SW Quattro 10" vs 12" for imaging

[Northernlight]

Hi All,

I'm contemplating a SW quattro and i've been looking on Astrobin for samples images from both scopes and i noticed that there are hardly any images taken with the 12" and 95% seems to be with the 10" and i just wondered if there was any reason for this.

I guess weight and general size would be the main factors, but wondered if there was anything else about the 12" that makes people favor the 10" instead. For me the slightly longer Focal length and larger aperture would be great and the pixel scale is pretty decent and based on OK seeing conditions then the larger scope is a better match for my qsi 683 ccd as at 1x & 2x both binning levels are a good match, whilst the 10" is great at 1x, but undersmaples at 2x

So why is it there aren't more 12" quttro's appearing on Astrobin, as it seems like a no brainer to me if your mount can handle it

Cheers.

Rich.

[Realtimedoctor]

Hi, 

To answer your question, I think the main reason is very few people have a permanent setup. 

Both the 10 & 12 are in a category where its cumbersome to move them around. Anyone who sets up and tears down the whole setup this will quickly become very frustrating. 8" is the sweet spot for people who set up and tear down every session, the reduced size/wt of 8" newt outweighs the benefits in imaging you may get with a 10 or 12. 

I'd highly suggest that if you don't have a permanent setup to consider an 8". On the other hand, if you have something permanent/semi permanent then go for 10-12". 

Good luck 

Nishant 

[Sp@ce_d]

On paper these have looked enticing but even with a permanent setup as you have, I was put off with the sheer size and flex worries with fast optics. Even in a ROR I’d be worried about gusts catching it. I guess if you have the time to invest in it & enough clear nights it can be rewarding. In the UK you know how that one goes 😏 For me I wasted enough time trying to image with the C9.25 to learn that lesson. I’m even thinking of going from the RC to a similar FL frac to simplify. So I guess the answer is probably that.. it needs patience & high maintenance. Considering my hard won subs are mostly grabbed while I sleep by ACP opening & closing the obsy several times a night, it is probably considered  too high maintenance for most automated imagers at least.

[Astrobug]

With the actual small pixels you are fine with 1m FL. More is oversampling most of the time. 

[alacant]

Hi.

I think that whilst the 10" will go on a €2000 mount, the same for the 12" is going to set you back -at least- three times that.

But hey, with a 12" f4 at just 1200mm, it would enable you capture targets in an hour or so which would take 3 nights for mere mortals  using equipment with similar fov. My 6" f8 for example.

If your climate limits the clear nights you have anyway, it maybe a good option.

Cheers

 

 

Edited August 15, 2020 by alacant

[dph1nm]

5 hours ago, Northernlight said:

Hi All,

I'm contemplating a SW quattro and i've been looking on Astrobin for samples images from both scopes and i noticed that there are hardly any images taken with the 12" and 95% seems to be with the 10" and i just wondered if there was any reason for this.

I guess weight and general size would be the main factors, but wondered if there was anything else about the 12" that makes people favor the 10" instead. For me the slightly longer Focal length and larger aperture would be great and the pixel scale is pretty decent and based on OK seeing conditions then the larger scope is a better match for my qsi 683 ccd as at 1x & 2x both binning levels are a good match, whilst the 10" is great at 1x, but undersmaples at 2x

So why is it there aren't more 12" quttro's appearing on Astrobin, as it seems like a no brainer to me if your mount can handle it

Cheers.

Rich.

I highly recommend the 12", but mine is on an EQ8! Here are some DSLR images (I only take 45sec subs in very light polluted skies, so don't expect miracles from these!)

http://community.dur.ac.uk/nigel.metcalfe/astro/photo_quattro.php

I use the Skywatcher Aplanatic f/4 coma corrector.

NigelM

[toxic]

i went for the 10 inch Quattro because the 12 inch didn't come with baffles and it would help cut down the light incursion down the tube and help in better contrast as i live where there is lots of street lights i haven't had much chance to complete an image due to other issues (and cloud)  but it  it is a very good scope when combined with the SW Aplanatic  CC.

setup consists of SW AZ EQ6GT - SW QUATTRO 10S - SW APLANATIC CC - ATIK 383L+ MONO - EFW2 with 36mm unmounted LRGB HA OIII S2 FILTERS all in a home made dome.

only 1 sample image to date it is 11 x 120 second HA total = 22 minutes  stacked in dss and converted for posting.

hope this is some help.

