Hemisphere:  Northern  ·  Constellation: Ursa Major (UMa)  ·  Contains:  M 101  ·  NGC 5447  ·  NGC 5449  ·  NGC 5450  ·  NGC 5451  ·  NGC 5453  ·  NGC 5455  ·  NGC 5457  ·  NGC 5461  ·  NGC 5462  ·  NGC 5471  ·  Pinwheel galaxy
Getting plate-solving status, please wait...
Messier 101 Again (HaLRBG), 


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Getting plate-solving status, please wait...
Messier 101 Again (HaLRBG), 


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Acquisition details

May 8, 2021 ·  May 9, 2021 ·  May 10, 2021 ·  May 23, 2021 ·  May 24, 2021 ·  May 25, 2021 ·  May 26, 2021 ·  May 27, 2021 ·  June 7, 2021 ·  June 11, 2021 ·  June 12, 2021 ·  June 13, 2021 ·  June 14, 2021
Astrodon Gen2 I-Series Tru-Balance Blue: 18×480(2h 24′) -20°C bin 2×2
Astrodon Gen2 I-Series Tru-Balance Green: 19×480(2h 32′) -20°C bin 2×2
Astrodon Gen2 I-Series Tru-Balance Lum: 16×900(4h) -30°C bin 1×1
Astrodon Gen2 I-Series Tru-Balance Red: 15×480(2h) -20°C bin 2×2
Astrodon H-alpha 3nm: 22×1800(11h) -30°C bin 1×1
21h 56′
Flat darks:
Avg. Moon age:
14.37 days
Avg. Moon phase:

RA center: 14h03m13s.200

DEC center: +54°2154.67

Pixel scale: 0.728 arcsec/pixel

Orientation: 91.187 degrees (flipped)

Field radius: 0.364 degrees

More info:Open 

Resolution: 2772x2298

File size: 304.2 KB

Locations: Sierra Remote Observatories, Auberry, California, United States

Data source: Own remote observatory

Remote source: Sierra Remote Observatories


After the lease where my friend had his remote observatory in West Virginia was not renewed, he invited me to participate in a team operating a system at SRO. It was an offer I couldn't refuse! The team consists of three of us right now although I did most of the configuration and acquisition for this, the equipment does not belong to me. Sure is nice having access to it though!

It took a bit of time to get everything operational and during that time we used M101 as our test subject. The LRGB was confined to times when the moon was not up and we gathered the H-a when the moon was visible. Since we spent a lot of time on tracking down a guide camera problem and working on mount modeling and guiding when the moon was up we ended up with 11 hours of H-a, quite a lot compared to the LRGB. But by the end of the testing I was pretty much done with spending time pointing at M101.

Although we had a fair amount of data I wasn't sure a lot of the earlier data would be usable but more than enough was and I decided to declare victory and process the image with what we had. That was probably a bit heavy on h-a, a touch light on Lum and about right on R, G and B. I figured if it looked like it needed help anywhere I would just get more data. As it turned out, I was really pleased with how the initial stacks looked

Although I had only recently completed M101 on my 80mm refractor from home this was like looking at an entirely new target! The detail was incredible. Between having 270mm additional aperture, a much finer image scale and the great seeing at SRO, it was an amazing step up in image quality. I was pretty happy with my earlier image but this made my earlier effort feel indistinct and humble by comparison. It would be easy to get spoiled by using such nice gear.

I haven't spent a lot of time on processing this so may go back and do things more carefully but I was so excited about this result that I wanted to share it.




Dynamic Crop


MLT Noise reduction

Deconvolution (using the method outlines on Jon Rista's website)

Histogram Transformation



Dynamic Crop

MLT Noise reduction


Histogram Transformation



Image Integration

Dynamic Crop


MLT noise reduction


Histogram Transformation

LRGBCombination with the Lum

LHE (two different scales)

Curves (contrast & color)

NRGBCombination with the h-a

Curves (contrast)

Adv Sharpening script