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Observation by Dean Ashton: M101 enhanced using a duo-band filter wi...

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Dean Ashton


Dean Ashton


2020 Mar 24 - 21:00


2020 Apr 20 - 07:35



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Ursa Major

Field centre

RA: 14h03m
Dec: +54°21'
Position angle: -2°55'

Field size

0°36' × 0°26'

  • Celestron 9.25 EdgeHD with 0.7x focal reducer
  • Celestron Nightscape 10100 OSC Camera
  • CGEM
  • Off-axis guiding with LoadstarX2 Guide Camera
  • Optolong L-Pro and L-eNhance filters

/f7; 75x600s with L-Pro filter: 30x600s with :-eNhance filter; 1x1-binning; total integration time was 17-hours and 30-minutes.


St Austell, Cornwall UK

Target name



M101 enhanced using a duo-band filter with a OSC camera.

About this image

I had previously posted this image of M101 taken with 75x600s light frames captured on the 15th, 23rd, 24th and 25th March with an Optolong L-Pro filter.  I have now added a further 30x600s light frames taken on the 15th and 26th March with an Optolong L-eNhance filter.  The difference is a significant enhancement of the red hydrogen-alpha regions in the galaxy.  

The L-eNhance filter allows transmission at the wavelengths of Ha, Hb and Oiii.  It brings narrow band possibilities for the one-shot-colour camera user.  In this image 75% of the frames were shot with the L-Pro (luminous) filter and 25% with the L-eNhance (narrow band) filter).  

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