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NGC 3718 (StellaLyra 6" RC and ASI533)


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Ever since I first saw NGC 3718 I've wanted to image it at some point so I decided to dedicate some precious clear skies to it recently. This was taken over three nights where the moon was rising well past midnight so it's effect varied as the early hours came round. 

Using the StellaLyra 6" RC and ASI533, it was taken at native focal ratio, so a very pedestrian F9 🙂

Original image was ~0.57"PP, so this was IntegerResampled in PixInsight (2x) before starting processing.

In total, 333 x 120s (~11 hours) of subs were integrated.  Captured with Voyager, stacked & calibrated in APP and processed in PixInsight.

Any and all feedback welcome, even "take the reducer out the box".  Thanks for looking.

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Here's what an average 120s sub looked like for each night and the final stack.  All AutoSTF in PI.

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Edited by geeklee
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Lovely image. Great details and colours and I like the bonus galaxies you captured too. This galaxy is in Ursa Major (I researched!) and one I haven't imaged yet (next target?). If I get something close to your result I would be happy!

Gerr.

 

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Thats a fantastic image Lee. super detail and your stars are great colours.

I'm mulling over more FL to go with my ASI2600mc and was thinking about a RC (possibly this very one) but am slightly put off by the talk of collimation. How do you find it with that scope?

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Yes, a great result, fantastic detail in the arms of the primary galaxy, and the smaller background results. 
 

Would the detail be as crisp with the reducer installed?

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Really nice image and yes, I think you should see about that focal reducer :Dand keep the practice of bin x2 as well.

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Posted (edited)
On 05/04/2021 at 13:33, Adreneline said:

I love the detail you've revealed across the galaxy - amazing.

Thanks again Adrian 👍  Good luck if you decide to go for this one in the next clear spell.

On 05/04/2021 at 14:04, Gerr said:

Lovely image. Great details and colours and I like the bonus galaxies you captured too. This galaxy is in Ursa Major (I researched!) and one I haven't imaged yet (next target?). If I get something close to your result I would be happy!

Thanks Gerr, I'll keep an eye out for your version if you decide to go for it.  You're right, Ursa Major, and pretty high throughout the night IIRC.

On 05/04/2021 at 16:01, mackiedlm said:

Thats a fantastic image Lee. super detail and your stars are great colours.

Thanks, really appreciate the feedback.

On 05/04/2021 at 16:01, mackiedlm said:

but am slightly put off by the talk of collimation. How do you find it with that scope?

Trust your gut.  Walk away 😅

On a more serious note, the image above is not perfectly collimated at all - likely well hidden by big stars and some challenging guiding.  Saying that, it was done by eye with a Cheshire in 15 minutes. Is that good enough, only you can be the judge.  Personally I won't be spending silly amounts of time or clear skies if it needs constant attention or if the stars are really poor - clear skies and life is too short! :) 

I've messed up the collimation and put it back many times (some on purpose to really see bad collimation), including three evenings recently where I tried to improve on my first eyeballing.  The best bit was when I thought I could tweak it while star testing... ho ho ho... after I gave up and put it back inside I realised I'd made a complete pigs ear of it trying to do it on the mount.  There are so many guides out there, so many ways describing how to do it, a few variables for a perfect collimation (secondary, primary, focuser).  Below is a great thread where a simple method is described but I haven't got there yet.  Here's the post with the link to the document davies07 kindly put together.

I have an artificial star as well, but find it difficult to get a location with a long enough distance to put between scope and star.  I quickly put the scope on the AZEQ6 mount to grab this photo of my basic setup just in balance in DEC:

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I take it your Meade can't be put onto another mount and/or isn't as good as you'd like for imaging?

On 05/04/2021 at 19:48, tomato said:

Yes, a great result, fantastic detail in the arms of the primary galaxy, and the smaller background results. 
Would the detail be as crisp with the reducer installed?

Thanks @tomato, there's a surprising amount of detail considering it's a little soft.  At full resolution before resampling, there really was nothing else to see.  That image scale didn't show anything further with my skies and equipment/capture/skill.  

With a reducer, say 0.75x, the image scale would be ~0.75"PP so I'd still resample that - maybe there I'd lose a little compared to the above (1.14 vs 1.5), but I'm not sure it would be noticeable.

On 05/04/2021 at 20:01, vlaiv said:

Really nice image and yes, I think you should see about that focal reducer :Dand keep the practice of bin x2 as well.

Thanks @vlaiv  I'll get it out the box and take a look next time!  Your image scale discussions throughout SGL are what prompted me to make sure I didn't bother with the 1x1 image.  So, thanks for your guidance.👍

Edited by geeklee
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thanks for all that @geeklee - I'll take a look at it. I'm not rushing into anything just trying to work out options.

 

I could defork the LX200 and the NEQ6 would carry it but honestly it would not  feel right - like ripping the doors off a vintage car I guess! And also its an old UHC model - before Coma Correction was invented so coma is awful - even with the Meade FF/FR.  If I could correct that then perhaps I'd consider deforking. But i'm so cack-handed I'd probably end up wrecking the thing!

 

BTW, I just noticed your location. Although I'm in Galway now, my mum was Aberdonian,  I grew up in Perth Studied Glasgow then lived near Stirling before leaving home 25 years ago now.

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Great image !!! 😀

I am heading out to my dark site tomorrow to shoot some galaxies with my ASI-533MC-Pro and AT10RC.  I hope I can turn out an image as nice as yours.

 

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7 hours ago, CCD-Freak said:

I am heading out to my dark site tomorrow to shoot some galaxies with my ASI-533MC-Pro and AT10RC.  I hope I can turn out an image as nice as yours.

Thanks John.  A slightly faster F8, increased aperture and dark skies should all be in your favour, good luck.  It would be great to see more of those faint arms - there's so much more to be seen there.

28 minutes ago, michael.h.f.wilkinson said:

Very nice image indeed. Still working on this target myself (I still need far more data without moonlight/haze)

Thanks Michael.  I've been keeping an eye on your great updates to this target recently and waiting to see your next "data dump" update.  Hopefully you get a chance during the up and coming new moon period.  I think my night 1 and night 2 had a little moon impact in the early morning (it was rising around 01:42 one day IIRC).  In all honesty I wasn't being very selective in the stacking so could probably take more subs out without damaging the image too much.  At F9, with light pollution I'm not sure what it would take to get more of those arms for me... too much I think.

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