C11 v FC100 DZ shoot out

[Trentend]

Another night, another scope shoot out, this time with a newly insulated C11 v the Tak. The former a little bit Blue Peter having covered it with aluminium foil to help with cool down. Really seemed to do the trick though and was excellent after just 30mins or so. Usual Jupiter and Saturn targets with the Binotron, powerswitch, with/without x2 Barlow and 24mm pans.

A clear winner tonight. The C11 was immense. Views were very steady, incredibly bright (to be expected given the much greater aperture) and Jupiter felt like being onboard Voyager 1! Multiple bandings, loads of detail, subtly different colours. Best view by far was without the Barlow and on the middle setting of the powerswitch. I think this gave x256 magnification, which by my reckoning was like holding a squash ball at arms length. Couldn’t take the higher setting or anything with the Barlow, which would have been well over x300 even on the low powerswitch. Saturn also very good but less time to take in as dancing in between the rooftops. 

Then moved over to the Tak with the Barlow. Views still very very impressive for such a small scope, very sharp and pretty bright. Perhaps not quite as warm as the C11 (shades of grey rather than the browns in the C11) and magnification understandably lower (like holding a marble at arms length). Worked fine on all powerswitch settings but again the clearer view by far was on the middle setting which I believe gave x140. Now I know I should be able to get far greater magnification than this and am wondering if the powerswitch high setting is the weak point in the set up. That would only be pushing x200 and I know the Tak is capable of more. In hindsight I should have stuck in the D14 on the middle switch to compare. Next time.

All in all still a great night and very happy with the scopes (next time though I’ll rotate the Tak so it sits upright - stupid boy!)

Edited October 30, 2021 by Trentend

[Stu]

Interesting comparison! Sounds like wrapping the scope did improve the views?

I’ve had similar results with a C8 Edge and C925 vs an FC100DC, though with unwrapped SCTs. I found I saw a lot more colour with the larger aperture. The views were less stable though, so I had to wait longer for sharp views. I found the frac the more relaxed and pleasant to view, but ultimately saw more through the SCTs.

[Trentend]

I’ve only had the C11 out once before around a month ago on the same targets and it was equally brilliant (best view ever of Saturn) but had been out a couple of hours before use. Not sure if the foil wrap works (only a 30min wait tonight) or is an astronomical placebo, but I’ll stick with it for the time being. One issue I had was the astrozap dew shield wouldn’t fit over the top of it and kept dropping off. Not sure if I’ll need to remove an inch of so right at the end so the shield can get more purchase.

[Trentend]

One other schoolboy error this evening. The AZ100 mount alt slow motion control only seemed to work in one direction (down). I spent half an hour or so balancing and rebalancing the scopes only to realise the screw attaching the handle to the mount was loose. Worked a treat once I tightened this up. I’ll try and remember next time.

[JeremyS]

Very interesting report @Trentend

Yes the SLO mo’s do tend to work better when the handle screw is tight 😊

[Highburymark]

Agree with Jeremy and Stu - very interesting comparison. I’m of the opinion that SCTs can be quite variable like solar telescopes - and even when well collimated, some of them just can’t deliver sharp views at higher powers. However, get a good one like you C11 and they are unbeatable as an all-round package. Great combination with a 100mm refractor.

[Stu]

10 hours ago, Trentend said:

One other schoolboy error this evening. The AZ100 mount alt slow motion control only seemed to work in one direction (down). I spent half an hour or so balancing and rebalancing the scopes only to realise the screw attaching the handle to the mount was loose. Worked a treat once I tightened this up. I’ll try and remember next time.

That’s when they are called no motion controls……

[GazOC]

I've found similar (on a smaller scale) when comparing my 7 inch Mak with my ED120 on the planets. Unless conditions are poor the Mak always shows more, I've never bought into that "a 4 - 5 inch apo I will show you all the detail you can see on most nights in the UK" line.

[Nik271]

I think its like pitting a Mini vs an Audi A8. The Mini is cute and nimble in the city but on the motorway the big engine of the Audi will blow it away.

11 inches vs 4 inches as an awful lot of aperture to compensate. The C11 creates such a large image in the focal plane that you will see a lot more detail in almost any condition. I think a fairer comparison could be between the Tak and a C6, perhaps even a C8. There comes a point where the aperture will win.

Edited October 31, 2021 by Nik271

[Stu]

I agree that SCTs are quite variable in their quality, and also rely on being accurately collimated for maximum planetary contrast and detail.

In good conditions, and providing they good examples and are well cooled the SCTs should show more detail and colour. A lot comes down to presentation preference I think. The refractor will show a generally steady image with good detail which is easy to view and concentrate on. The larger scopes tend to be more variable as the seeing comes and goes but show better detail when it settles. Convenience comes into it too of course. If you can’t be bothered to put the C11 out, then having a little ole Tak to pop out is a great alternative.

