Has anyone dealt with Istar?

[ed9428 (Kris)]

Just wondering if anyone has bought their products.
I have been in contact with Mike and Ales from istar and they both seem very open and honest about their scopes.
I think i am going to go through them to buy my first scope and wondering if any one here has gone with them. They also sell refractor lenses and parts for DIY. Is building a refractor something someone might recommend as i can get one of their 6" 2 element lenses for US $519 which will come under $500 with our exchange rate. This could be a cheaper option for me.
This is the company who will be bringing out the raycor either end of this year or early next.

Kris

[casstony]

I've only seen positive comments about Istar.

Be aware that for import prices above AU$1000 there is 10% tax plus some other courier processing fees - might have some bearing on whether you buy a full scope or parts.

If the item price is over $1000 the cost of shipping is added before tax is calculated (ie. you pay tax on shipping as well).

[ed9428 (Kris)]

Thanks for the heads up tony. Its nice how tbey can work it out that you pay tax on their shipping tax.
Its the shipping tax tax.

[casstony]

Hi Kris, I gather you're looking at a 6" achromat, either f/8 or f/5? The f/8 is more of an all-round instrument while the f/5 is mainly for low power/wide field.

You might be able to keep the scope import cost below $1000 by asking Istar to ship the focuser separately, or even the focuser and tube rings separately, say 2 weeks before the scope. Any accessories you wanted could be shipped with the focuser too - the Istar dielectric diagonal has a good reputation.

[ed9428 (Kris)]

Thank you again tony. Any tips on saving money are much appreciated.
Im hoping if i go the f/5 path i will use it for widefield until istar bring out their raycor, allowing me to take it to higher powers. They are claiming they may be able to pull near apo performance in all achromats. Much like the old chromacor from Aries but in a much user friendly design.

[casstony]

I haven't heard anything about the raycor Kris - do you have any links?

Previous devices for correcting chromatic aberration have not been designed for scopes as fast as f/5 AFAIK. Also f/5 achromats tend to be prone to astigmatism at higher powers so you'd need a well figured objective or an objective where the astigmatism of each element was nulled by the other before it would be worth considering additional optics.

[ed9428 (Kris)]

This is a response i got from Ales at istar about the raycor:

"we are working on two separate versions. Raycorr LT3 will be 3 element corrector strictly for visual use and we strive to get a near APO performance with limited FOV. The Raycorr Pro6 will be 6 element Fluorite Glass and Lanthanum glass combo, we are also looking into possibility of integrating CaF2 element into this design. Such design will be substantially more expensive over the LT3 version but it should turn any achromatic doublet into a Photo APO system limited to about 16x16mm chip size. In the future we would like to create version for even larger chip sizes but not sooner as 2013. These correctors will be produced for the following F/Stop ranges
F5 to F7,9
F8 to F/9,9
F10 to F15

we are way behind with this design, we hope to introduce first units by end of this year or beginning of 2012.
Have a great day, talk to you soon,
best regards,

Ales Patrick Krivanek"

The prices i've seen are about US$300 for the LT3 purely visual Raycorr (sorry it is spelt Raycorr with 2 r's i've been spelling with 1) and i think around 5 or 6 hundred US for the Pro6 but please do not quote my prices.
Sorry i cant really link you to any sites as it is still in design and developement phase but google "istar raycorr" and check out the chat online.
Ales and the team seem to be very active in the other forums and are more than happy to answer questions you may have through emails (info@istar-optical.com will get you in touch with Mike or Ales).
They are very busy at the moment but i was still emailling and getting fast responses from them this morning.
One of the reasons I am going with istar.

[casstony]

Very interesting. I've got a Skywatcher 6" f/5 achromat which I use for low power - now I'm curious to test it at high power with CCD filters or a nebula filter.

In the end though it is often better to have different scopes for different purposes rather than try to make one scope do it all. As a first scope I suspect you might be left wanting more aperture for DSO's or higher quality optics for planets.

For about the same cost you could buy a 12" dob (light bucket) and a 6" Celestron schmidt cassegrain (portable, good optics, $500 at Andrews). That's just one possible alternative though - there's nothing wrong with buying a 6" achro.

[ed9428 (Kris)]

Let me know how you go using your f/5 with the filters.
I see what you mean with different scopes for different jobs.
Im hoping to build up my collection, maybe piggy back a nice 100ed on the 6" f/5 when i get money together.
I will be attending the Ice in Space astro camp later this year so it will be a good chance to try out a few scopes.

[casstony]

Kris, I gave the 6" f/5 achro a run tonight at 150x (which was pushing the conditions) with ccd filters and a prism diagonal and it did better than I expected. Saturn was looking sharp though I couldn't quite pick the cassini division. I could split Porrima. The scope did best in green and blue, not so good in red.

I could see a little astigmatism and moderate spherical aberration on a defocused bright star. I expect the lens you'd get from Istar would be a bit better than my Skywatcher so your plan to use the raycorr for high power might work out.

The raycorr might even get a run on my scope if it comes out at $300; when you order you need to tell Istar if your scope is over or under corrected so I guess some spherical aberration correction is built in along with correcting chromatic aberration.

[ed9428 (Kris)]

Bit of a change in plans. I've doubled my focal length and im going for the 6" f/10.
With a moonlite focuser will come to about $1600 aud. No diagonal or anything else yet. But i may go the istar branded one like you say tony as they have good reputation.
There is about a 2 month production time at the moment but as i will be blowing my entire budget so far on the OTA this gives me time to source a mount and some accessories.
Glad to hear your getting better viewing than you expected with filters tony. Would like to know how the raycorr compares, even at f/10 i think i will still try one. At $300 its like buying a nice quality eyepiece really.
Might be interesting to see how the f/5 compares to the f/10 with raycorrs attached. Whether this brings them to similar CA.
If you could get the same performance from an f/5 that you get from a much longer achro then you will have a very impressive piece of equipment.

Kris

[casstony]

A 6" f/10 is going to need a very tall mount to avoid being on your knees when viewing objects toward the zenith; it will also need to be a very solid mount/tripod to avoid jiggles/vibration. Do you have a particular mount in mind?

I'd honestly suggest you keep it to no longer than f/8, especially for a first scope. Ease of use is equal in importance to the ability of the scope. A 6" f/8 high quality achro with the raycorr should be an excellent scope and a foot shorter than the f/10.

The 6" f/8 would also be easier to sell should you decide to change scopes.

[ed9428 (Kris)]

Im going to eventually get an eq6. But that may be 6 months away yet so in the meantime i will try making a dobsonian style mount. I have seen pictures on the net of large refractors on mounts like these and apparently they perform ok. It will just be a temporary fix anyway. I seriously considered the f/8 but i know i will want to be doing higher powers for planets so the f/10 will give just that little bit more.
This was a decision that ran over about a year with many changes but i am happy where i have ended up. Its all the waiting game now because i have put the order in. Now i will work on designing and building this mount.