SharpCap Forums

Elevation 39° at the meridian. Captured just after sunset, just past the meridian.
Hardware: Celestron C8, AVX mount, Baader 610nm red pass filter, Skyris 236M camera, Masuyama 1.5x Barlow, JMI Motofocuser.
Software: Sharpcap 4.1, BiggSky, GIMP, Microsoft Image Composite Editor.
Capture: SER, 1920x1200, 2000 @ 54fps, exposures ~5ms, gain 160.

Vallis Alpes, Aristoteles & Eudoxus
Hadley Rille
Apennines
Southern region
Ptolemaeus & Arzachel (2-panel mosaic)
Dave

Absolutely stunning detail, Dave! This is the kind of detail I only enjoy in Virtual Moon.

Brian

Thanks Brian.

Dave

superb detail..again
Tim

Thanks Tim.

Dave

Just as a point of interest - aside from the aesthetics and ever changing aspect of lunar scenery - have you now hit the theoretical limit for resolution at 610 nm -- ~ 0.6 arcsec. It looks to me as if you must have done (e.g based on known craterlet sizes etc) -- and maybe beyond in terms of detection (as opposed to resolution) of thin lines like surface rilles and crater edges when the contrast is high.

Tim

Using Virtual Moon Atlas I have been able to identify objects (craters, rilles) which are 2.0km wide. Although I do have objects on my images which are not shown in VMA. I think with the 1.5x Barlow this is about as good as it gets for my equipment, subject to the conditions. The scope is F10 and with the Barlow, F15. Sensor pixel size is 2.8µm - which gives 5 x 2.8 = 14. A fairly good match between the optics and the camera for critical sampling. With the Barlow/filter, I have had to push the histogram to ~70% (rather than the non Barlow figure of ~60%).

I am now aperture challenged.

Dave

According to my calculations, a 2.0 km crater equates to this resolution:

1.157 arcsec @ 356500 km (Moon closest)
1.014 arcsec @ 406700 km (Moon farthest)

using the formula: theta = s / r (radians)

Take the average and call it 1.1 arcsec resolution. Not bad. Maybe a little room for improvement.

I did the same back of the envelope calculation Brian but then my thought was that as finely detailed as they are the images are still not quite aperture limited then? A bit further is possible ?

Hi Tim,

I guess it all depends on how you define "resolve". Do you want to see the crater bowl or just the slightest hint of a light and dark side? In my opinion, Dave is aperture-limited in those images. Interesting that I have found that some of his most detailed lunary shots are with the Barlow. Even without the Barlow his pixel size is more than effective at achieving aperture-limited images. The only thing I can think of is that he can achieve more precise focusing with the Barlow.

Brian