More trials with PST/Quark Combo double stack on Aug29

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gabrieli
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More trials with PST/Quark Combo double stack on Aug29

Post by gabrieli »

This was another day with a variable sky with too many clouds that lent itself to more trials.
The combination of the PST etalon with the Quark Combo has great potential when more dramatic features appear. I say that because all the images taken with this setup were done in poor seeing where you see the sun's edge rippling. The unevenness that happens at wider views tends to go away when you reduce the ROI. One of my PST etalons is great for this but the other not so much.

Again, the shutter speed varies from 26 to 30 ms and a higher gain is required. I have yet to try imaging with higher resolution cameras with this optical setup. I'll try that next time.

The setup used involved a 180 Mak at f15(prime) with a full ERF , 35nm H alpha filter, PST etalon, Quark Combo, with a ASI290 instead of a Blackfly S (2.3Mp, 1/3 inch) this time because of its higher sensitivity. Anyway, here are 2 samples:

3.png
3.png (273.07 KiB) Viewed 234 times
5.png
5.png (339.32 KiB) Viewed 234 times


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Re: More trials with PST/Quark Combo double stack on Aug29

Post by Montana »

Wow!! I wish I could get that clear an image with rippling seeing :bow :hamster:

Alexandra


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Re: More trials with PST/Quark Combo double stack on Aug29

Post by MapleRidge »

Hi Lou...

Tremendous details in these images...very nice results from the system :bow

A question about the setup...I see that there is no additional 'barlow' type element ahead of the Quark, so it seems to be working well short of the f30 typically suggested. I might have to try mine again but at a faster focal ratio. Initial attempts had horrendously long exposures when running closer to f30.

Brian


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Re: More trials with PST/Quark Combo double stack on Aug29

Post by EGRAY_OBSERVATORY »

Well done Lou for your excellent Fiiaprom images.

Thanks for sharing
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Re: More trials with PST/Quark Combo double stack on Aug29

Post by gabrieli »

Hi, Brian

You're right Brian. There is no amplification beyond the scope's prime focus at 2700 mm at f15.
Somewhere, I read that Quark Combo is intended to be used at f15 or higher. I'm assuming that light passing through the PST (with its lenses) is delivering close to an f15 beam to the Quark (I could be wrong) and it seems to be working well.
The combination of this already high focal length and a small sensor gives relatively trouble free high res imaging once you find the right tilt in the very temperamental PST etalon.In my case the right amount of tilt happens near the counterclockwise rotation limit of the PST's tilting ring.

Also, for this level of magnification, I've always tried to stay well below 30 ms shutter speed, even going to single stack to for higher shutter speeds and maintain sharpness. Apparently, a shutter speed of 26 - 30 ms is adequate, all the more interesting that these images, and the ones from the previous 2 trials were done in poor conditions.

A caution about uniformity is that you will have to cut your ROI to snip out the off band or non uniform areas.
I'll play with other cameras I have to see if higher res cameras work out.

Lou


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