Is there such a thing as to much imaging data?

Discuss how you are able to get those fantastic images!!!
Post Reply
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Is there such a thing as to much imaging data?

#1

Post by Kerry C. »


Question for those in the know...
Is there such a thing as "too much data" on a single image, to where the image processing quality return is not positively effective?
Thanks,
Kerry

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
STEVE333 United States of America
Inter-Galactic Ambassador
Articles: 0
Offline
Posts: 3466
Joined: Sat May 11, 2019 5:01 pm
4
Location: Santa Cruz, Ca, USA
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#2

Post by STEVE333 »


Hi Kerry - Before answering your question it is important to know that the reason for getting more data on a single target is that it reduces the noise in the stacked image. The noise is reduced by 1/Sqrt(N) where N is the number of images that are stacked. This assumes that all the images are identical which isn't actually true (some taken through more atmosphere or with more light pollution, etc.). However, it is a good approximation to use to answer your question. So, taking more frames will always reduce the noise in your image.

For example:
If 4 frames are stacked the noise in the stacked image will be 1/Sqrt(4) = 1/2 of the noise in a single image.
If 9 frames are stacked the noise in the stacked image will be 1/Sqrt(9) = 1/3 of the noise in a single image.
If 25 frames are stacked the noise in the stacked image will be 1/Sqrt(25) = 1/5 of the noise in a single image.
This reduction in noise continues no matter how many images are stacked.

So, how many frames is enough?
  • To reduce the noise of a single frame by 1/2 you would need to stack 4 frames.
  • To reduce the noise by 1/2 again you would need to stack 16 frames.
  • To reduce the noise by 1/2 again you would need to stack 64 frames.
  • As you can see the number of frames required to keep reducing the noise by a factor of two is growing rapidly. That is why many APers stop at around 16 - 25 images. More images would always be better, but, the imaging time starts adding up. If each exposure is 10 minutes then 25 images is just over 4 hours imaging time.
I would answer you question by saying, if you stack your data and the resulting image still looks noisy (even after noise reduction) then you need more data to improve the image. However, if the image looks good after stacking and noise reduction then you likely have enough data. The required amount of time (number of images) will vary from target to target because some targets are dimmer than others and will require more time on target.

My personal experience is that I typically collect 24x10 min (four hours total exposure) for each channel of my NB imaging (Ha, O3, S2). That is normally a full night of imaging for each individual filter. I almost always wish I had more data to further reduce the noise! I image in a Bortle 5 zone. If I were in a darker location my 4 hours/channel might be enough.

Hope this makes sense.

Steve
Steve King: Light Pollution (Bortle 5)
Telescope + Mount + Guiding: W.O. Star71-ii + iOptron CEM40 EC + Orion Magnificent Mini AutoGuider
Camera: ASI 1600MM Pro + EFW Filter Wheel + Chroma 3nm Siii, Ha, Oiii + ZWO LRGB Filters
Software: PHD2; APT; PixInsight ***** My AP website: www.steveking.pictures
Image
Image
User avatar
KathyNS Canada
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 2584
Joined: Thu Apr 25, 2019 11:47 am
4
Location: Nova Scotia
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#3

Post by KathyNS »


My typical nebula image runs about 4-10 hours. For the more challenging targets, I shoot more. My record is 24 hours. More time definitely makes a difference for extremely dim targets, in order to lift the faint signal out of the noise.
Image
DSO AP: Orion 200mm f/4 Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,Oiii,LRGB filters; KWIQ/QHY5 guide scope; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on HEQ5 pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome; iOptron CEM60 (pier); Helena Observatory (H2O) Astrobin
User avatar
Juno16 United States of America
Universal Ambassador
Articles: 0
Offline
Posts: 8195
Joined: Sun May 12, 2019 3:13 pm
4
Location: Mississippi Gulf Coast
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#4

Post by Juno16 »


Very nice explanation Steve @STEVE333 .

My experience is similar to Kathy's @KathyNS .

When I first started, I was happy with the processed images that I had after two hours of data. As my expectations grew, I now find that I like to get at least 8-10 hours to get the noise down and the s/n high enough to produce a decent image. BUT, other variables like Bortle zone, transparency, and mostly the target itself has a huge amount to do with the quality of the processed image.

Sometimes 12 hours isn't enough in my skies for some targets (like my recent Cave nebula image). For the Cave, I don't think that I could get a quality image in my skies no matter how long the integration time.

Another point is how many clear nights are available. If you only average 1-2 clear nights a month, it would be impractical to try to collect 12+ hours on every target.