[Highburymark]

1 hour ago, GazOC said:

I've found similar (on a smaller scale) when comparing my 7 inch Mak with my ED120 on the planets. Unless conditions are poor the Mak always shows more, I've never bought into that "a 4 - 5 inch apo I will show you all the detail you can see on most nights in the UK" line.

Different experiences like this are what makes SGL so interesting. I had a C8 Edge for many years - nice scope. But my first night out with a TSA-120, I was amazed by the level of detail on Jupiter - more than I’d ever seen through hundreds of sessions with my (perfectly collimated) SCTs. I’d love to try a big Mak one day though. Just the cooldown time that’s prevented me buying one in the last.

[Highburymark]

‘In the past’ ….. that last line is supposed to read.

[GazOC]

I've got to admit, Mark. I had a 8 inch LX90 SCT years ago and was never particularly impressed with the planetary views it put up 

[kirkster501]

7 minutes ago, Highburymark said:

Different experiences like this are what makes SGL so interesting. I had a C8 Edge for many years - nice scope. But my first night out with a TSA-120, I was amazed by the level of detail on Jupiter - more than I’d ever seen through hundreds of sessions with my (perfectly collimated) SCTs. I’d love to try a big Mak one day though. Just the cooldown time that’s prevented me buying one in the last.

I agree.  I have had some spectacular views of Jupiter through my TEC140.  As I have through my C925 too - perfectly collimated.  The refractor image seems somehow brighter and "cleaner",  if that makes sense, and can compensate to some extent for the fact that the surface area is nigh on four times less.

[JeremyS]

You might be surprised to here my say this, but I think if I had to choose between my Tak TSA 120 and my C9.25 for planetary (and here I am talking Jupiter and Saturn), I’d probably go for the latter.

There: I’ve said it 🤣

I really want to try a Mewlon 210, though.

Edited October 31, 2021 by JeremyS

[Andrew_B]

12 hours ago, GazOC said:

I've got to admit, Mark. I had a 8 inch LX90 SCT years ago and was never particularly impressed with the planetary views it put up 

Quality control with SCTs seems to have been relatively hit and miss especially years ago, but I get the impression that newer models made by Synta have been much better and you're less likely to end up with a lemon.

[johninderby]

The American made Celestron SCTs were variable in optical quality. Since shifting production to China optical quality seems to be very consistent. Think it has more to do with no longer touching up optics by hand but relying on improved machine finishing equipment.

On CN this is a very touchy subject that the Chinese made optics are more consistant than the American made optics. 😁

Edited November 1, 2021 by johninderby

[Andrew_B]

28 minutes ago, johninderby said:

The American made Celestron SCTs were variable in optical quality. Since shifting production to China optical quality seems to be very consistent. Think it has more to do with no longer toiching up optics by hand but relying on improved machine finishing equipment.

On CN this is a very touchy subject that the Chinese made optics are more consistant than the American made optics. 😁

Indeed. They don't make 'em like they used to ... thank goodness! 😆

Touching up optics and carefully rotating elements into the perfect position is a valid method when you're talking about very high end optics like A-P / Tak / TEC, but if you're doing it with a value-oriented product like an SCT it's more likely to be a way of getting round poor QC and inconsistent manufacturing methods.

[jetstream]

13 hours ago, JeremyS said:

You might be surprised to here my say this, but I think if I had to choose between my Tak TSA 120 and my C9.25 for planetary (and here I am talking Jupiter and Saturn), I’d probably go for the latter.

There: I’ve said it 🤣

I really want to try a Mewlon 210, though.

I'm clutching my chest ☹️ and hope all goes well!

I just cant believe how high mag the TSA120 takes and gives a great presentation at lower mags. Mine doesnt care about which diagonal or eyepieces either, everything seems to work in this scope for some reason.

[kirkster501]

There is a reason that large refractors are still made.  For those that can afford them of course!  A TEC 250 refractor costs $56000 or say £44000 + import taxes and VAT so this scope were you to buy it would run you the thick end of £60000.  The same aperture as a Skywatcher Dob 250 for £539.  120 times more expensive.   There is a reason for that.  Views through such a refractor would be sublime, all else being equal.

Edited November 2, 2021 by kirkster501

[johninderby]

Or buy from a UK dealer.

https://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGTEC250-35

[Alan White]

But at 120x more expensive, well that would have to be a lotery win spend or not at all.
Based on how cloudy it can be and that it would need a big mount and observatory, sad as I find it to say, 
well the reflector would get my resounding vote.



 

[johninderby]

You could easily spend as much on the mount as the scope. 🙀🙀🙀

[johninderby]

I could be tempted by this beauty. 🙂

https://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGPWCDK20

[Stu]

27 minutes ago, johninderby said:

I could be tempted by this beauty. 🙂

https://astrograph.net/epages/www_astrograph_net.sf/en_GB/?ObjectPath=/Shops/www_astrograph_net/Products/AGPWCDK20

Can’t see any draw backs to that at all. I assume you can sleep in it and drive it too, so I can sell the house and car to finance it? 😉