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Scope for 8SE mount

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#1 kevinbreen

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Posted 13 January 2018 - 11:58 AM

I’m interested in a bigger aperture than my 8SE. Is there any SCT with aperture bigger than 8” which can be used on the stock 8SE mount?

Yours hopefully

KB

#2 Mitrovarr

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Posted 13 January 2018 - 12:03 PM

I wouldn't recommend it. Even the C8 is almost too much for it.


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#3 kevinbreen

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Posted 13 January 2018 - 12:05 PM

Thanks, but that is not the answer I was hoping for! Anyone else?🤣🤣

#4 NochesNubladas

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Posted 13 January 2018 - 12:33 PM

Hi Kevin,

 

I have the 8SE and the weight limit according to Celestron is 12 lbs.

As soon as I put a heavy wide angle FOV eyepiece ity's over the spec.

Running it a little bit over is probably ok but I am pretty sure if I was looking for a larger aperture, I'd also be looking for another mount as well. Even the 9.25" would push this mount past it's reasonable weight limit.

That being said...

 

You could do all the things we do to stabilize a weak/shaky mount:

 

1. Make sure the tripod legs are spread all the way apart.

2. Don't extend the legs at all.

 

3. Hang a gallon jug of water or sand from the tripod spreader. Alternatively you can screw one of those corkscrew things to leash your dog to and use a turnbuckle arrangement between it and the tripod spreader to adjust the tension until the vibration is at minimum.
 

This instability will be acceptable for visual but not AP IMHO. It will be more prone to bad frames due to vibration from wind at slower wind speeds than a more stable mount would be.

 

Not really sure if the measures outlined above wold be enough to stabilize it or not.

 

Edit: I also wonder about the radius of something like the Celestron 9.25" they have even fitting within the scope of that single arm fork. You might not have a lot of room to slew altitude wise...


Edited by NochesNubladas, 13 January 2018 - 12:39 PM.

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#5 kevinbreen

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Posted 13 January 2018 - 12:40 PM

Thanks Noches, that’s an encouraging answer!
I saw that the edge 9.25 came in fibreglass as well as metal housing (if my memory serves me right), and I thought maybe there are light-enough wider-than-8” aperture SCT OTAs out there, somewhere...🤓
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#6 M11Mike

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Posted 13 January 2018 - 12:42 PM

Recommend getting a 9.25" EVOLUTION if you want slightly more aperture --- even IF the 8SE mount could handle more weight than a 8" SCT --- you wouldn't have the height in the mount arm - and anything longer than the 8" SCT optical tube will bump into the mount when attempting to go vertical. 

 

Not sure if the additional 1.25" of aperture would justify the cost - that would be something you would have decide yourself.  It will of course give a bit more light and the faint fuzzies would be brighter --- but not buy a huge amount - more a subtle improvement.

 

 

MP/BL      


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#7 NochesNubladas

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Posted 13 January 2018 - 12:43 PM

Thanks Noches, that’s an encouraging answer!
I saw that the edge 9.25 came in fibreglass as well as metal housing (if my memory serves me right), and I thought maybe there are light-enough wider-than-8” aperture SCT OTAs out there, somewhere...

Yeah, with that corkscrew/ turnbuckle/ to tripod spreader I imagine you could get it pretty solid. Give it a run for it's money anyway right?



#8 Mitrovarr

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Posted 13 January 2018 - 12:44 PM

Even if the C9.25 wasn't way too heavy, it would be too long. It's going to bang into the base if it goes anywhere remotely near zenith.

 

But yeah, it's too heavy. The poor mount would be at nearly double the specified weight. I wouldn't load up a motorized mount way over spec, it might break it.


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#9 NochesNubladas

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Posted 13 January 2018 - 12:45 PM

Recommend getting a 9.25" EVOLUTION if you want slightly more aperture --- even IF the 8SE mount could handle more weight than a 8" SCT --- you wouldn't have the height in the mount arm - and anything longer than the 8" SCT optical tube will bump into the mount when attempting to go vertical. 

