M81, M82, M51, NGC2841

It's Spring and with Coma Berenices with its accompanying cluster of galaxies it's the beginning of galaxy season. I thought I would get a head start  practicing on with three of my favorite galaxies M81, M82 and M51. NGC2841 is thrown in as a bonus. These won't be my only  visits to these non-Coma Berenices targets as they grace my northern hemisphere zenith during the next month or so. The Coma cluster requires I get out of heavily light polluted Frederick Maryland  to one of my darkish sites and when the galaxies are highest in the southern sky. 

Sadly, as I write this, the world is in the midst of a crippling, deadly pandemic due to the covid-19 corona virus. The effects on public health and the world economy are still to be played out. I'm fortunate, a lifelong saver/investor to be in a decent financial position despite taking a hit in the stock market. I can also be grateful for a mind engaging hobby, this one, to distract me from the current goings on. Folks, follow the experts, hand washing, social distancing, staying at home if you can. We're in for pain but will get through this. 

M81 -- 15x120s @bin1

M82 -- 15x180s @bin1

M51 -- 12x180s @bin1

NGC2481 -- 10x180s @bin1

Comet C2017T2, IC405, IC410, M33, NGC281, M42, NGC7635

Here are a few recent images acquired this 2019 winter. All were acquired at F/4 using the recently with Celestron 8+Starizona Night Owl FR+Orion SkyGlow Astrophotography filter. Camera: ZWO ASI294MC Pro, Mount: Celestron Advanced VX, Guider: Orion Magnificent Mini Autoguider. 

Look closely at Comet C2017T2 and you might notice the glow slanting down to its left. That's residual glow not zeroed out by the flat frame. Vignetting from the Night Owl is very aggressive and tough to zero out.  

Using SharpCap 3.2 I have found collecting flat frames at a narrow range of different exposures that give a histogram just above and below the "above 20%" criterion should provide a flat frame that does a good job zeroing out vignetting and artifacts. *

* More recently I have found a 20% to 80% histogram range, as recommended by SharpCap documentation works best. 

Comet C2017T2 PANSTARRS -- 15x60s @bin2

IC410 -- 6x300s @bin1

IC405 -- 6x300s @ bin1

M33 -- 10x180s @ bin1

NGC281 -- 10x180s @bin1

M42 -- 25x8s @bin1

NGC7635 -- 6x300s @ Bin1