new toys

[muletopia (Chris)]

Hello Folks,
My first "warts and all' post using my new QHY8l elicited useful comments. One was about the coma arisin from the prime focus camerea on a Mewlon 210.
So I bought a flattener from Claude. It needed an adapter as the only cameras Tak support are EOS canons.. So I had the Canon adapter thickness and the fornt face to sesor distance of my Canon 60Da smoe arithmatic and Joshua bun made me the required adapter,step1.
Off axis guiding would require a more sophisticated adapter so I bought a 900 mm
fl Saxon refractor to use as a guide scope,step2.


Some time was spent experimenting with sub length and gain, I really must screw myself down and use Craig Stark's scientific method, given in three parts on Cloudy Nights.


The attached image is the result of six 20 minute subs at gain 3 and offset 125 with the QHY8l.


Processing in Nebulosity and Star Tools.


Comments would be appreciated.


Chris

[LostInSp_ce]

Congrats on the new toy Chris. It's a good start, nice colour coming through and the resolution is great. You can see some finer details starting to come through. Another couple of hours worth of data should really bring them out. One thing to maybe check is your stack settings. There seems to be a couple of stacking artefacts caused by hot and cold pixels that have remained in your final image. No biggie and it can be easily removed by adding some Bias calibration frames. If you're already doing this then you might just need to tweak the settings in the Bias/Offset tab. Apart from that you're heading in the right direction. Well done!

[Fernando]

Hi CHris. Beautiful colors over the nebulae. The stars in the upper left corner are kind of elongated?



Regards, Fernando

[PKay (Peter)]

Good effort CHris
The camera has brought out lots of colour.

I can see star elongation happening.
Not for me to give advice on that.

I targeted the triffid a few weeks ago (see below somewhere).
I used 180s subs, gain 140 (unity)

[muletopia (Chris)]

Thanks for the comments,
I do not know why the upper left is elongated, polar alignment? camera tilt?
The image is not cropped so the Tak fllattener is working.


When (if ) I get another clear night I will reduce my polar alignment error.



Chris

[Fernando]

Originally Posted by muletopia

Thanks for the comments,
I do not know why the upper left is elongated, polar alignment? camera tilt?
The image is not cropped so the Tak fllattener is working.

Chris

When (if ) I get another clear night I will reduce my polar alignment error.


Hi Chris. It is a great picture anyhow. I am not an expert and could not give you precise advices. I may tell you my experience with stars elongated in one side (all side, not only the left up corner as yours): the counterweight bar was kind of loose and shaking. Do not know how this happened. Maybe while balancing the mount. Anyhow, after that the one side elongation went away.

[muletopia (Chris)]

Fernando thanks for your history,
Just in case I went out to my ob to check my mount shaft and counter weight.
They were both tight.
My mount is permanently mounted on a pier so it would be surprising if they had come loose.


The pier is on the statutory cube of concrete, But the concrete is in clay so it moves with the seasons, hence my desire to redo my polar alignment.
Chris