Battle of the 127 Maks and 5 inch SCTs

[JeremyS]

My goodness, seldom has a thread been so rich in revelation. For ages I thought he was John Hinderby. But I’m slightly word blind when reading (not Reading, which is in the south)

[sputniksteve]

@johninderby I always thought Meriden was the centre of the country. Turns out, it ain't: https://en.wikipedia.org/wiki/Centre_points_of_the_United_Kingdom

[GazOC]

1 hour ago, John said:

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 ?

 

That'll be me 😉

The mirror is 200mm. It could be that that baffle coming out of the primary is cutting out light but it looks very carefully graduated in width as it approaches the primary

 

Someone has put a lot of thought into the width of the baffle at any given point. That's not to say they've not just got it wrong but they've not just stuck a tube on and hoped it's correct 

[John]

3 minutes ago, GazOC said:

That'll be me 😉

The mirror is 200mm. It could be that that baffle coming out of the primary is cutting out light but it looks very carefully graduated in width as it approaches the primary

 

Someone has put a lot of thought into the width of the baffle at any given point. That's not to say they've not just got it wrong but they've not just stuck a tube on and hoped it's correct 

Thanks Gaz - I'm glad I was not imagining it !

So I wonder just what Synta / Skywatcher did actually change to increase the effective aperture ?. Maybe nothing and the tales of the 180's operating at less than 180mm are myths ?

 

 

[GazOC]

2 minutes ago, John said:

Thanks Gaz - I'm glad I was not imagining it !

So I wonder just what Synta / Skywatcher did actually change to increase the effective aperture ?. Maybe nothing and the tales of the 180's operating at less than 180mm are myths ?

 

 

The mirror is oversized and there's lot of space in between the mirror and the tube so I can't see that being the problem

 

To me, that leaves the baffle coming out of the primary (realistically the secondary baffle isn't going to knock off 10mm from the effective aperture) as the only possible culprit but  whoever designed that part has made sure it tapers in as it gets closer to the secondary. 

Just MHO but I'd be surprised if Skywatcher redesigned the scope to give it an extra 10mm aperture and then said nothing about it ? 🤷

[John]

13 minutes ago, GazOC said:

Just MHO but I'd be surprised if Skywatcher redesigned the scope to give it an extra 10mm aperture and then said nothing about it ? 🤷

Me too. At the very least they would have called it the "Plus" version or "Skymax Pro Mk II"

 

[GazOC]

Or a "Skymax Pro 190" and chucked an extra 50 quid on the price 😉

[chiltonstar]

44 minutes ago, GazOC said:

Or a "Skymax Pro 190" and chucked an extra 50 quid on the price 😉

I measured mine a few times on an optical bench with a point source placed at the focal point, and the mean value of the projected disc of light was 179 mm in diameter - close to 180mm by my standards.  Whatever the effective aperture, it's a lovely scope though when it's insulated and the Seeing Gods are smiling down on us....

One negative point about the Bresser 127 I've seen raised (eg CN) relates to the effective obstruction, which comes out at about 40% because of the baffle. If so, it must surely lower the contrast??

Chris

Edited June 17, 2020 by chiltonstar

[sputniksteve]

I've just seen that FLO still stock the SW 127 on the older SynScan mount for £389. 🤔🤔

[Highburymark]

Mak - sharper, better for lunar, and perhaps has slight edge on planets.

SCT - better all round performer, wider fov for DSOs.

[JamesF]

16 hours ago, johninderby said:

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

They taught me that Derby is somewhere up near the Arctic Circle.  I figured that was close enough

James

[JamesF]

18 hours ago, johninderby said:

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

I've just had a quick look at my (blue Skywatcher) 127 Mak.  I reckon the clear aperture of the corrector alone is no more than 118mm.  119mm at the very most.

James

Edited June 18, 2020 by JamesF

[Louis D]

I look at the 127 Maks this way.  In the US, if you've got $200 to spend on a travel scope (and have a mount of some sort already), a used 127 Mak is the way to go over a new 90 or 102 Mak for similar money.  Why the used/new comparison?  Because so many 127 Maks turn up used over here compared to 90 and 102 Maks, and for not a lot more money.  I'm guessing a lot of newbies buy them new, grow disinterested or want to move up in aperture, and then sell them rather than keep them as a travel scope.  This tends to flood the used market and drive down used prices.  I don't see near as many C5s or C6s turning up in the classifieds, either.  Perhaps they don't sell as well new, or people like to hold onto them longer?

[GazOC]

1 hour ago, JamesF said:

I've just had a quick look at my (blue Skywatcher) 127 Mak.  I reckon the clear aperture of the corrector alone is no more than 118mm.  119mm at the very most.

