minyita

Hi everyone, long post incoming - excuse my ramblings - after I finally moved to a place with a secluded and safe roof terrace where I have enough space to put up two rigs, I'll plan to add another rig for smaller Targets next to my CEM25P with an 80mm Refractor (which I'll eventually upgrade to a triplet). Right now, I use a 183 MC Pro, which I'm content with - I like the small sensor, it's very forgiving in terms of FF / Reducers and also collimination for reflectors. I'd definitely keep an IMX183 Sensor, probably the Mono, for an 8" f/4 Newtonian, gives a good sample rate for galaxies and the light gathering of the scope is good enough for such a resolution, plus it's fast. I'd get an 533MM tho for an RC8, reduced it samples similar to IMX183 + 800mm focal length, and the sensor is still small, so I could probably do without a field flattener on the RC8. Other option, and likely the most expensive one, but probably also the most stressfree one, with the fewest light gathering, is going 5" Triplet, a decent Triplet that size would cost me between 2.5-3k, plus field flattener/reducer, so I could run it at f/5.6, which is still fine imo. Sampling would be a bit lower than on an f/4 Newton, but no stressful collimination. The mount I'm planning to put on this whole setup is either going to be an AM5 (dw, no carbon tripod for those scopes obviously, and I saw people running similar scopes just fine on it), or a GEM45/CEM40 (kinda expensive here in germany right now, and no option to order cheaply directly from china). Maaaybee a HAE43, but I barely find any experiences with it. So something in the 20kg class, which should be enough for imaging around ~0.7" with a scope that size. Off axis guiding would be a given under all those circumstances, plus a sensitive guidecamera. I'm mainly undecided about collimination on those RC8s and f/4 Newtons, which one is more forgiving / easier to learn how to handle? On the other hand, a 130mm f/7 Refractor has wayy less light gathering abilities and resolution... also I'm unsure on the IMX183 on a 130mm Refractor. Given I run it at f/5.6 and an 80mm Apo rn, it should only improve, but still... People keep talking about it being a niche camera and only good for RASAs which imo, is maybe a bit limited. I'd probably wouldn't use it on a focal ratio slower than f/5.6, and the focal lenght shouldn't be higher than ~800mm probably, but other than that... why not? So, that leaves the following options for getting decent galaxy shots: RC8 Carbon + New Focuser + Reducer + expensive collimination tools + eventually a tilt adapter = 1550€ + 260€ + 255€ + I don't even know how much those cost and what works best, but lets say another 300€ + 110€ = 2475€ -> suddenly, the "economic" RC8 doesn't seem as economic anymore. The 533MM and 183MM are roughly the same price, so I'll leave them out of the calculation for now. Skywatcher Quattro 200P (settled on that one, because here at least the optics seem toptier, and there's lots of DIY stuff to fix issues with mechanics, focusser also seems better than on the GSO f/4 Newtons) + Aparture Ring / New Spidervanes + Velour in the tube + Coma Corrector + expensive collimination tools = 750€ + 250€ + 40€ + 330€ + idk what I'd need here and how expensive it'd get, lets say 200€ for a really good laser? = 1570€ -> certainly the cheapest way to go, and even with a focuser upgrade, I'd stay under 2k. Altair Wave 130 Triplet imported from UK + Reducer/Flattener + bigger Dewband, and that's about it = 3000€ with customs, tax and everything + 350€ + 70€ = 3420€ -> obviously the most expensive one, but probably also the most comfortable one. No collimination, Dew is fixed with a Heatingband, no weird cables bringing in artifacts into the picture because secondary mirror heating, easy to do the same target on another day because no spikes that could potentially misalign, no weird artifacts, high contrast, Apos that pricerange usually have a good focuser.. yeah. The only thing putting me off is that I don't know how good a 5" Refractor reduced to f/5.6 around ~725mm focal lenght + IMX183 really is in terms of light gathering abilities and galaxy imaging... I know, some of them are faint, and more aparture is a trump, also the Dawes limit is like 0.89, which is... greater than my imaging scale, which is probably not good? I wouldn't have that issue with a 8" reflector of any sort, as Dawes limit is 0.58. Seeing