The Lazy Astronomer

I can't make a personal recommendation (I haven't done any planetary for a couple of years now), but the 462mc seems quite popular. ZWO have recently released a whole new bunch of cameras though, so not sure what the general consensus is these days. You could drop a message in the planetary imaging section for some solid advice.

No wedge required for solar system imaging, and no worries about anything limiting exposure time either - you will want to be using very short exposures (in the 10's of milliseconds or lower). You don't want a focal reducer either; depending on which camera you buy, you may want the opposite to a focal reducer - a barlow or powermate - to increase the f ratio. You'll see different values given for this, but I use: target f ratio = pixel size (um) × 5 The 8" should provide some good results once you get it all up and running though - it'll be worth it!

Consider using the GHS script for the initial stretch, if you're not already. It's quite good at controlling highlights but will leave a fairly low contrast image - this can then be corrected with subsequent stretching.

I think we suffer from the same affliction, Rodd! I can't count the number of times I've messed up an image trying to get more of particular element to come forwards in it... Not that I've ever seen a bad end result from you though, regardless of what you think of your own work (we are all our own worst critics). The first image does present better initially, but as you say, at full resolution, the second one has the edge, particularly the stars. I think my favourite is the top one of the original v2 you posted above (the one I 'liked') - the stars look very nice in that one, and I think the dark nebula looks better as well. That said though, I do very much like the extra goldish red of the top image in the first post... This processing lark's tricky, ain't it? 😁 Question: how do you get sooo much integration time? Do you pool data over several years, or do you have an army of scopes shooting away all night long?

Were you working on some algorithm to that effect, or have I completely made that up? Edit: ok, didn't see the link to the other post. Clearly you were! 😁 Do you know if anyone ever picked it up for PI?

FYI, don't count the filter thickness in your backfocus, instead add 1/3 the filter thickness on to your required backfocus. Doesn't really help much though as you'll still be ~5.8mm out. But worst case is you may need to look for a thinner OAG, or perhaps a Starlight Express filter wheel with a built in OAG. Frustratingly for you, it may require more £££ to be spent, but not a horrific outcome (your title had me thinking something had gone badly wrong!)

Thanks ☺ Yeah, it actually surprised me how good the data looked given the low altitude and fairly short integration time. Trying to get good detail and contrast for the pillars was the goal with the stretches on this image (l did some fairly aggressive 's' curves) and l think that's what's helped bring those flares out a bit. Now, if only I could get near the resolution of hubble....

Thanks very much! ☺ I am neither for nor against magenta generally, but in this case, I somewhat agree with you - there are areas where the magenta is coming through a little too much. I did try a simple invert>SCNR, but I felt that the image lost some depth. I think it'll probably require a bit of masking and fiddling. Stars wise, my thinking thus far was leave them magenta for the authentic hubble look. For the wider field shot of this I think I'll probably remove the magenta when l get around to processing it though.

Thanks - this was taken with my Esprit 100 with a 294MM paired with 6nm Astronomik Ha/Sii/Oiii filters

Arguably Hubble's most famous snap - the central region of M16. Very limited data - just a couple of hours each in Oiii and Sii, and a bit over an hour in Ha (as for all of us in the UK, it doesn't get particularly high in the sky for me). Wasn't really expecting much, given these restrictions, but it actually feels like there's an abundance of data (at least compared to my recent attempt at M101 - the advantage of narrowband, I guess). This central crop I wanted to process with fairly high contrast to get the pillars themselves to jump out a bit, but other than that, I had no particular vision for what I wanted. Like I say this is still a work in progress, so what are people's thoughts?

I second what Clarkey said, and is what I do too. In fact, my C:/ drive is the same size as the one above, and I have a much larger (and much cheaper!) regular HDD for file storage.

Either of those 2 options would be a good match to the z73. You'll be signficantly oversampled with the SCT, but that's pretty much unavoidable with a long focal length and modern small pixel CMOS cameras. Plus, you can fix that with binning in post processing. Out of the 2, I'd go for the 2600 (or equivalent from other manufacturers), just because I have a 4/3 sensor, and fairly regularly find myself wanting just a bit wider FOV. The decider might be whether you're planning to go OSC or mono - the 533 would allow 1.25" filters, the 2600 would need larger filters and would work out significantly more expensive. If OSC, then the price difference is not as large.

