ollypenrice

Really sorry that the dregs and scrapings of humanity have done this. The good news is that fiberglass is the most repairable material known to man. There are all sorts of ways of doing it but you'll find lots of information in the car and boat world. When fiberglass cars have a shunt, for instance, the body shop will measure how far up the shell the damage goes and order a partial shell from the manufacturer, so if the front left is smashed they just order the front left part to be moulded and they can feather it into the existing part invisibly. I'm sure that with a bit of patience and internet instruction you'll be able to make good. Always remember that the perpetrators will never know happiness or fulfillment. They know what they are. Olly

Have a go by all means but the stunning red-blue-gold colouring of the Rho region is extremely difficult even from my place at Lat 44. Further south still, Tom had a real fight with it from Andalucia. The problem is that it's all very faint and needs a good stretch, compounding the problems of LP and the atmosphere. It has to be worth a pop though. Olly

I think there are two key issues: 1) Your seeing on the night and your guiding will limit the real resolution of detail you can hope to achieve. Of one thing we can be pretty sure: you will not be able to resolve detail at 0.47 arcseconds per pixel. For one thing your guide error is unlikely to be less than half that figure, ie 0.24 arcseconds. Even premium mounts run somewhere in the 0.3 to 0.4" region. To find out, just give PHD your guide focal length and your guide camera pixel size and it will trot out the RMS automatically. Whatever it is, double it to see the minimum guide-able resolution at which you can usefully image. If your RMS is 0.5 arceseconds you shouldn't image below 1 arcsec per pixel. 2) You can lower your resolution in two ways, by reducing your focal length, which will also increase your field of view, or you can (on some cameras) bin the pixels 2x2 or 3x3 to make bigger 'effective pixels.' But beware: much of the discussion on the net concerns 'hardware binning' in CCD where 4 pixels can be read as one at capture, making them genuinely bigger pixels. You cannot do this with your CMOS camera. Any binning will be done in software afterwards. I haven't used a CMOS camera so I'll defer to someone who has their head around this. Still, it will achieve a similar result, I think. In any event, don't bang your head on a wall when processing by trying to get a perfect finish on an over-sampled image. It isn't possible because the detail simply isn't there. Bin it or resample it downwards and you'll lose noise without losing real details. You'll still have your object at the screen size allowed, ultimately, by your seeing and guiding. Personally I think I'd use the reducer by default. Olly

Don't apologize, I was only throwing in an alternative approach. If you make use of binning the aperture of the big reflector will be a powerful tool. Keep us informed of how it all works out. Olly

Yes, much better. I don't know how you'd do this in Pixinsight but in Photoshop I'd select just the background sky, reduce the colour saturation and run the noise filter to reduce colour noise. The background is still quite 'colour busy' but it's a cracking image. Did you try a light dose of SCNR Green? Olly

Very nice, Steve. The outer shells look excellent. Olly

This... https://www.cloudynights.com/articles/cat/articles/darv-drift-alignment-by-robert-vice-r2760 ...is a variation of the drfit method and one which most people find simpler and quicker. Olly

These outer parts really are difficult even from a dark site. Good going from Bortle 5. I know you like these tidal streams! 😁 Olly

I love the delicate outer OIII shell round the Crescent and the crisply defined Soap Bubble. Olly

Yes, your experience with the prism in two systems is similar to ours. I don't think you can assume that an OAG/camera can always be swapped between scopes without adjustment. Olly

That's a system which works! Olly

You'll need to reprocess from scratch because the original is significantly black clipped: The shiny, jet black sky was an instant give-away but the histogram in Photoshop levels confirms it. There needs to be at least a little flat black line showing before the histogram pedestal starts to rise. Your faintest signal - that which you rightly want to bring into view - has already been discarded. A healthy histogram looks like this: The peak of the pedestal rises a little to the right so no faint signal has been discarded. You need to watch this like a hawk throughout the processing job and only bring the black point in as the very last operation. (Also not you have two histo peaks which means one of your colour channels is out of alignment. For the kind of localized faint shell you're trying to reveal I would begin by doing a normal 'stretch and process' job and save that. The outer shell may be hardly visible but don't worry about that till you have a nice basic image. I would then make a copy layer and make the bottom active and the top invisible. In Curves I would then put a fixing point at the level of the background sky and another below that, then lift the curve just above the background. This should pull out the outer halo. Restore the curve to a straight line just above this so you're only stretching the faint part you're looking for. There are fancy ways of combining both layers but I like easy, so I'd just use a small softly feathered eraser to take off the top layer where it's blocking the faint stuff underneath. That's how I did the outer halo of the Owl. Olly

What you are suggesting is exactly what all deep sky imagers do. There is a somewhat precise debate over whether 10x1 minute equals 1x10 minutes. With CCD cameras it doesn't, but this is not a debate for entry-level imaging. With cooled CMOS cameras with low read noise, it more or less does. DSLRs lie somewhere in between. Who cares? You should do it. The free way to stack lots of short exposures is to use Deep Sky Stacker. It works. It isn't used by the majority of imagers trying to produce work at the top of the amateur scale but it is very competent and entirely free. You want brighter? We all do! What you need is more signal (from the object) and less noise (from the camera.) A lot of the noise is random but the signal is consistent. If you stack 20x1 minute you get 20 doses of real signal and 20 doses of random noise. The noise will cancel itself out, being random. The signal will build. Result! Olly

