#1  
Old 08-03-2020, 02:30 PM
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xelasnave
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A new rig advice.

With my father passing I plan to reside full time at Tabulam.

The only reason I visited Sydney was for him and certainly I prefer the quiet life in the bush.

Also I will have much more time to indulge astronomy...I don't have much time left being realistic (73 years old) so if I am going to do something I really need to focus on doing something and not just keep putting it off.

This additional time means I can look at yet another astrograph and being on site on a permanent basis my desires can become more than just a dream.

I had thought about a 16 inch but it is probably beyond me.

So I am thinking of a gso 12 inch RC (it may be beyond me also) which is for a start half the price of a 16 inch at $4 K approx...it seems reasonable to me. I am even hopeful I could use the stock focuser.

This won't happen for at least 6 months maybe 9 months so I have some time to think about the ideas.

The focal length at 2438 mm scares me and so my first question is can I use a focal reducer and if so what can I get FL down to.

Second for guiding I expect OAG is the only answer. I expect that irrespective of flex issues my 80 mm or 115 mm refractors FL would not be suitable for guiding.

I am thinking that a celestron gcx-l mount ($6k approx) would be an ideal mount...the CGX may do it but I am not sure.

Thirdly...what camera would be a good unit for this scope ( narrow band)...

I have pretty well decided against a Rasa .

And dropping down even to the 10 inch is an option...10 inch still would be rather decent I expect and the CGX would carry it ok I expect, cheaper again...so maybe a 10 inch.
Whatever I end up with will be in a permanent set up so weight is not a problem really.

Now if I was younger I would spend another three years on the stuff I have to learn so much stuff I realise that I do t know, but I don't have the luxury of all that much time..health wise...

Any help will be greatly appreciated.
Alex
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  #2  
Old 08-03-2020, 02:38 PM
Startrek (Martin)
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Alex
Just a suggestion
Why not use your 8” f5 newt and stick it on a new EQ6-R mount ( same as my set up down the south coast )
It’s my scope for life !!
Martin
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  #3  
Old 08-03-2020, 03:01 PM
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xelasnave
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Alex
Just a suggestion
Why not use your 8” f5 newt and stick it on a new EQ6-R mount ( same as my set up down the south coast )
It’s my scope for life !!
Martin
Hi Martin
The eight is great no question but since using the refractors I like the superior balance. I don't like the camera hanging off to one side is all.
I have had the cash set aside for years looking to the day I would be in one place permanent....and I had the money set aside for a van which I can assign to other things so even a 16 inch is not out of the question...
Alex
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Old 08-03-2020, 03:17 PM
glend (Glen)
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Alex, I can give you some feedback on the CGX, the 25kg imaging version, not the L version. They are pretty much identical in terms of how they are made, but the L has a longer saddle, stronger tripod ,etc. Tripod is not an issue if your going to pier mount the head BTW. Very smooth mount, spring loaded worm, belt drive, some of them need checking on arrival as the factory has a bit of a rep for not setting the belt tension, and spring pull back range correctly. Once adusted it gives excellent guide performance.
I have experience with the 8" GSO RC, and like many owners , had issues with collimation precision and focuser slop. In the end I sold it because it required too much attention to get the setup correct. The 12" maybe very different. I think Paul H still has his, or maybe it was the 14", but he has spent some money improving it. Definitely a pier mount scope. The 10" Truss RC would be easier for you to handle and are on sale at Andrews at $3499. The 10" RC weighs 15.7kg, so would be ok on a good pier mounted EQ6, or on a standard CGX with more weight range for the extras.
Re the comments on the 8" f5 Newt, I can agree they are a nice scope as a general allrounder, I have one. You can rotate the tube so the camera hangs below the body, aligned with the counter weight bar, this can give you perfect balance in my experience.
I don't do traditional imaging anymore, as you know, mainly visual now but trying some EAA and planetary imaging this winter.
I am considering the new 10" GSO Truss Cassegrain, which are due in Australia in a few weeks. Slower than the RCs, at f12, but likely ok for planetary imaging, which is how i would use it. With a good high frame rate video stacking planetary camera, like the ASI294, it might be a great setup.
Regarding the GSO RC reducers, they take the RC f8 to f6.
If you want something really fast there is the larger RASA, but the filters (in shooting mono) are pretty expensive I believe. Ask Houghy about his experiences with that scope.

Last edited by glend; 08-03-2020 at 04:33 PM.
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  #5  
Old 08-03-2020, 03:38 PM
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lazjen (Chris)
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Alex, if you go for a GSO RC, you're likely to need to replace the focuser to make your imaging not a frustrating exercise, e.g. with a Moonlite or similar. Go the OAG too - I very much doubt you'd ever have difficulties getting a guide star.

