Input from friends for new scope.

[xelasnave]

I know I have asked along these lines re a 16 inch but any comments from those who know me and prepared to speak their mind would be greatly appreciated. Mind you if you don't know me but think you can help I would also welcome your input.
I think going for a 16 inch may be beyond my ability..why would I want one..well for no other reason than I want one..what will I photograph..not sure but no planets.
So I am thinking maybe a 12 inch f8 with the carbon fibre rods...it must be good with carbon fibre right? Or maybe the 10 inch..the FL scares me so I at least have some idea...do these scopes manage a focal reducer...is that a bad idea...around 1200 FL would be a good spot to aim for..what do you think?.hopefully to use a little zwo 1600 mono but if you think of a better camera please say so...mount..the large celestron mount about 6k one.
I would like to order the new scope now as I expect some delay and I just want to get on with it.
So help me spend some cash I need your help to get organised as my head is not clear but that has not stopped me in the past I want to get things going so I can think about other stuff.
Alex

[glend]

Alex, I think I know you and your situation, well enough to offer some advice. First, consider the weight of any purchase and your ability to manage that weight. Secondly, how are you going to house it (the new observatory I would guess), and are you thinking of a heavy duty EQ mount say like an EQ8 or CGX-L (If a newt, RC, CDK, etc)? Also think about putting your mount on a good pier, and now is the time to think about the footing, and make that part of the observatory planning.
Three, you don't necessarily need really big aperture to image effectively. A 12" f8 that you mentioned, I assume your referring to say a GSO RC12, the 12,5" Planewave CDK, or the CFF 300mm RC, would be the limit I would suggest in terms of size, and they are still pretty heavy, the Planewave weighs nearly 50lbs naked. Another thing related, try to buy from a local retailer if you can, and I note that Bintel now supply Planewave scopes, in addition to GSO RCs (And I know you like Bintel)..
Four, keep your present camera, because this will simplify the transition to a new setup, you can always upgrade the camera later on, learn the new scope first. However, as a caveat, maybe discuss with Bintel a package deal, of mount, scope and new larger format camera; surely has to be worth a significant discount if bought at the same time.
Five, are you a collector or a user? There are people who buy scopes that get used very little, if at all, and I won't name any. IMHO do not buy something you will not use, there are better places to invest your money. Telescopes are not financial investments, Although I will add that a good quality scope from a desirable manufacturer with a great reputation, say like a Planewave, will likely always attract buyer interest.
So those are my thoughts. You have my number if you would like to talk in more detail. Good luck.
Glen

[Startrek]

Alex
Only a suggestion, why not go for a 10” f5 carbon fibre newt from Sidereal Trading ? It has a focal length of 1200mm and is lighter than a steel tube OTA
At least it’s manageable if you have to pull it off the mount and do some maintenance
A 12” or 16” truss newt is a beast of a thing, but maybe you want a beast up there in Tabby with your dark skies ?

Just a suggestion

Hope more experienced folk chime in with their advice !

Cheers
Martin

[xelasnave]

Bintel GSO RC12A Truss Ritchey Chretien Astrograph on a
Celestron CGX-L German Equatorial Mount & Tripod is where I am thinking.
Thanks Glen and Martin I have only had a quick read so need to get back to sit and think
Alex

[glend]

Alex, I highly recommend putting the CGX-L on a pier. You have this new observatory coming so this is a great time to be putting in a substantial footing (say a cubic metre of concrete) for a steel pier. Tripods are great for casual use and field work but in your own observatory a pier makes more sense (to me), and no tripod legs to trip over.
TPI Astro in Canada make nice CGX pier adaptors, I have one. Email Dave at TPI Astro to discuss.

http://www.tpiastro.com/cge_pier_adapter.htm

[Atmos]

It does largely come down to what camera you're wanting to use as to what path would be best. If you're considering a 12" F/8 then I can only assume that you've decided that you want to go after galaxies and small portions of nebula.

Using a ASI1600 at 2400mm would leave you with an image scale of 0.325"/pixel and a FOV like the image attached. So I guess it depends on what you're wanting to achieve.
You'd also JUST fit in NGC 253 if you got the camera rotation correct.

Ultimately I think you'd potentially be better with a 10-12" Truss Newtonian around the F/4-5 mark as it would better suit the ASI1600.

[croweater]

Hi Alex. +1 for Glen's suggestion of a pier. Daniel Reardon from Melbourne has posted a great offer in the Equipment section. He would build/weld a pier to spec at material cost only to practice with his new welder. This seems a good opportunity for a stable pier at a good price if thats the way you want to go.
Cheers, Richard :)

[Camelopardalis]

Yeah I’d go with the 10” newt, depending on your pain tolerance when it comes to collimating as to whether to go f/4 or f/5...

[xelasnave]

Thank you Colin I certainly appreciate the photos.
I guess I would really love ke to go after galaxies I am just worried that I am probably biting off more than I can chew.
Alex

[xelasnave]

Thanks Glen.
I don't plan for a pier first up on the basis that I want to be very certain about the height of the scope and if I keep it before I place it on a pier.
There is a hole in the floor of the new one which I can access the ground and dig out a hole...maybe hire my new mate to do that..the one who cut down the trees...I am not used to paying people to do personal stuff but he works as hard as I once would and does in a day what will now take me a month.
I may take you up on giving you a call but reception here is not great..hopefully.
Alex

[xelasnave]

Dunk you are correct really but it's the dialling in that worries me FL is sensible for me.
Alex

[xelasnave]

Thanks Richard...it will depend on timing...I will make provision but want to get a feel for the best height.
Alex

[xelasnave]

OK getting wild...what about my suggested rig with a ZWO ASI6200MM-P ...how would that go?
I suppose that would require a decent computer for capture and stacking.
No more 200 subs I expect.
Alex

[Camelopardalis]

Maximising the pain, Alex?! :lol:

A full frame sensor is pretty demanding on (relatively) inexpensive reflectors IMO

[xelasnave]

So it would be a headache on the RC 12 ?
It boils down to this..I was going to buy a decent caravan to live in but I am happy with this one I got for nothing so given I don't have much time left being realistic I figure to spend the accommodation money on astronomy.
I am crazy perhaps but I live for my astronomy..it's all I do really.
Alex

[glend]

I hope that is not true Alex ("the not much time left" bit) but I understand the viewpoint. You don't owe anyone an explanation. I am reminded of the lyrics of the Bon Jovi song, "It's my Life", .."..It's my life
It's now or never
I ain't gonna live forever
I just want to live while I'm alive".

