Flats Failing Me?

Discuss how you are able to get those fantastic images!!!
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Flats Failing Me?

#1

Post by fatboy1271 »


I saw from the first capture that I had a prominent dust mote. I had hoped that my Flats would fix that; however, here it is after BPP in PI. I took to heart the comments about keeping the Histogram to the Left 1/3; although it was also mentioned to worry more about the ADU... Anyway, did I do something wrong or can this be fixed post PreProcessing?

This night's session consisted of 30sec x 1600iso and 60sec x 800iso exposures:
Flat Failure.PNG
Tv11250s x 1600iso Flat
Tv11250s_1600iso.PNG
Tv1640s x 800iso Flat
Tv1640s_800iso.PNG
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#2

Post by Stuart »


Post a link to a single raw flat (not a screenshot or a .jpg).
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
User avatar
yobbo89 Australia
Moderator
Moderator
Articles: 0
Online
Posts: 2561
Joined: Sat May 11, 2019 7:44 pm
4
Location: australia qld brisbane
Status:
Online

TSS Photo of the Day

Re: Flats Failing Me?

#3

Post by yobbo89 »


flats will not remove dust motes completely that are directly on the sensor (see large darkish glob above m31) or light pollution, if the first image is calibrated then it looks pretty normal ie the corners have been improved from the flats, no vignetting ecttt

The image looks pretty even from the flat except for the bottom left corner that looks brighter, maybe it's light pollution or not calibrated correctly from flats, also make sure your light box is center correctly on the scope.
background gradient extraction is your next choice
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

Image
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#4

Post by Stuart »


My flats remove dust motes without much difficulty. The trick is to make sure the flats are exposed correctly. You're looking for a value that is about 45% of max ADU. (I usually shoot for 30-35K)
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#5

Post by fatboy1271 »


Stuart wrote: Wed Aug 28, 2019 10:20 pm My flats remove dust motes without much difficulty. The trick is to make sure the flats are exposed correctly. You're looking for a value that is about 45% of max ADU. (I usually shoot for 30-35K)
I thought a big part of Flats was to remove things like dust motes so I'm glad to hear it's possible.
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#6

Post by fatboy1271 »


Stuart wrote: Wed Aug 28, 2019 5:40 am Post a link to a single raw flat (not a screenshot or a .jpg).
Let me know if you can download the CR2 from here:
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
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: Flats Failing Me?

#7

Post by STEVE333 »


The CR2 at your link is a Light frame not a Dark frame.

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
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#8

Post by fatboy1271 »


STEVE333 wrote: Thu Aug 29, 2019 5:00 pm The CR2 at your link is a Light frame not a Dark frame.

Steve
Geez oh man... Thanks Steve! I'll upload a correct file :|
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#9

Post by fatboy1271 »


Ok, here are two Flats that I used; 1 800iso and 1 1600iso:

https://drive.google.com/drive/folders/ ... sp=sharing
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
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: Flats Failing Me?

#10

Post by STEVE333 »


I downloaded the Flat_TV1640s image and opened it up in PI. The image below shows how it looks in HistogramTransformation.

Image

The histogram settings are what was explained to me by one of the PI gurus. The main point is that the histogram (the bottom histogram is the one to look at) is only at about 15% of full scale which is low. You want it closer to 50%. It will still work, but, will do a cleaner job if you are able to raise the histogram with longer exposures.

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
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: Flats Failing Me?

#11

Post by STEVE333 »


FYI - You asked if there is a way to remove the effect of the dust mote in post processing. I tried Surface Blur Noise Reduction (see link below) and it completely removed the effects of the mote.

http://www.astronomyforum.net/astrophot ... ng-pi.html

When using the clone stamp portion of the technique I clone stamped out the majority of M31.

Hope this helps.

I can show the results of my attempt if you are interested.

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
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#12

Post by Stuart »


The reason why your flats aren't working is that they're almost black. Your exposure time is WAAAAY too short. I measured the ADU of both and at 16 bit they were about 1800-2000 average count. They need to be about 30,000 average count. So increase your exposure time by about 15 X whatever it is now and repost. To avoid shutter shadow on a DSLR your exposure time shouldn't be much less than 0.5 seconds. If your exposures are too bright, then darken it with a t-shirt or white copy paper.
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#13

Post by Stuart »


For example, here is a flat master from a project I did last year. Compare it to yours and you'll see what I'm talking about.
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#14

Post by fatboy1271 »


Alright, thanks Steve and Stuart! I've been battling the understanding of what Flats should look like and this is so helpful :)

Stuart I brought yours into PI and thought, "yeah, it looks brighter." Then I did an STF on it and I can see your dust motes!!!