I have just collected about 12 hours of data on IC63 and as dim as it is (mag 10) and how much lp I have, I am bracing for another image like the Cave. I did have fun imaging it and my equipment ran very well with no issues and that might just have to be my consolation.
No matter how the image turns out, it will be my best shot (for now) and I will post it here and save it to Astrobin just for my reference.

Just like everything else in AP, just do what you can do based on your experience and expectations and hopefully at least your equipment will run well and have fun trying!
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#5

Post by Kerry C. »


So then, as long as the quality of the data is good or uniform, then more interrogation time should build good/better SNR making a better photo depending on my processing skills.
I recently read while researching this topic… "I have too much data" said no astrophotographer ever!
Next week I hope to post my results of the target I am imaging at this time. I currently have more data on it than any other object I have imaged, 20hours. Tonight I hope to get another 5 hours on the same, then start the final processing. With 18:30 hrs on it I did a quick process to see what was there…so far it is promising.
Thanks for all the help…
Kerry
Last edited by Kerry C. on Thu Oct 20, 2022 9:04 pm, edited 1 time in total.

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
AstroBee United States of America
Moderator
Moderator
Articles: 0
Online
Posts: 2209
Joined: Thu Nov 14, 2019 11:03 pm
4
Location: Henderson, NV
Status:
Online

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#6

Post by AstroBee »


I'm in the process right now of doing a 40-hour project to see if the results are worth all the extra time. I'm doing 12 hours ea of Ha, OIII, and SII with my 2600mm monochrome camera, and then I'm doing 4 hours of OSC with my 2600mc camera.
So far, in three nights I've managed to capture the 4 hours of OSC, 11hrs40min of Ha, 4hrs 20min of OIII, and 3hrs20min of SII. At this rate, I figure I can complete the project in 2 or 3 more evenings.
Will it be worth the extra time? I don't know. However, with Noise Xterminator in PixInsight, I don't think the extra frames are worth it when I could be spending time on other targets.

Yesterday, just for grins, I ran the data through WBPP and it took 2hours 37minues to complete that step....
Greg M.~ "Ad Astra per Aspera"
Scopes: Celestron EdgeHD14", Explore Scientific ED152CF & ED127 APO's, StellarVue SV70T, Classic Orange-Tube C-8, Lunt 80mm Ha double-stack solar scope.
Mounts: Astro-Physics Mach One, iOptron CEM70EC Mount, iOptron ZEQ25 Mount.
Cameras: ZWO ASI2600mm Pro, ZWO 2600MC Pro, ZWO ASI1600mm
Filters: 36mm Chroma LRGB & 3nm Ha, OIII, SII, L-Pro, L-eXtreme
Eyepieces: 27mm TeleVue Panoptic, 4mm TeleVue Radian, Explore Scientific 82° 30mm, 6.7mm , Baader 13mm Hyperion, Explore Scientific 70° 10mm, 15mm, 20mm, Meade 8.8mm UWA
Software: N.I.N.A., SharpCapPro, PixInsight, PhotoShop CC, Phd2, Stellarium
https://www.nevadadesertskies.com
User avatar
chris_g United States of America
Orion Spur Ambassador
Articles: 0
Offline
Posts: 891
Joined: Fri Jan 15, 2021 4:30 am
3
Location: Louisiana, U.S.
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#7

Post by chris_g »


STEVE333 wrote: Thu Oct 20, 2022 2:14 am For example:
If 4 frames are stacked the noise in the stacked image will be 1/Sqrt(4) = 1/2 of the noise in a single image.
If 9 frames are stacked the noise in the stacked image will be 1/Sqrt(9) = 1/3 of the noise in a single image.
If 25 frames are stacked the noise in the stacked image will be 1/Sqrt(25) = 1/5 of the noise in a single image.
This reduction in noise continues no matter how many images are stacked.

So, how many frames is enough?
To reduce the noise of a single frame by 1/2 you would need to stack 4 frames.
To reduce the noise by 1/2 again you would need to stack 16 frames.
To reduce the noise by 1/2 again you would need to stack 64 frames.
As you can see the number of frames required to keep reducing the noise by a factor of two is growing rapidly. That is why many APers stop at around 16 - 25 images. More images would always be better, but, the imaging time starts adding up. If each exposure is 10 minutes then 25 images is just over 4 hours imaging time.
This analyst says thank you for the formula, exponential for noise reduction.

What about actual data though? Is there ever enough, I don't think so. A few hours on the Heart and I get blood red and not much else, several more hours and I got the gold/orange of the Ha and Sii channels mixed and longer still the blues of Oiii would have come out.

I also am in the middle of a long imaging session with M31, 24 plus hours so far with no evil Mistress of the Night. We'll see...

