Tim

Musing > It would be nice one day to have a reputable top UK supplier with an optical bench and staff trained by a certain Mr Reid, perhaps before said Mr Reid hangs up his gloves for good. My fear is that a lot of the skills our hobby depend on are at risk of dying out with nobody rising to take up the mantle... mirror makers, optical gurus, mirror aluminisers, lens polishers....... I do hope SW can iron out the wrinkles with the first batch of 150EDs, they have always been pretty good at improving QC when necessary.

I expect the SW150ED would outsell TEC140's by a considerable margin? Thankfully, the review here was not conducted by James, Steve, or Grant from FLO, and carries all the more authority for it. ?

You must know we are all checking the weather in your part of the country John

I'm sure I lose a few weeks of my lifespan every time I lift my Esprit 150 onto the mount. So nerve wracking, and not easy for anyone else to help really.

Does the diagonal/eyepiece holder have one of those clamping rings on that some Skywatcher Crayfords employ? Not ideal but sometimes can use them to rotate gear through 90° or so without fiddling with the two main locking screws, which nearly always end up too close to the diagonal to be readily adjusted with cold sausage fingers. There is talk in the US of a DX version, upgraded for imaging, anything we are likely to see here @FLO? Cheers

Not sure I've ever posted in one of these "Show me yours " threads before, but here's my little collection that gets used with my dobs and for telescope reviews. I also have a 2" 2X Powermate that is mainly used for planetary views on rare steady nights, but I don't like using the Paracorr, Powermate, and a chunky EP together, far too heavy There's a bunch of cheap Plossls, and other EP's that came with telescopes somewhere in the obsy, mostly shoved in drawers.

Are they included on any mounts these days? Would seem to be a useful addition.

An adapter similar to this one is what I meant, https://www.firstlightoptics.com/adapters/baader-clicklock-2-125-adapter-2956214.html

Ken is spot on Rodd, (as always ), the OAG chip must be physically brought up to the same focal plane as the ASI 1600 chip. I use mine with a whole range of different telescopes and cameras that happen to be on review. To attach the OAG to the filter wheel, I have an Atik, I use a Baader adjustable locking clamp. The distance of the OAG can be altered by positioning it in the clamp. On the odd occasion I need extra inward positioning to focus, I add a spacer in front of the imaging camera. But usually extra outward positioning is needed so I add a 1.25" nosepiece to the Lodestar. Perhaps post a pic of your rig and we can advise where and what you need to change. The only time it gets tricky is with field flatteners or reducers that have a critical back focus, sometimes a custom adapter is the only answer, but I have used my OAG's with every focal length from 70mm - 5500mm, there is always a way. Tim

"I rest my case." Well I hope Mr Fleck rests his eyepiece case on something a bit more solid than the arguments he used in the article.

PS, we got that irritating band of patchy cloud right overhead, ruining the night, so packed up at around 2. Had been imaging. Target? B33

Brilliant John. It really is an elusive filly, great that it all came together for you, I don't think there are many that have seen it in a 12" from suburban skies, a real tribute to your perseverence. As you say the close pair of fainter stars make the position certain. Just a thought, have you ever tried it with your Lumicon UHC? In an 18" we thought it gave a comparable view of B33 to the Astronomik Hb filter, enhancing the curtain of brighter nebula and making the notch stand out well. My best view of it to date was also my first, just happened to chance past an astronomer who was scouring for it with his 16" Meade and Hb filter. Another dob user nearby knew I'd know the location and star patterns well from imaging it, and he asked me to help, although I'd never seen it visually. Dropped to the position and BOOM! There it was, a fantastic sight ( you know, for us!), a real eyepiece filler. Now you need another "must see" tricky target

Not going up to my obsy to get pics, but I have the Guide to astronomical wonders, a couple of volumes by SPM, Interstellarum Deep Sky Atlas, and Star Testing Astronomical Telescopes by Richard Suiter (2nd edition). Also New Perspectives on Newtonian Collimation. I'm after a copy of Kriege & Berry's book for when I begin construction of a 12" dob.

