The Lazy Astronomer

I rate Astronomik - I haven't done a whole lot of work on targets with big bright stars in the FOV though, just 2 images; one with Alnitak, and another with Propus and Tejat (taken back in March/April but not even yet stacked!!!). If I get some time later, I can post some images of the stacks so you can see how filters perform.

Crop factor does not affect your focal length other than in apparent FOV - regardless of the size of sensor you use, your focal length on your imaging scope will always be 360mm. A smaller sensor will "see" less of the light cone coming through the telescope, so you get an apparent FOV equivalent to that of a longer focal length with a larger sensor.

I think you're looking at it in terms of megapixels, but in terms of sampling rate, the 533 would have a higher resolution than your current camera. Your current set up gives you a sampling rate of 3.4"/px, the 533 would give you 2.2"/px. If conditions and mount performance allowed, you would be able to record finer detail with the 533. What you sacrifice is FOV - it is obviously smaller with the smaller sensor on the 533. It can be calibrated, but there are enough discussions about it that you can tell it is not a camera for someone who wants a hassle-free life. I have the mono version - my Ha and Sii flats display some crazy patterns, but calibrate out just fine. Oiii has no pattern and just looks like a 'normal' flat (weirdly it's the broadband red filter that gives me the most difficulties), but the mono 294 seems easier to deal with than the colour one. I thought there was a recent discussion about a new 4/3 sensor released by Sony recently, and the possibility that might make its way into the astro cam market in the short to mid term, but I can't seem to find the topic now, so maybe I've completely made that up!

Very nice - a great deal of faint dustiness in there. My only crituque (and it's possibly just a personal thing), but the stars look a little hard-edged to me. Out of curiosity, what's your light pollution like? I've always wanted to have a crack at dark nebula, but not sure if it's worth it outside of a rural location.

Pretty much - use DBE and make sure you give it enough sample points for it to properly model the gradient. Might take a bit of trial and error, but once you get it you should be left with a nice neutral, even background. Edit: here's a live example - different gradients in all colours and bad flats in red. Still wasn't quite perfectly flat after DBE, but good enough to work with (nothing but ChannelCombination, DBE and an unlinked STF)

Found a review online comparing the a7iii to a standard and modded Canon DSLR: From that, it looks like you'd see a significant boost in capture of Ha wavelength if you went for an astro cam or modified your existing sensor. Set point cooling is the nice benefit with an astro cam, although with the more modern CMOS sensors coming out these days it seems like it's becoming less important (the need for dark frames may soon be a thing of the past). Amp glow is a total non-issue, it will always calibrate out completely with good darks, so don't let that put you off any sensor. The 294, although on the face of it probably the best astro cam option from your list, has well documented calibration difficulties, particularly when using dual narrowband filters, so for sanity, I wouldn't recommend that one. Although you've already discounted it, from your list, the 533 is probably the best option. Btw, an image of the same FOV with the same optics would have a higher resolution with the 533 vs your current sensor, owing to it's smaller pixel size, although obviously this would require a mosaic with the 533 to get the same FOV as the larger sensor. Whether or not you'd benefit from the increased resolution depends very much on the quality of your skies, and is a whole other topic in itself. If you could push yourself or save a little more (very, very tricky to do after moving house, I know!) then really your best option would be the 2600 - it's basically the same as the 533 but in a larger format. There are other companies that offer the same sensor in a cheaper package which may be of interest (search the forum for risingcam imx571, there have been a few discussions about it).

I would take the term "widefield landscape images" to mean images which contain terrestrial foreground, but maybe that's not right!

The Iris is a reflection nebula, so lose the L-extreme for sure - it'll likely be doing more harm than good.

Absolutely gorgeous! These RASAs almost seem like they have - to borrow a term from the auto industry - forced induction (for photons) Maybe I should get one - how much do I really need two kidneys I wonder... 🤔

Nice capture - top one is way too oversharpened for my taste (assume that's the version that's been through the AI process), bottom one is more natural looking and pleasing

Thanks very much Paul - I'm very much a fan of all the things tucked away in the background of wider-field images too.

