pipnina

I love the redder tone in the bottom one! I feel like if you could somehow combine the rich orange in the bottom with the slightly deeper blue of the top image it you'd have the best of both! Amazing!

I realised i forgot to link the corrector I found before: https://www.teleskop-express.de/shop/product_info.php/language/en/info/p14460_Starizona-Nexus-0-75x-Newtonian-Focal-Reducer---Coma-Corrector.html As I stated... it is not cheap! And only advertises correction to slightly shy of APS-C format (28mm circle, compared to diagonal of most APS-C sensors around 31mm). The example images look good, but aren't very high res and look like they might use some starless processing? hard to say. This is so far the only coma corrector to offer more than just a little bit (i.e. more than 0.95x) reduction.

Seems I've unintentionally paper bombed his workshop 😅 I used (per recommendation of a local store) printer paper scrunched up to cushion the bottom of the box, and the other end was cushioned with bubble wrap... And I forgot to mark which end was which! Plus, my botch job at affixing the focuser to the tube has failed on him as he lifted it from the box... Oh dear. I have apologised but he did say it made him laugh so there's that. On the plus side early impressions of the optics are promising!

The scope is now in the hands of Es, awaiting prognosis! I had to find a new post office as the one most local to me has closed down as if jan 1st, in the end postage via parcel force 48 came to £72! DHL didn't charge that much, but it's Es' preferred courier so I figure he trusts them for a reason (well he said Post office, but I think royal mail doesn't deal with items this size, leaving PF as the only other option). But I also don't know if DHL was told the sale value of the parcel when it was sent to me. Maybe I could have sent it cheaper if I undervalued the parcel (I used the value I bought the scope for) but even though glass isn't insured, I'd be devastated if the parcel was lost entirely while undervalued by the courier. At any rate, fingers crossed!

Sadly I think it's true. While I wish this not to be misconstrued, I do believe humans have managed to violently overpopulate and we would have been better off ecologically plateauing about 5BN people ago, which lines up roughly with what our planet could have provided for us without the use of fertilisers (originally bird poo scooped from islands and mined in a manner most irresponsible which would have led to the famine of billions if not for the discovery of synthesized fertilisers prior to WW1). We consume food in volumes that could never exist via "natural" means, much of which is grown on land claimed from ecosystems that are destroyed for farming, and then is fed to livestock (98KG of grain turns into 1KG of beef). We package everything, and make so many of our daily materials out of stuff we cannot dispose of. Plastic recycling is little more than a fantasy as almost all plastics go un-recycled and end up burned or in landfill eventually (many poor nations are effectively poisoned as richer nations pay them to take their plastic waste, those nations then have little choice but to burn it, which releases extremely toxic chemicals). Even PLA, which is made of corn starches, cannot be biodegraded as advertised in nature, it requires enzymes that are artificial and high temperatures. Plus, every PLA on the market is packed with additives or is even an "alloy" with other plastics which mean recycling and complete composting cannot happen in many cases, leaving us with incineration as the only option for proper disposal. Air travel (which still uses lead additive fuel) allows us to visit places en masse, and ruin them just as fast. I would very much like to travel and meet my distant friends, but it's hard to compare my feelings and desire to see other lands to the damage I would/could cause in collaboration with everyone else doing the same. I think this is only the tip of the iceberg for what we do to this planet, and ultimately ourselves. Plunder now, regret... Sometime in the future. I have developed a lot of anxiety around my own environmental impact. Near enough everything I buy or throw away gives me this inkling of guilt, but it's not like I can just... Stop living? If I didn't buy things that would eventually turn into waste, I'd just sit here like a lemon for my whole life, never enjoying anything, as all my hobbies cause some kind of unspeakable damage, and I'm not much one for reading and gardening is something you can only do so much of in a day, if you have a garden. I apologize for being so morbid but it's what weighs on me whenever ecological / environmental happenings get discussed 😕

I have only done research on this myself, but reducer coma correctors seem extremely rare, and when you find one, it's expensive! (Think £500+!) I found them with 0.75x mag, and they all claimed to be suitable up to APSC, but then the 4element GPU corrector claimed to be full frame suitable, and I don't think it was based on my own experience. From what I understand, parabolic mirrors are great if you plan on using them plain with eyepieces etc, but awful if you want to correct the peripheral field as well. This is because coma correctors end up creating some spherical abberation (like the Baader) at the center as a result of the parabolic mirror being perfectly corrected for sphere already. But if you paired the Baader mpcc with a hyperbolic mirror (somewhere around k=1.22 according to people on cloudy nights) the center would be corrected for sphere as well as reasonably corrected at the edges. I can see if I can find the correctors when I get home and drop you the links. For now though I might say it's a bit "untested" as I struggled to find high Res example images, let alone raw subs! Best of luck with your new kit!

