Pick 2 from 5 of these scopes:

[Flame Nebula]

Challenge : to pick two of the scopes below, so that the best blend of abilities is obtained on planetary and double stars, with respect to visual and planetary AP, with minimal overlap. Assume az-eq6. 

SW 120 ED

SW 150 ED

SW 180 mm mak 

C9.25 

C11 

Additional info: I already own a 127mm mak 

I'm hoping that there is enough experience in this forum (based on what I've seen, there is! 🙂) to help me avoid 'double - handling'. 

Looking forward to your help! 

Mark

 

[Cosmic Geoff]

I don't see why you would need two from this list. Just buy one of them.   I would need some convincing that the 120ED would be much of an advance on the 127mm Mak.

[M40]

Of those telescopes, the only one I have and use is the skymax180. It is a very fine telescope for solar system and doubles and even fully loaded would sit well on the eq6. 

Just to add, have a close look at a stellalyra 8" cc. May be one to add to your list.

All the best 

Edited March 16 by M40

[Flame Nebula]

9 minutes ago, Cosmic Geoff said:

I don't see why you would need two from this list. Just buy one of them.   I would need some convincing that the 120ED would be much of an advance on the 127mm Mak.

Hi Cosmic Geoff, 

Well, the list is based on wanting to do both visual observation and planetary AP. If I hadn't read several comments on this forum about mushy views from SCT scopes for visual, I would pick the C9.25. However, I don't like mushy views😬. I love sharp, contrasty views. Hence it could be the case, that two scopes can provide me with a blend of desired visuals, and good AP planetary. I have read some reports that indicate the 127mm mak is not as good as the 120 mm ed for doubles and planets. Is that what people on this forum think? Or would the better choice be to go for SW 150 ED for visual, and C9.25 for planetary AP. 

So, this is the main thinking behind the question. So, if anyone has direct experience with using any combination of these scopes, it would be very useful to hear their thoughts. I know at least one person here has the 150ED and C9.25 combination and it fulfils their requirements, but there are other permutations as well🙂

[Cosmic Geoff]

1 hour ago, Flame Nebula said:

mushy views from SCT scopes for visual

Not necessarily an inherent feature of SCT scopes.  The manufacturing quality seems to have been variable in the past. I have found them sensitive to slight mis-collimation.  Some people claim the EDGE HD models perform better visually.   Also ED vs SCT is not a level comparison, as (unless you can afford an 11" ED or APO) the ED scopes will have a smaller aperture and hence less vulnerable to atmospheric churn.

In theory, (asides from the effect of any central obstruction) you might get the same effect by stopping down the larger scope. 

[Flame Nebula]

1 hour ago, Cosmic Geoff said:

Not necessarily an inherent feature of SCT scopes.  The manufacturing quality seems to have been variable in the past. I have found them sensitive to slight mis-collimation.  Some people claim the EDGE HD models perform better visually.   Also ED vs SCT is not a level comparison, as (unless you can afford an 11" ED or APO) the ED scopes will have a smaller aperture and hence less vulnerable to atmospheric churn.

In theory, (asides from the effect of any central obstruction) you might get the same effect by stopping down the larger scope. 

Thanks Geoff, 

I agree with you that ED vs SCT is not a level comparison, but that's why I'm thinking that a combination of both may be the best of both worlds. 🙂, i. e. The ED scopes may be better for sharp, contrasty visual observation, whilst the larger diameter SCTs will almost certainly be better for planetary AP, which is very much aperture dependent. I just need to hear some  real world experiences from people who ideally have used combinations of these scopes for the type of purpose I've mentioned. 

 

[mikeDnight]

Visual:  120ED 

Imaging planetary:   C9.25 - though it would be a waste as I'd never image with it! It would make a potentially nice visual deep sky scope though!

[Flame Nebula]

2 minutes ago, mikeDnight said:

Visual:  120ED 

Imaging planetary:   C9.25 - though it would be a waste as I'd never image with it! It would make a potentially nice visual deep sky scope though!

