This has been one of the toughest targets I have imaged (The only other target tougher and still havent succeeded is the ISS using the C14/barlow combo).

I have been trying to shoot a decent Neptune for a while. In this season , this is the 4th attempt. I tried using ASI174MM / 2.5x - with 1 and 2s subs. Total failure, Next was ASI290MC with 2.5x barlow and IRCut filter. Failure. ASI290MC with IR685 - Too dim even with 1s subs.

Last night, I swapped out the ASI290MC with ASI224MC + IR685. I have been reading in the forum that the 224 has better IR performance than the 290 and it is 224MC + IR610 longpass that works well. I only have the Baader IR 685nm filter and used that.

The image train is: C14->Siebert 1.5x barlow -> ZWO ADC (no real use but it was part of my earlier run and I left it in there to avoid losing target and refocusing etc) -> Baader IR685->ASI224MC.

This is the first time I had to set very high gain (540 - 90%) to get a measly 4FPS framerate.

Total run was 2 hours. The seeing was quite good I think. Stacked 80% with 3x drizzle and processed using Registax.

Managed to get Triton as well to figure out orientation. I would be interested to see any other image around this time to compare any kind of detail.

Here is the capture setting: It might of some help to anyone imaging this. I had real hard time finding settings to start with.

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FireCapture v2.6 Settings

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Camera=ZWO ASI224MC

Filter=RGB

Profile=Neptune

Diameter=2.30"

Magnitude=7.83

FocalLength=6700mm

Resolution=0.12"

Filename=2020-08-06-0752_2-RGB-Neptune.ser

Date=060820

Start=065217.006

Mid=075217.050

End=085217.094

Start(UT)=065217.006

Mid(UT)=075217.050

End(UT)=085217.094

Duration=7200.088s

Date_format=ddMMyy

Time_format=HHmmss

LT=UT -6h

Frames captured=35123

File type=SER

Binning=no

ROI=424x380

ROI(Offset)=392x256

FPS (avg.)=4

Shutter=205.0ms

Gain=540 (90%)

USBTraffic=100

SoftwareGain=10 (off)

WBlue=95 (off)

FPS=100 (off)

AutoExposure=off

Brightness=1 (off)

AutoGain=off

AutoHisto=75 (off)

Gamma=50 (off)

WRed=52 (off)

HighSpeed=off

HardwareBin=off

Histogramm(min)=0

Histogramm(max)=156

Histogramm=61%

Noise(avg.deviation)=n/a

Limit=120 Minutes

Sensor temperature=32.1°C

Focuser position=4949