Your recommended planetary scope?

[Flame Nebula]

Hi Everyone 

I would like to ask what your favourite planetary scope is for visual and imaging? 

I'm torn between a C9.25 and 10" Newtonian, but I'm not even sure these are best choice. I'd love to have the benefit of your experience on planetary observation in uk. 

Thanks 

Mark 

[dweller25]

The 10” Newtonian was the best planetary telescope I ever had 👍

Edited March 5 by dweller25

[Flame Nebula]

6 minutes ago, dweller25 said:

The 10” Newtonian was the best planetary telescope I ever had 👍

Hi Dweller, 

Which make was it? Dobsonian or EQ? 

Thanks 

Mark

[dweller25]

Skywatcher 10” Dobsonian.

Times have moved on though and either the Stellalyra or Bresser variants would be my choice now.

Edited March 7 by dweller25

[mikeDnight]

Visual and imaging are two different things. Out of the two scopes you mention, the Newtonian would be the better visual scope, while the SCT would likely be the better planetary imaging scope. As a purely visual observer I'd choose neither. Although a 10" Newt' or Dob' will show an immense amount of detail, I find them cumbersome. 

 It's worth noting that the excellent British lunar observer Harold Hill began his lunar studies using a 6.25" Newtonian. Harold became famous because of his superb lunar drawings, and over time he moved up in aperture to a 10" F10 Newtonian.  Years passed by, then eventually Harold had opportunity to observe with his old 6.25" reflector that he'd used decades earlier. In side by side comparison, Harold commented that although "the image was dimmer in the 6.25""", he "could still see all the same detail visible in the 10" F10". It's food for thought!  You could perhaps get the SCT for imaging, and also a lovely 6" F8 Newtonian with tracking eq5, or Dobsonian reflector for visual. Using a binoviewer will greatly improve the ease with which more intricate and subtle planetary detail can be see. 

Then again you could get a nice 4" to 6" apo refractor and just enjoy the ride! 

As a comparison you can examine the two sketches of Mars below, one made using an excellent 8" Newtonian reflector, and the other made using an excellent 4" Apo refractor. Although there are differences in the level of detail, they are not that different. Which do you prefer?

And the scopes used:

Another worthy consideration is the generally hit and miss seeing conditions. During the 2016 apparition of Mars the planet was extremely low, and many observers simply gave up hope of seeing anything worthwhile on its small, boiling disc. The atmospheric conditions didn't have a crippling effect on the 4" refractor, at least not to the same degree, and this allowed me to make 36 detailed disc drawings leading to a cylindrical grid map and a small globe being produced from the observations. Not bad for a small but excellent refractor!

Of course it's not just Mars that responds well to observation in a small refractor.

 

Edited March 5 by mikeDnight

[Flame Nebula]

19 minutes ago, mikeDnight said:

Visual and imaging are two different things. Out of the two scopes you mention, the Newtonian would be the better visual scope, while the SCT would likely be the better planetary imaging scope. As a purely visual observer I'd choose neither. Although a 10" Newt' or Dob' will show an immense amount of detail, I find them cumbersome. 

 It's worth noting that the excellent British lunar observer Harold Hill began his lunar studies using a 6.25" Newtonian. Harold became famous because of his superb lunar drawings, and over time he moved up in aperture to a 10" F10 Newtonian.  Years passed by, then eventually Harold had opportunity to observe with his old 6.25" reflector that he'd used decades earlier. In side by side comparison, Harold commented that although "the image was dimmer in the 6.25""", he "could still see all the same detail visible in the 10" F10". It's food for thought!  You could perhaps get the SCT for imaging, and also a lovely 6" F8 Newtonian with tracking eq5, or Dobsonian reflector for visual. Using a binoviewer will greatly improve the ease with which more intricate and subtle planetary detail can be see. 

Then again you could get a nice 4" to 6" apo refractor and just enjoy the ride! 

As a comparison you can examine the two sketches of Mars below, one made using an excellent 8" Newtonian reflector, and the other made using an excellent 4" Apo refractor. Although there are differences in the level of detail, they are not that different. Which do you prefer?