Thanks Mike, 

You think the 120 mm ed would be a good step up from the 127mm mak then. I also have a 80 mm ed, I plan to do dso AP with, and in general I find it can hold its own against the mak, and seems to have a higher magnification per inch threshold before image starts to 'unsharpen'. So, I do suspect the 120 mm ed would remain sharper at high mags. I also saw one of these for £700 on astrobuysell recently, that's half new price. 

[vlaiv]

C11, ED150 for photo and visual respectively

[Earl]

having owned the SW 180 mm mak C9.25 C11 

A hand picked (by someone who knows about them in good detail) C9.25 is probably the best choice of those.

Edited March 16 by Earl

[Flame Nebula]

51 minutes ago, Earl said:

having owned the SW 180 mm mak C9.25 C11 

A hand picked (by someone who knows about them in good detail) C9.25 is probably the best choice of those.

Hi Earl, 

Do you know if FLO will hand pick? If not, who would do that? 

Thanks 

[mikeDnight]

1 hour ago, Flame Nebula said:

Thanks Mike, 

You think the 120 mm ed would be a good step up from the 127mm mak then.

Most definitely! I've seen a 120ED give significantly better lunar views than an excellent 200mm Dob; so much so in fact that the observers I was with were in disbelief at first. Then when both scopes were aimed at Saturn, the air turned blue with expletives, as they learned an important lesson - aperture isn't always King!

[Flame Nebula]

57 minutes ago, vlaiv said:

C11, ED150 for photo and visual respectively

Hi vlaiv, 

Certainly a potent combo! I did see a used C11 for £1000 recently. Strangely, hardly ever see used C9.25 on astrobuysell though. 

[Flame Nebula]

2 minutes ago, mikeDnight said:

Most definitely! I've seen a 120ED give significantly better lunar views than an excellent 200mm Dob; so much so in fact that the observers I was with were in disbelief at first. Then when both scopes were aimed at Saturn, the air turned blue with expletives, as they learned an important lesson - aperture isn't always King!

Thanks Mike, 

Very interesting indeed! 

[Earl]

6 minutes ago, Flame Nebula said:

Hi Earl, 

Do you know if FLO will hand pick? If not, who would do that? 

Thanks 

You would need to ask a specialist into which years are the best (bit like guitars) FLO might be able to help im not sure.

[vlaiv]

6 minutes ago, Flame Nebula said:

Hi vlaiv, 

Certainly a potent combo! I did see a used C11 for £1000 recently. Strangely, hardly ever see used C9.25 on astrobuysell though. 

There could be a number of reasons for that, but the fact is - if both scopes are diffraction limited (and I'm guessing they should be in 95% of cases) - C11 is simply better imaging platform. You can't beat the laws of physics, larger aperture allows for sharper image.

[Flame Nebula]

1 minute ago, vlaiv said:

There could be a number of reasons for that, but the fact is - if both scopes are diffraction limited (and I'm guessing they should be in 95% of cases) - C11 is simply better imaging platform. You can't beat the laws of physics, larger aperture allows for sharper image.

I have seen good images of saturn (my benchmark target) with both scopes, although probably more with C11. Certainly, Damien Peach showed the C9.25 is very capable. (not sure if he'd have done so well in the UK seeing🤔) 

[Earl]

5 minutes ago, vlaiv said:

There could be a number of reasons for that, but the fact is - if both scopes are diffraction limited (and I'm guessing they should be in 95% of cases) - C11 is simply better imaging platform. You can't beat the laws of physics, larger aperture allows for sharper image.

all depends on the qulity of the specific scope, its not mathematically black and white as there is no way of taking into acount the differences in build quality over the years.

Edited March 16 by Earl

[vlaiv]

1 minute ago, Earl said:

all depends o the qulity of the specific scope, its not mathematically black and white as there is no way of taking into acount the differences in build quality over the years.

In imaging it is much more "black and white" than in visual.

When observing - we can't exclude effects of seeing, nor can we increase contrast nor sharpen the image. We do all of that regularly when imaging and that sort of levels the playing field between different quality scopes. Of course, neither should be a lemon, but you'd be surprised what can be recorded with even moderate quality telescope.

