NigeB

Hello All, I've just become the owner of a used Pulsar 2.7 metre observatory. It's come with no keys (fortunately the door is unlocked!) The previous owner has sent me a photo of some keys, but he's not sure if they are for the observatory (he bought the dome second hand last year but had planning permission refused and never got to set it up and use it). I think this is a "Mk II" design. I've attached a rather poor photo of the door handle, and the keys. For those of you who own Pulsars with this kind of handle - do these look like the right keys? Thanks Nigel

That's spectacular! Nicely done indeed.

I watched the talk live last week - it was excellent - looking forward to the next. Having access to these recordings is a fantastic resource. This is a real service to the community - many thanks to the speakers and SGL team for putting in the effort to make this happen. As far as I can see this is a pretty unique initiative for the online astronomy community and you're setting a high bar for others.

Hello All, This is a bit of an odd one. I've bought a second hand observatory dome - it's a 2.9m AstroDomes one like this: http://astrodomes.com/2-9m-fibreglass-astrodome/ It's in Sussex (Lower Dicker - BN27 postcode). Once the Covid restrictions are relaxed enough to allow it, I need to go down and collect. It breaks down into two main sections and a few other bits (see photo). The two main sections are quite large, and likely to weigh around 160 kg each. So it's more than a 2-person lift. Aside from me and the seller, I'm probably going to need 2, possibly 3, other people to help me get the sections on the back of a dropside van. Obviously I can't do any of this until Covid rules permit it. But I'd like to ask if there are any SGL members in that area who might be willing to lend a hand for an hour for some lifting when that happens? I'd be happy to cover their travel costs and a bit more for their trouble. If I get any responses then I know it's possible - if not, then I'll have to look at alternative shipping. Please don't respond if you have a bad back! Thanks Nigel

Excellent - nice colour detection as well.

Hi All, After a hiatus due to other commitments, I've managed to get back in the observatory. Late last month I upgraded the computer, which was starting to creak somewhat, and I spent an evening swapping out machines and sorting out software configurations. I'd forgotten how many things have to be configured and all the bits that can cause a session to grind to a halt... At the end of the evening I used M51 as a test to make sure Voyager control was working properly. I didn't take much notice of camera orientation - it was simply meant to be a test run, but we then had a sequence of good nights and I just kept going, so the data set was pretty good at the end. I've had some great advice from SGL members about processing technique in the past - see e.g. my Whale post here and all the brilliant responses. For anyone trying to understand Pixinsight processes, there's a lot of useful information in the thread and it helped me enormously. For this M51 data set I tried to delve a little deeper into the process and understand a few more of the processing options and settings in PixInsight, including combining Ha with LRGB, and some more mask-based work. The result is below. I know I have a tracking issue that needs to be adjusted out, and I think there's a softness here which isn't so evident in the raw files, so I have probably over-cooked some of the processing and mask protection. I'm going to have another go, but I think after 2 days of being absorbed in tutorials and Pixinsight sessions, I'm probably pushing my luck with my family and need to go and plumb in the dishwasher, which will no doubt take a week to sort. So here's the result of the last few evenings of mis-spent time... Comments and suggestions welcome! If anyone wants to try processing the data, I've put the calibrated and stacked files on Dropbox here: https://www.dropbox.com/s/uzhrwsuyaupsfsn/M51_Stacked_And_Aligned.zip?dl=0 Nigel

Hi Wim, That's brilliant! Thanks for updating and posting your new method. Also interesting point about the tidal stream. Having read this I'm going to have another go at this object, with a much deeper set of images to see if I can bring that out. Light pollution here, while not horrendous, may still limit that, but I'll have a go and post here when I've got something. You can have the data set with pleasure! Nigel

Excellent! The weights look good; the bit on the other side looks even better...! Nice image. I've had similar weather issues. The latest annoyance is clear skies but lots of wind, which doesn't do much for guiding at 3916 mm focal length 😞

That's sublime.

Hi Tom, I have experience of only one autofocus solution - the Lakeside system which Ian King Imaging is the dealer for. I've fitted these on all my telescopes to date - C14, TOA150, C11 and Altair Wave 80. I find they work very well, including integration into SGP (there's an ASCOM driver). Lakeside provide the motor, mechanical connectors, control unit and mounting bracket - if there's not an off-the-shelf bracket already available for your chosen 'scope, they'll make one - all you do in this case is make a few simple measurements of your telescope focuser geometry, using a diagram which Ian King will provide. Other solutions available etc etc, but I've been very happy with my experience of Lakeside's offering. Regards Nigel