I was under the impression that the Flats should be in the 1/3 Left of the Histogram so that's what I was doing in BYEOS. I'm moving on to NINA and it has a Flat Wizard so maybe that can get me on the right path. I need to think about using PI when outside with my setup...
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#15

Post by Stuart »


Yeah, I see this a lot with BYEOS use. The histogram thing is misleading. I wouldn't use it. You're looking to have about 45% of your full well depth, but anything between 20-55% should be fine.

If you have PI, look at your flat with the Statistics process, and then look at mine with the Statistics process. You'll see what I'm talking about. The default is a 16 bit scale which is fine. Just know that your camera spits data out at 14 bit so if you're using another program that measures 14 bit your target ADU is about 8,000 (not 30,000). But 8000 will scale up to about 30,000 in 16 bit. The Statistics process has a drop down menu where you can pick your scaling factor.
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
User avatar
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#16

Post by fatboy1271 »


Awesome, I will use PI to check out your examples and then to also work on getting correct Flats. Thanks again, this means so much to me!
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
Stuart United States of America
Jupiter Ambassador
Articles: 0
Offline
Posts: 247
Joined: Sat Jun 01, 2019 11:12 pm
4
Location: East Bay, California
Status:
Offline

TSS Photo of the Day

Re: Flats Failing Me?

#17

Post by Stuart »


Cool. Once you figure it out, post another example and I can look at it again.
Personal equipment: TEC 140 F7 on Astro-Physics Mach 1 mount. Camera QSI 683ws7. Guide with Vario guiding scope
Shared equipment through Star Shadows Remote Observatory through PROMPT/ CTIO/Chile 16" RCOS 16803 chip
Shared equipment through San Diego Astronomy Society 14" RC with 16803 chip on a paramount
Software (for my stuff) PemPRO, SGP, PHD, Focus Boss, ASCOM, and Pixinsight on the other end.
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: Flats Failing Me?

#18

Post by STEVE333 »


Just FYI, I downloaded your M31 image and applied the Surface Blur Noise Reduction technique to it, and, it did indeed remove the dust mote. With the dust mote gone the image could be stretched and processed more. The result is a nice M31 with nice contrast. If you would like to see the result I could post it here. You have some nice data to work with.

Best of success in solving your flats problems.

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
fatboy1271
Pluto Ambassador
Articles: 0
Offline
Posts: 407
Joined: Wed Jun 12, 2019 3:34 pm
4
Location: SoCal
Status:
Offline

Re: Flats Failing Me?

#19

Post by fatboy1271 »


STEVE333 wrote: Fri Aug 30, 2019 4:55 pm Just FYI, I downloaded your M31 image and applied the Surface Blur Noise Reduction technique to it, and, it did indeed remove the dust mote. With the dust mote gone the image could be stretched and processed more. The result is a nice M31 with nice contrast. If you would like to see the result I could post it here. You have some nice data to work with.

Best of success in solving your flats problems.

Steve
Steve, you're awesome! Yes, please, I would love to see the result :)

I've not used Surface Blur Noise Reduction nor did I know it existed... So much to learn!!!
OTAs: Explore Scientific ED80 Essential Edition / The Little Guy (Celestron 90SLT)
Mount: Celestron Advanced VX
Gear: Canon 70D / Hutech LPS-D1-48 / ES 2" Field Flattener / QHY PoleMaster / Celestron GPS / ZWO ASI120MC / Orion 50mm Guide Scope / ZWO EAF
Software: CPWI / PHD2 / N.I.N.A / Stellarium/StellariumScope/Remote Control / PI / RegiStax 6 / AutoStakkert!2 / PIPP | Retired? BackyardEOS Premium
EPs: Stock Celestron 9mm and 24mm / Celestron Omni 32mm (I love this one!) / Celestron X-Cel LX 3x Barlow (I think 2X would have been smarter...)
Support Staff (Loved Ones!): CeCe, Ro, and Geno
Let's Go Pens!!!
User avatar
yobbo89 Australia
Moderator
Moderator
Articles: 0
Online
Posts: 2561
Joined: Sat May 11, 2019 7:44 pm
4
Location: australia qld brisbane
Status:
Online

TSS Photo of the Day

Re: Flats Failing Me?

#20

Post by yobbo89 »


I stretched your flats, it actually looks like your exposure time for it is too short,and that your flats light box may not be centered or there is problem in your imaging train,

you can see the dust mote which actual doesn't seem to be on the chip and should be able to be removed but the vignetting isn't centered
Attachments
flats upload.jpg
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

Image
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”