For example - this image was taken with 5" newtonian with spherical mirror (F/6.9):

That is remarkable level of detail for such scope and visual on such scope won't come anywhere near, but take any Jupiter image taken with any 5inch scope and you'll see about the same level of detail

[Earl]

1 minute ago, vlaiv said:

In imaging it is much more "black and white" than in visual.

When observing - we can't exclude effects of seeing, nor can we increase contrast nor sharpen the image. We do all of that regularly when imaging and that sort of levels the playing field between different quality scopes. Of course, neither should be a lemon, but you'd be surprised what can be recorded with even moderate quality telescope.

For example - this image was taken with 5" newtonian with spherical mirror (F/6.9):

That is remarkable level of detail for such scope and visual on such scope won't come anywhere near, but take any Jupiter image taken with any 5inch scope and you'll see about the same level of detail

If you could guratee the quality of the scopes howver I am very aware of a very large amount of variance in both the C9.25 and C11 a good C9.25 will outperform an average C11

[vlaiv]

Just now, Earl said:

If you could guratee the quality of the scopes howver I am very aware of a very large amount of variance in both the C9.25 and C11 a good C9.25 will outperform an average C11

If both are diffraction limited - Strehl >0.8, for imaging it won't.

[Elp]

It won't win any awards but this was one of my first attempts at Jupiter with a 60mm refractor:

A lot of those scopes on the list are quite close together. I'd rather have a widefield short FL refractor and a long FL scope if only having two scopes, in fact that's exactly what I have barring the third which sits in the middle (Z61, SF102, C6).

Visually in the Z61 Jupiter is around 4-5mm in real size, but you can see a lot of banding detail as it's so sharp.

[Flame Nebula]

19 minutes ago, Elp said:

It won't win any awards but this was one of my first attempts at Jupiter with a 60mm refractor:

A lot of those scopes on the list are quite close together. I'd rather have a widefield short FL refractor and a long FL scope if only having two scopes, in fact that's exactly what I have barring the third which sits in the middle (Z61, SF102, C6).

Visually in the Z61 Jupiter is around 4-5mm in real size, but you can see a lot of banding detail as it's so sharp.

Hi Elp, 

It's wanting visual and planetary AP that complicates matters. I have an ed80 which I will use for dso AP. But, if the sct9.25 isn't cutting it visually, it would be good to have a good backup that's better than my current scopes. With the az-eq6 mount, I could mount two scopes. Whilst sct cooling, I would use other one. 

[Elp]

I dont particularly like the views via my C6 if I compare it to my refractors both of which are apochromatic. The FOV I find restrictive. If using it on a manual alt az mount is also becomes a pain to use due to the FOV and FL, on planets it isn't so much of an issue but can be if trying to manually find the far outer planets. The 100mm refractor is far better to use as a visual instrument. The 60mm refractor I have is the most utilised as I've used it for everything, visual, AP, planetary, DSO, WL solar and HA solar, I find it's only limiting factor is focal length, but being able to frame M45 and other open clusters as well as the moon and sun full disks trumps that requirement. If I need FL the other scopes can do that.

After an apo refractor I find newtonians also offer excellent views.

Edited March 16 by Elp

[Flame Nebula]

2 minutes ago, Elp said:

I dont particularly like the views via my C6 if I compare it to my refractors both of which are apochromatic. The FOV I find restrictive. If using it on a manual alt az mount is also becomes a pain to use. The 100mm refractor is far better. The 60mm refractor I have is the most utilised as I've used it for everything, visual, AP, planetary, DSO, WL solar and HA solar, I find it's only limiting factor is focal length.

After an apo refractor I find newtonians also offer excellent views.

Hi Elp, 

I'm aiming to get some really nice images of saturn, and I've not seen any refractor images that can match sct9.25 and larger. I have seen excellent images taken with 12" Newts and larger, at the same or better quality than even a  C14 can give. 

So, the refractor would for me, be visual only, with the ed80 bringing up the rear for dso AP, and the sct going on point for planetary AP. 🙂