And the scopes used:

Another worthy consideration is the generally hit and miss seeing conditions. During the 2016 apparition of Mars the planet was extremely low, and many observers simply gave up hope of seeing anything worthwhile on its small, boiling disc. The atmospheric conditions didn't have a crippling effect on the 4" refractor, at least not to the same degree, and this allowed me to make 36 detailed disc drawings leading to a cylindrical grid map and a small globe being produced from the observations. Not bad for a small but excellent refractor!

Of course it's not just Mars that responds well to observation in a small refractor.

 

Thanks Mike, for this wonderful reply! 

I was toying with the idea of an az-eq6 mount for the C9.25 if I got one. In principle I could put a 6" scope on it at the same time in alt az mode. I need to account for the fact I also have a 127mm mak and 80ed, and I'd like to use the latter for dso AP, since I also have a D7000 dslr. Seems a waste not to utilise these, which I can't do with a dobsonian mount. I think the 6" F8 might be a nice compliment to these. I'll investigate further. The 4" apo is very tempting - I hear great things about these scopes. But  they're very expensive and I suspect a 6" f8 would match them for a fraction of the cost?

Thanks 

Mark 

[Flame Nebula]

8 minutes ago, Flame Nebula said:

Thanks Mike, for this wonderful reply! 

I was toying with the idea of an az-eq6 mount for the C9.25 if I got one. In principle I could put a 6" scope on it at the same time in alt az mode. I need to account for the fact I also have a 127mm mak and 80ed, and I'd like to use the latter for dso AP, since I also have a D7000 dslr. Seems a waste not to utilise these, which I can't do with a dobsonian mount. I think the 6" F8 might be a nice compliment to these. I'll investigate further. The 4" apo is very tempting - I hear great things about these scopes. But  they're very expensive and I suspect a 6" f8 would match them for a fraction of the cost?

Thanks 

Mark 

I forgot to answer your question - I prefer the 4" apo drawing you did of Mars. Is it my imagination or were the dark parts, darker than you observed in the Newtonian? 

[Flame Nebula]

9 minutes ago, Flame Nebula said:

Thanks Mike, for this wonderful reply! 

I was toying with the idea of an az-eq6 mount for the C9.25 if I got one. In principle I could put a 6" scope on it at the same time in alt az mode. I need to account for the fact I also have a 127mm mak and 80ed, and I'd like to use the latter for dso AP, since I also have a D7000 dslr. Seems a waste not to utilise these, which I can't do with a dobsonian mount. I think the 6" F8 might be a nice compliment to these. I'll investigate further. The 4" apo is very tempting - I hear great things about these scopes. But  they're very expensive and I suspect a 6" f8 would match them for a fraction of the cost?

Thanks 

Mark 

I forgot to answer your question - I prefer the 4" apo drawing you did of Mars. Is it my imagination or were the dark parts, darker than you observed in the Newtonian? 

 

• Quote

[mikeDnight]

15 minutes ago, Flame Nebula said:

I forgot to answer your question - I prefer the 4" apo drawing you did of Mars. Is it my imagination or were the dark parts, darker than you observed in the Newtonian? 

Yes they were darker or better defined. This may be due to the light mist that somehow steadied the view, or possibly because the brighter image of the 8" overpowered the subtle detail. I've heard someone recently say that large apertures can cause overexposure of the view because of their excessive light grasp, and in so doing, wash out the finest detail. This comment was in relation to fine lunar detail but it seems reasonable to assume the same could apply to the planet's. Saturn could be a case in point, especially when the rings are wide open, as the ultrafine detail gives the impression of the rings on a vynil record. I've seen this level of detail in scopes as small as 4" aperture. So there's a genuine reason why a 4 or 5 inch refractor may give better definition than an 8 or 10 inch reflector. Incidentally, the very best view of Saturn that I ever had, wasn't through a refractor, it was through an old 4.5" F11 Newtonian, which left the beautiful 4" Vixen Fluorite standing alongside it in the dust. Just when you think you've got everything under your belt in this game, something like this happens, and undermines everything you thought you knew as fact. 

[The60mmKid]

3 hours ago, Flame Nebula said:

Hi Everyone 

I would like to ask what your favourite planetary scope is for visual and imaging? 

