Zwo 294 MC pro - FLATS - Forums

Topic starter

Aug 26, 2021

Hello guys,

i've been using the 294mc pro camera for while and recently started using it with narrow band filters. i'm having trouble removing the gradient specially from the SII filter. is there particular ADU i should be using and exposure time for it. i'm using pegausus Astro flatmaster for my flats.
any advice will be great.

thanks
Jaspreet

Dave B

Aug 26, 2021 · Edited: Aug 26, 2021

How long are your flat exposure, probably the better way is to use a flats aid in APT or flats wizard in nina target value is usually around 20-25k ADU exposure time should be about 2-3 sec but that depends on your scope diameter and light source, on my 8” Newtonian I struggled to get decent flats , now using a zwo533mc and having dimmed my flats panel which is an El panel I’m using 3.3 sec exposure, note if you do use an el panel it’s advised to use exposure over 1 sec so the panel refresh rate doesn’t interfere , which when I used with a Dslr I did have issues with .

Astrosingh

Topic starter

Aug 26, 2021

How long are your flat exposure, probably the better way is to use a flats aid in APT or flats wizard in nina target value is usually around 20-25k ADU exposure time should be about 2-3 sec but that depends on your scope diameter and light source, on my 8” Newtonian I struggled to get decent flats , now using a zwo533mc and having dimmed my flats panel which is an El panel I’m using 3.3 sec exposure, note if you do use an el panel it’s advised to use exposure over 1 sec so the panel refresh rate doesn’t interfere , which when I used with a Dslr I did have issues with .

My Flats exposure is over 4 seconds and i'm using Flat wizard in NINA which connects to the Flats panel and controls its brightness. i have no problem with taking flats for RGB and Optolong L extreme its just the Sulphur narrowband filter creating this gradients. i'm doing flats for my William optics z81. I've tried taking flats for Sulphur with the ADU 20-25k still the gradient was there, also i'm taking flats at the same temperature as my lights.

CCDMike

Aug 26, 2021

Try a higher ADU for the narrowband filters (32k) and definitely use darkflats.

Best
Mike

Bob J

Aug 26, 2021

Hello guys,

i've been using the 294mc pro camera for while and recently started using it with narrow band filters. i'm having trouble removing the gradient specially from the SII filter. is there particular ADU i should be using and exposure time for it. i'm using pegausus Astro flatmaster for my flats.
any advice will be great.

thanks
Jaspreet

Hi Jaspreet,

I guess my first question is this is a OSC correct? The 294 MC is a color camera. How are your light exposures using an SII filter over the Bayer array?
Most flat panels are deficient in the red spectrum so longer exposures are generally required for HA and SII.

I have 2 -294 MM pros ( Mono) on my WO GT81s and I use an Alnitak Flatman for my flats. I aim for 30K for my flats. With my Baader Ultra Narrow band filters my HA and SII exposures are in the neighborhood of 30 seconds with the flatman at max power to get that ADU.

I use the SGP flat calibration wizard . This is what I have seen with all of my cameras and filters. I have or have owned SX 694 Trius, Atik 460 EX, ZWO ASI 1600MM, ASI 294MC, ASI 294MM and Baader, Astrodon, Astronomik filters. They are all in that 30sec range, except the 294MC as I never shot narrow band with that.

Also as stated above it is extremely important to shoot flat darks at the same temp and exposures as the flats to remove the amp glow. Also what gain and offset are you using? Matching the lights I would assume. I just can't believe you are getting the right exposure with 3 sec flats with an SII filter.

Just my 2 cents worth the info..

CS/Bob

Helpful

Astrosingh

Topic starter

Aug 27, 2021

Try a higher ADU for the narrowband filters (32k) and definitely use darkflats.

Best
Mike

Thanks Mike, i'll have a go at it with 32K.

Astrosingh

Topic starter

Aug 27, 2021

Bob J:
Hello guys,

i've been using the 294mc pro camera for while and recently started using it with narrow band filters. i'm having trouble removing the gradient specially from the SII filter. is there particular ADU i should be using and exposure time for it. i'm using pegausus Astro flatmaster for my flats.
any advice will be great.

thanks
Jaspreet

Hi Jaspreet,

I guess my first question is this is a OSC correct? The 294 MC is a color camera. How are your light exposures using an SII filter over the Bayer array?
Most flat panels are deficient in the red spectrum so longer exposures are generally required for HA and SII.

I have 2 -294 MM pros ( Mono) on my WO GT81s and I use an Alnitak Flatman for my flats. I aim for 30K for my flats. With my Baader Ultra Narrow band filters my HA and SII exposures are in the neighborhood of 30 seconds with the flatman at max power to get that ADU.

I use the SGP flat calibration wizard . This is what I have seen with all of my cameras and filters. I have or have owned SX 694 Trius, Atik 460 EX, ZWO ASI 1600MM, ASI 294MC, ASI 294MM and Baader, Astrodon, Astronomik filters. They are all in that 30sec range, except the 294MC as I never shot narrow band with that.

Also as stated above it is extremely important to shoot flat darks at the same temp and exposures as the flats to remove the amp glow. Also what gain and offset are you using? Matching the lights I would assume. I just can't believe you are getting the right exposure with 3 sec flats with an SII filter.

Just my 2 cents worth the info..

CS/Bob

Hi Bob,

Thanks for your feedback. Yes its the OSC Zwo 294MC pro. what i've noticed with the Sulphur lights is there is a-lot more noise in the lights even if i have 7hrs + integration with just the sulphur filter. I've been able to calibrate the flats for Ha and Oxygen with Astroflatmaster. my exposure for it is above 4 seconds and 5.5 seconds around 25kAdu which calibrated the HA and Oxygen. you are right about the sulphur my flat wizard was showing it needs 30sec plus exposure for sulphur, i wasn't sure if i'm doing right. i'll try 30k ADU next imaging night and see if that calibrates the sulphur. I'm taking dark flats as-well, both dark flats and flats are taken at the same temperature as my lights. my Gain is unity gain of 120 and offset of 20.

thanks
jaspreet

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