Witch's Broom NGC 6960

I’ve been continuing to image with the QHY268C camera and Optolong L-eXtreme filter. This combination has proven to be very good for astrophotography. The results I am getting are really fantastic.

The QHY268C is a cooled cmos camera with high resolution and low noise. It boasts a 26mp Sony IMX571 APS-C sensor with 3.7um small pixels. This back illuminated sensor also sports a 2gb memory buffer and has no amp glow.

QHY268C cooled cmos camera
The QHY268C cooled cmos camera

The new Optolong L-eXtreme dual narrowband filter, is designed for one shot colour (OSC) cameras. It has the ability to capture both H-alpha (Ha) and Oxygen III (OIII) emission lines at the same time. 

Optolong L-eXtreme

The difference between the L-eXtreme and L-eNhance filters from Optolong, are the emission lines. The L-eNhance allows a 24nm bandpass through the OIII and H-Beta region, and 10nm for Ha. The L-eXtreme, is strictly 7nm in Ha and OIII. This makes the L-eXtreme much more powerful in terms of capturing high-contrast images while strongly reducing the impacts of light pollution on your astrophotography. 

Optolong L-eXtreme
The transmission graph of the Optolong L-eXtreme Filter

I used the Skywatcher Esprit 100 triplet refractor for the Witch’s Broom image. With the QHY268C attached I get an effective 1.41 arcsec/px ratio which is in the sweet spot for my average seeing conditions here in southern Ontario. 

I took 5 minute sub exposures at gain 56 and offset 30. In discussion with another astrophotographer using the QHY268C, This was a recommended setting for high gain usage when shooting narrowband. I usually image at gain 0 in photographic mode for the QHY268C and this is most likely the better choice when dealing with objects that have highly bright areas such as some galaxy cores or very bright stars. The high gain mode may work better with mostly dimmer objects. My results using high gain mode on the Witch’s Broom were very good. In theory using the high gain mode for the QHY268C, I should have achieved an even lower read noise versus running at 0 gain in photographic mode.

Watch my video below for more on QHY268C and L-eXtreme…

Technical:

23 hours total

Skywatcher Esprit 100 F5.5 Triplet Refractor http://bit.ly/36w1F7Y

QHY268C cooled cmos camera, 26mp https://bit.ly/37OeYS5

Optolong L-eXtreme filter http://bit.ly/32a9Gfu

EQ6 Skywatcher mount ( https://bit.ly/2C9lap1 )

Acquisition: N.I.N.A  (PHD2 for autoguiding)

Processing: Pixinsight

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