Clear Skies,
Chris
Image Cam: Canon 6D (Ha mod), 600D (Stock), SVBony SV405CC
Image OTA: EvoStar ED80, WO Z73, C8-A XLT
Mount: EQ6-R Pro Pier, AZ-EQ5 Pro Pier
Guide OTA: Orion 60mm, WO 32mm, ZWO OAG, SV501P
Guide Cam: ZWO 120mm, 290mm mini
EAA OTA: Orion ST80
EAA Cam: SVBony SV705C
EP: Baader Hyperion Modular Set
Filters: L-Pro Canon EOS C, L-eNhance, L-Pro, Optolong Ha 7mm, Optolong Oiii 6.5mm, Optolong Sii 6.5mm, ES H-Beta
Session Control: Mini PC/Win11 Pro, APT 4.1, PHD2 2.6.10
Processing: PixInsight, DSS 4.2.6, Adobe PS CC, Astronomy Tools Action Set, Star Spikes Pro
Image
Image
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#8

Post by Kerry C. »


AstroBee wrote: Thu Oct 20, 2022 7:30 pm I'm in the process right now of doing a 40-hour project to see if the results are worth all the extra time. I'm doing 12 hours ea of Ha, OIII, and SII with my 2600mm monochrome camera, and then I'm doing 4 hours of OSC with my 2600mc camera.
So far, in three nights I've managed to capture the 4 hours of OSC, 11hrs40min of Ha, 4hrs 20min of OIII, and 3hrs20min of SII. At this rate, I figure I can complete the project in 2 or 3 more evenings.
Will it be worth the extra time? I don't know. However, with Noise Xterminator in PixInsight, I don't think the extra frames are worth it when I could be spending time on other targets.

Yesterday, just for grins, I ran the data through WBPP and it took 2hours 37minues to complete that step....
I really like that Noise Xterminator in PixInsight…
Wow, 2hrs 37min to combine an image! I did my test run using DSS I don’t know how long it took, I went golfing while it churned away.
I’m running the 20 hrs of data in PixInsight WBP2 right now to compare results. I will time this one.
Kerry

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#9

Post by Kerry C. »


KathyNS wrote: Thu Oct 20, 2022 11:43 am My typical nebula image runs about 4-10 hours. For the more challenging targets, I shoot more. My record is 24 hours. More time definitely makes a difference for extremely dim targets, in order to lift the faint signal out of the noise.
Thanks for the information Kathy,
I just saw your Ghost Reflection Nebula Sh2-136…WOW! Stunning image!
That actually is the image I am targeting now and was why I asked the original data acquisition question.
Unlike your data, mine is only RGB.
Kerry

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
chris_g United States of America
Orion Spur Ambassador
Articles: 0
Offline
Posts: 891
Joined: Fri Jan 15, 2021 4:30 am
3
Location: Louisiana, U.S.
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#10

Post by chris_g »


KathyNS wrote: Thu Oct 20, 2022 11:43 am My typical nebula image runs about 4-10 hours. For the more challenging targets, I shoot more. My record is 24 hours. More time definitely makes a difference for extremely dim targets, in order to lift the faint signal out of the noise.
Thank you for the information on how you shoot, along with what @STEVE333 said about noise reduction, pretty much tells me that not much more than 24 hours on 5-minute subs. I've got almost 24 hours on M31, it would take another 24 hours to get the noise reduction cut in half again, over 250 5-minute subs. This has been a very educational thread.

Now, if I can just get my processing down, :lol: Time and a tool designed for it, eventually. :lol:
Image Cam: Canon 6D (Ha mod), 600D (Stock), SVBony SV405CC
Image OTA: EvoStar ED80, WO Z73, C8-A XLT
Mount: EQ6-R Pro Pier, AZ-EQ5 Pro Pier
Guide OTA: Orion 60mm, WO 32mm, ZWO OAG, SV501P
Guide Cam: ZWO 120mm, 290mm mini
EAA OTA: Orion ST80
EAA Cam: SVBony SV705C
EP: Baader Hyperion Modular Set
Filters: L-Pro Canon EOS C, L-eNhance, L-Pro, Optolong Ha 7mm, Optolong Oiii 6.5mm, Optolong Sii 6.5mm, ES H-Beta
Session Control: Mini PC/Win11 Pro, APT 4.1, PHD2 2.6.10
Processing: PixInsight, DSS 4.2.6, Adobe PS CC, Astronomy Tools Action Set, Star Spikes Pro
Image
Image
User avatar
XCalRocketMan United States of America
Orion Spur Ambassador
Articles: 0
Offline
Posts: 507
Joined: Sun May 12, 2019 8:09 pm
4
Location: Reisterstown, MD USA
Status:
Offline

