Barlow Test with 11-Days Moon (Monochrome) (astropical)

Barlow Test with 11-Days Moon (Monochrome)

Link: https://www.astropical.space/moon/

Acquisition type: Lucky imaging

The purpose of this excercise was to obtain 3x focal length with a 2x barlow by placing the 2x barlow into the focuser, then attaching a mechanical filter wheel and finally the camera. The filter wheel acts as extender, while the 2x barlow lens throws the focal plane towards the camera sensor. The transparency was good but the air was trembling, shivering, dancing, you name it. A near worst case scenario but I believe that the result shows that this configuration yields more details and contrast as compared with using my 3x barlow (both a triple lens ED design). The effect is similar to placing a barlow in between focuser and star diagonal for visual observation. The 2x barlow works like a 3x barlow (magnification is approximate as dependent on barlow-to-sensor/eyepiece distance). I am not telling you anything new though. More than 3x does not seem to be reasonable for a 6 inch reflector unless the air is unusually steady.

One would assume that the frame rate halves when selecting the camera's 12-bit ADC (high speed=OFF). In case of the ASI290MM the frame rate does not change with speed modes when the exposure time exceeds 10 milliseconds. Basically, 10-bit are okay, however, when you compare the histograms you will see the advantage of 12-bit, yet not a striking visual difference between the finished images. When the intervals between clouds are narrow then short exposure below 10ms and a fast frame rate at 10-bit (high speed=ON) can help win the race.

The original/final image is a 2-panel panorama, 5ms, gain 200, 600x, 170fps, 10-bit. The 15.4" small Mars, taken on the same evening, is inserted to scale.

I hope to repeat this test when the air is both transparent and steady. The 11-days moon does not offer spectacular features.

Good health to all of you!

Final
Original
B
C
D
E

B

Description: 5ms, gain200, 170fps, 600x, 10-bit ADC, raw8, IR640, 1.5x drizzled

Uploaded: ...

C

Description: 7ms, gain200, 82fps, 600x, 12-bit ADC, raw8, IR640, 1.5x drizzled

Uploaded: ...

D

Description: 5ms, gain200, 82fps, 600x, 12-bit ADC, raw8, IR640, 1.5x drizzled

Uploaded: ...

E

Description: 4ms, gain200, 82fps, 600x, 12-bit ADC, raw8, IR640, 1.5x drizzled

Uploaded: ...

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