New Starmaster Super FX Dobs.

[StarGazing]

Hi All,

Has anyone seen the new Super FX Dobs from Starmaster. F/3.3 Wow?????. Apparantly makes the dobs much shorter with the same performance with their regulat F/4.3 Dobs. :question:
Whats your say ?. I am new to Astronomy, 1 year and counting. Love my dob and look forward to upgrading in a year or so to a larger appeture(FEVER). Has anyone seen a Starmaster in action and if so how do they rate ????

Alex.:)

[citivolus]

At such a low f/ratio, I would think you might be somewhat restricted in what eyepieces you could use. My understanding is that you would get kidney-beaning with a lot of them? Someone else will likely be able to elaborate on this, or let me know if I am wrong ;)

[Satchmo]

I doubt as the optics are very expensive there will be much market penetration at this 'speed' .I know from experience their is a massive increase in the labor to aspherise these fast mirrors. You won't find the bigger vendors who supply Obsession ( Galaxy , OMI ) etc moving into this area any time soon.

Mirrors this fast need a special coma corrector. Al Nagler has produced a prototype Paracor for F3 to F4 mirrors. I think the standard Paracor works pretty well down to F3.7 and acceptably at F3.5.

Fast mirrors require much greater integrity of the telescope structure as the collimation needs to hold at different tube angles to a higher tolerance due to the very small sweet spot that must be kept on axis with the Paracor. Focusing tolerance is also much less.

All that being said, if the new Paracor goes into limited production it will be one more option for the advanced observer to own.

[GrahamL]

http://www.starmastertelescopes.com/

There sure is a bit of bump in the price for the fast ones mark
pretty hand height for a 22" by that pic . :)

[erick]

Why f3.3?

Is it:-

* More compact
* Less materials/weight
* No ladder or step?

All of the above?

[JethroB76]

No/smaller ladders

[Starkler]

Yup , more aperture whilst keeping ones feet on the ground.

[StarGazing]

Sounds good guys ........... If they can manage to get it all right, having a 22'' dob and to be able to view at the zenith with your feet on the ground sure does make this a viable concept.
:thumbsup:

[FredSnerd]

One advantage of being short like me is no matter how short they make these scopes you still need a ladder.

[AlexN]

a 10~12" F/3.3 would make a superb imaging scope provided that either a paracor or a commercially available corrector could be utilised to correct coma... Take the ASA newts at F/3.8.. They make excellent imaging systems... With a bigger mount a 22" F/3.3 newt would be some extreme light gathering power!!

[erick]

:eyepop: How about this!

http://www.loptics.com/fast14p5.html

[bmitchell82]

... weeps in the corner :(

[Blue Skies]

Wow, Starmaster is finally shipping overseas! They never used to, to which I was going to make a comment about not getting your hopes up, but looks like thats changed.

[Satchmo]

I have to add that F3.3 systems are as yet generally unproven by the wider market as to their quality and effectiveness. At that F speed, even a 7mm eyepiece gives a larger than 2mm + exit pupil which is barely even past idle magnifcation wise , for a large scope. It takes a lot of experience to test/verify the quality of such fast system and there needs to be further independent evaluation and testing IMHO.

If the new F3-F4 optimised Paracor does come out it will certainly spur on the faster end of the market. Peter Read at SDM has had increased interest in the F3.7 ratio's in the larger sizes.

[erick]

I see Mike Lockwood, creator of the 14.5" f2.55 has just said:-

"The 14.5" shows that F/2.55 works, and now we know that a large scope at F/2.6 or slower will work too. A 30" F/2.8 is appealing, and imagine a 40" F/3. I am currently capable of working up to 50" mirrors, and up to 60" if I modify my large machine a little bit."

So we may see more prototypes and will see if some of the challenges that arise can be resolved.

[bmitchell82]

Im by no way a expert but dyam i salute guys like him for giving it a crack! whats the worst that can happen? it doesn't work? but if it does work and work well! as a astro photographer having such a large mirror that doesn't require folded optics or a 3 meter long setup is ABSOLUTE GOLD. i can only imagine what my EQ6pro could be sporting! :):wink2::face::rain:

[AlexN]

mmmm 14" F/2.55.. 860 odd mm focal length, large enough aperture to chase the dimmest of dim, and F/2.55 to chase it down fast... remove all the wooden nonsense, replace it all with carbon fiber and very light aluminum and you'd have yourself one VERY serious imaging setup.. Probably get it to weigh in at under 20kgs too... hrmmm... if only I knew how to grind mirrors...

[Satchmo]

Getting a coma/corrector field flattener that will work well with these fast f ratios with acceptable level of vignetting will be much harder and more expensive than finding a mirror...

[bmitchell82]

As Kevin costna kept on being told.... "If you build it They will come!" just like everything else CCD's came from the CCD Cook book... back in the early days. now look what they are doing, the demand was there somebody saw a potential for $$$ so they made them... the more they made the cheaper it became... The demand for Field flatteners are already there for everything else. so all they have to do is adapt to fit! as soon as one of the majors gets their hands on something that works and then starts cherning them out the price will go down! its simple really. Concept, invention, prototype, test, tweak, test, manufacture! and i belive they are upto the Tweak part now... give it a few years and you will see alot more of these around. even if its the cheap chinese varient that will no doubt be excelent bang for buck for the mass's

That said there is always need in the astro community for the high end custom jobs that require that special touch and i know i fall into this catagory as one day i would like to ATM something in the 16-20" range!

Exactly what i was thinking alex. ide pay good $$$ for a extremely fast and wide quality mirror and pay the $$$ to flatten it out as the benifits of doing so would be worth it! just a bit more testing and tweaking and i belive that it will be a quality product.!

[ausastronomer]

Hi,

Peter Read of SDM Telescopes at Shepparton in Victoria has already built a 24"/F3.6 and a 28"/F3.6 with mirrors by Steve Kennedy in the USA. I have used the 28".

www.sdmtelescopes.com.au

Peter is currently building a 22"/F3.6 for an Aussie client and a 30"/F3.3 telescope for a US client, both with Steve Kennedy mirrors.

Peter's scopes are as well, if not better built than anything else in the world and importantly are quite a bit cheaper than anything you could import from the USA. Peter's scopes which are built on the Obsession design with his own improvements are noticeably smaller and lighter for any given aperture than the Starmaster scopes which uses internal truss poles. Scopes in this aperture class and F-ratio are not cheap but if you did want to head down that path in the future a locally made scope from Peter would be a smarter option than importing something from the US

Cheers,
John B