I actually sold my sigma 105 f2.8 macro last year after I got rid of my DSLR. It did handle quite well but star shapes weren't exactly ideal at the corners, and that was on an aps-c sensor, and the lens is supposed to be full frame suitable. It was very good at normal photographs though, I definitely got my money's worth from it. This capture is very nice too, beats a lot of stuff I captured with mine for sure. Shows what happens when it ends up in the hands of someone capable ha. I looked at the art lenses, as well as the Zeiss lineup when looking for imaging lenses in the 1-200mm focal length range... Sadly while all very well corrected for distortion and chroma, ALL of the fast lenses have insanely high vignetting (most of the f1.4 lenses are only 30% illuminated at best by the corner of a full frame sensor) and the MTF curve is very dodgy. Plus they cost as much as or more than a redcat51 or askar ACL 200. I'm sure I'd adore those lenses for regular photography, but my mind does so much more pixel peeping with astro!

This might explain why my dad and I were struggling to see it, stellarium on mobile has it as mag 5.8, I was struggling to see the comet but mag 8, 9 stars were easy in my 10x50s tonight.

Also, you aren't following the topic - heads up

The only idea I have is to set the telescope up during a cloudy night, point it at a bright torch of some sort (could make a pinhole in a foil sheet to simulate a star maybe), and move the bright light source around the field of view of the scope, even out of field, and see if the reflection pops up. When you find it, be meticulous in working out where it's coming from. Remove the corrector and see if it's still there, then try the filter wheel, oag, even take the cam off entirely and see if it's also there in an eyepiece. Looking at where the focal point of that curve would land, way off screen, the only bright object in that area is mars... Does it show up in the field if mars is near by? It's brighter than any star by a long margin so if anything can cause a reflection in an otherwise dark sky that might be it.

The tipping point was probably that my 50mm/f4 finder was mounted on a 30cm dovetail on the top of the tube rings, about as far away as it could possibly be. This was to get it off of the tube itself as I suspected it was causing flexure when guiding. Plus I had a losmandy dovetail on the main scope which was heavier and a big flexible dew shield on the front of the scope to try and cut out some of those off-axis reflections. quite possible I simply added more accessories to mine / further away etc. The newt wasn't far off balance though, a piece of string with my star adventurer's 1kg weight on it hanging off the counterweight bar mostly fixed it.

Both my 8" F4 newt and 130mm f6.6 triplet are impossible to balance on my HEQ5. the 10KG of counterweights is simply not enough for either of them. I still get sub-arcsecond guiding (typical between 0.5-0.8RMS total) with both, but the refractor is definitely more stable with fewer wobbles, probably on account of having a lesser wind profile. I have wanted a mount upgrade for a while, but the market seems to be moving a fair bit at the moment and the choice is not as clear cut as i think it was when I bought the HEQ5 in 2017, many more options in the £1500-4000 price range than just stepping up to a higher tier skywatcher mount.

I can't remember where, so I don't know how accurately my memory serves, but I think I read/heard that areas in the lake district do their absolute best to keep tourists on specific paths so the sheer volume of people doesn't destroy the very thing they've come to see. We closed off stone henge with a fence because people kept vandalising it We can no longer enter the prehistoric caves with the paintings in france (discovered during WW2) because the presence of moisture from human breath and artificial lighting caused plants/moss etc to grow on the walls, slowly destroying the paintings so that we could view them. So they built a replica "next door" and closed off the original to everyone except scientists. Look at any major tourist / package holiday city before and after the rise of the aeroplane, the effect of the tourism industry is almost always unintentionally destructive. Best we can do is keep our own impact to a minimum when we visit, and for affected areas to impose limits and controls to preserve what makes them special. Most of these places only exist as they are once!

I can't attest to photoshop's needs, but as a Pixinsight user I find RAM quantity, drive speed and multi-core CPU performance to be very important. Some stacks I've done (where about 800 24MP subs were used) have literally consumed all 96GB of ram in my system and then started to eat into my 50GB swap on my SSD too. But Pixinsight's process is insanely poor performance compared to alternative stackers. It also takes up a lot of disk bandwidth and IOPS (in-out operations per second) so my SATA3 SSD only just keeps up. I use a Ryzen 5800X but given as the 5950x is faster in every way and also about the price I paid for my 5800x at launch these days... That might be the CPU to get as the new gen 7000s are a bit pricy for a slightly underwhelming gain I hear.

So if I wanted the ground to be properly exposed, I should get a meter reading with the center of the frame pointed at the ground, then frame my shot? Works for me if that's the case, I was probably exposing for the sky.

I guess I can only give it a shot and see what happens! My first thought was that I'd try another Rollei-IR film shot but stick it on my guided HEQ5 and do some half hour to hour+ shots and see if they come out better. I think I'll try the Illford film though as you suggest as you have prior experience. What sort of exposure times might one manage there before over-exposing it? My skies are around mag 3-4.5 NELM depending on where I'm facing. Funny you should mention a modern mount and a film camera together, as that's what inspired me in the first place to give this a go: https://petapixel.com/2020/04/25/how-i-photograph-the-milky-way-with-medium-format-film/ This shot in particular!

I've done some reading about this Tech Pan but I'm not quite sure what it does differently to normal film, or if the benefit for astro is in the development and processing. Some local person is developing it, through a local shop dedicated to film photography. I presume that "pushing" helps to increase the brightness of the film, but is that just exaggerating the contrast already present in the film (can't boost the brightness of something that already has no signal) or is it bringing out chemical differences that otherwise would not affect the transparency? I'll have a look at this illford film and see if I can try it out on my next attempts, I'll also speak to the guy in the shop as he may stock it and have advice for shooting too Thanks!

A few months ago I figured I'd give my dad's Canon Æ-1 Program a dust off after I found out about a film photography shop in my town center. I looked at the data sheets for a few kinds of film and seemingly only Fujifilm Velvia (colour, the same film used to capture the famous windows xp desktop background) and Rollei Infrarot (Black and white) have spectral response at the hydrogen alpha emission line. I figured I'd pick up the rollei. I am definitely grateful that the cameras and lenses of the day had good focusing marks, or i would not have been able to focus on stars at all without hoping a bahtinov mask would be bright enough. The focusing prism definitely only works in daylight conditions and when hard edges are present... I stuck it on my star adventurer mount and took some photos. In my notes I took them of Andromeda, Cassiopeia and Cygnus. Either at 35mm or 105mm (my dad used a vivitar 35-105mm lens, so I opted to only use the extremes). Sadly the best I got from it was this... Not exactly what I hoped... Weirdly enough even normal photographs I took came out very poor, despite using the camera's inbuilt metering system (and setting the ISO on the camera body to the 400 declared on the film can). Maybe some film photographers here might know what's going on, but I am going to mention it to the guy in the store because he seems very knowledgeable (has in-repair cameras all over the store!) and could point me towards user error, dodgy processing, bad scans etc. So here we go: 6 minutes pointed at Cassiopeia yielded me this. Oh dear. And this was the best one! It doesn't help that the scans I got back were in jpeg format, and the scanner is not bias frame calibrated (those noise bands!) This was clearly one of my Cassiopeia attempts at 105mm, as the W takes up most of the frame. Not much going on here though. The rest of the astro snaps plain haven't been scanned (Only got a download of 26) which suggests they were blank and the guy didn't even bother scanning them. Although it's a bit odd, as other shots that were scanned also appear blank, despite also being based on the camera's metering... I plan on having another crack at this... But I definitely need to review my process! Some snaps to judge the film on, or my photographic prowess haha.

Astro equipment is very sensitive to the quality of USB ports too. I always run my mount on a cable straight from the PC to the mount, never through a hub. The only hub I truly trust is my Pegasus Power Box Advance, which is the first one I've used that has supported even the fussiest pieces of kit.

I really like false-colour images made from mono Ha! Yours looks very clean and tidy as well! I have only ever botched it without starless processing, but something potentially interesting that makes the nebula pop a bit is letting the Ha fade in saturation towards the highlights, if it's something you'd like the look of for your pics anyway. I do like the moody red-only look

I take it the EQ mount is providing you with extra necessary height then? In such a case, if you find in a few more weeks or months (depending on how often you manage to keep observing in that time, clouds and all) that you still very much enjoy observing but find this scope and its wobbly mount frustrating: You could consider doing what I did and upgrading to a 250mm or 200mm dob, which would have more height than the 130mm dob You can also in theory put a block of wood or somesuch underneath a dobsonian to boost the height. At the end of the day if you know a tripod mount is best, I won't ague with you, but I do personally quite like the dob format for its cost & rigidity. An astro society or club visit would be a good idea!

I had this exact setup when I started in 2014, I know exactly why it's frustrating you! Carrying it around led to being poked and prodded by all parts of the mount... I switched it up by moving to a dobsonian mounted scope, and I notice that if the AZ4 is on the table as a mount switch, you could buy a skywatcher heritage 130 dob for the same price, if not a little cheaper. Dobs I think are much more rigid against touching the ota and against wind, vibrations are less noticeable and settle faster. Even my chunky HEQ5 EQ mount wobbles when I touch the focuser of my frac. Hope you continue loving your scope!

Strictly speaking I think many of the new CMOS astrocams are the same as the astrocams sensor wise. Many astrocams literally use the same sensor as a consumer camera on shelves today. The difference comes from the amplifiers (don't see many consumer or even professional mirrorless/DSLR cameras with 16-bit ADC...), and the software in the onboard computer, plus the absence of ir-filtering sensor windows. For all intents and purposes, a new mirrorless camera from sony would perform the same as an uncooled ASI2600MC without the ir filter and dodgy processing done onboard, sadly the consumer cameras are insistant on things like raw file tampering (mistaking stars for hot pixels), so even if you modify them they still come out lesser than the 2600MC will. I think the difference between CCD/CMOS astrocams and DSLRs was more prominent however, back when these sensors suffered from much more noticable dark current and brighter hot pixels. Even if I don't cool my RisingCam 571, and it runs as +5 or even +10c, I don't notice any intrusive dark current like I did with my old Nikon D3200. Strong dark current in older sensors paired with a lack of cooling I think makes the bulk of the older DSLR's struggles with astro. Now of course, a lot of people are using these cheaper uncooled zwo cameras with a good deal of success and not seeing much dark noise at all. I do feel like traditional camera makers COULD demolish the current astro camera makers with simple changes if they wanted to, like having a pure-raw setting (zero software involvement or post processing) and having the IR filters cutoff point moved to say 680nm instead of 650, which as I understand is just a holdover from the film days where you needed to make the film insensitive to deep reds so you could see the film you were processing during development? Maybe the 533mc or 585 would be a good starting point for Astro74? Low noise, high QE, dark current is relatively low even in outdoor summer temps (around 20c at night in the uk?). And also very cheap (by new camera standards) https://www.firstlightoptics.com/zwo-cameras/zwo-asi-533mc-colour-usb-30-camera.html https://www.firstlightoptics.com/zwo-cameras/zwo-asi-585mc-usb-3-camera.html

I was skeptical about this the last time the topic was brought up but I feel like I am much more inclined to agree with you now. Many of the smaller sensor zwo cameras are actually very capable even without cooling, and can even be price competitive with modern mirror less cams that aside from sensor real estate will produce worse images... I can't remember the model numbers exactly but I think it is the ASI 533, 585 ETC that are uncooled, a bit small but don't break the bank and have good sensitivity and noise characteristics... Despite the idea of wasting imaging circle area by not being able to record it, after thinking about it, your simple statement of "4x sensor area doesn't mean much if it's four times as much rubbish" has pretty much won me over at least. As you say as well, astro cam costs have plummeted at the low end while quality has shot up. The only thing I'll say for you Astro74 though is that I can't recommend trying the zwo120 for deep sky, as it really is only geared up for guiding, has poor noise compared to other cams, and at a gain level where noise is not at CCD levels, the full well capacity is well below 1kev, whereas most of the other cams like I mention above I think have lower read noise and full wells around 10kev+ at those low noise gain settings. Much easier to get a clean picture without having to resort to super short exposures. Also, I can't seem to move the quote block on my phone, so I guess it lives there now haha. Sorry!

Hubble Space Telescope: It is the source of all those pretty pictures whole generations have grown up seeing as THE bar for quality. Plus it allowed us to see back to near primordial times in a cosmological sense and continues its primary mission of observing and measuring extra galactic supernovae to this day, over 30 years later! Plus it was put into orbit in a space shuttle, one of the coolest things to ever fly. VLT: One of the first observatories to use a laser guide star system for adaptive optics, and THE best interferometer used for astronomical purposes. Besides being a technical marvel and living breathing science and technological development of the most impressive order, it also pinpointed the exact location of the black hole at the center of our galaxy and constructed an image of betelgeuse with surface detail! Arecibo: aside from simply being massive and cool (the dome was a 5 story tall building by itself!), the telescope's ability to perform active radar imaging of asteroids was pretty unique and cool. It also captured the minds of many.