I'm torn between a C9.25 and 10" Newtonian, but I'm not even sure these are best choice. I'd love to have the benefit of your experience on planetary observation in uk. 

Thanks 

Mark 

Hi Mark,

How is the seeing where you live, typically? Will your scope be set up outside in a dome, or will you take it outside from your home when you observe?

[John]

I don't image but my current favourite planetary scope is either a 4 or 5 inch refractor. More often it's a 4 inch because of the unsettled weather we have had in the UK lately. 

In the past I have had fabulous planetary views with a 12 inch F/5.3 dobsonian when the planets were high in the sky but as the planets got lower and lower  I found refractors usually doing a better job of cutting through the atmosphere.

As the planets start to achieve higher positions in the sky again I might be tempted by something like a 10 inch F/6.3 newtonian again. We will have to see 🙂

 

[Cosmic Geoff]

I think that any kind of scope could be used as a planetary scope, with the exception of short-focus achromatic refractors.  Aperture is desirable, the more the better, the constraints being budget, portability, and the greater sensitivity of big scopes to poor seeing.

If you want to image, the SCT scores on account of having a wide focal range, meaning you can attach a camera, diagonal, filter wheel, or flip mirror or some combination of these, without any danger of being unable to get focus.  With a Newtonian you may find that you can't even attach a camera without having to modify the scope, and anything like a flip mirror will be a no-no.

Then there is the question of the mount. A big scope, if you require GoTo, requires a heavy expensive mount and , and in large sizes, maybe  even a permanent observatory.  Here again the SCT scores in the larger sizes as it is shorter and lighter than an equivalent Newtonian and the mount requirement scales accordingly.

If you are not going to image,  a Dobsonian will offer a big cost saving over a SCT or German equatorial mounted Newtonian

 

[Flame Nebula]

1 hour ago, The60mmKid said:

Hi Mark,

How is the seeing where you live, typically? Will your scope be set up outside in a dome, or will you take it outside from your home when you observe?

Hi, I'm not sure about the seeing in my area, if I'm being honest. The scope would likely be stored indoors if an sct or the garage if a newt. I'm aware of cool down issues. I think that if I'd heard more favourable comments about the C9.25 with respect to visual observation, I would be going for it. I'm interested in visual observation but would like to do planetary AP too. 

Thanks 

Mark 

[John]

5 minutes ago, Flame Nebula said:

Hi, I'm not sure about the seeing in my area, if I'm being honest. The scope would likely be stored indoors if an sct or the garage if a newt. I'm aware of cool down issues. I think that if I'd heard more favourable comments about the C9.25 with respect to visual observation, I would be going for it. I'm interested in visual observation but would like to do planetary AP too. 

Thanks 

Mark 

Here in the UK the positioning of the Jetstream can make a lot of difference to the quality of the seeing conditions. This can vary hour to hour.

When the Jetstream is positioned overhead, the seeing (and therefore planetary sharpness and contrast) can be awful in whatever scope you are using. 

 

[Flame Nebula]

23 minutes ago, John said:

Here in the UK the positioning of the Jetstream can make a lot of difference to the quality of the seeing conditions. This can vary hour to hour.

When the Jetstream is positioned overhead, the seeing (and therefore planetary sharpness and contrast) can be awful in whatever scope you are using. 

 

I think that's probably why the C9.25 would best be suited to planetary AP, as hopefully an imaging camera taking lots of short exposures would capture a certain % of sharper moments. I'm tempted by the idea that MikeDknight suggested of a C9.25 for AP and a 6" F8 for visual. 

Mark

[The60mmKid]

6 hours ago, Flame Nebula said:

Hi, I'm not sure about the seeing in my area, if I'm being honest. The scope would likely be stored indoors if an sct or the garage if a newt. I'm aware of cool down issues. I think that if I'd heard more favourable comments about the C9.25 with respect to visual observation, I would be going for it. I'm interested in visual observation but would like to do planetary AP too. 

Thanks 

Mark 

If you're in an area with variable seeing, as many of us are in the UK, and the scope will need to thermally acclimate each time you use it, then I'd recommend the 4" refractor for the reasons others have shared.

