Eagle Nebula

[Gavin1234]

Thought I’d try Eagle nebula tonight.
It’s probably not the right target for my scope seeing how small it is in the fov. This is one is 7 x 10 min subs. Also a cropped version to try make it easier to actually see the eagle �� .

Some of the stars in the centre a kind of morphed together, is that because my focus isn’t good enough?

[xelasnave]

Your ficus does seem a little out.
Do you have a mask?
Alex

[Gavin1234]

Thanks Alex. No mask but it’s been a while since I checked the focus. I can usually get it to about 0.85-0.95 HFR but not much lower than that. I think I might have bumped the focus knob while setting up last night.

[Imme (Jon)]

Hi Gavin,
During an image run I check focus at least once per hour to adjust for temperature changes.

[rcheshire (Rowland)]

Originally Posted by Gavin1234

Some of the stars in the centre a kind of morphed together, is that because my focus isn’t good enough?

Hi Gavin.

Apart from focus, the brighter stars appear over exposed, too big and merge together, particularly near the brighter areas of the image.

EDIT: I read your Helix post - camera is an ASI071MC - APS-C colour CMOS

Balancing read noise and saturation is tricky. A combination of slowing the exposure down / or less exposure time and dithering to handle noise. A 10 - 15 pixel dither is a good value between images - if your gear supports it.

[Gavin1234]

Thanks Rowland and Jon. I’m taking some more frames of Triffid/Lagoon at the moment. This time I took more time setting it up properly. I managed to get the HFR down to about 0.78.

Can anyone tell me what is an acceptable HFR to have?

Also, this time I actually did a proper polar alignment. Up until now I’ve just been plonking my mount down facing true south and doing a two star alignment. I’m embarrassed to say that I actually thought that was polar alignment until I saw the polar align option on my hand controller tonight.

Trying 150 gain at the moment but I think 120 might be better. The auto stretched preview is showing the core of lagoon as very bright.