[Northernlight]

thanks all,  I really  appreciate the feedback.

Chris / Nigel, many thanks for sharing your images.  Whilst I really like idea of the  slightly longer Focal Length and larger optics of the 12",  I think  i'll probably go for the 10" 

I like the idea of the tube baffles on the 10" and also Telescope Austria sell a very hig end focuser that is a direct replacement for the SW stock focuser, i.e. no drilling holes. The focuser is called the  OctoPlus508N but they only have tube base plates supporting up to 10" so that would rule out the 12"

Teleskop Austria also sell primary mirror baffle, which help to greatly reduce the diffraction spikes, but again these are limited to 10"

So everything is pointing towards the 10"

[toxic]

On 16/08/2020 at 17:52, Northernlight said:

thanks all,  I really  appreciate the feedback.

Chris / Nigel, many thanks for sharing your images.  Whilst I really like idea of the  slightly longer Focal Length and larger optics of the 12",  I think  i'll probably go for the 10" 

I like the idea of the tube baffles on the 10" and also Telescope Austria sell a very hig end focuser that is a direct replacement for the SW stock focuser, i.e. no drilling holes. The focuser is called the  OctoPlus508N but they only have tube base plates supporting up to 10" so that would rule out the 12"

Teleskop Austria also sell primary mirror baffle, which help to greatly reduce the diffraction spikes, but again these are limited to 10"

So everything is pointing towards the 10"

the primary mirror baffle is just a ring that covers the mirror clips to stop the dark spikes it will do nothing for the diffraction spikes caused by your secondary mirror supports and i have not found any thing wrong with the 10s quattro focuser so no need to spend unless you find a problem.

[Northernlight]

Hi Chris,

Agreed that it solves the issues with the mirror clips, and not the secondary.  When i look at diffraction anonolies, there are usually 2  produced. The clips create  what looks like flares from the star istself which are greatly reduced, but the secondary spider will still create the 4 distinct spikes and the only thing that helps with that is using a double veined spider, which coincidentally helps with focusing. So for 90 euros by the time you add shipping, it's not cheap, but in the grand scheme of things it's still peanuts.  When i look at lacerta scopes that use this mask, the stars in ther images just looks visibly cleaner with substantially reduced flaring on the brighter stars, and the smaller stars to look more crisp and tighter, which i dont think is just down to processing. 

In regards to the focuser, i've ready many many reports of significant play / slop in the draw tube, so it makes collimation pointless if it's going to immediately be pulled out of collimaiton by your camera.  I've also inspected a lot of Quattro images where people we using the stock focuser and they all seemed to have slightly elongated stars in 1 corner,  which i'm not sure is focuser tilt, slop or to do with the coma corrector.

My plan is to buy the scope, see how i get on and then if find the focuser has play, i've just replace it with the nice Lacerta OctoPLus508N which appears to be built like a take a have literally no play in the draw tube.

On the other hand, in the back of my mind, i tempted to hold off a few months and see how lacerta gets on releasing their new scope design towards the back end of the year.

Rich.

 

 

[Starflyer]

I thought you'd recently ordered an arm and a leg's worth of ONTC scope?

Good luck with a Quattro if that's what you're after now  😜

[Northernlight]

StarFlyer dont get me started on TS and ONTC scope.  this is now the second time that TS has screwed me over when i've tried to purchase one of their ONTC scopes. A long story short I paid for a 10" F4 ONTC with upgraded conical mirror and and waited 16 weeks with loads of different excuses to the point the got themselves tangled in their own lies and started contradicting themselves and then finally admitted after 16 weeks they hadn't even started the scope.

Last year i had exactly the same issue with TS, paid for the scope with a few custom upgrades then after waiting 14 weeks i gave up and cancelled the order and demanded a refund.

Not entirely sure what i want now - I wanted a high end scope but had 2 bad experiences with TS, so now looking at possily buying a Quattro and upgrading it with a good focuser, primary mirror mask, flocking etc etc.

