Looking for a flexible refractor, any tips?

[VigdisVZ]

Hi SGL

After talking to some of my club buddies yesterday and smacking myself over the head a few times for not thinking of this myself I realised that I might as well get a good little frac instead of the cheapest one as a guide tube.

If it get a better one I can fill two more roles like super wide AP and portable visual instrument.

I was looking at a used WO Zenithstar 66 SD doublet APO in sweden, but the seller hadn't updated the post and it was no longer available.

When looking at new stuff the Megrez 72 seems pretty light and usable. Also there are the Zenithstar ZS70 2012. These are a bit costlier new, but if I no used alternatives appears I might have to go down that road sooner or later anyway.

What other brands and scopes will fit the following:

*Light enough to use as a guide tube and be portable

*400mm focal length... or thereabouts

*Optical quality enough to be usable for AP and visual. I realise I might have to get a corrector for true AP.

It really doesn't have to be ultra quality, but something that is usable in all 3 modes (AP, guide and visual).

Or you can just tell me to stop trying to eat the cookie and still keep it.

Thanks guys.

[ronin]

The Megrez 72 has not been made for some time so that would also be a used item now. WO stopped it, made the Zenithstar 70, then updated it to the Zenithstar 71.

The widest choice seems to be from TS. They have a 70mm f/7 ED refractor for 320 Euro. Carbon tube so a bit lighter. They have a 66mm for 375 Euro.

In the Astro Professional (sold byTS) line there is an 80mm f/7 for 400 euro.

[VigdisVZ]

Oh ok. I listed the Megrez 72 as new because they still sell it at a few shops in sweden. Still I'm considering it if I find a used one. The TS ones, how does the optics rate in your opinion?

Thanks

[John]

Skywatcher Equinox 80 ?

It's 500mm focal length though so maybe too long.

I had a Zenithstar 70 (older type) for a short while and that seemed a nice scope for visual, within the limitations of the aperture. I don't image so can't comment on that.

[Marki]

Can you get a reducer with the Equinox 80mm? to bring the FL down? Great little scope though - well built, pretty light but robust. I use it as my grab and go and have been very happy with it - pretty good range of things can be seen well with this, and recently I;ve had some lovely detailed and crisp views of Jupiter at x100 with it. Stars are pretty good pin points across most of the field too (not the whole field though - may be my eps, or maybe my scope needs some sort of flattener - not an imager so it doesn't bother me though). May be worth looking at the Skywatcher ed 80mm pro - cheaper, but with a fixed dew shield and non-rotatable focusser (I think) - quite often recommended for ap work.

EDIT - I see the 80mm ED pro has a fl of 600mm so even longer than the equinox.

[VigdisVZ]

Thanks for the hints, looked at the ED but the focal length is to close to my newt, and ideally the OTA should weight less. The equinox is interesting also.

[Dunkster]

I'm travelling with the Zenithstar 71 at the moment and I'm quite impressed so far. It's well built and looks good (not that that matters in the dark!). I'm only have 1.25" EPs with me, but by my calculations I should be getting around 3.7 degrees with the 24mm Panoptic...quite a contrast with my usual SCT Gives sharp stars across the FOV with the EPs I have with me, and I was picking out stars at mag 10.5 on the night of full moon. It's 2.7kg and 305mm long.

There's also a 0.8x reducer available but I'm not sure if this is for imaging only or whether it's suitable for visual also.

Not the cheapest option, I know...

[VigdisVZ]

Not the cheapest option, I know...

And thats exactly why I did this thread. If I wanted cheap I'd mod something or get a startravel. But if I can kill 3 birds in one throw I'm all for looking at the zenithstar. Thanks for adding your input Dunkster, a Zenithstar is definetly under consideration.

[Dunkster]

OK, I'd just like to make an amendment to one of my earlier comments "sharp stars across the FOV"...

Had second light last night and spent some time trying to assess image behaviour. There appears to be a little field curvature but I'm not surprised I missed it first time around (with the excitement of actually seeing stars!). It starts about 80% out and is quite subtle, but it's possible to focus it out, at least to satisfy my eyes, focussing on a star towards the danger zone left the centre intact. I checked for similar behaviour using all 3 EPs that I have at my disposal with the same (or indistinguishable) effect. Maybe this is why they offer a field flattened for imaging? Anyhow, I also tried seeing if focussing in the centre only made the centre of the FOV sharper than focussing out toward the edge and I couldn't tell the difference, maybe a more experienced member could.

So far I'm still liking the little scope a lot... the FOV with the 24 Pan is something I'm only used to seeing with bins, but to have a stable view with slow motion controls is neat. And it fits comfortably in my carry-on backpack, along with EPs finder and all