Battle of the 127 Maks and 5 inch SCTs

[sputniksteve]

Hi everyone. New here so pleased to meet you all!

I'm looking at restarting my astrojourney. I had been looking at the various guises of the C6, but I'm now looking at the powerful little Maks - the Skywatcher 127 and the Celestron equivalent. The latter now comes on the Astro Fi mount/tripod and the SW comes on the AZ=GTi Wifi mount. This one can be put into EQ mode apparently. I'm leaning towards the SW because I think the mount looks better, but I'm curious about the optical performance of the OTA. I know they're both Synta nowadays, so I wonder if the OTAs are essentially the same. 

 

I'd be grateful for any views on these, and if anyone has any experience of them. 

 

And then, of course, we can through into the mix the Celestron 5" SCT ...

[johninderby]

The SW and Celestron are identical scopes except for the colour. The Bresser 127 mak is a bit better as it is actually 127mm aperture unlike the SW that is about 118mm. Also a bit longer fl of f/15. Comparing the two found the Bresser had the edge in lunar / planetary which is down to it’s greater fl and aperture. Would fit on the AZ-GTi mount.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-mc-127-1900-maksutov-cassegrain-ota.html

[sputniksteve]

39 minutes ago, johninderby said:

The SW and Celestron are identical scopes except for the colour. The Bresser 127 mak is a bit better as it is actually 127mm aperture unlike the SW that is about 118mm. Also a bit longer fl of f/15. Comparing the two found the Bresser had the edge in lunar / planetary which is down to it’s greater fl and aperture. Would fit on the AZ-GTi mount.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-mc-127-1900-maksutov-cassegrain-ota.html

That's a nice looking OTA. I guess you could get that and by the SW mount separately ...

[johninderby]

3 minutes ago, sputniksteve said:

That's a nice looking OTA. I guess you could get that and by the SW mount separately ...

Yes you could get both from FLO although would be a bit more expensive than the SW mak option.

[sputniksteve]

2 minutes ago, johninderby said:

Yes you could get both from FLO although would be a bit more expensive than the SW mak option.

Well. My birthday is August - that's the SW. Xmas is December - that's the Bresser. 

[sputniksteve]

@johninderby I've just realised that you're in Derby! I am just down the A38 from you in Sunny Lichfield. 

 

Although I'm not at the moment as I'm shielding with my parents in Brum.

[Stu]

1 hour ago, sputniksteve said:

@johninderby I've just realised that you're in Derby! I am just down the A38 from you in Sunny Lichfield. 

 

Although I'm not at the moment as I'm shielding with my parents in Brum.

🤣🤣, and there’s me thinking his surname was Inderby all these years 😉🤣

[GazOC]

It took me longer than it should have to realise, Stu 🤣🤦

[johninderby]

I could change it to. johninoakwood which would be more precise as it’s the suburb I live in..🤔

Edited June 17, 2020 by johninderby

[Stu]

6 minutes ago, johninderby said:

I could change it to. johninoakwood which would be more precise as it’s the suburb I live in..🤔

But then I would have no idea where you are....at least at the moment I know you are ‘up north’ somewhere... 🤣

[Captain Scarlet]

Haha I also thought Inderby was a surname. I only twigged when I bought something...

[The Admiral]

30 minutes ago, Stu said:

🤣🤣, and there’s me thinking his surname was Inderby all these years 😉🤣

It seems I belong to an increasing group as well then :<).

Ian

[johninderby]

Actually dead centre  of the country which is the southern part of the midlands. 

[mikeDnight]

3 hours ago, johninderby said:

The SW and Celestron are identical scopes except for the colour. The Bresser 127 mak is a bit better as it is actually 127mm aperture unlike the SW that is about 118mm. Also a bit longer fl of f/15. Comparing the two found the Bresser had the edge in lunar / planetary which is down to it’s greater fl and aperture. Would fit on the AZ-GTi mount.

https://www.firstlightoptics.com/bresser-telescopes/bresser-messier-mc-127-1900-maksutov-cassegrain-ota.html

You say the SW 127 Mak is only 118mm aperture John?  That's a big difference between the stated aperture and the actual aperture if true. Have you any idea why?

[johninderby]

All the Skywatcher maks were actually smaller aperture than  the listed size. The 150 and 180 were revised a few years ago to bring them up to the stated aperture but nothing has been done about the 127 mak.

The problem is the size of the primary mirror which limits the usable aperture to about 118mm. 127mm is the diameter of the corrector.

Edited June 17, 2020 by johninderby

[Stu]

12 minutes ago, mikeDnight said:

You say the SW 127 Mak is only 118mm aperture John?  That's a big difference between the stated aperture and the actual aperture if true. Have you any idea why?

I think it’s because the corrector (which is 127mm) actually diverges the light beam, meaning that you would need an oversized primary to maintain the 127mm aperture. 
 

@Captain Magenta did a fantastic post on the 180 here.

 

[Graham Darke]

Given a fight between a 5 inch Mak/SCT and a 6 inch SCT, the latter is always going to win. I’ve owned both and the difference is quite marked. The original post mentioned the C6. I would go with that every time against a 5 inch. One inch difference doesn’t sound much but at that size one inch makes a massive difference. The C6 is very light and just as portable as a 5 inch but crucially has the extra light grasp. 

[johninderby]

But the C6 is rather expensive compared to a 5” mak so that is a factor in the decision.

[Captain Scarlet]

24 minutes ago, Stu said:

I think it’s because the corrector (which is 127mm) actually diverges the light beam, meaning that you would need an oversized primary to maintain the 127mm aperture. 
 

@Captain Magenta did a fantastic post on the 180 here.

 

... one of the upshots of that was that the primary on the skymax 180 is 200mm, allowing full use of the width of the corrector. I have a skymax 150 in London for which I’ll make the same measurement when I’m back there. Alas I don’t have any more a skymax 127, it would be interesting for someone to quickly pop the back end off and have a quick measure...

[johninderby]

I’ve read claims of between 120mm and 132mm but no one seems to know for sure. The only thing that is consistant is that those who have measured the usable aperature come up with between 118 and 119mm

Edited June 17, 2020 by johninderby

[John]

55 minutes ago, johninderby said:

All the Skywatcher maks were actually smaller aperture than  the listed size. The 150 and 180 were revised a few years ago to bring them up to the stated aperture but nothing has been done about the 127 mak.

The problem is the size of the primary mirror which limits the usable aperture to about 118mm. 127mm is the diameter of the corrector.

I've seen a thread somewhere on the original gold tube 180 which showed that it has a primary the same diameter as the more up to date one that @Captain Magenta took apart recently. Is there some other modification that would increase the effective aperture such as a re-designed secondary baffle ?

 

[Louis D]

50 minutes ago, johninderby said:

But the C6 is rather expensive compared to a 5” mak so that is a factor in the decision.

Agreed, even on the used market, the C6 goes for 50% more than the 127 Maks over here.  The OTA is also a few inches longer than the 127 Maks, so compactness relative to a backpack may become an issue for travel.

[Stu]

2 hours ago, johninderby said:

Actually dead centre  of the country which is the southern part of the midlands. 

Yep, up north! 😉

[sputniksteve]

I'll be honest - it is the price difference that makes me hesitate over the C6, especially given what I've been told about the stability of the tripod on the AstroFi and SLT variants. These are each around £650, whilst the same scope on the SE is almost £900. Meanwhile, the 127s and C5 are around the £500. The SW on the AZ-GTi Wifi is £445 at FLO right now. 

[johninderby]

Pity they don’t teach geography in those  remote out of the way places in the south..😁😁😁