Wow... Some great advice and suggestions here, thank you everyone. Olly, thanks for your further input. When I processed this first time around I did see some really strong dark rings around the galaxy, so I went back to the start to try and reduce that, but obviously not enough. I'll keep a closer eye on that. That's an interesting "thuggery" approach - and it looks pretty effective. I'll look at that though I don't have PS; I weighed up the software options and went for PI as my first processing splurge - maybe PS is in my future. In the mean time I'll look at GIMP to see if there's a similar approach. Neil, thanks for the Astra image pointer - I was not aware of this piece of software - looks very interesting. Dave - very useful comments; I did see the colour gradient in the stretched background though I didn't think much of it at the time since it seemed to drop below visibility after processing, but indeed, there's probably some useful information there to help track down the cause, and I missed that difference in the elongation across different colour frames. I'll need to look back at the logs and correlate the image times to see if there was a flip at that time - there certainly were flips over the nights I took the data. And it's a while since I checked alignment - it's a permanent pier mounted setup, and I use an OAG, but I've been messing about, experimenting with dual mounting telescopes and swapping them around (covered in another thread) so I'll need to give that a check. Typical - it's cloudy tonight... I'll re-post once I've done some more digging. Thanks once again. Nigel

Hi Dave, Neil, Olly, Many thanks for your positive comments - it's good to know that this is heading in the right direction and people don't find the issues too distracting. I'm going to re-process with more H-alpha and a green correction in SCNR and see how that goes - I appreciate your suggestions. Dave, I agree the elongation isn't immediately obvious. But I knew there was something amiss when I saw the subs next morning, even before I looked closely at the individual stars. The images just didn't look quite right. I get grumpy over star shapes because I know that if all is well, then in the well corrected central portion of the FOV the stars should be perfectly circular. They're a very sensitive indicator of some types of problem, like guiding, so if the stars are slightly out of circular, then that indicates a problem which is affecting the whole image, including diffuse features. Attached is a screenshot of a small portion of the stacked L frame not far from the field centre (all the stacked frames and individual subs show the same). I can see the issue in all of the stars here - the diameter in the horizontal axis is slightly, but noticeably, larger than in the vertical. To my eyes the zoomed view has a sense of minor but noticeable "motion blur" as if things were moving from left to right. So features like the dark lanes aren't as clear as they could be from this setup because I'm basically smearing out detail. Anyway: yes, please do have a go at processing this - post the results (and preferably summarise your steps - it's a great way of learning technique!) Last time I did this people told me they only used the stacked and aligned frames, not the raw subs. So I've put stacked and aligned L, R, G, B and H-alpha frames (after bias, dark and flat field correction) on my Dropbox area here: https://www.dropbox.com/sh/1kmko02tkbxqxhx/AACjT-ptgRiiVyxz7yX6nPTGa?dl=0 Let me know if you have problems accessing the files - and thanks again all. Best Regards Nigel

John, Many thanks for this reminder and for a great web page on Parsons and Sinden. I think I may even remember that Look North report when it went out originally - seeing Mike Neville again takes me back. I occasionally attended Newcastle Astronomical Society and some meetings at Close House when I was much younger, and met David Sinden on a couple of occasions (somewhere in my drawers I have a small fragment of glass which I acquired at one of those meetings - supposedly part of the material drilled out for the central hole in the UKIRT mirror blank). Later, long after I'd moved to Leicester, we invited him to come and give a talk to our research group. He accepted, and gave a fascinating account of his work and some of his ideas for the future - delivered with great modesty, though it was clear to everyone in the room that this was a man with not just a deep knowledge, but an innate feel, for his subject. That was not long before he died. Listening to David talking in the TV interview, it strikes me that the eloquent description he gave of Sir Howard Grubb, is every bit as fitting a description of David himself. Nigel

Hi Peter, Many thanks for your comments; I'm pleased the elongation doesn't look too obvious. Once I saw it, I couldn't stop seeing it... I did wonder about wind, but it was a pretty calm sequence of nights. Good point about the extra sensitivity at F/11. I've gone back and looked at the subs again; the extent and direction of trailing seems consistent in all of them. I've checked the orientation of the long axis of the stars, and it seems to be very well aligned with the RA axis, so I'm still thinking that a poor PHD2 calibration before moving to this high Dec could be to blame. I might have another go with a forced re-calibration on something near the celestial equator and try a couple of subs on the same target to see if it behaves any differently. Thanks for the suggestion about changing the Ha balance; that's very useful feedback. It's the first time I've tried adding Ha to an LRGB image and I went with a very light touch. I'll revisit at the weekend and post an update. Best Regards Nigel

Thanks Spaceade!