Geez I can't believe I am quoting Jon Bon Jovi, haha.:lol:

[xelasnave]

I am 73 that means another thirty years and I probably will have lost interest and want to take up bowls.
Alex

[Camelopardalis]

Alex, I honestly couldn't tell you, I have no experience of an RC other than what I see written in these fine pages :shrug: but from what I hear they can be a bit of a pain to collimate.

If you're not afraid of collimation, then go with a faster newt...the truss newts look nice and solid. The difference in speed between f/8 and f/4 imaging is pretty stark, and if you're skies are good, the pixel resolution on the 6200 should be pretty revealing for a 10" or 12" fast newt.

Ultimately, we're all on borrowed time...IMO we've all got to do what we love, within sensible bounds ;)

[xelasnave]

I got the impression they are not a problem but I will look into that. Thanks Dunk.
Alex

[Camelopardalis]

There will be correctors for them, so that's worth investigating.

But I'm not entirely certain what the fundamental pros and cons are between the different scope designs.

I think with RCs the field curvature is the problem, whereas with newts it's coma, but that's (almost certainly) oversimplifying it.

[Slawomir]

Lot's of great advices.

If you do not mind Alex, I am happy to share my take on your choices.

If you are going with 1600MM, then 1000mm FL is around optimal for imaging DSOs, and with 16200, around 1500mm FL should give optimal sampling for multi-night imaging of DSOs.

With those focal lengths in mind, for DSO imaging, I would look for the fastest scope I could afford. So either a quality 10"RC with a quality reducer, or a quality Newtonian.

Last but not least I would consider either top mount that would not hinder the resolution (what's the point of getting a huge scope for high resolution long focal length imaging if data gets blurred by the mount?), or a decent mount but with a camera with Active Optics.

Good luck and please keep us updated :thumbsup:

[xelasnave]

Thank you Suavi I appreciate your input.
I am changing ideas ever hour.
I think the Celestron mount and the 12 rc if I can get a good reducer and a quality focused.
This morning I thought an f4 GSO Newtonian.
The reality my demands are not high so I expect whatever I end up with will make me very happy..I mean I have been happy with my little 80 mm and 115 mm refractors and my eight inch GSO Newtonian...I guess the money I will throw at it will mean some sort of compromise but I just can't pull the trigger on a Planwave ... I think it would be like me buying the largest Caterham sports car...I am never going to drive any of these things to their potential...and funny last night I was imagining with the little 80 mm and was happy as I could be...All I need is two more mounts, three more cameras and three more desk tops...
At least I now have enough observatories...two here and one in Sydney ..which reminds me I have to dismantle it and get it up...so that's room for four mounts all up.
My behaviour is normal right? So I can see the future ..the observatories all producing data, the over powered Caterham sports car sitting outside and the classic yacht alongside the jetty in the dam.
Hopefully the new observatory will be in place next week so I can start to set up a bed and stove for coffee..I have a new floor for it..still have to clear these trees and make the park...for astronomy guests...plus I want to learn to play poker..what an easy way to make millions.
Alex

[xelasnave]

It's now the 10 inch on a Celestron mount..or 150 Espirit.
I need to get out of here I am going crazy.
Alex

[Camelopardalis]

Hmmm that’s a tough one...the Esprit 150 is plug-and-play but is f/7, whereas a 10” f/4 newt is a bit more frigging...but that’s an awful lot more photons :shrug:

[glend]

I built a 10" f5 truss newt using GSO mirrors, it was a very nice scope, and f5 is alot more useful in my opinion than f4. An f4 has a focal length of 1000mm, the f5 1250mm. Alex's TS115 has a focal length of 900, not reduced. So i think an 10" f4 Newt is not gaining much in terms of reach. Of course it has greater photon grab but it also has a central obstruction.
And yeah, an f4 Newt with secondary offset considerations is a bit more frigging around with in collimation. I am all in favour of easy to use scopes.

[xelasnave]

Actually this one with a reducer..I need to work out if it would be happy with one...a 0.5 or o.6 ...I thought about the 12 but it's fl scares me but hopefully I could manage this..if not at least I gave it a go...could always add a Barlow and go for planets.
I hope I can make it work.
Alex

[xelasnave]

I have a twelve inch f5 which needs a new surface and I may get it going as at f5 it appeals and I have imaged with it..but maybe a new focused and a new aluminium surface... I plan on the Celestron mount which should carry the 12 if I call it up...but I won't go near a f4 reflector.
Anyways lots to do before I get one..I will ring and find out delivery etc.
I have checked on Bintels calculator and the ten inch seems as it should work with the zwo but there will be something out there if not...I will have three mounts all housed so I want two more cameras in the long term..but another zwo can go on either of my current scopes...oh and there is the eight inch but it needs a focused to make me happy with it.
Alex

[Camelopardalis]

Looks like a beast of a scope :eyepop:

TBH, I’ve never understood the appeal...it’s like an SCT without a corrector plate :shrug: