Tim

Hi Stu. Try and get the opportunity to use the H beta on the North American nebula. I got one an used it on the horsey and Californian as you might expect, but failed to be blown away by it and was all but ready to sell it on (actually, to give it back to the guy I borrowed it from for a 2 year evaluation :p) On the NAN it was a revelation, loads more structure than with UHC or Oiii, much better contrast too. I could take it or leave it on the horsey tbh, and I reckon it is just as good with the Lumicon UHC, or even unfiltered if the skies are right. Really hoping for clear skies at Winterfest next week, exploring the Rosette with the UHC is an annual highlight.

OSC cameras are a bit tricky during bright moons, especially if transparency isn't great. Reflection nebulae like the iris nebula or pleiades are much better in darker skies. I normally choose low northern targets or clusters on moony nights, or even just use the clear sky time to stress test the system, and check and adjust variables like polar alignment etc. I dont care what the meteorological folk say, there has to be some relationship between full moons and clear skies, far too many to be coincidental. We even arrange outdoor events around full moons, with the greater probability of good weather! Tim

Thanks for the updates. It was comets that got me interested in astrophotography, though I've never been any good at shooting them 😜

It's a great question Also worth remembering that not all filters are created equal. I just assumed they were when I started looking for them for my dobs, I have a 10" and an 18", and got myself a Baader Oiii and a cheap UHC filter, maybe a Skywatcher one, but I cant remember now. The performance was underwhelming to say the least, and the Baader Oiii was a little too dark for my liking, even in the larger Dob. In fact I compared it side by side with my Baader Oiii imaging filter and there wasn't a massive difference. Being able to try a selection of filters out at star parties made a big difference for me, and over the years I have settled on three old Lumicon filters, UHC, my favourite, a bright Oiii, and a Hb filter. The Hb has a much more limited range, but used on the North American nebula for instance it knocks the socks off the other filters. Sadly the original Lumicon brand filters are out of production now, but they come up every now and again on the used sites. If you can find quality used filters you can probably try them and sell them on if you don't like them without losing too much of what you paid for them. Tim

Not flocking as such, but something I have been considering for the interiors of my dob tubes is the blackest of black paints. I use it in art and it is remarkably unreflective, if that is a word? Any light that hits it just disappears. The only thing I'm worried about with it is that it is pegged for indoor use only, and wonder if it would run like mascara in the dew 🤔 It is acrylic based so may be fine, or I could apply a matte lacquer over it I suppose, but it would be better without. Might try it out on something and leave it in the rain to see what happens. It is surprising how much new kit arrives for review with bright or even shiny parts inside the tube. A particularly common reflective surface is the internal end of the gear on rack and pinion focusers. Whether it makes a material difference is hard to say, but why take a chance ? 🤔 Oh, and the beveled edge on primary dob mirrors.....grrrrrr 😜

An interesting read on the subject, with useful illustrations, is New Perspectives on Newtonian Collimation by Vic Menard. FLO used to stock it, maybe still do. Following the read of that I now use Jim Fly's Catseye system on all my reflectors, much more accurate than a laser, the precisely machined autocollimator allows for very accurate collimation. Very few Newts are properly set up out of the box, quite often have to square up the focuser to the optical plane and so on, and don't forget that the optical plane does not necessarily have to be square to the tube 😜 So many variables!!! Tim

This is a fact. But I still get nights, even when nothing has changed, when things just don't seem to want to work. When this happens I turn everything off and on again, and if that doesn't fix it, I go to bed, and sleep soundly in the knowledge that it will be fine again on the next session. Inscrutable gremlins!