I don't mean to embarrass you, but there was a link literally 2 posts above yours 🤣

The only issue I can see is when balancing, you'd have to move the mount during the balancing, so unless your mount has encoders or you can get the mount axes back to exactly the same places, the alignment would likely be off. If you can get the axes back very close to their parked positions, maybe the alignment would only be very slightly off (so maybe good enough to work with).

Love it - I really like the colours you've got in there, lots of orangey-red. What colour pallette did you use?

I'm gonna do that thing where people reply on forums with literally 0 knowledge 🤣... but have you checked out the Stellarium app? I only use the Windows version, but it has images of most nebulae I've looked for, but like I say no idea if the mobile app is as comprehensive.

Yes, think that's the case! Not necessarily, as image scale is a function of pixel size as well as focal length, but assuming everything else was the same between the two setups, then yes, the image scale at the longer FL would be better. Whether the atmosphere would allow you to see the benefit of the finer image scale though is a whole other topic in itself!!

I think the discrepancy is just a result of rounding errors (80^2*(4.63/480*206.265)^2)/4 = 6333.599 80^2*((4.63/2)/480*206.265)^2 = 6333.599

With a ZWO filter wheel, mounted straight onto the camera, you can get away with 1.25" filters. There will be a small amount of vignetting, but flats will remove it completely. Be aware though, not all 1.25" filters are created equal! Some have smaller clear apertures than others - my Astronomiks have a clear aperture of 27mm, but my old ZWO ones, only 24mm. The ZWO ones caused hard vignetting due to the frame introducing, this could not be removed by flats.

An astrophotography setup in LEO, obviously. Failing that, an atmospheric turbulence calmer and weather control machine. If neither of those proved feasible, then I guess I'd settle for a Mesu 200... Oh, and a quadruple scope and camera set up to sit on it. Boy, would it feel satisfying to gather 24hrs of data in just one night!

I use an Esprit100 @ F5.5 with a full suite of Astronomik filters: L3 for luminance, deep sky RGB, and 6nm Ha/Oiii/Sii Here's a side by side through HaLRGB on Alnitak (nothing done to them except STF): Ha much tighter for obvious reasons, and the size difference in R compared to L, G and B I assume is just because Alnitak is a big bright blue beast of a star, so naturally would emit stronger towards the blue end. There is a slight halo on B, but nothing too severe (in my opinion, at least). Here's the fully processed snippet of the image (in this instance, I attempted to apply RGB colour to the Ha stars, but looking at this now, I can see some ringing around the smaller stars (urgh, poor processing... 😆) I also quickly stacked some Jellyfish nebula data in Ha, Oiii and Sii (not properly as I'm lazy, so no calibration frames or anything), so here's the side by side on Propus, approx 4 - 5 hours per channel, and again, nothing but STF: Haven't processed at all, so nothing further to show on this one, but hope it's useful!

This is very much vlaiv territory now, so I'm going to sit back and try to finally properly absorb the theory myself as well 😁

I think we're basically saying the same thing, but I find these things difficult to judge in text-based conversation! 😁So, just to clarify, you can get the same effect by cropping the image from the full frame sensor in post processing - you don't get any more reach with a smaller sensor, an object is just framed tighter because the smaller sensor can't "see" as much of the area of sky around the object. The 0.8 reducer seems a good shout for larger objects with the 533 - that looks like a pretty good framing on the heart nebula. That veil nebula image (side note: xenomorph nebula is a much better name for that portion of it), I think that's been drizzled x2 during integration as the pixel dimensions are just under double the count of the sensor (it's probably had some slight edge cropping to remove the stacking artifacts).

Ah, ok, the 294MM is a special case (I should know this really, as an owner of the 294MM myself!!). When I say I shoot bin1, I mean using the originally 'locked' pixel size of 4.63um, not the 'unlocked' 2.31um sub-pixels, so l actually do shoot at bin2, but in my head it's bin1 (apologies for confusing the situation 😁). With the 294MM, bin2 is done on-camera.

Makes no difference with CMOS as the binning is in software even if done at point of capture, so may as well capture at bin1 and bin in post based on measured FWHM of the stack. I always hold out hope for some excellent seeing and the chance to leave it at bin1 in post, but alas, it is yet to happen 😔