M42 The Orion Nebula - An Unscientific Comparison

[David_Pickles]

It has been a long time since I last posted on here; primarily due to a change in job that keeps me away from home during the week and a clear sky during my weekends at home has been a rare event in deed.  However, the recent planetary alignment has obviously brought me luck, as a combination of being at home and having clear skies, stable atmospherics and no moon finally provided me with an opportunity to fully test the potential of the Altair Wave 115 ED Triplet Refractor, combined with the Planostar 0.79x Reducer/Flattener - and boy was it worth the wait!

I wanted to compare the results to my previous scope - the extremely capable (in my humble opinion) Sky-Watcher Explorer 190MN Pro Mak-Newtonian Astrograph.  So I chose one of my all-time favourite subjects - M42, the Great Orion Nebula and Running Man.  The image I captured using my 190MN was the first of my own astro-photos that made me go wow!  The image comprised of 10 x 300s, 10 x 200s and 25 x 45s exposures, captured using a QHY8L and Nebulosity 3 then processed using Photoshop CS6.  The final result is now framed and has pride of place on the wall above my desk.  I was convinced it was going to be hard to beat.

 

My previous attempt at M42, using the Sky-Watcher Explorer 190MN Pro

Now, before I compare the images I must point out that this is not going to be a direct, scientific comparison.  For a start, there are a couple of significant differences between the 2 scopes; FOV being the most obvious, with 1.35° x 0.9° for the 190MN Pro, vs 2.13° x 1.42° for the 115ED with the 0.79x Reducer/Flattener fitted.  The aperture being another significant difference, with the 190MN Pro being 65% larger than that of the 115ED.  The 190MN Pro is also marginally faster, with a Focal Ratio of 5.3, vs 5.53 for the 115ED.  However, I did use the same QHY8L CCD camera to capture the image and the NEQ6 mount and Lodestar XPress guide camera were also the same.

In an attempt to compensate for the smaller aperture and slightly slower Focal Ratio, I increased the length of the exposures to allow as much light to reach the camera's sensor as possible.  The final image, which you can see below, is the result of 14 x 600s and 15 x 30s exposures, captured using the QHY8L and Nebulosity 4, then processed using Photoshop CS6.  Some may say this is an unfair comparison, but all I wanted to do was see if the Altair Wave 115ED was capable of achieving similar results to the Sky-Watcher Explorer 190MN Pro.  The answer is yes - definitely!  But that is my opinion - let me know what you think.

My latest version, using the Altair Wave 115ED and 0.79x Reducer/Flattener

[laudropb]

They are both very nice images. I think I marginally prefer the first, but that is probably because of the fob and the fewer stars present to distract the eye.

[Tim]

Nice result from the 115, but I would take that MN190 over most refractors any day. I know they are bulky and need setting up right, but the Mak-newts are as close as you will come to a 6'' refractor for a fraction of the money.

 

Still, the best scope for you is the one you can get the best results from. Glad to see you still have the bug

[Stephen Green]

They are very nice images

[ollypenrice]

I don't think we can conclude anything about the scopes here, other than that both are good. For me the greater field suits the target, allowing it more room to breathe and show its extremities. But on a different target that could be reversed. I'd expect the biggest difference between the scopes to be in their ease of operation with the 115 being the hands down winner. However, like Tim I don't think much beats a finely honed MN190. It's that 'finely honed' bit that contains the devil...

 

Super images. In the second one I think you have a small top to bottom green bias with an excess of green at the top turning into a sight deficit at the bottom. HLVG for Ps or SCNR green in Pixinsight would nail it.

Olly

[Starlight 1]

Two very nice images ,as Olly said about the green, but the blue around the Stars in image 2 just push me to liking image 1 more.

[michaelmorris]

Two great images.

[gorann]

Both great images, and it is hard to pick a winner. It could be the longer exposures with the refractor that brings out that extra dust. I wonder a bit about the spikes you have on the stars in the 2nd image. Is that not odd for a refractor? I have a similar set up (ES 127ED with a TS 0.79 reducer/flattener) and have seen small spikes but not any long ones.

[Fay]

Very nice, |I like the second one best, even if a little green here and there

 

Fay

[xtreemchaos]

great shots mate,well done.thanks for sharing,  charl.

[gnomus]

I prefer image 2 because of 1) the FOV and 2) it looks marginally sharper to my eyes.  I'm a bit confused by the angle of the star spikes in the lower left quadrant.  What is causing that effect?