I wasn't sure what your intended use was. I'm sure it won't matter for visual. Olly

It can affect imagers, particularly when taking flats. Olly

You can fine focus with the Crayford while leaving the mirror locked. Olly

I've tried both and settled for two monos. I found that Ha/OSC worked fine, as in this camera lens image: However, L/OSC did not work as well as I'd hoped. The colour was rather thin under a dedicated luminance layer. Other members have also tried it and given up on it. If you're not robotic you'd only need a manual filterwheel on one side because you could shoot L and Ha in blocks. I agree with Vlaiv on the difficulty of mixing reflector and refractor data and I would also warn you that any mirror movement will mess up your captures because you only have one guider. To my mind a dual rig is best made with refractors. We did once try and fail, here, using two reflectors on a dual rig. One always trailed. Olly

Sorry, I wasn't thinking of camera lenses. It's ultra-fast scopes which don't tempt me. Olly

OK so a really simple tweak in Ps would be to go to Image-Adjustments-Selective Colour and it will open by default in the reds. Try moving the top slider to the left to lower the cyans in the reds. This usually makes Ha signal pop, but no promises! Olly

I'll take the risk of being totally honest: I don't like faffing with kit. I have a hell of a lot of it on the premises - three rigs that need to 'just work' for our guests - so simple beats fickle. I also host six robotic setups and these make demands on my 'kit faffing' time, if you see what I mean! The ultimate 'sky hoover' for me was the Twin Tak FSQ106/Full frame CCD/Mesu 200. The Taks were F5 so two of them equate to F4, give or take a bit of nerdy argument. That was perfect for me. Very fast and residual noise diminished by data combining from two cameras. This rig has now become the Twin TEC140/Atik460/Moravian8300/Mesu 200 rig which is still pretty mean. It is more seeing-dependent but that's inevitable at higher resolution. No sub F4 optical single optical system currently available tempts me in the slightest but I can perfectly well see why it tempts others. They are not wrong to be tempted! I just need 'easy.' Olly

More initial setup than maintenance, I think. Olly

I agree, that's very good indeed. Sharp focus, good tracking, sympathetic processing. Processing advice can be very software-specific so what are you using? Olly

Yes, there's a difference between permanent setups and portable ones. Maurice Toet has a high end portable one: modified professional DSLR, Tak Epsilon, AP Mach One. If you divided the image quality by the length of cable in the rig he would be unbeatable! 🤣 He's pretty unbeatable as it is... Olly

Nice. I wouldn't want this proposed duel to the death to take on a serious character! 🐰 But to take it seriously for a moment, restricting exposure time and object faintness would be like proposing a race between a Dacia Sandero and a Porsche 997 in a 3Omph zone. In a 30mph zone they both do 30mph. Round Silverstone things might be different. The whole point of a premium mount is that it can reliably knock out 30 minute subs while supporting a very high resolution. And the whole point of a premium apo is that it can focus all visible wavelengths onto very similar planes. Ha is almost monochromatic so it doesn't test the lens correction. And the whole point of a cooled CCD is that it can benefit from 30 minute subs. Etc etc etc. In truth the conclusion of the original video is correct: on mainstream targets you can do very well indeed with well chosen budget gear and the advantage of the posh stuff lies mainly in its convenience. I processed some of Singlin's M101 data from a 10 inch Quattro recently and it was in no way inferior to my TEC140 data. Sorting out the Quattro took him a while, though. Big budget brings an easy life more certainly than it brings better pictures. Olly

The good news is that you seem to have a very accurate EQ6. They do vary. Any guiding will be better than none but, as you understand already, an OAG is better suited to a scope with a mirror (especially a moving one) and to long focal lengths. Will you find stars? I wish I knew but, binned 2X2 I think you might. Set up the OAG prism as deeply as you can, so entering towards the long side of the chip. I'm not sure what you mean, here: 'I plan to use phd2 software for autoguiding rather than relying on the build-in guide port on the mount. Instead of integrating for hours, I am planning to do DSS stacking of few mintues long multiple shots, hopefully this will put less strict requirements on the autoguider.' PHD will guide using the ST4 guide port on the mount or through ASCOM/EQ Mod using a special adapter. Personally I just use the old ST4 method but pulse guiding might work better for you. Nobody does integration of hours at a time. (Well, somebody will have tried it but 30 minute subs are considered very long.) Your plan to stack lots of short subs is perfectly normal. You'll probably want to make them as long as possible but this will be down to experimentation. Your combination of long focal length and small pixels is absolutely not the optimal choice but you know this. However, FLO will supply a new 130P OTA for £176. https://www.firstlightoptics.com/reflectors/skywatcher-explorer-130p-ds-ota.html If I had to back either your guided Mak or the 130P unguided I'd put my money on the 130P. And you could add guiding later. Olly