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#52 ArneN

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Posted 26 June 2020 - 08:40 AM

Option 3, Bill, and probably a MyT.

 

Arne

What does "using a camera" mean exactly? 

  1. Are you going to hold your iPhone up to the eyepiece and snap a pix? 
  2. Or are you going to mount a digital camera on an eyepiece like a Hyperion to shoot pix? 
  3. Or are you going to get a dedicated astro-imaging camera and stack images and do lots of post processing? 

1 and 2 do not really require must skill, and can get away with any mount when taking pics of bright objects.  3 though requires skill and a rock-solid and very expensive tracking mount for any large instrument, plus lots of time at the computer doing post processing.  Are you already adept at doing #3 or will this be new to you?  And what is your primary desire for using a camera -- shoot pics of Moon, planets, closeup DSO, widefield DSO?  Anyway, kind of need to know where you are coming from with the "use a camera" to make reasonable recommendations.

 

And if #3 is the primary intent, then not sure an f/12 CC would be the wisest choice unless one can get a strong reducer to get the focal ratio for a more reasonable for imaging number.  Otherwise your exposures will need to be long which means the mount needs to be be much more precise.  Many refractors have dedicated reducer/flatteners.  But if imaging is the primary and the plan is to go deep rather than wide, then C8, C9.25, C11, C14 would be more convenient and imaging accessory-laden platforms, especially with Faststar.  If planetary the primary then C11 of not C14.



#53 Daniel Mounsey

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Posted 26 June 2020 - 09:46 AM

This is why I read everything Bill posts...he values others experiences and doesn’t try to argue over who’s got it right!

It's verbal judo! lol.gif BTW, BillP has had to deal with a lot of politics so now he's become very skilled at responding tactfully.  lol.gif


Edited by Daniel Mounsey, 26 June 2020 - 09:48 AM.

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#54 Echolight

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Posted 26 June 2020 - 11:55 AM

I would take a C14 if someone gave me one. Probably a little easier to tote around and look through than a big dob.



#55 Bomber Bob

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Posted 26 June 2020 - 12:08 PM

To me, a refractor guy, any mirror- based scope will be a challenge re collimation. But the reviews the new GSO CCs have got here at CN plus Dennis´ in S&T are great.

So I have narrowed it to either a 10 inch CC or a Celestron 9,25 SCT.

I have this summer to think while I am building my RR.

And then there is the mount..........

 

Arne

I don't have any experience with the GSO CC, but I have shared time on a friend's EdgeHD 9.25" mounted on an A-P 1100GTO.  IMO, an outstanding imaging system for an amateur -- WAY more $$$$$ than I'd spend, of course...



#56 ArneN

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Posted 26 June 2020 - 01:02 PM

Hmmh, a 9.25 XLT plus a ZWO 533 is about the same price as a 10 CC.

Might be the way to go.

 

Arne


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#57 Jeff B

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Posted 26 June 2020 - 01:11 PM

It's verbal judo! lol.gif BTW, BillP has had to deal with a lot of politics so now he's become very skilled at responding tactfully.  lol.gif

Bluntly:  "Your face would stop a clock".

 

Tactfully:  "When you're with me, time stands still." 


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#58 sg6

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Posted 26 June 2020 - 02:50 PM

What I have realised over time is that for Mars you need 250x almost as a minimum, many people push up to 300x.

So which one will deliver those magnifications both consistantly and well. Maybe 250x consistantly and well and 300x when conditions allow.

 

Not sure either really would.

My experience of an SCT has been poor, others seem to have better experience.

 

Just realised I should have a chance to view with a 16" DK, hopefully that should be fun. Especially as the DK has a full set of Delos with it.



#59 ArneN

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Posted 26 June 2020 - 03:41 PM

I dont USE EPs!
 

Arnr


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#60 barbie

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Posted 26 June 2020 - 09:53 PM

If my skies hold out till October, I'll be using my 76mm F12.75 Fluorite Apochromat refractor for Mars observation. Last time around, I used an 80mm F15 achromat and got some superb views of Mars with surface detail and polar caps easily visible. I expect my Tak FC76DCUCQ to do even better, if my skies are clear by then.



#61 Cbaxter

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Posted 27 June 2020 - 12:21 AM

What does "using a camera" mean exactly?

  • Are you going to hold your iPhone up to the eyepiece and snap a pix?
  • Or are you going to mount a digital camera on an eyepiece like a Hyperion to shoot pix?
  • Or are you going to get a dedicated astro-imaging camera and stack images and do lots of post processing?
1 and 2 do not really require must skill, and can get away with any mount when taking pics of bright objects. 3 though requires skill and a rock-solid and very expensive tracking mount for any large instrument, plus lots of time at the computer doing post processing. Are you already adept at doing #3 or will this be new to you? And what is your primary desire for using a camera -- shoot pics of Moon, planets, closeup DSO, widefield DSO? Anyway, kind of need to know where you are coming from with the "use a camera" to make reasonable recommendations.