An SCT can be an excellent visual observing instrument, and the C9.25 is highly regarded as such. But a couple of the reason many observers in the UK prefer refractors are the seeing conditions (a smaller telescope with fine optics is less stymied than a larger telescope from reaching its full resolving potential under poor-average seeing) and the refractor's ability to thermally acclimate far more quickly than other telescope designs. Both of these factors are crucial yet often underestimated.

It's also worth considering that a larger SCT or newt will require a beefier mount than a 4" refractor, for visual and especially for imaging. Setting up a heavy mount can become a chore and deterrent over time.

One can do a lot with a 4" refractor. @mikeDnight sketches are incontrovertible evidence! If I lived somewhere with steady temperatures and steady air, I'd certainly favor larger scopes. But here in the UK... 😁

[Ratlet]

Lot of great comments here but one thing I found is that observing is a skill that you'll learn.  How much power to use, how to discern detail amongst the brightness.  It all comes with time.  Don't be surprised if your first looks don't seem impressive.

One weird thing though is once you 'see' something it becomes easier to see the next time.  It's like your brain pump has been primed.

At least that's my experience as a very green observer.

[Flame Nebula]

59 minutes ago, The60mmKid said:

If you're in an area with variable seeing, as many of us are in the UK, and the scope will need to thermally acclimate each time you use it, then I'd recommend the 4" refractor for the reasons others have shared.

An SCT can be an excellent visual observing instrument, and the C9.25 is highly regarded as such. But a couple of the reason many observers in the UK prefer refractors are the seeing conditions (a smaller telescope with fine optics is less stymied than a larger telescope from reaching its full resolving potential under poor-average seeing) and the refractor's ability to thermally acclimate far more quickly than other telescope designs. Both of these factors are crucial yet often underestimated.

It's also worth considering that a larger SCT or newt will require a beefier mount than a 4" refractor, for visual and especially for imaging. Setting up a heavy mount can become a chore and deterrent over time.

One can do a lot with a 4" refractor. @mikeDnight sketches are incontrovertible evidence! If I lived somewhere with steady temperatures and steady air, I'd certainly favor larger scopes. But here in the UK... 😁

Thanks for this useful information. Obviously for visual, alt az is preferred. What mount would you use for a 4" Refractor? And which make of refractor would you buy? 

[johnturley]

On 06/03/2024 at 01:28, Flame Nebula said:

Hi, I'm not sure about the seeing in my area, if I'm being honest. The scope would likely be stored indoors if an sct or the garage if a newt. I'm aware of cool down issues. I think that if I'd heard more favourable comments about the C9.25 with respect to visual observation, I would be going for it. I'm interested in visual observation but would like to do planetary AP too. 

Thanks 

Mark 

Based on the comments observers have made in other threads, there does seem to be a lot of variability in the optical quality of C9.25's, if you get a good one it will be an excellent planetary scope, and at the time I got mine they were highly recommended by Damien Peach (a renowned planetary imager), and some claimed that they gave better results on planets than the C11, due to the longer focal ratio of the primary mirror. I don't know whether the quality control is better with the Edge HD versions, but they are a lot more expensive, although the 8in Edge HD works out about the same price as the 9.25 XLT.

My C9.25 was quite good on planets, but other observers have said that theirs' gave mushy views, and were outperformed by a 4in APO. Unfortunately I never got round to doing a side by side shoot out with my 14in Newtonian and Esprit 150 (which is an excellent planetary scope, but big and heavy), before I sold my C9.25. As I stated in another thread, I would not recommend the CPC version of the C9.25, as (especially with suffering from back problems), I found the combined OTA and fork mount too heavy to lug around)

John 

Edited March 7 by johnturley

[John]

1 hour ago, Ratlet said:

Lot of great comments here but one thing I found is that observing is a skill that you'll learn.  How much power to use, how to discern detail amongst the brightness.  It all comes with time.  Don't be surprised if your first looks don't seem impressive.

One weird thing though is once you 'see' something it becomes easier to see the next time.  It's like your brain pump has been primed.