 

Not sure if the additional 1.25" of aperture would justify the cost - that would be something you would have decide yourself.  It will of course give a bit more light and the faint fuzzies would be brighter --- but not buy a huge amount - more a subtle improvement.

 

 

MP/BL      

Hi Mike,

 

Yeah, that last thought I had is really the deal breaker in my mind on whether or not you could get away with the 6/8SE mount for the 9.25...

You'll have nearly zero vertical travel and be stuck below 35 degrees (I'm just guessing here) or something like that.



#10 jallbery

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Posted 13 January 2018 - 01:02 PM

I’m interested in a bigger aperture than my 8SE. Is there any SCT with aperture bigger than 8” which can be used on the stock 8SE mount?

Yours hopefully

KB

 

No.

 

The 8SE is really at its limits to begin with with the C8 on it (a 12-pound OTA on a mount rated at 12 pounds).

 

A C9.25 is 30% longer and 67% heavier.  So not only do you get significantly more weight, you have a longer moment arm, too.  This is not a recipe for success.


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#11 ShaulaB

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Posted 13 January 2018 - 01:21 PM

I have had the opportunity to work with a Celestron 9.25" SCT as well as many 8" SE's.  Have you noticed that the 8" optical tube has very little space between the end of the front of the OTA and the Alt axis of the mount? A C 9.25" (or 11" or 14" etc) has a longer optical tube, so even if the mount could carry it, you would not be able to observe within 30 degrees of zenith.

 

OTA for an 8" is 17 inches. OTA for a 9.25 is 22 inches. Look at your current scope. Do you have 5 inches of clearance when the OTA is pointed straight down into the mount? Probably not.

 

There is no way to point the optical tube straight up, or even close to straight up. Compare the weights: 20 pounds for the 9.25" OTA only vs 12.5 pounds for the 8" OTA only. Since a 9.25" OTA has almost twice the mass as an 8" OTA, it is unlikely that the mount for the 8" will happily move a 9.25 inch. That's just how things are designed in the 21st century: get the job done, but do not expect more.

 

It is easy enough to look up all these bits of data online. You're welcome.


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#12 jallbery

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Posted 13 January 2018 - 01:46 PM

 Do you have 5 inches of clearance when the OTA is pointed straight down into the mount? Probably not.

 

While I do not disagree with your conclusions, I do feel compelled to point out that you don't need 5 inches of additional clearance because the C9.25 is 5 inches longer.   If both scopes balanced at the center, you'd only need 2.5 additional inches.  Since SCTs actually balance closer to the rear cell, if the C9.25 was merely proportionally longer, the additional clearance required would be less than 2.5 inches.   However, the C9.25 has a different optical design a disproportionately longer tube, which means that the difference probably is more like 2.5 inches.   But you still can't use the scope at the zenith, and it's still too heavy for the mount.

 

A Meade 10" weighs almost as much as a C11.

 

If the OP wants a bigger scope, he needs more suitable mount.   Or perhaps custom a 10" F/1.8 conical mirrored newt in titanium Serrurier truss...



#13 Mitrovarr

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Posted 13 January 2018 - 01:49 PM

 

 Do you have 5 inches of clearance when the OTA is pointed straight down into the mount? Probably not.

 

While I do not disagree with your conclusions, I do feel compelled to point out that you don't need 5 inches of additional clearance because the C9.25 is 5 inches longer.   If both scopes balanced at the center, you'd only need 2.5 additional inches.  Since SCTs actually balance closer to the rear cell, if the C9.25 was merely proportionally longer, the additional clearance required would be less than 2.5 inches.   However, the C9.25 has a different optical design a disproportionately longer tube, which means that the difference probably is more like 2.5 inches.   But you still can't use the scope at the zenith, and it's still too heavy for the mount.

 

A Meade 10" weighs almost as much as a C11.

 

If the OP wants a bigger scope, he needs more suitable mount.   Or perhaps custom a 10" F/1.8 conical mirrored newt in titanium Serrurier truss...

 

It's not just the weight of the 10", it's the size. You can just look at it, look at the SE mount, and see that it's an absolutely ludicrous idea.