Hello All I managed to get what I thought were some reasonably good subs of the Fireworks Galaxy last week and have been trying to get a good result in Pixinsight. Results shown below. I used the processing workflow described by @MrsGnomus in an earlier thread, with some additional adjustments. I've added some H-alpha into the red channel. Exposure details: 15 x 10 min L, 10 x 10 min R, 11 x 10 min G, 10 x 10 min B, 8 x 10 min H-alpha added to R channel (0.9 R + 0.4 Ha). Taken with the TOA-150 and 1.5 extender (so running at f/11). On closer inspection the exposures aren't as good as I'd hoped - the star shapes are consistently elongated. Another set of images I took of M57 the week beforehand, have nice round stars. No change in configuration between the two targets, so I'm wondering if the higher declination of NGC 6946 has something to do with it - maybe my PHD2 calibration wasn't good. Comments & criticism welcome - as always, I'm happy to provide raw data or stacked subs if anyone else feels like having a go! Regards Nigel

Looks fantastic! Thanks for the process information - very useful indeed. Nigel

Hello Everyone, I've been at a meeting in London all day so am just catching up now. This has been a fantastic thread... thanks to everyone for their responses. MrsG, I was going to ask you where you learned your processing skills, and you've answered that. In the BC (before children) years my wife and I used to tour France in our Caterham - I reckon I was within about 20 miles of Olly's place on at least 5 occasions over the years. I may need to suggest to Herself that we attempt a revival and book a stay at Les Granges... Gorann, I really like what you did with the data - yes of course, please go ahead and use/post however you want (same for everyone else). I've added a note on my Astrobin entry that points back to this thread and credits the advice I've received from everyone here. I'm also getting the feeling that perhaps an image is never finished - there's always the temptation to go back and adjust processing. I know I'm going to be re-working the image (and revisiting some earlier targets) over the coming days. Nigel

Hello Again, I've had an entertaining evening reprocessing the original files following the methods described in this thread. The difference is quite amazing. My version is not up to the standards of those posted here - my stars are rather "loud" at the moment and they seem to pop out of the image. I think I can see how to tone them down - I'll work on this a bit more. I don't have PS, so I'm trying to do as much as possible in PI - although I do have Gimp... I suspect I'm going to be working on this for several more days, but I feel like the image quality has already improved enormously thanks to your posts and is probably worth showing the delta here. So here are two versions from this evening. Many thanks again - this has been a real revelation. Nigel

Hi Geordie85, MrsGnomus, Olly, Wow.... I'm astonished - your images are fantastic - thank you so much for your efforts. I have to say this is a revelation to me; I knew I was not getting the best out of the data, but I didn't expect to see such a big difference between my outputs and those of people who really know what they're doing! I guess I'm partly pleasantly surprised that the data I took was good enough to achieve these results; it's also sobering to see how far off my own processing approach is. I've just shown my wife, and she is similarly amazed. Thanks also for setting out your processes in detail - this is an enormous help, and I'm going to go back and work through this from scratch this evening following your methods. MrsG... Yes, that's a flat field problem in the L frame - I took twilight flats on the first evening, but not subsequently - big mistake, because this feature appeared in the later nights. Not at all! Thank you for your comments and efforts! Olly, am I right in thinking you're not a big fan of PI? Why is that? (I recall a post from you some years ago where you were talking about the usefulness of layers, which as far as I know, PI doesn't have). Thanks again; it's going to take me a while to go through the information in your posts and properly understand the logic, but I'll post an updated version of my own once I've done that. Much appreciated! Nigel

Hello All, Yesterday I posted the results of a recent imaging attempt on NGC4361 (The Whale Galaxy) over in the Imaging - Deep Sky section. Here's the original thread with a description of my method and what I'm not happy with: https://stargazerslounge.com/topic/313366-thar-she-blows/ In the post I asked for comments/criticism and some suggestions on how to get a better result. One of the suggestions (thanks @Allinthehead) was to make my data files available for others to work on - which sounds like a great idea. So I've posted the (~1.5 GB) of raw lights, flats, darks and bias frames on my DropBox area. I've also posted four fits files, which are corrected, aligned and stacked L, R, G, and B frames, in case anyone wants to have a go at processing but doesn't want to start from the very beginning. (Of course, these aligned and stacked frames may also contain errors from my processing method - so it's better to start with the raw files if you can!) So if anyone is looking for something to do when the nights are cloudy, I'd be really interested to see what others can do with this, because I'm well aware that my processing technique leaves much to be desired. I'm particularly keen to hear from people using Pixinsight, which is the system I decided to invest in. If you can make this look good, please post, preferably with a summary of your processing steps, so that I can better understand how to improve my technique. Here is the link to my Dropbox area containing the files - the zip files contain the raw data: https://www.dropbox.com/sh/th6595cdneqr24u/AADdUywsfzkARZ-917O_gHFta?dl=0 Thanks! Nigel (My own attempt shown below).