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11h on the Sadr Region -- Nikon D5300 & Zenithstar 61II -- Multiband

Astrophotography DSLR Refractor Imaging
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#1 Nicolarge

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Posted 02 August 2021 - 10:07 PM

Hi everyone,

 

This is my largest project to date.... 11+ hours on the Sadr Region in Cygnus. This is also my first time using a filter (quadband narrow band). I got lucky to have 4 clear nights in a row to try out this filter.

I had been thinking of going narrowband and for a while now but was afraid of diving into it. But being to image from my Bortle 7 backyard with the moon out instead of waiting the new moon and driving 1h30 to my Bortle 2 site is great. I was afraid that 3min subs would not be enough with such an aggressive filter but that worked out well.  Finding targets with such a strong filter and without a Goto mount or plate-solving is definitively challenging.... Doing it 4 nights in a row while trying to manually frame the target the same way is VERY challenging.

I did not guide. I just used a simple star tracker without autoguiding. I've just bought my first autoguiding system but still waiting for the guide cam and guide scope.

What do you all think?

 

Sh2-108 (Sadr Region) - Narrowband - 2021-07

 

 

General Info:
Target: Sadr region
Dates: 2021-07-28; 2021-07-29; 2021-07-30; 2021-07-31
Location: San Antonio, TX (Bortle class 7)

 

Setup:

Mount: IOptron SkyGuider Pro
Camera: Nikon D5300 astromod
Scope: William Optics Zenithstar 61II + Field Flattener FLAT61A
Focal/Aperture: 360 mm @ f/5.9
Filter: Radian Telescopes 2" Triad Ultra Quad-Band Narrowband Filter (H-beta:5nm, OIII:4nm, H-alpha:4nm, SII:4nm)

 

Acquisition:

Lights: 225x180s (total exposure: 11h15)
Calibration frames: 4x30xdarks, 4x30xflats, 4x30xbiases
ISO 3200

 

Processing:

Stacked in DDS and Processed in GIMP, Denoise AI:
1- Histogram stretching / Levels adjustments
2- White balance adjustment & RGB channel alignment
3- Curve adjustments on starless image (obtained using starnet++)
4- HighPass filter
5- Slight noise reduction (DeNoise AI)


Edited by Nicolarge, 02 August 2021 - 10:10 PM.

  • Thomas Marshall, md11spotter98, limeyx and 2 others like this

#2 Ibuprofen200mg

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Posted 02 August 2021 - 10:37 PM

Very nice image, not sure how you pulled off sharp stars at 360 mm and 3 minute subs on a star tracker with no guiding...but great work!


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#3 Nicolarge

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Posted 03 August 2021 - 11:46 AM

Hey. Thanks. For the Sharp star I guess it's a combination of two things: A good polar alignment and the use of the narrow band filter. I've learned pretty early on that polar alignment and balance were critical so I'm trying to do it better and better at each session. Here I've spend quite a bit of time to get it as good as possible and I was really happy with my stars. Although, I had to throw out several subs each nigh for slightly elongated or blurred stars.

The filter also helped keeping the star pretty small too.




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