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#11

Post by XCalRocketMan »


AstroBee wrote: Thu Oct 20, 2022 7:30 pm I'm in the process right now of doing a 40-hour project to see if the results are worth all the extra time. I'm doing 12 hours ea of Ha, OIII, and SII with my 2600mm monochrome camera, and then I'm doing 4 hours of OSC with my 2600mc camera.
So far, in three nights I've managed to capture the 4 hours of OSC, 11hrs40min of Ha, 4hrs 20min of OIII, and 3hrs20min of SII. At this rate, I figure I can complete the project in 2 or 3 more evenings.
Will it be worth the extra time? I don't know. However, with Noise Xterminator in PixInsight, I don't think the extra frames are worth it when I could be spending time on other targets.

Yesterday, just for grins, I ran the data through WBPP and it took 2hours 37minues to complete that step....
Indeed, I have done many experiments with how many subs are needed (currently working on a blog with the data I collected). And I agree, with Noise Xterminator, you can stop collecting more data rather soon as it does a bang-up job of removing noise. I too would rather go for more objects than spend potentially unnecessary time on a single object.
Scopes Celestron EdgeHD-11; William Optics GT102; William Optics ZS61; Criterion Dynamax-8 SCT
Mounts AP1100GTO mount w/APCCpro; iOptron iEQ30 Pro; Criterion Dynamax-8 SCT
Lenses Hyperstar-III; Celestron 0.7x FR; WO Flat/Reducer 0.8x
Guiding Celestron OAG w/ASI174mm mini; WO 50mm; Orion ST80
Cameras and Filters ZWO2600mm Pro w/Optolong 3nm NB and RGB; ZWOASI1600mm Pro (ZWO LRGB and Astrodon Ha-5nm, Oiii-3nm, Sii-5nm), QHY10, Canon 50D; ASI174mm mini; ASI462MC; ASI120MC
Misc Moonlite focuser on Edge - Feather-Touch focuser on GT102; ZWO EAF on ZS61; ZWO 2" and 31mm FWs; Kendrick Dew System, Temp-est Fans
Software NINA; PHD; APT; BYE; PI; APP; PSP; Registax; FireCapture; SharpCap
Blog at: SkyAndRockets
User avatar
OzEclipse Australia
Moderator
Moderator
Articles: 2
Online
Posts: 2329
Joined: Sat May 11, 2019 8:11 am
4
Location: Young, NSW, Australia, 34S, 148E
Status:
Online

TSS Awards Badges

TSS Photo of the Day

Re: Is there such a thing as too much imaging data?

#12

Post by OzEclipse »


Hi Kerry,
Sorry, I am a bit late to this thread.

I agree with what Steve says particularly his explanation of the noise reduction being proportional to the square root of the number of frames.

However, I note that all three cameras you use, ZWO ASI294 MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i, are RGB OSC's.

The length of the sub exposures is a bit different for RGB than NB.

I image RGB in a Bortle 1/2 zone using a low noise DSLR and mostly use these three optics:-
135mm f2,
300mm f4 telephotos and an
8" f6.4 astrograph.

I find diminishing returns kick in somewhere around 15-30 images for brighter objects and 40-60 images for fainter objects.
My sub lengths vary from
1-3 mins for the 135mm @ f2 - f2.8
1-4 minutes for the 300mm f4
1-4 minutes for the 8" f6.4

cheers
Joe
Image
Amateur astronomer since 1978...................Web site : http://joe-cali.com/
Scopes: ATM 18" Dob, Vixen VC200L, ATM 6"f7, Stellarvue 102ED, Saxon ED80, WO M70 ED, Orion 102 Maksutov, ST80.
Mounts: Takahashi EM-200, iOptron iEQ45, Push dobsonian with Nexus DSC, three homemade EQ's.
Eyepieces: TV Naglers 31, 17, 12, 7; Denkmeier D21 & D14; Pentax XW10, XW5, Unitron 40mm Kellner, Meade Or 25,12
Cameras : Pentax K1, K5, K01, K10D / VIDEO CAMS : TacosBD, Lihmsec.
Cam/guider/controllers: Lacerta MGEN 3, SW Synguider, Simulation Curriculum SkyFi 3+Sky safari
Memberships Astronomical Association of Queensland; RASNZ Occultations Section; Single Exposure Milky Way Facebook Group (Moderator) (12k members)
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as too much imaging data?

#13

Post by Kerry C. »


OzEclipse wrote: Sat Oct 29, 2022 8:45 am Hi Kerry,
Sorry, I am a bit late to this thread.

