Advice needed: 'New' Newtonian....

Hi All,

Some advice needed.

I'm thinking of changing to a simpler Newtonian Telescope (OTA).

On my list is:

Skywatcher 250 Synta F4.7
Orion Optics Eurpoa F4

I have two questions:

1. Coma.....how much do I need to worry about this, especially on the Orion?

2. Suitability of my CG-5 mount for the Skywatcher.

I'll be using the scope for both visual and a little imaging (mainly webcam...but will try some DSLR...which may need a mount upograde).

And advice would be most welcome!

Oh! Both scopes (actually 3, 2 Synta's) are roughly in the same price range.

Thanks in advance,
Peter

peterako wrote: 1. Coma.....how much do I need to worry about this, especially on the Orion?

The answer is, a lot. With an F/4 scope you will certainly need a coma corrector. From experience I can certainly recommend the Baader MPCC. You WILL need it for a scope this fast. Also keep in mind that with scopes this fast collimation requirements are exacting and can't be overlooked.

The f4.7 scope will ease the situation slightly but I still think you need a coma corrector.

peterako wrote: 2. Suitability of my CG-5 mount for the Skywatcher.

I think you'd be ok with the f/4 and ok for visual with the f/4.7. I did astrophotography before with a CG5 and C9.25". It can be done. The problem with a newt is the moment of arm is large and even a slight breeze will mess it up for you.

HTH

Dave.

That's really great advice given from Dave as that's the man to listen to about newtonians.I actually bought a 10" f/4 newt from him not too long ago but I don't think he stressed enough how crucial collamination is on fast newts.I was amazed at the results with only a small turn on collaminaton knob...as for comma,yes you will get and coma cirrector is highly recomendet.
As for your mount I don't know the load capabilities of it and if you are looking at skywatcher OTA on adverts I would presume you would only be able to use it for visual on your mount as it weights 15kg on its own...I was actually thinking about it but at the end didn't chanced my arm mounting it on neq6.
Haven't tried any AP yet as still playing around with the mount but you will have to get better eyepieces for it.I have quite a bit of plossls and recently got meade swa which made a big difference...it really complimented the OTA.

Thank you Dave and Nerro.

My dilemma remains

But you've confirmed my worries and I'll have to think hard now.

A Coma Corrector is not cheap

Was tempted by Dave's 10" Newtonian and was so close to contacting him on many occassions, it was a great deal!
I hope you make the most of it Nerro!!

Awaiting some replies on the 8" Orion from the owner.

I'll update this thread when/if I make a decision.

Yes Nerro, one of the Synta's was the one on Adverts.
Went to see it last week, and while it doesn't appear to be much heavier than my existing scope it is much longer and, as Dave highlighted, the moment of the tube will be an issue in breezes....


Hmmm.....

Thanks again guys!
Peter

Peter, the beauty of a fast newt is if you can tame it, you will get a similar performance to a same sized apo. It took me some time to get my head around all the nuances of the scope but once I did, it was worth all the effort. The thing is Peter, if you found that the CG5 wasn't cutting it, you could look at upgrading at a later stage. However, if you go for a lesser scope you will probably end up upgrading both at a later stage. I had the opportunity to test out the tele-vue coma corrector for a short while. I found that although it *might* be slightly better than the baader, it is not superior enough to justify the extra cost and weight. The baader is perfectly good enough.

I always use the following image to demonstrate what can be done with a fast newt and good seeing one everything is tweaked and working well.

www.webtreatz.com/gallery/displayimage.php?album=14&pos=3

Good luck with whatever you choose.

Many thanks again Dave!

I remember being 'Wowed' by the shots on your website.

Simply amazing.

I'm so tempted by the 8" scope

I overhauled my CG5 when I first got it (second hand) and it's pretty good. Only time will tell if I need to upgrade it. The weak link it it at the moment is teh tripd, and I may just build one of wood, or put a pillar up somewhere.....out of site of the wife

Imaging is fun, but I always try and spend at least an equal amount of time doing visual observation.

I'm still a beginner at both!

Taming a fast scope sounds like a nice challenge!

Thanks again, your advice is much appreciated,
Peter