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Red Hot New Concept OTA's

Started by mikey cee , Jan 10 2013 06:23 PM
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68 replies to this topic

#26 ISTAR Optical

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Posted 11 January 2013 - 07:11 AM

Because than the entire quest for a super low weight refractor would be over with :ooo:

#27 ISTAR Optical

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Posted 11 January 2013 - 07:14 AM

Dear Scott,
you are absolutely right. This concept is not needed for small sized refractor. This is why we will offer these only for the following apertures: 150, 160, 180, 204, 220, 250mm. Bigger you go, more benefit there is to gain, especially if you combine with R30 SLIM lenses (weight cut down by 40 percent on average)
cheers,
Ales

#28 ISTAR Optical

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Posted 11 January 2013 - 07:21 AM

Yeap.. go for it.. but use light materials, try to stay away from plywood. You can get these aluminum or alloy bars pretty much anywhere (but make sure to get those with strict tolerances intended for further CNC work.. stay away from those made for garden fence poles..) and we dont mind ATM-ers to use this idea in parts or whole. I just "cant wait" to hear all the bad and ugly things about this fancy scope design style... something one man can not avoid...

#29 meade4ever

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Posted 11 January 2013 - 07:30 AM

Ales I can only be admirative by all the new concepts ISTAR offer to our hobby and especially custom work, that I hope will continue.
Even if I prefer the look of traditional refractors, the weight reduction is a great advantage.

How about the prices vs original models ?

#30 Thomas Karpf

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Posted 11 January 2013 - 07:50 AM

First one of these new TCR style scopes (Truss Construction Refractor)is already listed with price.


Perhaps I'm being blind. On which page is the price?

Nevermind. It's on http://istar-optical.com/istar_009.htm . $2177 for 6" f/12 achromat, about $300 more than the 'tubed' version.

#31 csrlice12

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Posted 11 January 2013 - 09:02 AM

Wouldn't there be thermals from your body when viewing near the zeinith????

#32 t.r.

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Posted 11 January 2013 - 09:13 AM

As Jon pointed out, I'm sure you would have to deal with all the same things truss reflector owners deal with, but on a much smaller scale of course. At first glance, it seems to delete the positive attributes a refractor is known for. Still, the design is interesting. I have wanted a 180 F/12 for some time, but with better correction than a standard C-F. Maybe this is worth a try...I certainly like the idea of less weight and mass in a scope of this size!

#33 csrlice12

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Posted 11 January 2013 - 10:57 AM

I imagine cool down would be a "breeze" though.....

Nice looking scope, may change the definition of a 1000mm f10 to a "GrabnGo".....

#34 hottr6

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Posted 11 January 2013 - 11:06 AM

I'm impressed that iStar use magnesium alloy for the tube and baffles. However, if ever you have seen magnesium burn, the OP subject title of "red hot" may not be the best choice of words.

#35 bcuddihee

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Posted 11 January 2013 - 11:13 AM

Ales, as an industrial designer I can truly say that you have created a functional and elegant design here. Out of the box thinking combined with a true aesthetic sense have really opened up Pandora's box here...in a very good way. Wishing you all the success you deserve.
Brendan

#36 Pinbout

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Posted 11 January 2013 - 11:31 AM

All will be introduced one by one during 2013.
regards,
Ales



will you bring any to NEAF?

#37 ISTAR Optical

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Posted 11 January 2013 - 11:31 AM

Hello Brendan,
thank you so much for your wonderful comment. I truly appreciate that from someone like yourself.
respectfully,
Ales

#38 ISTAR Optical

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Posted 11 January 2013 - 11:37 AM

Hello Danny,
we will definitely bring these to NEAF.. and hopefuly more than just one. By that time we should have the 180 and 204mm versions available too to demonstrate that even 8" refractor no longer requres an expensive mount and can be handled by one man. For sure we will have at least this 6" F12 there...
best regards,
Ales

#39 ISTAR Optical

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Posted 11 January 2013 - 11:46 AM

Meade4Ever,
at this moment we can offer these with some 15 percent increase over the standard models. But we are working hard on narrowing this gap as much as we possibly can. I want anyone who can afford the traditional design scope to be able to afford this TCR low weight variation.
Cheers,
Ales

