Antares Optics secondary mirrors

[sasup (Stacey)]

I am looking at buying a 2.6 Antares secondary 1/30 wave, has anyone tried one or is using one now? Also is there options on the holder?

[gb_astro]

Stacy, I have just replaced my 3.1 AstroSystems 1/10 wave with an Antares Optics 3.1 1/30.

I bought it directly from Antares Optics.
Took about two weeks to get here.
Postage was US$10.

Antares don't seem to do holders but it fitted in the old AstroSystems holder nicely.

Unfortunately my SDM is off the road for other reasons so I have not been able to test it.

gb.

[pgc hunter]

I'm also considering a 1/30 Antares secondary, 2.6" size. I posed the question on Cloudynights and the feedback regarding the Antares Optics secondary was very positive, both in terms of quality and customer service.

Link: http://www.cloudynights.com/ubbthrea.../o/all/fpart/1

[richardo (Rich)]

I have been using a 78mm 1/20th wave secondary from Antares and I notice the difference straight away after replacing the Protostar one I had.
Money well spent.

If you want to get the most out of a good primary mirror, don't skimp on the secondary. Only as good as your weakest link imo!
Of course if your primaries not up to scratch... well

Rich

[sasup (Stacey)]

thank you all I am getting a high end mirror finally so Ill heed the advice and get the Antares 2.6 1/30

[Satchmo]

I'm a skeptic when it comes to these super flat flats in amateur telescopes. I think if you have a genuine 1/12 or 1/15 wave flat it is amply good. Most mass produced flats polished on a planetary polishing machine the error is a pure concavity or convexity. Zemax ray- trace simulations suggest that a 1/2 wave spherical flat causes a 4 or 5 % reduction in the Strehl ratio due to theoretically causing primary astigmatism in the image which still makes a high Strehl ( 0.98 to 0.99 ) mirror come in the mid nineties close to perfection in the image.

I don't believe , particularly in the light of the real thermal conditions a diagonal is subjected to that you will ever realise the difference visually between a true 1/12 wave and a 1/30 wave flat. I understand that there are anecdotal reports ( my fire proof suit is donned ! ) as such but I would like to see the results of some double - blind tests in identical instruments under superb conditions. Comparing instruments , even the same one with tweaks to the optics is a very difficult thing to do given constantly changing seeing and thermal gradients on different nights.

I have my own anecdotal experience of comparing view through a very fine 20" binocular telescope in good seeing conditions. One of the 5" diagonal flats was no better than 2 waves and we really were hard pushed to see the resulting astigmatism caused by the bad flat - the image was still very good in both sides . That night brought home to me the very different effects in the instrument that errors can produce in both primary and secondary. A 2 wave error in the primary in the form of spherical aberration would have rendered the instrument completely useless !

[Acrab (Victor Martinez)]

http://www.ostahowskioptics.com/elliptical.htm

[sasup (Stacey)]

Thanks mark, that is great as it saves me over $100 US.dollars. I just want something to match that Satchmo primary that's coming .