Carina Nebula HOO

[RyanJones]

Merry Christmas all,

I’ve spent a lot more time on my setup than using it over recent times so it was nice to give it a run and see what I could produce. The plan was for M42 but the corner of my house has other ideas so it will have to wait till it’s closer to the meridian. Along with Horsehead, Rosette etc. So off to the south east horizon I went and returned to an old target. Good enough to see the differences I’ve made but not my favorite target. There are some artifacts around the stars but I think I know what they’re from so that can be part of my next project.

200 x 180sec subs
ASI071-MC pro
STC Duo Filter
200mm f/4 GSO imaging Newtonian baffled
HEQ5 pro guided
ASIair capture and guiding
Bortle 8 backyard
APP stacking and PS processing

Astrobin : https://cdn.astrobin.com/images/4208...441171397.jpeg

Thanks for looking

Ryan

[Astronut07 (Ben)]

Ryan

Excellent image
What filter did you use?

Cheers
Ben

[RyanJones]

Originally Posted by Astronut07

Ryan

Excellent image
What filter did you use?

Cheers
Ben

Thank you Ben,

Sorry I forgot to mention that. It’s the STC duo.

[Startrek (Martin)]

Ryan
Lovely image, great depth, detail and colour on one of our biggest and most popular southern nebulas. It’s nice to see Carina again early in the summer
Well done !!
As you mentioned, your stars seem slightly eggy or odd shaped ?
Doesn’t look like coma as it’s right across the field
Collimation ?
Something in the image train ? Filter ?
Cheers
Martin

[RyanJones]

Thank you Martin,

The Astrobin version shows the issue with the stars in more detail. I recently baffled my OTA which although has helped my contrast no end, I think I’ve got light just catching the edges. They’re not knife edged as would be ideal and as such are giving me artifacts. Not a major issue as all I need to do is make a small knife edged mask for the edge of my primary. Just enough to cover the mirror clips so no big deal.

I’ve also found with interest that the maximum angle of incidence with the ZWO dual band filter is 8deg. Although I can’t find the figures for the STC, I figured it may be similar. Given my F/L I calculated my light angle is about 13 degrees. I moved my filter to the camera side of my MPCC and although the FWHM only changed slightly, I felt like my focus shot was considerably sharper. Another thing to address. ZWO filter draw coming in Jan.

Thirdly my MPCC is the series 1 which is only quoted down to F/4.5. At F/4, I’m pushing it. The series 3 is quoted to f/3.5 so I think I’ll invest in one of those too.

All of these things are going to be contributing to a less than perfect image. Step by step I’ll work through them.

As far as collimation goes. I’ve spent a lot of time and effort improving my scope to make it easier and hold better. Soft wedges in the mirror cell to hold the primary from moving around, better springs on the adjusters both primary and secondary and drilling, threading and fitting grub screws in my focuser to adjust the bearing plate to hold the draw tube dead center and not tilt when I use the focuser lock. It gets and holds collimation really really well now.

Thank you again for your nice comments

Cheers

Ryan

[jahnpahwa (JP)]

Originally Posted by RyanJones

Thank you Martin,

The Astrobin version shows the issue with the stars in more detail. I recently baffled my OTA which although has helped my contrast no end, I think I’ve got light just catching the edges. They’re not knife edged as would be ideal and as such are giving me artifacts. Not a major issue as all I need to do is make a small knife edged mask for the edge of my primary. Just enough to cover the mirror clips so no big deal.

I’ve also found with interest that the maximum angle of incidence with the ZWO dual band filter is 8deg. Although I can’t find the figures for the STC, I figured it may be similar. Given my F/L I calculated my light angle is about 13 degrees. I moved my filter to the camera side of my MPCC and although the FWHM only changed slightly, I felt like my focus shot was considerably sharper. Another thing to address. ZWO filter draw coming in Jan.

Thirdly my MPCC is the series 1 which is only quoted down to F/4.5. At F/4, I’m pushing it. The series 3 is quoted to f/3.5 so I think I’ll invest in one of those too.

All of these things are going to be contributing to a less than perfect image. Step by step I’ll work through them.

As far as collimation goes. I’ve spent a lot of time and effort improving my scope to make it easier and hold better. Soft wedges in the mirror cell to hold the primary from moving around, better springs on the adjusters both primary and secondary and drilling, threading and fitting grub screws in my focuser to adjust the bearing plate to hold the draw tube dead center and not tilt when I use the focuser lock. It gets and holds collimation really really well now.

Thank you again for your nice comments

Cheers

Ryan

I like the image a lot, Ryan
But just as much as that, I like how deep you continue to dive into gear set up and optimisation. Just about every sentence in this post was a point of learning for me. Thanks!

[RyanJones]

Thank you JP,

I have this habit of really TRYING to understand what’s going on and trying to improve on things. I enjoy tinkering and I think I’m getting more knowledgeable as I go along but I still have so much to learn.

Cheers

Ryan

[Sunfish (Ray)]

Great image and combination of colour.

[RyanJones]

Originally Posted by Sunfish

Great image and combination of colour.

Thank you Ray