I'm also thinking about a lacerta as Tommy is finishing up on a new design newt - so not sure if i want to hang fire for that or just buy a Quattro and not have to worry about another custom scope not materialising.

Really dont know at the moment.

[Robindonne]

Really helpful talking.  Just sold my quattro8(with a custom made mirror-cooling-ring😑). Basically sold it because i wanted to go bigger, and because the focuser is really really really a monday morning product!  
 

Had a new 12” in mind to eliminate the chance of wanting bigger in the future, and because i thought they upgraded the focuser 2 times after mine version.  
I know they sold a upgraded Quattro last year.  When you look at the detailed pictures its again upgraded I think.  Also buying New equipment in the uk, before it gets 2021, is really interesting at the moment.  
 

But all the mentioned facts are so true.  The weight and length was already a bit bothering with the “short 80 cm tube”.  
 

if the focuser is still bad, the 10” and focuser upgrade is probably te best option like you all say.  

[Northernlight]

I'm still waiting to hear from Teleskop Austria to see if their OctoPlus508N focuser will fit the 12" Quattro,  if it does i'll probably end up getting the 12" quattro and just modify it with the new focuser, flocking, and upgrade the  primary mirror to good quality springs, as 1200mm F/L @F4 will be might nice on Galaxies.

 

 

[ollypenrice]

To go back to the beginning, the 10 inch is going to give you 1.11 arcsecs per pixel. Is your guide RMS consistently no more than half that, so 0.55 arcseconds or so? If not, there is no point in going for a longer FL. The 12 inch would take you to 0.93"PP. In the real world will you see much difference? I have both image scales, more or less, side by side on a dual rig and, to be honest, the difference is scarcely visible because, most of the time, the seeing isn't allowing the higher res to show an advantage. The mount, a Mesu 200, delivers around 0.33 arcsecs RMS so it is not the limiting factor.

Of far, far greater importance would be tuning out the errors of a very fast system. The tiniest bit of tilt at F4 would make a mockery of the difference between 1.1 and 0.9 "PP. It would be very nice to have 10 inches of aperture at 1000 mm FL but keep your eye on the ball: you have to make it work.

Olly

Edited August 20, 2020 by ollypenrice
Typo

[Northernlight]

Fair point olly - and in the UK most of the time the seeing is average. I had originally considered this and thought about getting a refractor, but i need the combination of faster optics & larger aperture to allow for shorter subs as clear nights dont come around too often in the UK, so have to make the most of them.

I just worry about trying to fettle a cheap chinese scope. I did try and buy a high quality TS ONTC newt but got screwed over by TS on 2 occasions - so now considering the quattro with some upgrades to try and get into a good workable state.

 

 

[dannybgoode]

9 hours ago, Northernlight said:but i need the combination of faster optics & larger aperture to allow for shorter subs as clear nights dont come around too often in the UK, so have to make the most of them.

Loads of people image very successfully in the UK with a good frac. In reality you’re going to be collecting the same amount of data time-wise whatever scope you use and, unless your focussing and guiding are spot on there’s a chance you’ll get poorer quality subs from the ‘fast and wide’ scope than you would a nice easy to handle frac.
 

 

[alacant]

1 hour ago, dannybgoode said:

the same amount of data time-wise

Hi

Mmm. Look at what 22 minutes with a big reflector can do. You'd be all night with a refractor to get anywhere near. Unless it was a 10" refractor of course;)

Cheers

[toxic]

28 minutes ago, alacant said:

Hi

Mmm. Look at what 22 minutes with a big reflector can do. You'd be all night with a refractor to get anywhere near. Unless it was a 10" refractor of course;)

Cheers

thanks alacant  and even at 10 inch i struggle to finish an image up here in cloudy Darlington but i am still amazed at what you can get from your own back garden even with limited sky and weather that's why i keep going hopefully i can add to the image before it disappears for another year.

 

[alacant]

On 21/08/2020 at 11:51, toxic said:

i struggle to finish an image up here in cloudy Darlington

I've visited UK a few times, but it's always been raining. I loved York which i think is close to you.

I really admire the keep-at-it attitude of the astrophotographers there. Even here in Spain where it's clear most nights, I still prefer to get several targets rather than going all night on one. I began with the oft (ill?) recommended ed80. It's only when you're side by side with the guy with the 6" reflector you realise how slow dim it is -useless for a 20 minute gap in the cloud. With 10" you stand a chance of getting something -even with a Ha filter- as you have admirable demonstrated.