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#14 kevinbreen

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Posted 13 January 2018 - 01:58 PM

I suspected it was a ludicrous suggestion/question actually, but one can always hope. In particular I was hopeful there would be a lightweight larger-aperture OTA that I hadn’t heard about....
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#15 Mitrovarr

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Posted 13 January 2018 - 02:01 PM

I suspected it was a ludicrous suggestion/question actually, but one can always hope. In particular I was hopeful there would be a lightweight larger-aperture OTA that I hadn’t heard about....

Not that I know of. I thought about it, but realistically, no available design is shorter than an SCT, and the scope has to be short, so every other design is out before they even begin.



#16 NochesNubladas

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Posted 13 January 2018 - 02:05 PM

Seriously Keven,

 

why not just...

Get a 12 to 16 inch Hubble Optic light weight Dob. The 12 inch you can back pack with.

 

This is what I'm going to save up for:

 

http://www.hubbleoptics.com/UL16.html
 

Oddly on their website it says the 12" and the 14" are the same price.

 

I mean, if you want more aperture, I'd go at least 12 inch light weight / travel Dob and then the mount question is moot.

 

Edit: I love my 8SE. It's always easy to setup. But I do want more aperture as well...


Edited by NochesNubladas, 13 January 2018 - 02:07 PM.


#17 M11Mike

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Posted 13 January 2018 - 02:50 PM

No way you'll make ZENITH with an additional 2.5" of length.  I run my 8SE all the way at the primary end of the Vixen rail and even with just a 1.25" diagonal the "clearance" is like 1".  So, if a 9.25 OTA with visual back and star diagonal is 2.5" longer - no way a 8SE mount will allow a 9.25" scope to reach zenith.   (no less tolerate the excessive weight)

 

MP/BL


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#18 moonwatching ferret

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Posted 14 January 2018 - 08:28 PM

moving up to  a celestron 9.25 isnt ging to be much of a jump to make your eyes pop like mine did when i first saw jove on my laptop with the 16. if finances are an issue thats on thing  perhaps you should think of selling your scope. not sure of your mechanical skills but if you can work with wood you can buld a tracking platform and throw a 12 inch dob on it.

 

Not sure how meade 12 inch  sct's stack up to celestron edge but if my memory suits me you could get a 12 inch meade sct for around 2000. also theres the 12 inch orion wood box alt az mount scopes with orions version of servo cat drives. wavy davy has the 16 inch version and gets very similar images to my 16f7 that may be your best bet



#19 moonwatching ferret

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Posted 14 January 2018 - 08:35 PM

Seriously Keven,

 

why not just...

Get a 12 to 16 inch Hubble Optic light weight Dob. The 12 inch you can back pack with.

 

This is what I'm going to save up for:

 

http://www.hubbleoptics.com/UL16.html
 

Oddly on their website it says the 12" and the 14" are the same price.

 

I mean, if you want more aperture, I'd go at least 12 inch light weight / travel Dob and then the mount question is moot.

 

Edit: I love my 8SE. It's always easy to setup. But I do want more aperture as well...

this doesn't seem like a bad idea at all wonder why the 6 inch longer f ratio is 300 dollars cheaper lol just get a tracking platform i would compare the price tag with the orion with tracking


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#20 moonwatching ferret

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Posted 14 January 2018 - 08:41 PM

https://www.telescop...e/p/102637.uts 

 I think other then the 16 this is your best bet. setting up a tracking platform and trying to center jove is going to be a nightmare 2000dollars


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#21 moonwatching ferret

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Posted 14 January 2018 - 08:43 PM

sorry the link didnt work i was refering to there 12 inch with drives its only 2000 dollars


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#22 Kokatha man

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Posted 14 January 2018 - 09:38 PM

Kevin, somehow I don't think any of the replies have helped fuel your enthusiasm...& probably with good reason btw. wink.gif

 

Whilst the idea of seeing what sorts of (second-hand) mounts & larger-aperture scopes are available in your neck of the woods & possibly doing a switcheroo where selling your existing scope for the trade-up keeps you off the streets & a buck in your pockets still wink.gif I'd strongly urge you to work with your current scope to see how much you can improve your imaging. waytogo.gif

 

The Moon is always going to be around & while the "Big 3" (Jove, Saturn & Mars) are going to take some time to get up to decent elevations for you, working at maximising what you can get will pay dividends!

