High res "EEA" with SC autostacks + Blur Xt

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timh
Posts: 530
Joined: Mon Aug 26, 2019 5:50 pm

High res "EEA" with SC autostacks + Blur Xt

#1

Post by timh »

Whether the below really counts as EEA I am not quite sure -- but it does seem extraordinary that technology has advanced so rapidly over these past few years that it is now possible to observe four or more objects - in this case local galaxies - in really very high detail from a Bortle 7 back garden in the course of a single night.

The set up was as follows ....

Orion Optics (UK) VX12 F4 Newtonian, SW aplanatic coma corrector, CEM 70 mount
ASI294 MM mono camera
Camera set at 46 Mb - pixel size 2.315 u - to capture 10s short frames at gain 200
Image scale 0.406 arcsec/ pixel

The VX12 was accurately collimated with a Howie Glatter laser and tublug -- in fact the final images were surprisingly sharp after BlurXt star correction and deconvolution even when the collimation was consistent but slightly out. But unsurprisingly - the very best final images were obtained when collimation was spot on.

The above 10s gain 200 camera setting at 0.406 image scale about hits the sweet spot for semi 'lucky' imaging with a 12 inch telescope at F4 under my B7 moonless dark. Under dark skies could go for shorter frames to possibly improve resolution but - SNR is just as important. In order for RC BlurXt deconvolution software to work optimally not only is SNR important but also sampling - so 0.406 provides a better potential for final resolution than does the alternative 4.63 u pixel (0.81 image scale) setting available on the camera (although the 4.63 setting provides better SNR - so everything is a compromise).

Sharpcap capture is set up for autostacking (up to 60 min), and filtered to reject frames with low brightness and/or with an FWHM > ca. 6 pixels (FWHM ca. 2.4 arcsec).

EEA is of course ongoing as you watch the image of each object build up until the point that the autostack is saved and then move on to the next target.

The variation here on the usual EEA procedure is simply to have a second computer available running PixInsight with the RC Blur Exterminator software. The additional processing then just takes about 2-3 minutes in exchange for an enormous increase in image quality. Simply upload the Sharpcap autostack and 1) apply star correction and then 2) Blur Xt deconvolution (usually settings ca. 0.4-0.6 non-stellar - zero star reduction)

The improvement from deconvolution seems almost like magic but comparison with HST NASA/ ESA images convinces me that the process is not introducing noticeable artifacts. Generally the better (scope well collimated skies not too turbulent) integrated autostack images are starting out at an FWHM estimate of ca. 2 , Eccentricity ca. 0.5 -0.6 and apparently ending up at about 1.1 and < 0.4 after deconvolution.


The quality of these obviously varies - sometimes conditions were better and worse. I have a more full details and analysis on quality of captured frames etc should folk want them -- in addition the more conventionally processed images but I thought it interesting just how good the images were just direct from the EEA Sharpcap autostacks

Tim
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Xio1996
Posts: 43
Joined: Fri Feb 21, 2020 10:15 am
Location: Isle of Wight, UK

Re: High res "EEA" with SC autostacks + Blur Xt

#2

Post by Xio1996 »

Hi Tim,

Brilliant images, the detail is amazing. A great use of technology while observing.

+1 on the technology moving forwards in leaps and bounds. Look at all the incredible features Robin has added into SharpCap in the last 18 months!
timh
Posts: 530
Joined: Mon Aug 26, 2019 5:50 pm

Re: High res "EEA" with SC autostacks + Blur Xt

#3

Post by timh »

Thank you Xio, Indeed that is true and the other - probably unique - thing with Robin is that he takes the time not only to address any bugs but to also engage us in suggesting/ prioritising new features. SC 4.1 is a toolkit packed with features covering a wide variety of interests. Tim
timh
Posts: 530
Joined: Mon Aug 26, 2019 5:50 pm

and after EEA - real imaging with all the saved frames

#4

Post by timh »

Just to show that beyond the pleasure of the initial EEA -- the individual frames that Sharpcap co-saves along with the autostacks do not go to waste. Here is the result of stacking about 1200 x 10s frames of M51 from the past two nights.

I will be adding the below as luminance into a colour image in future but in some ways I prefer the grayscale which provides an almost 3 D effect showing M51a to be in the foreground with NGC5194 behind


Tim
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ChrisR Oz
Posts: 167
Joined: Tue Sep 28, 2021 11:03 am
Location: Melbourne

Re: High res "EEA" with SC autostacks + Blur Xt

#5

Post by ChrisR Oz »

Great detail Tim. Very inspiring.
Cheers, Chris.
Celestron EdgeHD 8, reducer 0.7x, Star Sense, CGX-L mount, Focuser, CPWI; Starlight Xpress AO, OAG and Filter Wheel; ZWO 294MC/294MM Pro and 174MM mini; SharpCap Pro, PHD2, Televue Powermate 2x, Baader Neodymium, Astronomik CLS-CCD, ZWO UV/IR, Duo filters
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turfpit
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Joined: Mon Feb 13, 2017 8:13 pm
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Re: High res "EEA" with SC autostacks + Blur Xt

#6

Post by turfpit »

Tim

Very good , looking forward to the colour arriving.

Dave
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