Cheers and clear skies

Edited August 22, 2020 by alacant

[Northernlight]

3 hours ago, dannybgoode said:

Loads of people image very successfully in the UK with a good frac. In reality you’re going to be collecting the same amount of data time-wise whatever scope you use and, unless your focussing and guiding are spot on there’s a chance you’ll get poorer quality subs from the ‘fast and wide’ scope than you would a nice easy to handle frac.
 

 

Sorry buddy, but i have to completely disagree. I have a 102mm Frac already and i know how slow it can be.  There are some arguments that for a "like for like" aperture, then you wont see much of a difference between F4 & F7,  but when we are talking Faster F4 optics and double the aperture size then there is a huge difference no matter what any frac lover might tell you, it's basic Physics that you just can't argue with.

Yeah sure if i won the lottery - there would be no doubt, i would have a huge mount and a 10" APO any day of the week over a newt, Unfortunately being a mere mortal i dont have £60,000+ spare sitting in the bank for that kind of setup, so i'm stuck with the next best option which is a fast newt.

[Sp@ce_d]

23 hours ago, Northernlight said:

Sorry buddy, but i have to completely disagree. I have a 102mm Frac already and i know how slow it can be.  There are some arguments that for a "like for like" aperture, then you wont see much of a difference between F4 & F7,  but when we are talking Faster F4 optics and double the aperture size then there is a huge difference no matter what any frac lover might tell you, it's basic Physics that you just can't argue with.

Yeah sure if i won the lottery - there would be no doubt, i would have a huge mount and a 10" APO any day of the week over a newt, Unfortunately being a mere mortal i dont have £60,000+ spare sitting in the bank for that kind of setup, so i'm stuck with the next best option which is a fast newt.

This is true... however there’s two things to consider, aperture and time. Ideally we want both, but if we can only have one, which one ? Not quite the same as a light bucket but I tried going dual and even triple frac shooting, even with a permanent setup that required too much messing about and no sleep. So l started looking at it from the other  end... time. l automated the obsy and was quite surprised how many gaps in the clouds there can be while I’m actually getting some sleep and it adds up. Certainly in my case to a situation where finding  time to process the stuff is more of an issue 🤣

[ollypenrice]

If you fix the focal length the aperture plays exactly as F ratio says it plays. Of course the big reflector is quicker. Once you've got it working, of course. If you are strapped for good sky time, or simply want to keep on churning out quickie images the like of which we have seen endlessly already, then go for 'quick.' Once you want to start going for 'good' it all gets much more difficult. It depends what you want. It's perfectly obvious that one can find top quality images taken with every kind of serious scope. The devil is in the detail: exposure time, expertise in optical tuning, etc etc.

Olly

[Northernlight]

Olly, for me speed is they key, so the comination of the faster optics and larger aperture is a must. Dont get me wrong i love the plug and play nature of a frac, but my scopes are perfmanently pier mounted in the obs, so should only need little tweaks to collimation from time to time once it's been fettled.

At the moment i'm just waiting on Tommy from Teleskop Austria to reply in regards to his new Lacerta scope design - if it will releases soon, then i will buy one of those, as well made hand crafted newt with good quality components can only help to make things a little easier, but if it's not releasing this year, i'll go the hard route and buy a quattro and try to fettle it through upgrades.

 

[ollypenrice]

1 hour ago, Northernlight said:

Olly, for me speed is they key, so the comination of the faster optics and larger aperture is a must. Dont get me wrong i love the plug and play nature of a frac, but my scopes are perfmanently pier mounted in the obs, so should only need little tweaks to collimation from time to time once it's been fettled.

At the moment i'm just waiting on Tommy from Teleskop Austria to reply in regards to his new Lacerta scope design - if it will releases soon, then i will buy one of those, as well made hand crafted newt with good quality components can only help to make things a little easier, but if it's not releasing this year, i'll go the hard route and buy a quattro and try to fettle it through upgrades.

 

That makes perfect sense. I'll make my usual point that 'faster optics' and 'larger aperture' really mean the same thing but I take your point entirely.

Olly