As for the mount, I had reasonable success with an RC10 and G11, so something in that class would be enough. You could look at the iOptron CEM mounts as a possibility.

I've got a 0.67 reducer (AP CCDT67) that works well with the RC10 too - "speeds" it up, etc. Might make it easier to match a camera to it, e.g. a ASI1600 (which I use) - or something better by the time you get to buying.
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Old 08-03-2020, 05:53 PM
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Thanks Glen. Too much time on my hands and stuck in Sydney. I still love the 115mm but I have the "wanties"
Alex

Thanks Chris maybe that $6k camera
Alex

Last edited by RB; 12-03-2020 at 06:52 AM.
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Old 08-03-2020, 06:25 PM
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lazjen (Chris)
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Actually the ASI6200 would be very good (bin 2 or 3), but you would need a different reducer and the larger filters, etc would add so much extra cost.
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  #8  
Old 08-03-2020, 07:52 PM
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That camera is 60 meg which was inconceivable just a short time ago.
The game is rather expensive the scope is just the start, add mount, pier, shed, focuser (near the price of a scope) camera, filters, filter wheel, OAG and a camera for it...probably need a better lap top, and step up to Pixinsite...and a new printer to make the cash...no just joking.
I found Planewave on Bintels site...$90k for a 24 inch, don't know the cost of a mount and camera...next year maybe if my paintings take off..so no chance..croud funding maybe. But I could not run such high end gear.

I am lucky as I am happy with my current gear so I can work on the next set up with no pressure...there is so much I need to go over.
Alex
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Old 08-03-2020, 08:35 PM
Startrek (Martin)
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Alex
I’m making the jump from my Canon DSLR to a cooled OSC Camera later this year ( I’m still going to use the DSLR in the winter months plus it’s a great planetary camera )
Looking at the new ZWOASI2600MC ( APS-C sensor ) which suits my 8” f5 and the 6” f6 newt. Just waiting on some reviews over the next few months to make a decision
Take as much time as you need to make a decision on upgrading, it’s worthwhile chatting with and getting hands on advice from IIS members
Good luck !!
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Old 08-03-2020, 10:01 PM
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Camelopardalis (Dunk)
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Alex, if you’re going to upsize, maybe a 12” f/5 newt? Would still need a decent sized mount, but balancing as Glen described will do the trick.

Maybe and getting old and bitter, but unless you regularly get nights of above average seeing at Tabbie, then I wouldn’t be keen on going for the extra focal length. Beyond what the atmosphere wants to give just looks like a blur at the camera end
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Old 08-03-2020, 10:48 PM
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Gravity does not Suck

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Quote:
Originally Posted by Startrek View Post
Alex
I’m making the jump from my Canon DSLR to a cooled OSC Camera later this year ( I’m still going to use the DSLR in the winter months plus it’s a great planetary camera )
Looking at the new ZWOASI2600MC ( APS-C sensor ) which suits my 8” f5 and the 6” f6 newt. Just waiting on some reviews over the next few months to make a decision
Take as much time as you need to make a decision on upgrading, it’s worthwhile chatting with and getting hands on advice from IIS members
Good luck !!
Martin go mono you won't regret it ..HA is really something.
Alex

Quote:
Originally Posted by Camelopardalis View Post
Alex, if you’re going to upsize, maybe a 12” f/5 newt? Would still need a decent sized mount, but balancing as Glen described will do the trick.

Maybe and getting old and bitter, but unless you regularly get nights of above average seeing at Tabbie, then I wouldn’t be keen on going for the extra focal length. Beyond what the atmosphere wants to give just looks like a blur at the camera end
Your suggestion re f5 appeals. I did do some photos with my f5 12 inch back in the day..on an eq6 ..kept it withing 20 degrees of top dead centre..it worked ok.
When I lived full time at Tabby I only did astronomy all night every night and slept most of the day..when the weather did me no favours I worked on gear. I lived like that for five years which were the best years of my life. I am basically a hermit and enjoy astronomy so much I need nothing else.
I am confident I will get back to that way of life...the conditions when good are as good as one could want...a d going narrow band lets you image every night and not worry about the Moon.
Alex

Last edited by RB; 12-03-2020 at 06:51 AM.
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  #12  
Old 09-03-2020, 01:31 PM
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Camelopardalis (Dunk)
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Living the dream, Alex

The realities of mainstream cost-sensitive construction may dent the usefulness of the cheapest newts, but there are ways of shoring them up and alternative constructions that can make them effective imaging machines.

And of course, starting at f/5...it only needs a good Barlow/Powermate to get going with planetary imaging. Best of both worlds?
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