GSO image optimized newtonians?

[5ash (Philip)]

Has anyone any experience or comments on these scopes. I am trying to avoid the complication of off axis or guidescope guiding. With my ED80 unguided on an neq6 mount i can get ~70% pictures with round stars at exposures of 3-4 minutes. My other scope is a c9.25 which even with a .67 focal reducer will still give me a focal length of around 1600mm , which is unlikely to give me long exposures without elongated stars. I was considering the advantage of using one of the 6 inch F4 GSO image optimized newtonians. Same focal length as the ed80 , about x3 light gathering power , better resolution and should track on the neq6 mount like the ED80. On the other hand coma may be more of a problem. Any thoughts?
Philip

[MrB (Simon)]

I have been weighing up the options for a fast newt too.
So far I have found out that the GSO's do need a bit of fiddling to get them to work well, no surprises there. Apparently the secondaries are a bit undersize (63mm for the 6") and not offset. The new linear focusers are apparently better than the old GSO crayfords.
I've been toying with getting the 10" but basically just for the primary.

[strongmanmike (Michael)]

What's your budget like? If you can stretch it a bit you could look at an Orion Optics UK AG8 = 8" F3.8 corrected Newtonian FL ~ 760mm. Top quality, proper sized off-set secondary, stable, well corrected and rigid and with an Aussie dealer even...just a thought

Mike

[Tandum (Robin)]

I got one in the mail and the coma corrector will be my major issue. If your camera sensor can be illuminated with a 2" corrector you're laughing. I have a cheap 2" corrector to get going with but my camera needs a 3" corrector which costs more than the scope

[5ash (Philip)]

Thanks for all the info , have been getting some nice pics with the Ed80 and NEX5 combo on the neq6 and would have to off axis guide with my observatory setup as the roof opening is asymmetrical and fairly small. Adequate for observing and general prime focus photography but too small to enable two scopes to view simultaneously all the time .The fast newt looked a possible answer but only at a comparative price to a radial guider and guide camera. May well consider this option again though still resisting the complication it imposes.
Philip

[alistairsam]

How about using a finder guider where the normal finderscope would be?
Light enough, wide fov would match a fast newt and you can go long exposures. An 8inch f4 would work well with the neq6
Weight would be very close to a normal finder as the guide camera would be very light

Would need some reinforcing around the focuser with or without the finder guider
You'd need an mpcc with an f4

[MrB (Simon)]

Originally Posted by strongmanmike

What's your budget like? If you can stretch it a bit you could look at an Orion Optics UK AG8 = 8" F3.8 corrected Newtonian FL ~ 760mm. Top quality, proper sized off-set secondary, stable, well corrected and rigid and with an Aussie dealer even...just a thought

Mike

What's your commission?
Worth every cent, but going from ~$400 to ~$5000 is a big stretch!
I had (very)briefly considered, but just can't justify.
Maybe one-day.

[strongmanmike (Michael)]

Originally Posted by MrB

What's your commission?
Worth every cent, but going from ~$400 to ~$5000 is a big stretch!
I had (very)briefly considered, but just can't justify.
Maybe one-day.

Are they really only 400 bucks..?

No commission on this, just happy with my AG12 and I imagine getting a $400 scope to really shine might be a bit of a task..?

Only $400 though...maybe buy 2 and make a bino scope?

Mike

[naskies (Dave)]

..

[naskies (Dave)]

Originally Posted by 5ash

With my ED80 unguided on an neq6 mount i can get ~70% pictures with round stars at exposures of 3-4 minutes. My other scope is a c9.25 which even with a .67 focal reducer will still give me a focal length of around 1600mm , which is unlikely to give me long exposures without elongated stars.

The EQ6 has a huge periodic error (45 arc secs peak-to-peak, I've heard) so it's no surprise that you'd lose a lot of exposures without auto guiding.

There are several people here (including me) who use a GSO RC8 at prime focus on an EQ6: the focal length is just over 1600 mm.

Here's an example of round stars with 6 min exposures at 1600 mm - guided with an Orion 50 mm mini guide scope (162 mm focal length) and QHY5 using PHD.

I've tested longer exposures on that set up and it still worked fine, but the DSLR subs were becoming waaay too noisy.

[MrB (Simon)]

Originally Posted by strongmanmike

Are they really only 400 bucks..?

No commission on this, just happy with my AG12 and I imagine getting a $400 scope to really shine might be a bit of a task..?

Only $400 though...maybe buy 2 and make a bino scope?

Mike

Yeah I know, was tongue in cheek

Hard to believe eh? The 6" is 400, 8" is 450, 10" is 699 and 12" is 899, all are f4.
The 8, 10 and 12's come with rings (the 6 might too but they aren't mentioned) and the 10 and 12 also have 3" focusers, so can take a Keller/Wynne corrector, which would cost more than the OTA

Thru my research, there are plenty of people getting acceptable images from them, but they're obviously no AGx. You are right, getting them to really shine would be difficult, but as an entry level system, can't be beat!

[Kunama]

What about the Vixen R200SS, might be more within the budget
8" F4 fl800 with an excellent mirror.

[strongmanmike (Michael)]

Originally Posted by Kunama

What about the Vixen R200SS, might be more within the budget
8" F4 fl800 with an excellent mirror.

Yes good alternative...although still not anywhere near $400

[Tandum (Robin)]

And free delivery at the moment. I'm expecting a 12" to arrive tomorrow. The 3" corrector is another issue.They are talking 3 months delivery and $1500 from ASA I've asked steve if the orion optics ones are sold seperately.