 

Absolutely "nail on the head" stuff there 👍

Observing planetary detail is a real skill that has to be worked at. Sketching what you are looking at helps the process and makes you "look" harder, even if you don't do anything with the sketches later.

There are also plenty of nights when the seeing will not permit larger apertures to really show what they can do. You might get occasional glimpses during the moments of good seeing which is why prolonged study of a target is needed to pick out the most detail.

Very occasionally you get a night when it all comes together but a lot of the time the seeing conditions will favour the smaller aperture scope, acting as a kind of "aperture equaliser".

And of course for some of the year, the interesting planets will not be well placed for observing so you need to find something else to look at 🙂

Edited March 6 by John

[The60mmKid]

8 minutes ago, John said:

And of course for some of the year, the interesting planets will not be well placed for observing so you need to find something else to look at 

Such as astronomy forums 🙃

[Flame Nebula]

11 minutes ago, John said:

Absolutely "nail on the head" stuff there 👍

Observing planetary detail is a real skill that has to be worked at. Sketching what you are looking at helps the process and makes you "look" harder, even if you don't do anything with the sketches later.

There are also plenty of nights when the seeing will not permit larger apertures to really show what they can do. You might get occasional glimpses during the moments of good seeing which is why prolonged study of a target is needed to pick out the most detail.

Very occasionally you get a night when it all comes together but a lot of the time the seeing conditions will favour the smaller aperture scope, acting as a kind of "aperture equaliser".

And of course for some of the year, the interesting planets will not be well placed for observing so you need to find something else to look at 🙂

Thanks John. 

I do hear stories of 4" apos being capable of 200+ magnification without image becoming 'fuzzy'. Any new scope must be capable of seeing sirius B and the e and F stars in trapezium. I've failed to ever do this with my current scopes (80ed,127mm mak), but I've heard 4" apo stories that often bag these. My 127mm mak maxed out at around 140x mag before bloating kicked in. I think with 200x and sharp stars, a 4" may out perform my mak. 

[Cosmic Geoff]

My personal relevant experience was that visual observing of planets was a somewhat disappointing activity.  I could reveal much more detail by imaging.  For instance, with my 127mm Mak I'm not sure if I ever saw the Great Red Spot visually, but I managed to image the GRS easily.

Re. SCT vs Newtonian, my C8 SE performed rather better on double stars than my 8" Newtonian (now sold).  I also found that SCT performance was significantly affected by an almost un-noticeable error of collimation, only revealed by a side-by-side test with two 8" SCTs.

 

[Mr Spock]

I had a C9.25 for close to ten years. It never really performed unless the seeing conditions were perfect. Most of the time it was, put it out to cool, go back hours later, see how mushy the view was, bring it back inside.

The 10" Newtonian I had prior to that was superior in every way. It was just too bulky to lift on to my EQ6. I had my best ever views of Mars with that scope. It was just an ordinary blue tube Skywatcher, but it performed well.

These days I use my 4" apo most of the time. When the seeing is good I get the StellaLyra 12" Dob out. That spanks everything else I've ever looked through.

[Flame Nebula]

21 minutes ago, Cosmic Geoff said:

My personal relevant experience was that visual observing of planets was a somewhat disappointing activity.  I could reveal much more detail by imaging.  For instance, with my 127mm Mak I'm not sure if I ever saw the Great Red Spot visually, but I managed to image the GRS easily.

Re. SCT vs Newtonian, my C8 SE performed rather better on double stars than my 8" Newtonian (now sold).  I also found that SCT performance was significantly affected by an almost un-noticeable error of collimation, only revealed by a side-by-side test with two 8" SCTs.

 

Hi Cosmic Geoff, 

My clear preference would be one scope, C9.25 on an AZEQ6. But my confidence level for the visual side is 50%. This scope has such a mixed bag of positive and negative comments. If it was a cheap scope, I'd gamble on it, but it certainly isn't cheap. If I could afford it, I'd get this and a 4" apo, then I'd be confident on the AP and visual obs front. I'm not so bothered about faint fuzzies. Sharpness and contrast is important to me, and I'm also interested in splitting tight doubles. The az-eq6 mount could also be used with my ed80 for dso AP.