New 8-inch f/2.8 from ASA

[dvj]

http://www.astrosysteme.at/eng/h-series.html

60mm image circle as a feature for use the big arrays.

The images are starting to come in from the ASA gang taken with this instrument and Proline 16803.
New images here: and more getting posted weekly.

http://www.astrostudio.at/1_Deep%20Sky%20Objects.php?PHPSESSI D=c4576cc0428da0e44cda29a8eb77d034



jg

[2stroke]

Dam thats one fast newt :) lol just when you thought a F4 was hard to collimate think of this haha. Whats the price tag?

[cometcatcher]

At some point, a lot of us that are into imaging go through f/ratio fever like visual observers go through aperture fever.

I have a 5.5" f3.64 Schmidt Newtonian and it's a pain.

[alocky]

The only cure for aperture fever is more aperture :-), I suspect the only cure for Ffever is to encase oneself in a glass sphere.
Cheers,
Andrew.

[gregbradley]

On paper sounds great.

The obvious question is how much can you trust their quality control or ability to engineer a repeatable reliable scope?

How's about you get one first and let us all know!

Would they be any better than these at less than 1/4 the price?

http://www.powernewts.com/page-0#!

Greg.

[RobF]

The ASA appears to have double spider vanes. Wonder what that does to difrraction spikes?

[Peter.M]

I dont know about the viability of these fast newts, the secondary is 90mm which is 20% of the area of the primary. So the aperture is only 160mm useable, this makes it a f3.75. It also has 45% central obstruction. I think personally I would prefer the FSQ106 with reducer that gives f3.6, I know the focal length would be shorter but I think it would be the cheaper more reliable option.

[RobF]

I couldn't see a reference to what corrector, and if included (presumably Keller and is included)

[cometcatcher]

Equivalent to, yes. I believe they call this a T-stop. So the F/ratio may still be F2.8 but the T-stop would be higher due to light loss.

http://www.youtube.com/watch?v=DzSlQRewS7Q

I discovered this with my f3.64 SN also being no real advantage over an unobstructed f5. It's a bit of a false economy really!

[Peter.M]

I dare say this is the corrector

http://www.optcorp.com/product.aspx?pid=16897

[Peter.M]

Ahh thanks, I was only going from logic!

[gregbradley]

I have seen side by side comparison shots between Tak Epsilon 180 F2.8 and FSQ 106 (not with reducer).

The Epsilon shots were always less time for similar depth of shot and perhaps slightly deeper but the star sizes were always much larger and a less fine look to the images than the FSQ ones. Bottom line was the FSQ images always looked better.

The sample images of this ASA 200 though do have very fine small stars which is very appealling. So perhaps the ASA corrector is better than the Tak Epsilon one. The 7750 Euros seems way over the top for an 8 inch scope though. That would be about AUD$13,500 by the time you got it here. Surely you can do better than that for that sort of money.
You could get a Planewave CDK12 for that or an Orion Optics AG12 with money left over. Or you could get an AP140 or TEC140 with money left over for an 8300 chipped camera.

Greg.

[cometcatcher]

Anyone remember those 8 inch f1.5 Schmidt cameras? They were somewhat of the rage back in the 1980's when film was slow and painful. They had a curved focal plane, so a matching curved film strip holder was used to image with. Not for visual work, they were purely photographic.

If someone was to bring out a matching curved CCD array they may be resurrected lol.

[Terry B]

Greg
The AAVSO has a few of these and they are doing a great job as survey scopes. A pretty image displayed on the pdf below isn't too bad either. :D
see
http://www.aavso.org/apass
and
http://www.aavso.org/sites/default/files/henden_aas.pdf

[marki]

There was one for sale in the classifieds a few years back, think it was Mark (satchmo). Looked like a right challenge to use even if you found suitable film.

Mark

[CometGuy]

So is it f2.8, f2.9 or f3.0? I look on their website and I see 200mm aperture + 600mm focal length, which is f3.0. Then on a caption I see f2.9, then in the title it says f2.8 :)

Re the Celestron/Epoch I bet there are a few still around. I wonder how easy it would be to get one to work with a field flattener + CCD?

Terry

[RobF]

Yumm! Paramount ME with dual astrographs. I want one!
2xAG10's perhaps, one shooting NB, the other LRGB? :question: :evil:

[dvj]

The price includes the corrector.

It's close to 9,000 euros by the time you add rings, camera adapter, shipping case, shipping. Just wait for the Euro collapse!

Fast does have penalities, like high cost. Honestly, I want an 18-inch F/2.8 with the camera at prime focus. Astroworks 18-inch Centurian was well ahead of its time.

I have yet to see any good image out of the Officina Stellari 8-inch f/3.0 which is unfortunate because that is such a cool portable scope.

My little $2500 FSQ still wins.

j

[Danack]

While your point stands I think your maths is a little off, and it's not quite as bad at that.

200^2 = 40000

90^2 = 8100

40000 - 8100 = 31900 = 178^2

Which is still a significant reduction it's not quite as bad as to 160mm.



And is it 8 inches or 200mm?

[gregbradley]

That's the N model which uses Newt mirrors (parabolic). The H model which is the one discussed here is hyperbolic mirrors which cancel out aberrations like an RC. They are much harder to make.

Greg.

[gregbradley]

It's close to 9,000 euros by the time you add rings, camera adapter, shipping case, shipping. Just wait for the Euro collapse!

Fast does have penalities, like high cost. Honestly, I want an 18-inch F/2.8 with the camera at prime focus. Astroworks 18-inch Centurian was well ahead of its time.

I have yet to see any good image out of the Officina Stellari 8-inch f/3.0 which is unfortunate because that is such a cool portable scope.

My little $2500 FSQ still wins.

j[/QUOTE]

I nominate you as the guinea pig John.

The sample images look great. It comes down to how much can you trust your supplied model to match the sample images model. I think we have seen a substantial difference in the past!

I also remember seeing H8 earlier sample images that showed misalignments when it was a prototype. Coma in corners etc.

I presume they got on top of that but of course that will be the touchy issue with any of these fast scopes no matter what configuration - super fast = super rigid and accurate engineering to work.

Greg.

[KenGee]

I have one of those 8 inch f1.5 Schmidt cameras it's on the to do list.