michael.h.f.wilkinson

Great image!

I used that kit to add GoTo to my older Vixen Great Polaris mount (the EQ5 is a clone of that one), and that works fine, so I wouldn't see any problems with the EQ5.

Absolutely stunning work!

Very nice indeed

Increasing ISO is equivalent to amplifying the signal linearly. It basically controls how many counts of the analog-to-digital converter (ADC) are registered for every electron in the pixel. These electrons stem from actually detected photons (the desired bit) and "dark current" electrons from thermal noise. Basically, if the ADC gives more than one count per electron, it isn't adding any extra information, because amplifies both signal and noise equally. Worse, the maximum signal at which the ADC starts clipping the result goes down. This means the dynamic range (ratio of the maximum to minimum detectable signal) goes down. Thus every camera has a sweet spot in terms of ISO or gain. I used ISO 200 on my Canon EOS 80D at only 30s per sub, and got these results on NEOWISE

The shorter focus 0.25" further out to be exact, whereas the 14mm focuses 0.25" further inwards, compared to the XWs.

The Burst only has USB 2.0, which is rather slow. I do not know the Neximage 10, but it has really tiny pixels, so I would worry about well depth (leading to lower dynamic range). I personally have been using ZWO cameras for planetary and deep sky, and rather like them. The ASI178MM I have is great on solar imaging, and planetary imaging with a filterwheel. For one-shot colour planetary and lunar imaging I now use the ASI183MC (bigger chip, more expensive, and pretty decent on DSO imaging too). If planets are the main goal, the ASI224MC and several newer ones would be worth a look, as using 10 MP on planets doesn't really make sense. I use these cameras in my C8, as well as in an APM 80mm F/6 refractor, and a 6" F/5 Schmidt-Newton.

Not really necessary, I feel. The 14mm is part of my planetary and smaller DSO line-up, together with the T4 Naglers, whereas the shorter Delos and the XWs are my planetary bunch. In the latter, parfocality is far more important, as you want to adapt quickly to changing seeing conditions. For DSOs that is not as important

This is precisely my point. Standards like sRGB don't solve this. Even behind a telescope, it depends heavily on the exact white balance of the eye (very different in the dark winter nights compared to the grey summer nights here in the north). Furthermore, an experienced observer will spot many subtle details a novice might miss, so the perception is different again. As a third variant of my Jupiter shots, what about this one:

+1 for stacking in APP, it is much better in my view. I have ditched DSS a while ago, and find APP both more intuitive and much better quality-wise.

I have done a couple of multi-session images, all readily supported by recent editions of Astr Pixel Processor (also available for Mac, but not free). You simply assign different lights/flats/darks/bias frames to different sessions/filter bands, and it stacks away. Personally, I tend to use a slightly different, short-cut approach of first stacking the data of each session, and letting APP compute a weight map for each pixel. Once I have a set of processed results from each session, I load these into APP with the weight maps and integrate the results. In this way, it is far faster to add a new session to an existing interim result. I do not see any problems in the resulting images that suggest this is somehow the wrong approach. Below is a three-session result (which needs more data, of course) Maybe Siril supports a similar workflow.

I have just had a look at the specs of your camera, and the pixel size is about 4.8 micron. That means you get optimal sampling of the image at about F/20, so a 4x Barlow would in theory be the right one. However, shooting at 0.5 s exposure will cause enormous trailing, quite apart from the fact that you will not be freezing the seeing at that exposure time. Normally, even on my tracking mount, I shoot Jupiter at just a few tens of milliseconds, and capture thousands of frames. For planets, I really don't feel the camera you have will work well. A proper planetary camera (even a cheap one) will get better results. For the moon, you have a better chance, because you will be able to use many very short exposures. Don't forget the moon is lit by the sun at essentially the same distance to the sun as our planet, so with a 2x Barlow, at F/10, you should be able to use very fast shutter speeds (much as you would on a sunny day).

