chiltonstar

Absolutely brilliant Avani.

Interesting to see how bright Io is against J. when the resolution is so good, ie small Airy disk.

Chris

9 minutes ago, Stu said:

A warm welcome @Moonlit Knight. I’m sure you will find lots of good information and many friendly members here. There are also, as you see, many fellow worshippers of 4” refractors including myself. Last count was three of the little beggars 🤣

...or big beggars when they're f13 like mine.

Nice. I gave up as the scope, laptop and I were all dripping.

Chris

As the seeing was half decent, I barlowed my 180 Mak up to about f24 to give a slightly better image scale. 

The disk is now about 98.6% full, giving the impression of a nearly round disk. Syrtis is close to the centre.

Chris

Nice Neil. I always think Mars start to get interesting when the Tharsis trio start to appear.

Chris

3 hours ago, geoflewis said:

Looking good Chris. I haven’t been able to capture any Mars images since 31 October, so I’m beginning to get anxious when the conditions will break for me….. The forecast for tomorrow (Saturday) looks good, but 2 days ago that’s what the forecast indicated for tonight (Friday), but that’s all gone….

Poor weather here too. I had to set up when the online weather satellite said I had about an hour of clear sky...Needs must.

Chris

Another Mars, with Xanthe Terra centre field. It's good to see some detail starting to appear, even if it has to be coaxed out due to the average seeing, high wind and dew everywhere! Visually, the white N and S polar areas were very obvious, even more so on the monitor during image capture.

180 Mak, with ASI120 colour camera.

Chris

Very nice!

Chris

Very nice detail and colour rendition Neil.

Chris

Welcome! As mentioned above, Abingdon Astro is a good local society, which you can also find on Facebook, as well as the twice weekly meetings, and observing sessions (dreadful climate permitting).

If you aspire to the Dark Arts, there is also a good Facebook group Oxford Astrophotography.

Chris

Tvm for the heads up, looks a good one. The night before is also nice with the GRS and Io almost coincident as they transit. Surely the Weather Gods will give us some clear sky....

Chris

Many thanks both.

Since posting this,  I tried reprocessing the image without derotation and got rid of the bayering on the shadow side of the disk.

Chris

I watched it visually for an hour with the frac, but the cloud kept on drifting across.

Nice images!

Chris

Some decent detail beginning to emerge, even though the disk is only 14.3 arcsec. 180 Mak, ADC, ASI120. Herschel is the dark/light feature bottom left centre. If I push the brightness to silly levels, Phobos is visible to the left of the disk.

Chris

It is extraordinary if correct. Interesting that the coordinates are polar.

Chris

Nice Geoff  I tried as well but gave up because of the ppoor seeing.

Chris

Nice image(s) Neil.

The colour question always interests me wrt Jupiter. Without a scope, I see J as a blue white object, similar in colour to Vega perhaps. If I process images without messing around with the colour at all, I get a slightly blue background for the disk, with the main bands a dark chocolate colour. NASA images, and for example the simulation on SkySafari always look more yellow, with the main disk set to the colour balance perhaps of sunlight. However (with my spectroscopist hat on), looking at the spectrum of J, it is of sunlight minus bands mainly in the red end of the spectrum, indicating that the true colour is indeed blueish, not yellow-white like the sun.

Maybe it comes down to personal preferences; I like it looking as close to reality as possible, but I can fully understand folk who want it to look more like the NASA images and more yellow for aesthetic reasons.

Chris

Two images from the night of 6th October at 23:30 to 23:50, when the haze descended. Mars was about 20 degrees up, even so I think a polar cap is beginning to show through.

180 Mak, ADC, ASI120 Colour camera. No barlow used, each avi was 6000 5 ms frames, stacked in AS, then combined in Registax.

Chris

Thanks for all the advice.

Trying a few days later with better seeing certainly gave a better result and I was less tempted to over-sharpen. Interestingly, I found that some of the artefacts in the original image were introduced by rotating the image in PS Elements, particularly any sharpening operation after rotation. It is awkward for me to use the camera in the correct orientation as the cable pokes up under my chin using the flip mirror. I need to find a way round that. This is the new image (unrotated ) on the 6th Oct.

Chris

1 hour ago, neil phillips said:

Either seeing was bad. Or your slightly out of focus, or both?  I think Chris ?

As Vlaiv said it doesn't respond as a good tight capture should. Probably for reasons mentioned. No wonder you're getting noise when you're hitting it with such extreme sharpening. Which is evident in the detail you have managed to extract from a blurry a capture. And how unnatural and spotty its appearance is texture wise.

Solution better seeing. Better capture. And or more in focus.

Good quality captures actually require very little sharpening. And with more sharpening a wealth of detail comes out, with minimal noise. Thats my current thoughts from the raw you uploaded. Unless I am missing something? 

Thanks for this Neil. I think the focus was good as detail comes out with over-sharpening like the eye of the GRS, but the seeing was "unexceptional". That was the point of the post really, how to get the best out of a capture in less than (ie typical) conditions.

Chris

1 hour ago, Laurieast said:

@chiltonstar Did you have sharpened on in AS3 ? 

 

Yes, but I used the non-sharpened file (not the .conv)

Chris

17 hours ago, vlaiv said:

Could be down to processing as well.

Maybe try to limit how much you push the data - find that place where noise starts to show too much and then back off a bit?

You could also post raw stack so people can process it with their workflow and confirm if data is really noisy or maybe it is just processing.

Good idea - maybe me just overdoing it a bit on a file that isn't sharp enough. This is the stacked, unsharpened file.

Chris

10 minutes ago, johnturley said:

I usually use a 2.5 x Powermate with my Esprit 150 (f7), so similar sort of focal ratio at f17.5 

John 

Camera then maybe.

Chris

39 minutes ago, johnturley said:

That's surprising, I usually operate at around a Gain of about 300, and an exposure time of around 5ms, when imaging Jupiter with my ASI 462 through my Esprit 150.

John

The 180 is very slow, only f15, probably nearer to f20 if you take the adc and flip mirror into account.

Chris

ASI120 MC, gain at max ....May explain some of the noise, but I can't get down to 5ms otherwise.

Chris