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I'm quite happy with my c9.25 but have always fancied to have a go with a SM180 especially after seeing some stunning Lunar images taken with one. 

I have the opportunity to buy a new 180 at almost half price BUT do I really need it?

I have read as much as I can find. There are split opinions  but views of people that have been through the comparison would be good. 

I'm quite happy to be told am daft and don't need another scope, save the money!

cheers for looking

David

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Imaging field of view is very similar. See image using a Canon and Jupiter as an example. Save your money.

Peter

Capture.JPG

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Sorry can't say I can compare them having never owned either, but I'd also say save your money... your C9.25 is more than capable of creating those stunning lunar images too!

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Posted (edited)

I'm all about spirit of adventure (or fool and his money etc if you prefer) At half price you can easily move it on for the cost of postage or thereabouts. Scratch that itch.

Edited by steveex2003
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If you can purchase it without selling your 9.25 then give it a go, you can then sell the "loser". Good 9.25 lunar images are hard to beat.    😀

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8 hours ago, PeterCPC said:

Imaging field of view is very similar. See image using a Canon and Jupiter as an example. Save your money.

Peter

Capture.JPG

very similar but its hi resolution image quality i'm looking at

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savers & spenders......I'm not unhappy with the images I get from the sct, here's one. Maybe a should stick with it and keep pushing...............still thinking

212505_g3_ap396_convps.jpg

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10 hours ago, Stardust said:

I'm quite happy to be told am daft and don't need another scope, save the money!

I always need at least one more scope 😂

Dave

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16 minutes ago, Davey-T said:

I always need at least one more scope 😂

Dave

Trouble is I'm not sure I have the weather to get the use out of the ones I've got. Just a shame that my local friends don't have one I could try....

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I have no right to post an opinion as I haven't owned either... but I would say go for it.

I spent a couple of years looking out for a 180 maksutov and hardly any ever came up and I missed out on those that did. In the end I gave up and decided to look for a C8 instead. Within a few weeks I had a C8. Therefore if a good opportunity for a 180 maksutov is a rare event but opportunities for sct's come much more often, I would take this opportunity.

My other reason to volunteer an opinion is that I still have my 127 maksutov and the C8, whilst good, did not result in my smaller maksutov being dropped from use.

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Posted (edited)

Ok my sensible side has won  I'll save my money and play with what I have.

Edited by Stardust
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Are the Skywatcher mak-cassegrains operating at full aperture these days ?

Their design used to mean that the effective aperture was a bit less than stated so the 180 was in fact a 170 etc etc.

I had a Skymax 180 for a short while but found the cool down time too long for my observing circumstances. 

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2 minutes ago, John said:

Are the Skywatcher mak-cassegrains operating at full aperture these days ?

Their design used to mean that the effective aperture was a bit less than stated so the 180 was in fact a 170 etc etc.

I had a Skymax 180 for a short while but found the cool down time too long for my observing circumstances.

The 180 is a true 180 John (I've  tested mine and found 179mm when it is in focus and the rear focus position is normal (ie no long focusers to extend fl).

There are a number of threads on cool-down time and cladding on CN; my own experience is that post-cladding (insulation), cool down is not a problem for me provided the air temperature is not dropping too fast. It has not been an issue in Summer, but last Winter cool-down was slightly more noticeable on days with bright sunshine and warmish, but with clear frosty nights. To be fair, on these occasions the seeing was poor anyway.

Chris

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Thats good to know Chris. It must have been the earlier ones that were working at less than full aperture. Neil English was convinced that his (branded Orion USA) was nearer to 170mm and referred to it was such in his review of the scope. This is an extract from that review:

"It was discovered that the effective aperture of the large Orion Maksutov was nearer 170mm than 180mm. I was alerted to this after performing double star tests earlier in the summer of 2014. When I observed Zeta Herculis, I detected the faint companion to be located on the first diffraction ring of the primary star. Now, the locus of the first diffraction ring from the Airy disk is 185/D where D is the aperture in mm. The latest information on its angular distance from the primary is 1.1″. Something interesting occurred to me when I set the formula to find D for a 1.1″ separation. Thus 185/1.1 yields 168.2mm. Then I remembered a review on a lady’s website from the UK where she talked at length about the same (albeit Sky Watcher incarnation) telescope and reckoned the actual true diameter was nearer 170mm than 180mm;

"Subsequent flashlight tests confirm that many of the Synta/Orion Maksutov have slightly smaller apertures than advertised (the 127mm model being closer to 120mm). This is due to the fact that the primary mirrors are the same aperture as the corrector plate which results in slight internal vignetting. In comparison, the older Meade 7 inch LX 200 Mak as well as the Questar 7 have an over-sized primary mirror to correct for this."