 

There's fellas from Moscow in Russia & Finland who work wonders with ADC's & those planets at lower elevations than you - my advice about more distance from the ADC to the camera was something John reinforced to me only a month or so ago & it really did make a very noticeable difference...I don't mean to be (overly! lol.gif ) arrogant but if I can learn/apply something that made a significant difference then you can also - tbh I was always a tad jealous of those Arctic dwellers wink.gif getting such great ADC results, thinking it was mainly the seeing lottery at work.

 

It's all hard-graft tbh & you go forward a few steps & then seem to stand still a lot of times before you move forward again...& the penny sometimes only drops after quite a bit of head-banging as well.

 

That 8SE is more than capable of creating great planetary as well as Lunar images...or "white light" Solar stuff even if the sunspot maxima has come & gone...


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#23 kevinbreen

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Posted 15 January 2018 - 05:59 AM

First off, thank you all for your valuable comments. I've spent some time over the last few days considering all your inputs, while also peering despondently at the weather forecast, noting that clouds and rain appear to be the best on offer, at least for the foreseeable future. 

From my latitude of 52 degrees I am in with a chance of Jupiter and Mars, weather permitting of course, and willpower permitting, which is not to be sniffed at - to see Jupiter or Mars at their highest prior to sun up: I'll have to lug my gear 100 yards to the bottom of the garden in the dark and in the mud to be in with a chance due to the tall trees to the south. Hopefully next week the atmosphere will cooperate.

If only I'd started AP a year earlier, I'd have been in good stead for 2017's Jupiter and Saturn and probably would have opted for the ASI224 and ADC two years ago. That said, I was gobsmacked at my humble colour images of Jupiter last March/April with the NI5, even with no UV cut filter and ADC (which I'm DETERMINED to get to work for me, ****!), and I've turned at least one other person on to the idea of shooting the planets. A local science group wants me to present my pics at a talk down the local next week having been suitably impressed with my images so far, and the national astronomy mag has published a few of my shots, which is kind of funny, as they're nothing to write home about. It's all relative I guess.

As the chances of winning the Lotto remain remote, and with it the realization of a permanent outdoor observatory with a big 14" scope a distant dream, I think I'll stick with what I have and taking Darryl's advice and hone my "skills" to eke out the best my scope can achieve. 

My immediate priority is to change my Celestron X-cel 3x Barlow for an X-cel 2x Barlow, having bought the former before I realized it wasn't suitable for my scope. You live and learn.

I've also recently installed high speed fibre to the home broadband, which will now allow me to save future AVIs in the cloud in an instant, something I was unable to do until now. I wish I'd kept my lowly AVIs from last year to work on now that I know better!

 

I can't wait to capture Jupiter again, and Mars is particularly exciting as I haven't had a chance yet. So onwards and upwards for me. 

 

Thank you all for your time and advice. Here's to a great 2018.

 

Kev


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#24 Lacaille

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Posted 15 January 2018 - 10:58 PM

Good decision!  You can do impressive work with an 8SE.  Squeeze every last drop out of it by honing your skills and equipment, and only then upgrade!  I found with the 8SE that I made a big step up in image quality once I realised how important was telescope management - letting it come to temperature, taking time to collimate it carefully, weighing down the tripod etc.  Then it becomes a powerful tool!

 

Agreed re 2X Barlow - but at least you didn't buy a 3X AND a 5X like me!

 

Mark


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#25 moonwatching ferret

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Posted 16 January 2018 - 12:05 AM

if your imaging with a neximage 5 a zwo asi 224 and adc will be a huge step up alone but i still say save the money and get the orion 16 with drives  or at least the 12 you cant go wong at 2000 dollars




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