CG30 & CG31 in HaRGB

[gvanhau]

Hello
I's been a while since my last post here.
I was very busy at work, and trying to resolve serious flats problems with my settup.

Here this nice object I took during march.
Here you can see the full res image.
https://www.flickr.com/photos/astro_gvanhau/32916148623/in/dateposted-public/
Telescope: RC12 on MI250 mount
Atik383L camera and astrodon filters Ha 53*1800 R,G,B each 105*300 binx2

Hope you like it.


Geert

[gregbradley]

Wow, cool image. I have not seen those before.

What flat issues did you have? I find flats touchy with my CDK17.
These days with most mirrored scopes having a corrector/flattener you tend to need excellent flat procedures.

Greg.

[gvanhau]

Thank You Greg.
I mainly had two issues; The frist one and easyest to correct had to do with timing; I was taking 2 seccond flats, until I realiced that I had a shadow of the shutter in my images; I had to extend the time above 10 secconds to minimize this behavior.
The second issue was that the foccuser I was using was not abble to support the weight of my imaging train and had some flexure. So, the shadows created by the dust particles were not fully corrected by the flats (it was dependant of the angle I was imaging). To solve this, I modiffied and motorized another foccuser and replaced the previous one.
Geert

[JA]

Congratulations Geert. It's an amazing image

It's a outreaching hand, with the palm facing upwards. :thumbsup:


Best
JA

[Atmos]

Not an area I've seen before, 50+ hours certainly shows it's depth.

[RickS]

Excellent image, Geert :thumbsup:

[gregbradley]

Ouch. Yes I can see that would have been difficult. I find 3 seconds is long enough to overcome shutter shading but it may vary with different brands.
I go for 30,000 ADU. dusk flats with a white cloth in front of the scope and the scope pointing to the east. About 5 or 6 flats. I average combine them make sure when applied there is an accurate dark, an accurate bias subtracted from the flat and a bias applied to scale the dark if needed. I sometimes use a flat dark when the flat is longer than a few seconds. Not sure if it makes any difference. I check various combos of the above until I get a good correction on one of the images. Best to be done while you are a the imaging setup. I also sometimes do flats during the day with the roof closed. It works if the day is not hot as then its too hard to match the camera temperature but if you can it works as well with a white cloth over the scope and the scope pointing at a neutral part of the wall with even illumination. Some use light panels. I haven't done that.

Greg.