here is decent, at around 1.5 Arcsecs usually, sometimes lower, sometimes a bit higher, according to meteoblue. Fully focused on my doublet apo I often get ~2.3 FWHM on my images. Only in the summer nights, seeing is usually not that great, but that's widefield time in my opinion anyways, so I'm not worried about that. I'd be imaging from a bortle 5 rooftop in a 40k suburb, not great, but also not the worst. Going mono should help with light pollution as well. I'd gladly pay the premium if I know I can actually spend my time imaging and getting good galaxy shots with that 5" Refractor - I'm worried about spending more time troubleshooting / colliminating with a f/4 Newton or RC8 than with the Refractor. The thing is, I have decent seeing, light pollution is tameable with going Mono, but the thing that's not great around here is how often I get clear skies - and that's not often. and if I'm going to waste those precious clear nights colliminating instead of imaging... yeah I don't know. A f/4 8" Newton is economical, I know it works well with the IMX183 sensor, it gives me good sampling rate and resolution, I think I'd also have less central obstruction than with an RC8 (unsure tho, feel free to correct me!) which should result in a higher contrast... but, collimination is... well. I'll have to build up the scope because I won't leave it mounted on my roof terrace of course, every time I'd image. Does that screw over collimination already? Another thing tempting about the Newton is that I could toss in a good barlow, and do easy planetary with my 183MC if I want to do that at some point, Refractors and RCs are less suitable for that, I guess. RC8 seemed economical at first, but no way I'm gonna use the IMX183 at around 1100mm focal lenght reduced, not the biggest fan of the square 533MM sensor, but I don't want to go a bigger sensor size, as it gets more expensive in everything - bigger filters (I already have 1.25" SII and Ha laying around), bigger filter wheel, bigger OAG needed, reducer is super iffy on the RC8 with APS-C, field probably not flat anymore, bigger camera, bigger focuser due to all the extra weight due to everything being bigger, so 533MM it would be to achieve the desired sampling between 0.6-0.7"/pixel. It seemed promising at first - what I like about the RC8 is, that well colliminated, it gives nicer and less prominent spikes than a Newtonian, also it's shorter, so less of a wind sail. What I don't like is: Focuser attached to primary mirror, gives issues with collimination - but at least once you dial them in, they keep the collimination, apparently that's not the case with an f/4 Newtonian. I know aperture is king for galaxy imaging, but both reflector systems have a secondary mirror introducing central obstruction, so how much worse is a 5" Apo really in terms of light gathering abilities? Also what I'm wondering is, if I'll go mono anyways, can Chromatic Abberation on a doublet be fixed that way? each wavelenght gets focused seperately anyways, right? So a 130mm Doublet might even be more affordable - but I'm unsure, I imaged 3 years now with my 80mm Apo - first with a DSLR, then with a cooled colour cam, and CA is a nightmare on an FPL 53 Doublet imo. I tend to pixel peep, but if I zoom into my images, colour fringes are visible around every star - and that's after seperating the color channels and aligning them on green and putting them together again, which does help a bit, but it's still there. Would that issue disappear on a Doublet if imaging mono? So yeah - I'm very undecided, and I want to decide on a scope first, before I choose my second mount, which will probably end up whatever is most affordable in the 20kg range at that point, and seems trusted for delivering 0.5" guiding consistently if everything is dialed in correctly (I mean I get that on my CEM25P with 6-7kg load after I did surgery on on her meaning belt and meshing fixing according to iOptrons guides, which reduced my Dec backlash to a sweet, sweet 700ms, should be doable on a 20kg mount with 60% payload as well imo, so I'm not worried about that). I'm thankful for every insight, recommendation, what to do if I want to image galaxies in the M64 range of size decently I'll keep my CEM25P + 80mm refractor for nebulas, widefield, etc - it's great for that and literally plug and forget at that point... but galaxy imaging... yeah no. Thanks and Clear Skies to everyone, Mina