tomato

Great image, not captured with a RASA! On the subject of the long neck, if they couldn’t lift it up due to blood circulation restrictions, why did it evolve? When I was at school the theory was these giants spent a lot of time in the water to help support their massive bulk, so maybe they did use it to graze weed growing under the surface. Amazing what topics come up for discussion on this forum.

Sadly I think the prices stem from the core hardware, and I can’t see that coming down anytime soon.

If you polar align regularly then only warpage within a session would be a problem, it’s exposed and outside all the time so I can’t see rapid changes occurring.

TBH, cutting a thread half an inch long by hand shouldn’t be a problem. Even if it wasn’t 100% square on the end the bar would still be totally functional.

Maybe @Tomatobro will comment on this, as he has a lot more experience than me of working with these different materials, but I would suggest given the relatively undemanding duty, whichever is easier to cut the thread,. Do you have to thread it just enough to screw the bar into the mount?

I’ll keep loading them in the vain hope that I find one with a more optimistic outlook. For some reason a better forecast, even if it’s inaccurate, makes me feel better.😊

I agree a permanent observatory improves the good to bad nights ratio no end, but boy, it’s even more frustrating when the established setup decides to play up. I’m not sure how, but I recently managed to corrupt the software that runs my mount. After unplugging and plugging in numerous USB leads and restarting the software repeatedly, I eventually had to restore the file from the backup. In the meantime 3 hours of pristine, moonless sky had slipped through my fingers.

That’s a good idea Olly, I like the idea of bringing in a physical comparison of the actual sky condition, just need the clear sky time, (as usual).

Out of interest I ran the stacked data through APP's LP removal tool, this seems to have generated a more even background, without clipping the data. Horses for courses?

Yes, I always look at a variety of existing images to get a consensus on how it might look. I guess on wide field views with a lot of tenuous nebulosity present, there isn’t much else you can do. From a quantitative perspective I think @vlaiv has got it as close as it’s able to get.

Agreed, I think the tool as I have applied it, has clipped the data.

Thank you Vlaiv, for as ever a well thought out and detailed reply. It does bear out why I like imaging small galaxies in a restricted FOV, sorting out the background is usually quite straightforward.

The trouble is the scope in it's original configuration would be an absolute pain to use, the speculum alloy mirror would tarnish almost in front of your eyes in the damp atmosphere . Even if it now has a modern aluminised mirror, you have to wait for an object to come into view, and then have a team of assistants on hand to keep it there. And with my ex H&S Managers hat on, I wouldn't like to sign off the risk assessment that puts the general public half way up a rickety wooden staircase which they have to lean over in the dark. Also it's in the centre of Ireland, what a location for a large, fixed telescope! I bet they have fewer clear nights than I do, all that green pasture needs frequent watering.

I have some Ha data which I am processing, the final stage being in Affinity Photo. I am experimenting with the Astrophotography Remove Background tool and wondered if there is any definite way to decide what is legitimate background to remove? The first image is after processing in PI with DBE, EZ denoise and star reduction, then onward adjustments in AP but no background removal, the second has had the tool applied. There is a slider to bring up the background but if you bring it up too far you arrive back at the original image. The second one looks clipped to me but it looks like there is still some LP background in the first one, even though I prefer it. Perhaps I shouldn't be using the AP tool at all, given the processing already done in PI? What gets me is that there are clearly some regions of dark space in the image, which is my reference point, but elsewhere how much is faint nebulosity and how much is LP? This is why I prefer galaxy imaging, it's a lot more straightforward.😉 No Affinity Photo Background Removal: AP tool applied:

These days I tend to rely on SAT 24 and my own estimate of whether the cloud is going to hit me, and my all sky camera, which is a high tech more convenient equivalent of getting up and looking out of the window.

If you are dithering between subs you can set a post dither settle time in NINA, which has to elapse before the next sub starts. This would normally be a few seconds but I don’t see why it can’t be extended to 20 or 30 seconds. The only problem is if the mount has settled down within that time it may start the next sub, rather wait for the designated time interval to elapse.

Yes, we know what it is like to keep nudging a manual Dobsonian to keep the object in the FOV, imagine shouting to your assistants to pull all those chains to keep it there.

I don’t think it would make any sense to go from a mono CCD with filters to a OSC CCD, but moving to a modern CMOS OSC is a different story. My own view is that the sensitivity and performance of the latest CMOS sensors, plus modern dual band NB filters and ‘fast’ optics, makes this a viable option in the cloud plagued UK. I am in the process of doing exactly this with my setup. If your goal is premium images with integration hours in double figures, CCD or CMOS mono will deliver but be prepared to produce only a handful of images per year if based in the UK. If you want to get something decent from a single session, then it’s worth giving CMOS OSC serious consideration. One other point, CCDs don’t appear to be as popular on the used market as they were a few years ago, so you might need to be realistic about the resale value of the mono camera and ancillaries.

Great report and photos. On another thread I nominated this telescope as the worst telescope I could ever own. In no way was it meant to detract from the folk who built and used this monster, it was more a tribute to their commitment, tenacity and dogged determination required to construct, maintain it and actually make observations.

Working on an unusual orientation of the Soul Nebula it occurred to me that it looked uncannily like half a head of a vintage Cyberman of Dr Who fame. I have clearly spent too much time in front of an image processing screen...🤪

This was from last night, 37 x 4 mins with the RASA8/QHY268c/NBZ combo, before the mist got too bad. Not much OIII signal but the moon was quite close. I know, terrible framing, but this time I was concentrating on getting both the Heart and Soul in the FOV on the SY135 rig, so this image was compromised. I guess I could have rotated the camera on the RASA but then I would have to have fiddled with the tilt adjustment. Conditions were not great so I didn't bother. Now I wish I had as this has come out much better than I expected.

Brilliant project! On ‘mass produced’ mounts axis size is dependent on the intended payload, but as you say the bigger the diameter, the stiffer the axis will be. I wouldn’t go below a 1” diameter shaft and 1.5” would be better. Sorry for the imperial units.

Firstly apologies for the terrible framing, my other scope on the rig was pointing at the Bat with a much smaller FOV, I couldn't do much about cutting the Elephant's Trunk region in half on this scope. This is 120 mins OIII and 90 mins Ha with a SY135/G2-8300 CCD. I still can't get my head around NB processing, I have again allowed the artist (such as it is) in me take over and I took a liking to this hellish red/orange palette, to me it looks like Mordor from The Lord of the Rings. Atmospheric, but not very scientific.

Indeed, on a recent data run APP wanted over a 100 Gig of free disk space to do the integration. I had to pause it and move some stuff off the drive to allow it to run. Small pixels and lots of them...

Wow! To my eye it has a curious oil painting look about it. I continue to be impressed by not only your ability to find these faint and somewhat obscure targets, but also your ability to use your array of equipment to image them to excellent effect.👍