I think that with a new generation of CMOS cameras inbound, and the advances in sensitivity evident in the cmos chips in phones (my s8+ is great in low light), the "rules" may change again in the not too distant future. At the moment, OSC cameras, and DSLRs, even modified ones, are pretty sucky at capturing Ha emission nebulae. When you split apart the results of a OSC image into R, G, and B, you see that very very little of the Ha signal makes it onto 3/4 of the result. Oiii imaging is different, with good signal collected by both green and blue sections, but still nowhere near the result you get with a mono camera. Personally I'd like to try a colour astro camera with an RGBR matrix. How are you getting on Jez? Are we helping or hindering

Jez, here's what I do, and the rationale behind it, it may help you. At home, on the edge of a badly light polluted city in the heart of the midlands, I have an observatory with permanently mounted telescope and the opportunity to image the samd object for weeks on end if necessary with pixel perfect precision. Narrowband imaging is very important to me at home, and it opens up the opportunity of moonlit imaging. At home I use a MONO camera. Unless the desired target is something unusual, short lived, or generally requiring short time on target. These may be comets, asteroids, supernovae etc, in which case I use a OSC or DSLR camera. Downside of LRGB imaging is the hassle of calibrating four sets of images, including taking flats through each filter, for each session. This process I find fiddly, tedious, and time consuming. LRGB images take a lot longer to process than OSC, require more discipline, more knowledge, and MUCH more disk space. The tortoise OSC catches up with the mono hare here somewhat. There is nothing more precious than time...... When I travel to dark sky locations, with a portable setup, and limited consecutive nights on one target, I take advantage of the darker skies and use my OSC. This way, even if I only get clear enough skies for one 10 minute sub, I still have a reasonable, true colour record of the target in question. Typically, when I travel to star parties, when I go with a OSC I get more useable results than when I have taken a mono camera. I am lucky that my imaging scope of choice has excellent colour correction, which makes OSC imaging possible. This is the UK, dark, clear, transparent skies are rare. I like to have the right tool available as the conditions dictate, and this may be a mono or a colour camera. As mentioned previously, there are compromises. Aesthetically, colour images taken with a OSC camera always appear more "realistic", or natural to my eye. It is entirely possible, and is best practice, to calibrate RGB colour imaging by using a G2V star with similar colour to our sun. In many images however the colours can appear a little forced, although this is a personal opinion and preference. I guess, what i'm getting at, is go for a mono camera, you'll need it in the UK. But if you can, get a colour camera too to really maximise your astro imaging potential. Hope those ramblings help a bit. As you can see, the answer to your question is, "it depends...." Cheers Tim

What set up have you opted for Jez? That might have a bearing on the advice. Also, what do you want to photograph? What are your average skies like? Do you get plenty of time under clear skies or does work etc get in the way? How is the light pollution where you live? Do you have much time available for processing your images? What level of quality of astronomy image are you aspiring to? It is helpful to put some links to the type of results you hope to achieve if you can. Whichever camera you choose, there will be some compromises to be made, but we can help you ensure that those compromises are the least worst for your circumstances. Cheers Tim

"Hello SGL" would have been nice for a first post...........

I'd be surprised if you could Mike My 18" orion mirror has really bad astigmatism. John at Orion tested it the other day and confirmed that the primary is the cause, and pointed out a couple of dinks on the rear edge of the mirror and a heavily ground chamfer on the rear edge, stating that the mirror has been reworked by somebody, not them, and that the dinks cause the 'stig. I'm getting a second opinion, naturally, as Orion quoted £2200+ VAT for a re-working of the mirror. I'll also be chatting with the only other party to have had the mirror in their possession since it was made to see if he has anything to say about the reworked edge. One thing I know for sure, the mirror was ordered at f4, but was sent out at f4.5, so was sent back to OOUK for re-doing. Will keep you updated

When I was in their office a couple of weeks back there was a note written on the whiteboard about a 1/10th mirror, marked as "urgent", I wonder if it was yours? Hang in there Mike, it'll come in the end, just hope it lives up to its intended specs.

That mirror style is a real innovation, and should make for lighter larger cheaper mirrors in the future, if it works as a design. When you watch a mirror go through varying shapes as they cool down, via the views through the eyepiece, you start to get an idea of the major impact on views that only tiny changes in temperature can have. With so many additional variables added to the rear of the Skywatcher mirror, I would be amazed if the views would ever be comparable with a traditionally made mirror under the same conditions. I would be delighted to be proved wrong That isn't to say you cant enjoy amazing views. My 18" dob has a slight astigmatism issue, but the views of galaxies under dark skies are still breathtaking. Please keep us updated about your progress. I think Peter probably has a point about slackening of the 3 collimation screws first btw, but you live and learn Tim

I've always found the visibility figures available on the metoffice website to be a reasonable indication of seeing quality, along with humidity and high level cloud and jet stream position, but it is hugely variable. Decent visibility is about the best indicator of a good nights viewing/imaging ahead though.