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FastStar/HyperStar?

SteveL

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SteveL

SteveL

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Anyone here used a FastStar or HyperStar system with their Celestron OTAs? Sounds like a dream come true for wide field imaging, and the incredibly short subs required... but just wondering what the down side is of all this. They say it can be used in AltAz due to the short subs, but I`ll still be using it on a wedge, and i`ll still be autoguiding....

So, any users out there wish to give some feedback?

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CELESCOPE

CELESCOPE

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Greg and myself , used the fastar and Hyperstar, the hyperstar needed alot of setting up and had no end of problems ,but greg stuck with it, and produced some super stuff , , we both had success with these systems, each in turn reducing the f ratio to around 1.95, i took all mine in ALT -AZ, i would think Steve if this new system worked , it could be an evil tool in reducing your exposure time dramatically, but i think you would need to get some sound advice on first.

Rog

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MartinB

MartinB

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You need a small pixelled (ideally <7 microns but 7.5 might be ok) round camera otherwise you can end up with square stars. With fastar the absolute limit is an H9 sized chip. Even then it is very problematic with some vignetting and problems with collimation. The hyperstar is supposed to be the better system. Greg developed a method of collimating it which I think is more of a possibility with the hyperstar than fastar.

Focus is critical at this F ratio and gradients are another problem.

It does give incredible signal to noise ratio of short subs - in fact you couldn't really go beyond 30 secs in RGB because the sky glow became excessive. Wonderful with smaller chips.

I would want evidence that the new hyperstar worked with larger chips

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SteveL

SteveL

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The Hyperstar v3 for C8 has collimation screws, and also says it copes with larger CCDs. I have seen some images from a QHY8 and they are OK... actually, I think they are over exposed and taken in AltAz, but I am keeping a very close eye on the Yahoo fastar user group.

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MartinB

MartinB

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sounds promising Steve. The other significant problem is that narrow band filters (esp the narrower narrow band ones - 6/7nm) aren't as effective at this fast f ratio but that is unlikely to be a factor for you. I'm not surprised the images look over exposed. It takes time for people to realise that 30 secs is equivalent to 7 mins with an ED80!!

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moondog

moondog

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Interesting thread as I have a C8

I've gone down the Meade F3.3 reducer route. Even at F3.3 I can confirm that the subs need to be very short to avoid over exposure.

I have yet to try the Meade with my Celestron F6.3 reducer. This is supposed to give F2 - the same as the Fastar. When I next get the skies I'll try this combination with my small chip Atik 16iC.

MD

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moondog

moondog

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Rog

The instructions that came with the Meade F3.3 reducer says it will work with an F6.3 SCT.

I didn't have enough time with the carp skies to get the 2 reducers to quite focus. They are nearly there but I need to play with the extension tubes that come with the Meade to get exact focus. It looks as if it's going to work though. I'll keep you informed.

MD

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