I agree with what Steve says particularly his explanation of the noise reduction being proportional to the square root of the number of frames.

However, I note that all three cameras you use, ZWO ASI294 MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i, are RGB OSC's.

The length of the sub exposures is a bit different for RGB than NB.

I image RGB in a Bortle 1/2 zone using a low noise DSLR and mostly use these three optics:-
135mm f2,
300mm f4 telephotos and an
8" f6.4 astrograph.

I find diminishing returns kick in somewhere around 15-30 images for brighter objects and 40-60 images for fainter objects.
My sub lengths vary from
1-3 mins for the 135mm @ f2 - f2.8
1-4 minutes for the 300mm f4
1-4 minutes for the 8" f6.4

cheers
Joe
Thank you Joe,
90% of my imaging is done with the ASI 294MCP. The object in mind when asking this question was the Ghost (Sh2- 136) a dark nebula. Up until now I have never gathered data on a “dark nebula”. I ended up using 660 120 second subs @125 gain using the 2” Optolong L-Pro filter in my Bortle 6-7 skies on moonless nights. You can see my results in the deep sky part of this forum. “First Try at Dark Nebula”.
Kerry

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
Kerry C. United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 380
Joined: Tue Dec 31, 2019 6:20 pm
4
Location: Idaho U.S.A.
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#14

Post by Kerry C. »


I would like to thank everyone for the information provided.
In part, the reason I asked the question was for gathering data on dark nebula.
I ended up shooting The Ghost Nebula, Sh2-136 gathering a total of 22 hours of useable data, 660 120 second subs on moonless nights in my Bortle 6-7 skies using Optolong L-Pro filter.
You can see my results here, viewtopic.php?p=222566#p222566
Thanks,
Kerry

Scopes; William Optics GT 81mm Triplet, TS Optics APO 102mm f/7refractor, Cestron Nexstar 8SE, Gskyer 80mm x 400mm refractor
Mount; Sky-Watcher HEQ5 Pro
Cameras; ZWO ASI 2600MC Pro, QHY5iii462C, ZWO ASI224MC, Canon 600D DSLR T3i.
Guide scope; ZWO 60280 f/4.6
Guide camera; ASI290mm mini
Filters; Optolong L-eXtreme 2”, Optolong L-Pro 2”, QHYCCD IR/CUT, QHYCCD IR850
User avatar
chartram United States of America
Saturn Ambassador
Articles: 0
Offline
Posts: 359
Joined: Fri Jul 05, 2019 6:34 pm
4
Location: Kathleen, GA
Status:
Offline

TSS Photo of the Day

Re: Is there such a thing as to much imaging data?

#15

Post by chartram »


@Kerry C.

Sorry to be late :-)

A lot of EXCELLENT info provided here. One thing I tend to consider when guesstimating both the integration time and subexposure times required is the surface brightness of the object. Some objects can be captured nicely in 60 subs or even far less. Others with very low surface brightness, like many dark nebulae/molecular clouds, might require much more. I think it really depends on the equipment used, sky darkness/local conditions and most of all desired result.

NoiseXterminator mentioned above is an amazing tool that is worth every penny. But my opinion is that just like any other processing tool, it is only as good as the data it is given to work with. The math regarding noise reduction may be and true, but the other part of the equation is signal. A really faint object may require a significant TOT investment just to get enough signal to survive post-processing... as well as provide NoiseXterminator with enough data to work with. Again, it is an amazing tool, but it can't fix what is not there... and used with too heavy of a hand, NoiseXterminator can negatively affect what is.

Your Ghost Neb image is beautiful, and appears to be worth every second of the 22hrs spent. It is sharp, smooth and the color & details are clear and stand out strongly against the background. It belongs on your wall- Very well done!!!

Out of the different schools of thought between capturing many targets and relying on processing aides vs. capturing fewer but with better overall SNR, it all boils down to individual preference. My opinion is that data is like that old wood screw in the junk drawer. Would rather have it and not need it than need it and not have it :lol:

Mike
Mike Chartrand
Scopes: WO Star 71 Gen-II (F/4.9), Astro-Tech AT115EDT (F/7), Celestron 8" Edge HD (F/10)
Cameras: ZWO ASI1600MM w/ Baader 1.25" LRGB & Narrowband Filters, ZWO ASI174MM mini, Starlight Xpress Lodestar X2
Mount: Skywatcher NEQ6 Pro
Guiding: Orion ST-80 (f/5) w/ADM MiniMax (side-by-side), ZWO OAG
Software: PHD2, Sequence Generator Pro, PixInsight
Dark Site Transportation System: 2020 Telluride SX
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Image processing”