Here's an annotated version as well

Details: Esprit100/294MM/Astronomik filters, data captured throughout Feb, Mar and Apr this year. ~23hrs captured, but chucked the worst ~25% of frames, so total stacks are ~17.5hrs, split as: L=~8hrs, RGB=~2hrs each, and Ha=~3.5hrs. LRGB were all 30s subs @ unity gain, Ha was 180s subs @ 200 gain Stacking and preprocessing in Siril Post processing in PI Hideously complex gradients in the raw stacks (combination of light pollution and less than optimal flats which unfortunately I wasn't able to reshoot). Fortunately though, there's a lot of background to play with and DBE seems to have saved me. Tried to process to bring M101 forwards whilst still maintaining something close to a natural star field. As such there was no star reduction done, other than the use of a mask and curves adjustments on the 50 or 60 most prominent stars to try to lessen their impact. It may be my mind playing tricks on me, but I think I can now see some slight dark ringing around some of those stars, so I may need to revisit that and make some slight adjustments. The general processing steps involved were: DBE (all channels individually) Deconvolution (L only) Denoising with TGV and MMT (possibly went too far with denoising, would appreciate opinions on that) Stretch L, using a combination of GHS, HT, curves, HDRMT and LHE (with various masks) Combine RGB, BN and CC, boost saturation and stretch using GHS Subtract (linear) red continuum from Ha, stretch Ha Blend Ha into red channel using RBA's PM formula (they might be a little too pink, but I wanted the Ha contribution to be quite subtle, rather than overpowering blobs of red interspersed throughout the galaxy) A few iterations of LRGBCombine, with saturation boost and slight blur between each one - there was still quite a lot of chrominance noise after this, so I then used quite a heavy application of MMT, followed by a final LRGBCombine Many additional curves adjustments to boost faint signal and bring forward more colour (I referenced a Hubble/ESO image to try and prevent myself going too far wrong with the colour - I await @vlaiv's opinion on that!! 🙈😀) More slight (masked) curves adjustments to reduce impact of the more prominent stars Slight application of ACNDR to push down the last of the noise Final (very) slight colour tweaks Slight sharpening with MMT Slight black point adjustment I should also mention I've been going back and forth on the processing for almost 2 months now - only after capturing all the data did I read about (and then discover for myself) how difficult this one is to process!!

In keeping with my usual theme of posting images well behind the curve; as we approach the end of summer nebula season, here's my singular effort from galaxy season: M101 in HaLRGB (capture and processing details to follow in another post below, for anyone interested, and as always, comments and critique welcomed!) Perceptually, I think it presents best in this orientation (cropped and rotated): Full image (lotta background galaxies in here):

How is a single sub? Any calibration frames?

From this chart, 100 gain seems to be the maximum for this camera. What's the reason for desire for higher gain?

I recently bought myself a new monitor too (to replace something like a 15 year old 24" 1080p one!) and settled on a 27" 1440p as well. For me, it was definitely the right comprise between cost, size, and resolution. I'm not really a big gamer (occasional FPS use), my aging graphics card just about coped at full screen resolution and I was happy enough. I still find I want a little bit more space with image processing, but PI can be very greedy with screen space!

Any half decent CPU from the last 10 years should support AVX instructions. Before I upgraded my processing PC, I used to run starnet on a 10 year old i5-750 with 4gb RAM and a basic SSD. It wasn't particularly quick (about 5 or so minutes), but it got the job done.

2.5"/px will not be an issue at all. My native resolution is 1.7"/px and based on the measured FWHM of the stacked image I usually bin 2x2 during processing, which takes me up to 3.4"/px with no ill effect to the image.

This tells me something about my typical seeing then!! 😁

The general advice l follow for planetary imaging is to increase the gain to achieve low read noise and drop exposures to as low as possible. Looking at the read noise graph for the 120mc, there seems to be little benefit to using higher than about gain 65. Assuming gain 100 = 100%, then really it looks like it doesn't matter particularly whether you pick 70 or 80%.

Now that is sublime!! So much structure and detail.

Welcome to the forum Roger! From my experience, red always seems to be the sharpest channel, so yes l believe there is an advantage, provided your camera is sensitive enough in the red part of the spectrum that you're still able to achieve somewhere on the order of 100 - 200 fps (shouldn't really be a problem for a planetary camera with something as bright as the moon).

As others have said, it's some kind of directional light pollution, be it the moon, street lights, or whatever. You've got a good amount of background to play with, and it looks like a fairly simple gradient, so you should be able to remove it entirely with proper placement of sample boxes. I'd advocate for DBE over ABE as it's more effective in my opinion - it really helped remove some hideously complex gradients in an image of M101 I'm working on.

30 - 60 seconds with LRGB @ unity gain, 3 minutes Ha/Sii/Oiii @ 200 gain The narrowband exposure is set as the minimum required such that the sky background swamps the read noise by a certain factor (I can't recall what the factor is right now). My minimum required exposure for LRGB is <10s, so the sub length is set such that I don't end up with many thousands of frames to have to stack.