And if #3 is the primary intent, then not sure an f/12 CC would be the wisest choice unless one can get a strong reducer to get the focal ratio for a more reasonable for imaging number. Otherwise your exposures will need to be long which means the mount needs to be be much more precise. Many refractors have dedicated reducer/flatteners. But if imaging is the primary and the plan is to go deep rather than wide, then C8, C9.25, C11, C14 would be more convenient and imaging accessory-laden platforms, especially with Faststar. If planetary the primary then C11 of not C14.

The OP clearly stated that they will by doing lucky imaging of mars. I completely disagree that the OP would need a "rock-solid and very expensive tracking mount." Lucky imaging (video not long exposures) can yield incredible planetary images with as little as an evolution 8 SCT and an ASI224MC in prime focus. I am not trying to be argumentative here nor start a who knows more war, but planetary lucky imaging, as the OP has indicated is the intent, can be done with almost any tracking mount and extremely long effective focal lengths (barlow) to get a desirable planetary image scale. Lucky imaging is very very different than long exposure astrophotography. https://www.astrobin...?page=5&nc=user taken with an AZ mount and ASI224. Mount tracking has very little to do with planetary lucky imaging and 4000mm effective focal lengths are very common for the task. a quick browse of astrobin will show many amazing Mars images taken with even dobsonians and an asi224 in prime focus. Planetary lucky imaging is often shooting at 30 to 60 frames per second in order to catch the very brief moments of steady atmosphere, the planet only need be in the cameras field of view during video capture, tracking is not critical. I will also add that planetary image photo post-processing at the computer often takes considerably less time than traditional long exposure astrophotography post-processing.

Kindest regards.
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#62 Jared

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Posted 27 June 2020 - 01:10 AM

Jared,
Glad you're staying on topic. Not trying to be hard but what classical cass are we talking about and what did the OP say about imaging? Nobody is making a good classical cass these days. The design is a nightmare to do properly. All this talk about classical cass's and nobody is even sharing a review. Also, imaging and visual are black & white issues and do not belong in the same discussions. I would share reviews on the design but I CAN'T. I'm a vendor.


I assume it is one of the GSO classical Cassegrains given the price point he referenced. I have owned one of their 10” RC’s and found it better than I expected optically, but certainly not exceptional. I’m sure the refractor would have a significantly higher Strehl than the CC.

The OP said he was interested in the upcoming Mars opposition in particular for this scope. In a later post he clarified that he would be using the scope photographically using lucky imaging rather than using an eyepiece due to failing eyesight and health issues.
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#63 Jared

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Posted 27 June 2020 - 01:16 AM

What does "using a camera" mean exactly?

  • Are you going to hold your iPhone up to the eyepiece and snap a pix?
  • Or are you going to mount a digital camera on an eyepiece like a Hyperion to shoot pix?
  • Or are you going to get a dedicated astro-imaging camera and stack images and do lots of post processing?
1 and 2 do not really require must skill, and can get away with any mount when taking pics of bright objects. 3 though requires skill and a rock-solid and very expensive tracking mount for any large instrument, plus lots of time at the computer doing post processing. Are you already adept at doing #3 or will this be new to you? And what is your primary desire for using a camera -- shoot pics of Moon, planets, closeup DSO, widefield DSO? Anyway, kind of need to know where you are coming from with the "use a camera" to make reasonable recommendations.

And if #3 is the primary intent, then not sure an f/12 CC would be the wisest choice unless one can get a strong reducer to get the focal ratio for a more reasonable for imaging number. Otherwise your exposures will need to be long which means the mount needs to be be much more precise. Many refractors have dedicated reducer/flatteners. But if imaging is the primary and the plan is to go deep rather than wide, then C8, C9.25, C11, C14 would be more convenient and imaging accessory-laden platforms, especially with Faststar. If planetary the primary then C11 of not C14.

Your comments about wanting a slower scope might be appropriate for deep sky imaging, but for planetary imaging it is likely that the OP would want as much focal length as possible. Barlows are common in planetary imaging, even with C14’s and small pixel cameras.
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#64 Jared

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Posted 27 June 2020 - 01:32 AM

I dont USE EPs!

