M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#2

Post by roelb »

NICE!
Roel
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#3

Post by oopfan »

Hi Minos, great image! I am curious if you used the Brain? If you did then where did you position the analysis selection box? Was it somewhere within the frame or did you slew away from M45? I ask because there is a lot of nebulosity and stars that you want to exclude from the analysis. I tried The Brain just once on M1 a couple weeks ago with inconclusive results. I will have another chance at AP tomorrow so hopefully I will have better results to report.
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#4

Post by mAnKiNd »

Hi guys thanks for your comments :)

I haven't yet tried the "brain" yet, I'm really looking forward to it as it seems awesome and very useful.

I approach my targets a little different lately, I've set myself a 30 second challenge on every target and simply adjust the gain to compensate for the brightness of the target until I'm satisfied with the histogram of a single frame. I want to redefine my possibilities for deep sky imaging towards ease and efficiency and away from the cable calamity and rigors of guiding etc...I pick up my rig from indoors, which is fully setup, place it outside, polar align with sharpcap, slew to target and focus, turn on team viewer, go inside where its warm, adjust exposure/gain settings and start the live stack. I have a filter wheel with a dark frame filter to make new dark frame averages for subtraction. I want to be done with acquisition by the end of the night and not have to worry too much about following up exposures, flats and other things in the next session etc etc. I setup, acquire, set down, process the image and my session is done, nice simple and a seriously enjoyable experience. Im really trying to squeeze out the most quality out of this approach, as I think it can reach a level comparable to the old-fashioned way of doing things. Sharpcap has the right tools for me to do this (need dithering though ;)

I'll try the brain and the smart stuff in histogram at some point soon, I'm sure it will be very insightful and helpful to my goals in fine-tuning this approach :)

Cheers
Minos
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#5

Post by turfpit »

Minos

I like the modern thinking to using modern (CMOS) equipment and modern software; plus the de-cluttering resulting in reduced set-up time.

The dark frame filter is an elegant solution - never thought of that. I found an Orion dark frame filter on Amazon for £23.

If I understand the details, the AVX mount tracked for 2 hours unguided?

Any chance of posting your capture settings file?

Dave
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#6

Post by mAnKiNd »

Here you go Dave! :)

Yes, unguided, used PHD2 to create a PEC curve with celestron's PECTOOL software using the scope itself to guide instead of a guide camera.


[QHY183C]
Debayer Preview=On
Output Format=TIFF files (*.tif)
Binning=1x1
Capture Area=5544x3684
Colour Space=RAW16
Pan=0
Tilt=0
Enable Live Broadcast=Off
Use DDR Buffer=On
USB Traffic=0
Offset=67
Amp Noise Reduction=On
Frame Rate Limit=Maximum
Gain=36
Exposure=30000
Timestamp Frames=Off
White Bal (B)=128
White Bal (G)=128
White Bal (R)=128
Contrast=0
Brightness=0
Gamma=1
Temperature=-20
Target Temperature=-20
Cooler Power=71(Auto)
On Camera Filter Wheel=L-PRO
Apply Flat=None
Subtract Dark=C:\Users\*****\Desktop\SharpCap Captures\darks\QHY183C\RAW16@5544x3684\30.0s\gain_36\dark_23_frames_-20.1C_2018-01-06T16_34_48.fits
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1
TimeStamp=2018-01-13T18:55:15.7636685Z
SharpCapVersion=3.1.4931.0
TotalExposure(s)=7650
StackedFrames=255
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#7

Post by turfpit »

Thanks for this Minos.

What are the gain & offset as % figures? I appreciate that there may not be equivalence across manufacturer/camera models but it is something to work with.

So inbuilt PEC was the big step forward for the Celestron mounts (compared with the CG5).

Thinking about this more, M45 is a fairly tricky object to image - being a mixture of relatively bright stars + nebulosity.

Dave
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#8

Post by admin »

Lovely image Minos!

To answer the question about gain values between camera manufacturers:

QHY gains are in dB above minimum gain (20dB is a factor of 10). If the gain value goes higher than 100 then they are in 0.1dB instead of dB
ZWO gains are in 0.1dB above minimum gain
Altair gains are in % of minimum gain - minimum gain is 100, 1000 gain is 1000% which means 10x brighter than minimum gain.

cheers,

Robin
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#9

Post by mAnKiNd »

Thanks guys!

Dave, gain would be 36/54 so 67% and offset is 67/255 so 26%, hope this helps someway! Yes, PEC is awesome and the PECtool software with PHD2 used to capture it works well. I would like to do a comparison 30s frame livestack with PEC on and off to see if there is a noticeable effect. It's just i thought of using the scope itself to do the PEC curve as to negate any possible flexure from the guidescope. Yes, Pleiades can be a tricky subject, but the way I see it, the stars are gonna blow out anyway, so I'll try and get some nebulosity with my capture settings.

Lovely software Robin, thanks!
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Re: M45 - Pleiades/Seven Sisters | SC 3.1 Livestack 255x30s QHY183C L-PRO Esprit80 f/5 AVX PI PS | 14/01/2018 | Minos K

#10

Post by turfpit »

Robin - thanks for the explanation - I didn't gain much from the first read ;) I think a few re-reads with paper and pencil are needed for me to progress.

Minos - I can try those gain/offset figures against the same object and see what happens.

:idea: Looks like the histogram is still my best friend.

Dave
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