#40 ISTAR Optical

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Posted 11 January 2013 - 11:54 AM

Yes, the cooling time takes nearly one third of the original time required. We tested two lenses so far. From 1,5 hours on classic enclosed tube to 40 minutes here. Temperature difference was 15° Celsius. This is one of those very important aspects and improvements. And if you blow a fan at the lens you can have it done in 15 minutes... nice. We found out that you should optimally use the forced air flow like 10 minutes front and 5 minutes rear. But it does make sense... . If you blow air from only one direction you need additional time to have the temperature evenly distributed throughout the lens set.

#41 dscarpa

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Posted 11 January 2013 - 12:14 PM

Impressive! Will you be using this design with any of your APOs? I'm definitely interested in the 140 F-7.5 APO you're working on. Do you know when the 140 F-7.5 will be available? I'm fine with a regular OTA on that scope but a lighter one would be a plus. David

#42 tim53

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Posted 11 January 2013 - 12:31 PM

Keith Lawson won a Merit Award at RTMC in 2010 for an open tube refractor he'd built. He was camped across the road from me, so I had a chance to look through it a number of times. A very nice performer, actually. Very good contrast.

Posted Image
Posted Image

-Tim.

#43 tim53

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Posted 11 January 2013 - 12:34 PM

As for thermal plumes off the observer?

Perhaps installing a fan would help?

Posted Image

-Tim.

#44 Pinbout

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Posted 11 January 2013 - 12:48 PM

Keith Lawson won a Merit Award at RTMC in 2010 for an open tube refractor he'd built.



Cool pics Tim, thanks.

#45 ISTAR Optical

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Posted 11 January 2013 - 03:44 PM

Dear Tim,
Im aware of this rail scope. This consruction is known and Keith made a superb job putting this thingn together. He used Istar 204 F8,8 achromatic doublet if I remember correctly. Thank you so much for sharing!!
cheers,
Ales

#46 ISTAR Optical

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Posted 11 January 2013 - 03:54 PM

Gotta love some of these... right? Personally I suggest four independent fans with controlled variable speeds and a 4-stage Marlow Ind. thermo-electric (TE) cooling device attached directly to the operators' forhead. :roflmao: :tonofbricks: :roflmao:

#47 johnnyha

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Posted 11 January 2013 - 04:29 PM

Dear Tim,
Im aware of this rail scope. This consruction is known and Keith made a superb job putting this thingn together. He used Istar 204 F8,8 achromatic doublet if I remember correctly. Thank you so much for sharing!!
cheers,
Ales

Ales that is what I was talking about earlier, I like Keith's short dewshield/back extension offering protection for the lens as well as shielding stray light.

#48 mikey cee

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Posted 11 January 2013 - 05:56 PM

Yes I agree with that short dewshield and rear extension. I'd get awfully up tight with a big lens exposed both front and rear. Couldn't really enjoy or relax without that provision at a starparty with the public involved. Nervous like a cat on a hot tin roof! :smirk: Mike

#49 ISTAR Optical

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Posted 12 January 2013 - 06:41 AM

Hello Johnny,
this is exactly what we have planned for the dew shield construction. We are looking into two versions so give us some tim to experiment and decide. The bottom line is that if anyone buys one of these TCR scopes, they will be given a choice of a dew shield later on this year, I suspect second half of 2013, possibly sooner.

#50 Astrojensen

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Posted 12 January 2013 - 08:16 AM

I think the dew problems is not something a rolled up newspaper cannot solve... I often make makeshift dewcaps out of a newspaper, which I roll around the dewcap or end of the scope, then hold in place with tape or rubber bands. Works extremely well and is very inexpensive. When it gets too ugly, I just throw it away and make a new one.

I once tried to make a prettier dewcap from some soft, thin bubble foam plastic. I thought it was going to be perfect, as it was longer than the newspaper tube, but imagine my surprise, when the scope often dewed up, when it never did so with the old newspaper tube!

So, bad news (on print) can be good for something allright! ;)


Clear skies!
Thomas, Denmark
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