Arnr


I would recommend asking your question in the Solar System Imaging and Processing forum to get some additional perspectives. Planetary photography does not have the same requirements as visual observing or even deep sky imaging. We may be steering you wrong unintentionally. For example:

- F/12 would be a “problem” for deep sky imaging but is actually an asset for planets.
- Maximum contrast in the optics is hugely important for visual observations of surface details on planets, but drastically less important for imaging
- Lucky imaging with a high frame rate camera may well let you take advantage of extra aperture in ways that would not be possible with an eyeball since the effects of seeing are minimized at 60-100fps
- Mounts with lots of capacity and extremely low periodic error are critical for deep sky imaging at long focal lengths, but are likely much less important with planetary imaging where exposure times per frame are a small fraction of a second. I would expect your MyT to be just fine for anything you are talking about putting on it.

We know our refractors on this forum, but most of the advice you are receiving is from visual observers. I am primarily an astrophotographer, but I don’t know much about planetary imaging, just deep sky. I think you may have more luck with the people on the planetary imaging forum. They can tell you what is critical for success for lucky imaging.
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#65 ArneN

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Posted 27 June 2020 - 01:36 AM

Thanks, Jared!
 

Arne



#66 Bomber Bob

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Posted 27 June 2020 - 09:59 AM

I dont USE EPs!
 

Arnr

I'd rather be at the eyepiece, but I gotta be honest:  In my imaging sessions with my APM 152ED, the "view" of Jupiter on my laptop or tablet screen was awesome!  And, I could sit comfortably, sketch, stretch, have a drink, etc. while the gear did all the work...  So, yeah, I can see the attraction...


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#67 Daniel Mounsey

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Posted 27 June 2020 - 10:08 AM

Imaging planets has never been as nice as what I see visually. 


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#68 Bomber Bob

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Posted 27 June 2020 - 10:31 AM

Imaging planets has never been as nice as what I see visually. 

I agree, and after decades of planetary observing, my brain can "stack" what I see in a way analogous to a digital imaging system -- especially if I sketch at the same time.

 

But, if you physically can't get to an eyepiece; or, you have vision issues, that Big Image on a screen is a reasonable solution. 


Edited by Bomber Bob, 27 June 2020 - 10:31 AM.


#69 ArneN

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Posted 27 June 2020 - 10:36 AM

A clear winter night here in Norway means -15˚C, that is no fun anymore when you are 67.

 

Arne


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#70 BillP

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Posted 27 June 2020 - 10:17 PM

Imaging planets has never been as nice as what I see visually. 

ubetcha.gif


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#71 BillP

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Posted 27 June 2020 - 10:32 PM

Lucky imaging (video not long exposures) can yield incredible planetary images with as little as an evolution 8 SCT and an ASI224MC in prime focus. I am not trying to be argumentative here nor start a who knows more war, but planetary lucky imaging, as the OP has indicated is the intent, can be done with almost any tracking mount and extremely long effective focal lengths (barlow) to get a desirable planetary image scale.

Everything is in the eye of the beholder.  If you feel that 8" of aperture yields "incredible planetary images", no argument that that would be true for your tastes.  But mine, anything less than a C11 I feel is wanting.  This opinion not based on my skill imaging, but what I see the best imagers can do.  Apertures or 9" and less produce some pretty OK images, but they are not interesting, intriguing, or incredible like what a C11 or larger can do.  And the OP's tastes?  Only the OP can answer that.  And for post processing, it is about skill too.  Every time I spend "less" time on post processing still images, well one can certainly tell that.  Critically precise renderings with artificial artifacts smoothed or removed takes time.  Snapshots do not.  Here's a person that is a master at post processing --  bow.gif  https://astronomy-im...mian-peach.html   bow.gif  And again, what is the OP's goal for their planetary imaging, snapshots or perfection or someplace in between?  Only they know that.  And exactly what their goals are can change everything.  Best they address their question in the imaging forum, not here, and provide all the missing details about what all aspects of their goals are for their imaging.


Edited by BillP, 27 June 2020 - 10:36 PM.


#72 Bomber Bob

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Posted 28 June 2020 - 09:45 AM

IMO, I think the OP would enjoy just watching the screen than capturing, stacking, & post-processing.  It's a lot of work for maybe one really nice image from a scope...


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#73 ArneN

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Posted 28 June 2020 - 10:37 AM

Correct!



#74 Bomber Bob

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Posted 28 June 2020 - 11:16 AM

Arne, if you go that route -- camera to screen -- the computer becomes as critical as the camera.  I upgraded my laptop first, to get better video; then, I switched to a Microsoft Surface tablet... much better!



#75 ArneN

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Posted 28 June 2020 - 11:41 AM

Thanks for that advice. My current laptop is an old HP, have been thinking of an upgrade.

Upgrades! That is all this hobby is about......

 

Arne


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