Colour perception is highly dependant on whoever is looking at it, and viewing conditions. A good exampe is the apparent "steel blue" colour of sunlight towards totality of an eclipse. Objectively, the colour is still ordinary daylight, but because light is dimming, and normally that means the sunlight turns more yellow/orange, the brain interprets this as a more blue colour of the light. The white balance of the eye when looking at Jupiter might be very different of that when looking at the finished image under daylight conditions. I always perceive Jupiter as pretty yellowish, but often got comments that images where I hadn't used the auto-white balance of Registax were too yellow, even though they matched my perception of the image through the telescope. Using auto white balance turned the images much whiter Which one is correct? You would have to measure the spectral content through the telescope (with all calibration problems that entails), and compare it to the spectral content of the images, which would depend heavily on the monitor or printing procedure

Very nice indeed. The background is still a bit noisy, but that is to be expected. As ever, adding more data should improve that. You could also consider going to a lower ISO value. I have an EOS 80D which has a similar sensor, and I find I tend to get best results at ISO 200. For the older modded 550D I tend to go for ISO 800, but the more modern cameras get better dynamic range at lower ISO values, so less chance of blowing out stars or the cores of bright nebulae

Cloudy and rainy here, hopefully I will be able to get out the solar rig tomorrow

I had a Morpheus 14mm for a while, and apprecieated it a lot, but I did notice some (slight) issues with sharpness at the very edge of the FOV which seemed to be due to very slight field curvature in both my C8 and my APM 80mm F/6 (as shown by refocusing). The field stop didn't seem quite sharp, either, and FC is something that really gets to me for some reason, so when a brand new Delos 14mm came up for sale I snapped it up and sold the Morpheus. I almost had the feeling that if they had kept the AFOV down to 70 or 72 deg I might have kept it. In all other respects it had a Delos/XW like quality, and it focused at the same point as my XWs, something the Delos 14 won't do (my Delos 6 and 8 have been adapted with parfocalizer rings, but that won''t work for the 14)

Just gave APP's new comet stacking feature a spin on data from July 15, using 40 subs of 30s. Outlier rejection reduces the stars a bit, but they do show up as trails. Quite pleased with the extra detail in the tail, but I would like to get the stars back as points.

Last night had my first sighting of the comet from my back garden during twilight. I was too tired after a 753 km journey back home to wait for darkness to set in, or do imaging. Hopefully Monday night I will have another chance

Just had another go in twilight, and it is still an easy target in Coma Bernice. Didn't spot a tail, but I think the skies were too bright for that. Edit: just had another look under darker conditions, and I can still faintly spot the tail.

Spotted it once more even during twilight, some time after the ISS passed overhead. The comet is still hanging in there, a lovely binocular target

Just spotted the comet easily in the 16x80 bins, simply dropped down from Cor Caroli and found it. Actually comparing it to M3 again, I am not sure the comet has dropped below it in brightness

Had a few sightings of the comet in my Helios LightQuest 16x80 bins in the last few days. It is fading quite fast. Three nights ago I estimated the coma as distinctly brighter than M3, and the visible tail spanned almost the entire FOV, two nights ago the coma was no brighter than M3, and the tail seemed shorter. Yesterday I couldn't get a very good view, but still picked it up easily. Hope to have another go tonight.

Did a slightly better job of removing gradients. Still more to be had out of these data, I feel

Had some beautiful clear skies here in northern France yesterday evening, so set up the Vixen GP mount with EOS 80D and the trusted Sigma 50-100 F/1.8 zoom. Got a load of data on the fast fading comet, made a quick stack of 22 exposures in APP and polished the results in FITSwork and Gimp. Quite pleased with this. I should of course have rotated the camera more to catch more of the ion tail, but the green tint of the coma is quite clear

The old ones were wearing thin. Might also get some printed with NEOWISE, or some DSOs on them. The solar H-alpha shot in the middle has "Here comes the Sun" printed on the back. I might also get a black one printed, probably with some spectacular prominence on it, combined with the words "Hier komt die Sonne", with a wink to Rammstein 😁😁