UHC & OMB Filter Test With M18 & M17

I did not plan on doing this test it happened because I wanted to image M18 and thought I would redo M17 while I was at it since I never imaged it with the Astronomik UHC (Ultra High Contrast). Previously I did it with the Astronomik CLS (link to image).  Unfortunately I put the Astronomik OWB (Original White Balance) filter in my camera (modified Canon T3i/600D) and the UHC filter.  So I had to go back on another night to do what I wanted to do in the first place. 

Results:

Figure 1 shows the the enter image using the OWB filter used for turning a modified camera back factory white balance. 

Figure 2 is the same image using the UHC filter.  The UHC allows for more Ha light to pass with less light pollution, thus more contrast and more of the nebula.  The UHC filter allows the transmission of nearly 100% of the radiation from both O-III and the H beta lines. UHC filters are mainly used for emission nebula and not recommended for star clusters and such as it blocks some of their light. Notice the smaller size of the stars.  I like how the OWB has a better star field.

Figures 3 and 4 are a combined image of both the UHC and OWB images.  I wanted increase the star field but keep the increased nebulosity.  I used different blending methods to achieve this.

Figure 5 is the open cluster, M18. 

Figure 1 - M17 - OWB

Figure 2 - M17 - UHC

Figure 3 - Combined 55% UHC - 45% OWB Normal Blend 

Figure 4 - Combined 55% UHC - 45% OWB Luminosity Blend

Figure 5- M18 - OWB

Image Details:

OWB
M17 - M18
Location: Happy Frog Observatory, Monroe, CT
Date: 6-24-17
Camera: Canon EOS Rebel T3i(a), Backyard EOS
Telescope: Orion ED80 80mm f/7.5 Apochromatic Refractor Telescope
Barlow: None
Focal Length: 600mm
f/7.5
Focal Reducer: Orion 0.8x Focal Reducer for Refractor Telescopes
Mount: Orion Sirius EQ-G GoTo Telescope Mount
Filter: Astrodon UV/IR, Astronomik OWB
Autoguiding: QHY-5L-II-M attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: 18 x 180s
ISO: 1600
Temp: 20 C
Post Processing: Deep Sky Stacker, Photoshop, Lightroom, Gradient Exterminator, Astronomy Tools, StarTools.
https://kurtzeppetello.smugmug.com/

UHC
M17 - M18
Location: Happy Frog Observatory, Monroe, CT
Date: 7-16-17
Camera: Canon EOS Rebel T3i(a), Backyard EOS
Telescope: Orion ED80 80mm f/7.5 Apochromatic Refractor Telescope
Barlow: None
Focal Length: 600mm
f/7.5
Focal Reducer: Orion 0.8x Focal Reducer for Refractor Telescopes
Mount: Orion Sirius EQ-G GoTo Telescope Mount
Filter: Astrodon UV/IR, Astronomik UHC
Autoguiding: QHY-5L-II-M attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: 22 x 180s
ISO: 1600
Temp: 20 C
Post Processing: Deep Sky Stacker, Photoshop, Lightroom, Gradient Exterminator, Astronomy Tools, StarTools.
https://kurtzeppetello.smugmug.com/