raadoo

As @callisto said, weight is your primary concern, so as light as possible is the way to go. On top of that you're also quite constrained by your budget, but I think you have a few more options aside from the RedCat: Nikon 180mm f/2.8 ED AF-D — found one used at Ffordes for £379 Assuming 180mm is tighter that what you're shooting now, this one is widely regarded as one of the best Nikon lenses for infinity focus, coma correction and sharpness, even at f/2.8. And at a mere 800g it's not going to cause your tracker to break into sweats. I had one and used it a few times with my D610. It's an excellent performer and that f/2.8 really helps with getting a lot of detail out of short exposures. Nikon 300mm f/4 D IF-ED — found one used at mpb for £519 If you want to get in tighter and really give small 60mm refractors a run for their money, then this is the one. Yes, there's an f/2.8 version of this but that one is a) over your budget and b) much too heavy for a tracker. The f/4 fits your budget, weighs in at 1400g at will perform well at f/4 and excellent at f/5.6. I had an older version of this (non D) which was very good and the D version here is supposedly even better in terms of sharpness and aberration correction. Askar FMA230 ED — can be had new from FLO for £589 It's a real refractor. It's got a reducer that can get you to a field corrected 230mm f/4.6. It weighs in at just shy over 1kg. It's made by Sharpstar. And while I haven't used it specifically, I am beyond thrilled with how its bigger cousin, the FRA400, performs, so that should tell you that Askar/Sharpstar know what they're doing (which is no secret, really). In case you didn't know, Askar is the sort of photo lens technology applied to astronomy division of Sharpstar and any of the Askar lenses is quite well suited to take a DSLR / MILC at the back end. Worth keeping in mind that depending on the model, your camera may be able to autofocus the Nikons above, which would render them quite useful for daytime photography.

Hopefully this won't attract the wrath of all you Isles dwellers, but in my deep inland, continental Europe, Clear Outside has been nothing short of a soothsayer. In the past 12 months, it's missed the mark exactly twice. Evidence from experience isn't much evidence at all, so I'm not suggesting it's magically perfect in its predictions, just putting forward my overwhelmingly positive experience with the service.

I'll try and do a quick write-up of what I did, but keep in mind, this was all done on a non-linear, compressed JPG, so doing the below on the original data should yield much better results, both in terms of noise and star reduction, and detail enhancement. I've also attached a screenshot of the layers panel in Photoshop, so hopefully it's not completely dry reading 😀 saved the JPG as a 16bit TIF (this was necessary for the next step and further edits being as non-destructive as they can be) used Starnet++ to separate the stars from the nebulosity opened both starless and original in Photoshop (from here on out, it's just Photoshop, by the way) and did the classic Difference blending of the two to create a Nebulosity layer and Stars layer Nebulosity: applied frequency separation so I can work on the detail enhancement without affecting colour colour layer was left mostly untouched until later steps (though I did do some White Balance and slight saturation adjustments in Camera Raw) for the detail layer I mostly used High Pass and Camera Raw to sharpen and enhance texture and detail, while also throwing in the odd Noise Reduction along the way in the detail layer (which is mostly 50% grey by this time, bar the actual detail in the galaxy), I also took a grey brush to the core of the galaxy, to remove the banding that was happening in the original merged the frequency separated layers and did more cosmetic / colour work using Camera Raw together with some blended LUTs Stars: slightly increased the saturation as the whole Starnet++ process usually leads to undersaturated stars created a Highlights mask which was then used to reduce most of the stars' bloat a few of the stars have diffraction spikes that the mask messed up, so I manually went in and brought back the original spikes for those merged the whole thing and uploaded it My experience with StarTools has been very limited, but from what I can tell you could probably replicate the steps above without much hassle and with likely better results; especially as there seems to be a way to use Starnet++ in linear mode!

I had a stab at processing it (hope you don't mind) and I noticed a couple of things: there seems to be some backfocus issue with the sensor being to far back (stars in the corners take are circularly distorted around the center of the image) 120s @ ISO 25,600 is far too much exposure for Andromeda's core which, subsequently, got blown out. Now, there's not much you can do about blown highlights, so, when that happens to me, I just lean into it rather than try and fix it by going ham on the Highlights adjustment, as this leads to grey light instead of white and, to me, looks off. interestingly, even if the stars are not fully in focus, the arms have a ton of detail in them, which is a very cool surprise My first attempt at M31 didn't even include a tracker of any kind, just a 300mm f/5.6 lens, a DSLR, and me manually cranking out 5s exposure like an absolute madman and the result is more akin to how you'd see Andromeda through a pair of binoculars. All that to say, really good job! 👏

Something to do while I wait for CEM40s to come back in stock. 😁

Is this maybe one of those bad-ish polar alignment is good type of situations I've heard of? I think the thinking behind this was that guide pulses tend to be a bit higher in value and some mounts respond better that way? I've always been a stickler for as-good-as-possible polar alignment (I don't quit until I get it under 0.5") but then again my guiding experience has been frustrating to say the least (aka spike-a-delic).

I have the same FRA400 and am in awe of what you’re doing with it! I definitely went on a bit of an Urban Astrophotography binge on your website just absolutely gawking at your work. Top shelf, altoghether!

At some point you're going to get fed up with the AZ-GTi's quirks. Sometimes it's great. But often it will point to the ground for no apparent reason. Other times it'll guide under 1" RMS. Most times it's a spiky mess. And if I should dare to try and guide while near the meridian, then it's just spike galore on the guiding graph. Sometimes it stops tracking, as if it's got a mind of its own. Other times I can do 3min exposures with no trailing. All that to say that I am never getting rid of mine, for the simple reason that doing planetary imaging with it and a tiny Mak is dead simple. It's also pretty fun to take the little [removed word] apart, clean, re-lube and realign everything.