That's what I was talking about

Once you go green and black.....you never go back

Is the image from the exact centre of the frame? The poor focus emphasizes the issue of the misshapen stars, which may have several causes, including inherent coma, focuser slop, camera tilt, or poorly collimated objective. See if you can post a full frame picture, it will reveal a lot more. Tim

Being in a similar position at our place I can fully appreciate what a brilliant thing this is to be able to achieve with an existing system. A big pat on the back for Grant

Took this on holiday as thought my eldest lad would like it, he is mad on Land Rovers. Turns out he does like it, he entered the pic into a competition and won himself free tickets to the Land Rover show Samsung S21 Ultra in Pro mode

I know what you mean, can still remember the first time a mono image came through on my setup, it was the horsehead with a Ha filter on an old Starlight H9 camera and it just blew me away. I'd been using the original old QHY8 OSC up to then. If I could only have one camera it would be the mono, but the luxury of both is much appreciated. In an ideal world I'd have a matching telescope and run both cameras at once, imagine the cables!! Are you going to Kelling for Winterfest Carole? I can't remember the answer if I already asked you!

Things might be a little different in the future, maybe. I have always hankered after a mono camera that could be switched to a OSC via single filter, but the reality is more likely to be a OSC that makes a perfectly good mono camera with binning, especially the way cmos chips are developing at the moment, my phone has a 108MP camera now and goodess knows where they will end up!

What telescope are you using, or intending to use? And what are your skies like? Mono cameras with filters are more forgiving if the telescope has less than perfect colour correction. Personally I like to have both options available, mono for when the conditions, weather patterns, and DSO allow, and for narrowband targets, but also a OSC for patchy skies, smash and grab imaging, star parties and dark sky sites. There's no easy clear winner, you just have to work out what your best compromise will be. Many that come from DSLR imaging find that mono+filters is a lot of faffing around in comparison, and the newer ranges of 14 and 16 bit large chip OSC coming on to the astro scene these days is changing the thrust of astrophotography a little, making it more accessible to newcomers. Have fun choosing Tim

Wow, that is stunning! Can I ask, what were your skies like for this image? Tim

Yes, me too. I haven't been in a dark room for over 30 years, but can remember the smell of the chemicals for B&W processing like it was yesterday. It was in school that I learned to load my own film cassettes in total darkness, taking the specified amount from a larger roll, taping the new film onto the reel, winding it in, the right way round, before packing everything away in light proof cases before putting the lights back on. I didn't realise it then, but those procedures in complete darkness were setting me up well for astronomy in the future

Looks like the neighbour I had at a "dark site" recently..... My neighbour at home is similar, massive floodlights on all night, I spoke to him about it once and he did angle them down a bit, but then upgraded to even brighter, much worse ones. They drive you mad don't they 😕

Good one Carole, nice to see something a bit different

First time trying this while at Kelling star party, quite pleased with the results, going to have to see what it can do on a scope. Samsung Galaxy s21 Ultra, Pro mode, iso 3200, 50 x 30 second exposures in RAW mode. Phone resting on my Dob's equatorial platform. Voice control used to activate each shot to avoid touching it, although it must have sounded weird shouting "SHOOT!" in the middle of the campsite in the dead of night Observing report to follow in the right section.

Yep, were going, if the forecast is good we will take our 18" dob and happy to share views if the Covid situation makes that sensible. In 2018 we had particularly brilliant views of the rosette nebula, it remains my favourite deep sky observing experience. If the weather is crappy, or even if it isn't, it is worth going to see the steam trains all lit up for their xmas event, the lights in the steam make for quite a spectacle.

Aliens! We are at Kelling Heath star party, and as usual we arrived a week earlier as part of a longer holiday. With a beautiful clear night happening, but lots of other campers with lights on we left the immediate campsite and headed out into the heathland, away from stray lights. Suddenly, out of the blue, there appeared a starnage light in the sky, unlike anything I have ever seen, and beyond any reasonable explanation I could give to my son who also saw it. It gradually faded and appeared to set in the NW, and we finally went to bed not knowing what on earth, or in space, we had seen. Next morning we saw news of an Atlas5 rocket launch delivering satellites We feel really lucky to have witnessed it, and it just adds to the enjoyment of our holiday. Clear skies Tim

Lots of unpredictable variables I guess, the same issues are facing a whole range of unrelated businesses at the moment. And not just on imported goods either.

Incredible!

That's brilliant, just used it to check on a known reflection source in a rig I was testing, and it performed brilliantly. Thank you