Ngc6559 tec180

[Stevec35 (Steve)]

I'm late chiming in on this one Greg but that's a lovely image.

Cheers

Steve

[avandonk]

Greg the diffraction spikes around the bright star are produced by non uniform edges of the metal holding your optic elements. It usually is a mixture of specular reflection and diffraction. Any diffuse reflections will lower the overall contrast.

If you get an aperture laser cut that is a few mm smaller than the entrance aperture of the scope and mount it in front the bright stars will be far cleaner.

Even though this is a tiny fraction of the incident light as sensors and filters get better it then rears its ugly spikyness.

To test this just cut an aperture out of black card or paper and take a few test exposures of very bright stars.

It is about time that top telescope makers put an exterior baffle or aperture to eliminate any light hitting the edges of the element holders.

The basic rule is to eliminate any light not contributing to the image before it enters your optical train.

I use an exterior aperture on the 300mm lens and an extended dew shield. The lens only 'sees' an area of sky just a bit bigger than the area being imaged. The increase in contrast is quite noticeable and is the difference that gives detail in dim dust. This is because a lens is not as well internally baffled as a high quality APO. Any off axis light that is not from the area being imaged gets scattered inside the lens and lowers contrast.

Bert

[multiweb (Marc)]

That's a great shot. Colours and details are terrific. Your finest to date I reckon. Text book processing.

[Tom Davis (Tom)]

Wow, I almost missed this one. What a wonderful image with such rich color and nice framing! Great setup!

Tom

[gregbradley]

Originally Posted by Stevec35

I'm late chiming in on this one Greg but that's a lovely image.

Cheers

Steve

Thanks Steve.

Cheers Greg.

Originally Posted by avandonk

Greg the diffraction spikes around the bright star are produced by non uniform edges of the metal holding your optic elements. It usually is a mixture of specular reflection and diffraction. Any diffuse reflections will lower the overall contrast.

If you get an aperture laser cut that is a few mm smaller than the entrance aperture of the scope and mount it in front the bright stars will be far cleaner.

Even though this is a tiny fraction of the incident light as sensors and filters get better it then rears its ugly spikyness.

To test this just cut an aperture out of black card or paper and take a few test exposures of very bright stars.

It is about time that top telescope makers put an exterior baffle or aperture to eliminate any light hitting the edges of the element holders.

The basic rule is to eliminate any light not contributing to the image before it enters your optical train.

I use an exterior aperture on the 300mm lens and an extended dew shield. The lens only 'sees' an area of sky just a bit bigger than the area being imaged. The increase in contrast is quite noticeable and is the difference that gives detail in dim dust. This is because a lens is not as well internally baffled as a high quality APO. Any off axis light that is not from the area being imaged gets scattered inside the lens and lowers contrast.

Bert

Thanks Bert. Great tip. I will try that out with some cardboard and if it makes a difference I'll get one made up.

I did a similar thing to my 12.5 inch RCOS on its primary. I think it made a difference with it.

Originally Posted by multiweb

That's a great shot. Colours and details are terrific. Your finest to date I reckon. Text book processing.

High praise, thanks Marc.

Originally Posted by Tom Davis

Wow, I almost missed this one. What a wonderful image with such rich color and nice framing! Great setup!

Tom

Thanks Tom. I may even try a few dusty areas now I can image at F5.25 with it!

Greg.

[TrevorW]

Nice one Greg maybe a tad oversaturated IMO but well done

[richardo (Rich)]

Top image Greg!
This is just such a fantastic area to image and with this particular imaging setup of yours, with huge amount of hi res real estate crtainly gives us a taste of how busy things are in this area of our galaxy...
Some thing for every one... young clusters, HII emission, reflection, dust, dark nebs... it's a 'gol darn' feast

Now, how's your RC going???
Am really looking forward to some images from this baby!

All the best
Rich

[marco (Marco Lorenzi)]

Really good picture Greg, I really like the way you make this lovely nebula shining out

It's not easy to avoid to over process areas so crowded of stars having the nebula standing out at the same time, well done!

Clear Skies
Marco

[gregbradley]

Originally Posted by TrevorW

Nice one Greg maybe a tad oversaturated IMO but well done

You should've seen the first edition! I personall prefer the colours rich and I have been prone to oversaturate no doubt about. I have checked othes images on this area and you're right mine is probably a tad brighter than others. Its a hard standard to work out - what is to rich? I suppose its a G2V star measure would be one way. I haven't done that yet.

Originally Posted by richardo

Top image Greg!
This is just such a fantastic area to image and with this particular imaging setup of yours, with huge amount of hi res real estate crtainly gives us a taste of how busy things are in this area of our galaxy...
Some thing for every one... young clusters, HII emission, reflection, dust, dark nebs... it's a 'gol darn' feast

Now, how's your RC going???
Am really looking forward to some images from this baby!

All the best
Rich

I'm in the pocess of sorting out the little setup issues, software, drivers.

I got the mount balanced and a finder scope installed. And am now going through the connecing it up to run with the software whic hopefully won't be too tedious but hit a few barriers already. A day or so I imagine.

Originally Posted by marco

Really good picture Greg, I really like the way you make this lovely nebula shining out



It's not easy to avoid to over process areas so crowded of stars having the nebula standing out at the same time, well done!

Clear Skies
Marco

Thanks Marco.

Greg.

[gregbradley]

This one made Anacortes Picture of the Day!

http://www.astromart.com/forums/view...post_id=699845

Greg.

[spearo (Frank)]

lovely
frank

[gregbradley]

Originally Posted by spearo

lovely
frank

Thanks Frank.

Greg.