Skywatcher Quattro f4 Imaging Newtonian telescopes

[shaunster]

You also have to take into account the size of a 10" tube..

[Deneb]

Unfortunatly it won't fit through my door, otherwise I would have ordered one instead of the 8"

Nadeem.

[MikeWilson]

Any reason for 8" over 10" Mike?

£300 + weight + more "sail like" in the wind.

[fatwoul]

Any news on OTA length and weight yet? I'm idly curious to know whether the 10" would fit in my POD. :-D

Before anybody laughs at the idea outright, I've just checked, and I have a good 12" moving room front and back of my MN190 in all directions, possibly up to 16" at the front end.

The idea of the 10" is very appealing considering could have up to 180% of the light-sucking ability of my MN190. Obviously the "sail effect" wouldn't be a problem to me since the scope would be in a dome, sheltered from the prevailing winds.

[Coco]

Any news on OTA length and weight yet? I'm idly curious to know whether the 10" would fit in my POD. :-D

Before anybody laughs at the idea outright, I've just checked, and I have a good 12" moving room front and back of my MN190 in all directions, possibly up to 16" at the front end.

The idea of the 10" is very appealing considering could have up to 180% of the light-sucking ability of my MN190. Obviously the "sail effect" wouldn't be a problem to me since the scope would be in a dome, sheltered from the prevailing winds.

Ditto... I'd like the total length of the 8" OTA please The MN190 was a we bit long for my micro obs..

[Deneb]

Is it not meant to be 800mm

[Revs]

That's the FL. My TS OTA is 700mm long, the 8" f/4 Quattro should be similar.

[Macavity]

That's the FL. My TS OTA is 700mm long, the 8" f/4 Quattro should be similar.

Yup. It does have one heckuva backfocus tho'. <G> At first I thought there was somethin "wrong" with mine [TS]? But "supplier treachery" aside, FLO also supply some nice 2" extension tubes. I actually do need the 80mm for visual use of Hyperions in 2" mode. A 50mm even for my Watec. Hmmm...

First Light Optics - Two-inch Focus Extension tubes

[Coco]

The OTA does look nice and short, looking at the image FLO has up it looks like a standard 30cm dovetail, my reconning its around 700 long..

[fatwoul]

So at that rate the 10" might actually be shorter than my MN190?

[MikeWilson]

The OTA does look nice and short, looking at the image FLO has up it looks like a standard 30cm dovetail, my reconning its around 700 long..

Correct me if I'm wrong (and I'm probably a noob when it comes to these matters) but isn't 700mm long / 200mm wide = f/3.5?

This is an f/4 scope so 8"/200mm aperture should give us an 800mm long scope. f/4 focal ratio x 200mm width = 800mm length.

All the best,

Mike

[Macavity]

Once you allow for the ninety degree diagonal reflection, sundry allowances

for back-focus etc., the TS F4 8" Photo-Newt, is a mere 700mm in length.

[Revs]

The focal length is from the primary to some point past the focuser, after doing a 90* turn at the secondary. This is why you need a large secondary on such a short FL newt. Too small and it won't fill a 35mm sensor/film.

The OTA length has no direct relationship to the FL. Some newts are even shorter and this is achieved by having a huge secondary, a 3" focuser and a really long focuser tube. This means the sensor/film will be very far from the secondary, which, unless you have a really strong focuser and OTA, causes even more of a flexing problem.

Check out the Orion AG8 to see what I mean

EDIT: Mac got in 1st

http://www.opticstar.com/images/astronomy/telescopes/OrionOptics/AG/Setup-594x498.jpg

[MikeWilson]

Thanks chaps, that's very very interesting - I quite like the idea of a stubbier/shorter OTA

All the best,

Mike

[Macavity]

EDIT: Mac got in 1st

Ah, but you included more details.

The 8" would be a pleasantly, un-troubling (sizewise) thing though?

[Revs]

Agreed, very manageable, size and weight wise. I can't see the CF Quattro being much lighter than it's steel tubed brother, though. I think the reasoning will be to reduce flex. I'll be sticking with the TS, though

[Coco]

Is it not meant to be 800mm

No!.... did you not know that?

[Deneb]

Of course I did :D

[Tim]

So at that rate the 10" might actually be shorter than my MN190?

I'm working on the reasoning that it is unlikely to be much longer, and that it will be able to be mounted a little further forward in the rings because the weight is at the back, whereas the MN190 is fairly balanced.

If it is too long I have just ordered a dob without a base

The main advantage as I understand it with CF is that thermal expansion is minimal. Given that even 0.5mm expansion will put your focus off at f4, steel tubes are more prone to getting longer/shorter as the night goes on.

And CF doesn't go rusty

[Tim]

PS: Steve, the FLO website needs updating. Unless it is first week of July next year? :eek:

Cheers

Tim

[Tim]

This is from OVL, guess I'll stop holding my breath for a while :/

We are awaiting delivery status of this ourselves. There is a production delay

[Deneb]

It's funny I was listening to the news this morning, their saying China is starting to slow down, their getting hit with inflation, thus slowing down production...

Maybe we might get some better weather, as North London is not looking good this week. Im wandering how many scopes will there be in the 1st shipment.

[fatwoul]

I'm working on the reasoning that it is unlikely to be much longer, and that it will be able to be mounted a little further forward in the rings because the weight is at the back, whereas the MN190 is fairly balanced.

If it is too long I have just ordered a dob without a base

The main advantage as I understand it with CF is that thermal expansion is minimal. Given that even 0.5mm expansion will put your focus off at f4, steel tubes are more prone to getting longer/shorter as the night goes on.

And CF doesn't go rusty

Thanks Tim. I always forget about that big piece of glass at the front of my MN190, which is why the balance of "normal" newtonians looks so peculiar to me.

[Coco]

Thanks Tim. I always forget about that big piece of glass at the front of my MN190, which is why the balance of "normal" newtonians looks so peculiar to me.

And why I would like the tube total length, it may fit my ob's if it does I'd buy one.

[Revs]

If anyone's interested, I'm gonna be trying out a Baader RCC-I on the f/4 as I've found the MPCC isn't quite up to the job. Despite my best efforts playing with the MPCC's spacing, it seems f/4 is a bit much for it. I'll post my findings once I've done some testing. Hopefully this weekend, weather permitting. The MPCC is optimised for f/4.5, whereas the RCC-I is optimised for f/4, with a triplet design.

EDIT: This is as good as it gets with the MPCC... http://img268.imageshack.us/img268/6436/lrpic2resize.jpg