Presumably Synta must be incorporating a larger primary mirror with the later models ?

 

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Posted (edited)
6 hours ago, John said:

Thats good to know Chris. It must have been the earlier ones that were working at less than full aperture. Neil English was convinced that his (branded Orion USA) was nearer to 170mm and referred to it was such in his review of the scope.

Presumably Synta must be incorporating a larger primary mirror with the later models ?

 

Some have been updated including the 180 and 150 I believe - it must have been carried out some months before I got my 180 in 2015; the rear of the scope was modified as well with a 2" focuser. Some models have not been modified (eg 127 Mak), although this is such a good scope that whether it's 127mm or 119mm aperture is not that critical for most of us.

I am not sure that the Orion models (also Synta of course) were modified at the same time as those branded SW here - Skywatcher could maybe help on this point. Again, there are several threads on CN that go into the apparent and true apertures of the various Mak models made by Synta. I've taken this from another post (from Skywatcher/Synta originally) and it gives some idea of the true optical arrangement:-

Per the OP's question the SW rep listed the 180's as:
•True Aperture: 182mm
•Primary Aperture: 199mm
•Baffle Opening: 31.9mm
•Rear Cell Opening: 31mm
•Secondary Diameter: 41mm
•Obstruction by Diameter: 23%
•Obstruction by Area: 5%"

The obstruction figure quoted is for the front mirror though and does not include the baffles apparently.

Chris

Edited by chiltonstar

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3 hours ago, chiltonstar said:

.....The obstruction figure quoted is for the front mirror though and does not include the baffles apparently.

 

Which flare outwards towards the primary I seem to recall so they would be the true secondary obstruction of the scope I suppose.

 

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Posted (edited)

Hi David,

I think you have made a sensible choice in keeping your C9.25. Looking at your lunar image cannot see any great advantage in going for the 180 Mak.  Don't get me wrong I have actually owned 3 of them  along with 3 C9.25 's. All you will gain is extended cool down times  and perhaps a minuscule improvement in image sharpness and contrast and if optics perfectly collimated from factory they more or less stay permanently that way. Unless you keep in an  unheated garage/shed /obsy getting  perfect thermal equilibrium can actually take several hours especially if temperature is dropping away.  I still love the 180 Mak  and  if I did not have either scope I would happily go for a used  180 purely on cost . I do think the C9.25 is slightly  more versatile for general purposes at f10 and extra aperture always welcome , however as I own neither at the moment I am tempted by John in Derby's  180 Mak in the for sale section 🙂!

 

Cheers

Dave

 

 

Edited by DaveGibbons

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8 minutes ago, DaveGibbons said:

Hi David,

I think you have made a sensible choice in keeping your C9.25. Looking at your lunar image cannot see any great advantage in going for the 180 Mak.  Don't get me wrong I have actually owned 3 of them  along with 3 C9.25 's. All you will gain is extended cool down times  and perhaps a minuscule improvement in image sharpness and contrast and if optics perfectly collimated from factory they more or less stay permanently that way. Unless you keep in an  unheated garage/shed /obsy getting  perfect thermal equilibrium can actually take several hours especially if temperature is dropping away.  I still love the 180 Mak  and  if I did not have either scope I would happily go for a used  180 purely on cost . I do think the C9.25 is slightly  more versatile for general purposes at f10 and extra aperture always welcome , however as I own neither at the moment I am tempted by John in Derby's  180 Mak in the for sale section 🙂!

 

Cheers

Dave

 

 

Hi Dave

thanks for your input. I had pretty much decided on not getting the Mak till a few more conversations which has me back on the fence. It's to do with our turbulent seeing conditions in the UK and that a smaller scope could cope better, where a larger one can amplify the poor seeing effect which I understand. I'm lucky in as much that I can still keep the C9.25 if I bought the MAK. Pity I can't just borrow it but that's not generally how sales work.   I like the focus mod on the one in the sales section, quite neat. I tend to swap a Moonlite between my 2 SCT's. I'll sleep on it again but I know the seller wants to move it on soon. 

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As an update, my sensible side was caught napping and the "gun hoe - lets spend some cash" side of the brain bought the 180 Mak today.

I'm mad, it's lovely and now the clouds are here. Oh well there's a season ahead to see how things pan out.

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Posted (edited)

Well done Dave, cant wait to see the results, ive always fancied one myself.

looks like I may be making a gun hoe purchase myself in the morning, unless my sensible side takes control again by then 😜

see you on Saturday 

Lee

Edited by Magnum
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I have a C9.25 it is by far, the best and only SCT I have ever owned.

It was a review I read by Damion Peach that made me buy one. I don't use it half a much as I should. But when I do use it. I can see what a good telescope this is.

Save your pennies.

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