James

I've taken the corrector out my blue Mak and made a couple of *very quick* measurements. 

The clear aperture of the front of the corrector seems to be 127mm, the back of the corrector is harder to measure but the ID of the cell is 133-134mm with a ~3mm lip all around near the corrector so somewhere very near 127mm.

I wish I'd have measured the primary when I had the thing stripped a few weeks ago as that is often given as the reason for the restricted aperture but haven't got the stomach to attempt that job again 

Edited June 18, 2020 by GazOC
Typo

[Alfian]

19 hours ago, sputniksteve said:

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. 

It might be stating the obvious, but in terms of budget had you considered buying second hand equipment? Many people here, myself included, have or have had much used 'scopes, eyepieces, etc in their astro' arsenal. The budget goes much further this way and astronomers do tend to look after their equipment. I've never had any regrets.

On the geography, "where is Derby" question, I originally hail from Northamptonshire but have spent much of my life in Yorkshire. In the latter, I was seen by most as a southerner. I came to the conclusion that anywhere north of Watford and south of Sheffield fell into a large no mans land, unknown and generally avoided by folks north and south unless circumstance demanded, in which case it was down to the satnav to provide the knowledge. My dear departed mum used to talk  to me as if Yorkshire was just south of the arctic circle. Now I live in Scotland I think I must be spitting distance from the north pole. Way way up north. (Currently nicely warm with blue skies and very pleasant)

[sputniksteve]

Hi Ian,

Yes - I'm browsing ebay, Facebook marketplace and the for sale threads here too. As I'm shielding currently,  I won't be able to go and check of the things out but hopefully I will. It's certainly an area I shall use for additional equipment and accessories and whatnots.

 

Do you get to see the aurora up where you are?

[Stu]

10 minutes ago, sputniksteve said:

Hi Ian,

Yes - I'm browsing ebay, Facebook marketplace and the for sale threads here too. As I'm shielding currently,  I won't be able to go and check of the things out but hopefully I will. It's certainly an area I shall use for additional equipment and accessories and whatnots.

 

Do you get to see the aurora up where you are?

https://www.astrobuysell.com/uk/propview.php?view=162602

[Alfian]

11 minutes ago, sputniksteve said:

Hi Ian,

Yes - I'm browsing ebay, Facebook marketplace and the for sale threads here too. As I'm shielding currently,  I won't be able to go and check of the things out but hopefully I will. It's certainly an area I shall use for additional equipment and accessories and whatnots.

 

Do you get to see the aurora up where you are?

No, not yet, but live in hope at some point. I live in south west Scotland. Good skies but less of a chance aurora wise than way way way up north in the NW Highlands and beyond. AstroBuySell is a good source for used stuff too.

[sputniksteve]

11 minutes ago, Stu said:

https://www.astrobuysell.com/uk/propview.php?view=162602

🤔 Well now ...

[Louis D]

1 hour ago, sputniksteve said:

🤔 Well now ...

Avoid ebay for the most part unless you really know what you're doing.

If you have a Craigslist equivalent for local ads over there, it could be good for acquiring large, bulky items like Dobs locally.

[Louis D]

2 hours ago, Alfian said:

I came to the conclusion that anywhere north of Watford and south of Sheffield fell into a large no mans land, unknown and generally avoided by folks north and south unless circumstance demanded, in which case it was down to the satnav to provide the knowledge.

I had to look that up.  Isn't that most of central England including Birmingham, Nottingham and Cambridge?

In the US, that which isn't on the east or west coast (95% of the US by land area) is derogatorily referred to as "fly-over country" by folks from the coasts.

[sputniksteve]

Ah man!! I've just realised that Meade still has something in this category? Any thoughts on this vs the SW/Celestron? 

 

https://www.harrisontelescopes.co.uk/acatalog/meade-ng-125.html#SID=1703

[Louis D]

3 hours ago, sputniksteve said:

Ah man!! I've just realised that Meade still has something in this category? Any thoughts on this vs the SW/Celestron? 

 

https://www.harrisontelescopes.co.uk/acatalog/meade-ng-125.html#SID=1703

The original Meade ETX scopes were made in the USA.  I don't know where they're currently being made since Ningbo Sunny bought them.

[sputniksteve]

7 hours ago, Louis D said:

The original Meade ETX scopes were made in the USA.  I don't know where they're currently being made since Ningbo Sunny bought them.

Yes, I've been reading some very unhappy comments elsewhere about Meade in recent years. 

[Nigeyboy]

On 17/06/2020 at 18:50, johninderby said:

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

Lol - that makes me Nigeinchaddesden then!!!! Small world