Roy Foreman

Very nice, and ethereal. Well done.

What an awful thing to do to a telescope, but I suppose they have to test these things so we can enjoy our equipment safe in the knowledge that we can hang heavy cameras on the corrector plate and its gonna be ok !

It was worth a try but I imagine there can be some distortion in a photo especially if a wide angle lens was used. And the balance position could be in a different place too.

Just measured mine. It is 620mm from the balance point to the tip of the camera - ZWO 6200MC Pro full frame, which is a large camera. Cables will obviously require another 75mm or so depending on how you route them, and in use you will almost certainly require a dew shield as well.

Attached a photo just in case it helps.

According to Celestron, it takes 55 lbs of weight to break the corrector plate - a figure I find very hard to believe !

Love the colours and smoothness of the image. Nice neutral stars too. Well done.

Looks nice and sharp considering the conditions. Well done.

Neil - I am sure you will get good results from the 178m when you get it, as your imaging skills are certainly up to the task of getting the best out of it.  There will be a learning curve, of course, and yes you will see what I am up against in using the larger chip. Like you I got a large chip camera to do whole disc mosaics, and I also like to pixel peep.  Sometimes, using small pixels, I find I can get better results from doing a selective enlargement than from using optical amplification in the imaging train.  There seems to be so many variables that there is no ' one size fits all' solution.  but it is fun to experiment and see what works and what doesn't.

As for registax, maybe I did write it off a bit too soon.  No matter how I played around with wavelet settings I still could not match what I could achieve in Photoshop. I also found that it produced too many artefacts and triangular blocks.  I am using AS3 which is faster, easier to use, and has an inbuilt sharpening routine - it blends the sharpened image with the unsharpened, and you can adjust the blend ratio, but I found the default of 50% to work best.  I further sharpen in Photoshop, and here I found the best method was to do it in 2 or 3 small steps rather than one large one.  I tend to use a large sharpening amount with a small radius, and use the threshold setting to limit it's effect on tiny features - like noise for example ! 

Thanks for all your input, which I find valuable, and good luck with that 178m - look forward to seeing the results !

Roy

Neil - bit of a delay in responding, I've had some (non astronomical) problems to deal with !

Thank you for the compliments on my self built mount. It helped that I have some metal working experience, and that I am a design engineer by profession, but it was still a huge leap of faith and expense. I was fairly confident that it would work, but I wasn't sure how well.

As far as the lunar imaging goes, I have just remembered that these images were taken in twilight using a red filter which saps 3 stops of light. I had to up the gain a bit to compensate - hence the noise in the selective enlargement.  I take on board all your comments and you are absolutely right in what you say. I am grateful for your offer to work on one of my images, and hope to take you up on this once I have selected a suitable image.

I plan to do and experiment next time the moon comes around.  To image the same area of moon reducing the imaging area each time with corresponding increase in frame rate and frame numbers. This way I will be comparing like with like and can determine the optimum settings. I also intend to experiment with different gain settings to see the effect that has. maybe one of these images will be suitable for you to work on in noise reduction !

You are right - the cheap and easy option is the first one to try !  Incidentally, I never got on with Registax and wavelets.  I use Autostakkert as I find it easier, faster, less artifacts, and better results. It has it's own sharpening routine which I further enhance in Photoshop.

Roy

Thanks guys for the suggestions for reducing noise and improving image quality - I am always striving to do better and am glad to take on board any new or revise technique that might help.

One of the reasons that noise is visible in Ptolemaeus is that it is a pretty substantial selective enlargement from the image above it - and that was taken at a focal length of 5400mm.  But some of it may be down to the camera I am using - a ZWO 183 MM.  This has tiny 2.5 micron pixels and a fairly large sensor resulting in a 20 megapixel output. At full frame it can't go any faster than 19 fps. And the resulting data stream is too much for a conventional spinning disc hard drive. I got myself a half terabyte SSD but it filled up too quickly, so had to replace it with a 1 terabyte SSD !  

It is for this reason that I limit myself to 900 / 1000 frames. Even so it still takes nearly 2 hours to stack each video stream - and that is with an i7 quad core processor. After an imaging run my poor computer is running all day for a few days !

I tried reducing the imaging area, first to a half, then to a quarter, of the sensor area. This allowed 64 fps and 2000 frames. Much quicker to process, but a significant drop in quality.  I also experimented with stacking differing percentages - 10, 15, 20, 25 and 50%.  15% seemed to be optimum, as with greater percentages you are stacking worse quality images.

Once again, I am open to any suggestions, and I am so glad that my images have impressed - I am a deep sky guy really !

Finally, several people have asked to see images of my self built mount. It is extremely difficult to photograph a large telescope in the confines of an observatory. I had to use an ultra wide angle lens with all the distortion a weird perspective that goes with it.  So here are a few of the more successful ones.  Please excuse the clutter and dust in the observatory !  The spring tensioning on the Dec drive is experimental but seems to be working really well, so I am in the process of upgrading the RA as well.  There is an ED 120 Equinox riding on the tube, and it can be swapped out for a 180 Mak or an 8" edge SCT, or in fact any other scope less than 10Kg with a vixen rail.

You are right, John, it has done a pretty decent job of reducing noise and, as far as I can see on screen, little or no effect on the sharpness.

thanks for that, and glad you like the images

Roy

With my SW 180 Mak and my Celestron 8" Edge SCT,  I use the electric focuser from a Meade LX200. It just screws onto the back like any other SCT accessory and takes up less back focus than a crayford focuser. Does the job nicely, albeit sounding like a coffee grinder.  Mine came with an LX200 (obviously) but I think you can buy them as a separate unit. I also purchased a dedicated hand controller for it from Telescope House, but  I am not sure if they still make them.

Yes love the star colours - well done

Fantastic - almost like being there on the moon !

Very nice - love the colours !

Wonderful !

All sorted !  

I now have colour images

Thanks again Alan

Thank you for that info Alan.  I will check it out when I get time and report back.

Cheers

Roy

All was going well last night gathering data on M63 and M64, using Sharpcap and a one shot colour camera.  Then at 1am, freezing cold and tired, I realised that somehow the captured images had all been saved as 16 bit Tiff, not Fits.  That's when I gave up thinking dark (Bortle 1) thoughts.  I've had this happen once before.  Both DSS and Photoshop will only read them as monochrome.  Does anyone know if the colour info been lost forever, or is there a means of recovering it.  The resulting monochromes look sort of ok, but colour is prettier.

Nice image Craig - lots of interesting detail to look at. Well done.

Nice detail in those images Neil. Well done.

Interesting.  I use a Nikon D810a, a remarkable DSLR designed specifically for astro imaging. I do not generally need to take dark frames with it, the noise levels are so low.

A couple of years ago I moved to cooled CCD cameras thinking that they would produce lower noise levels with shorter exposure times. Not so. I have yet to produce an image with these cameras that matches what I can achieve with the Nikon. More specifically, 60 min of exposure on M51 with a ZWO 294 MC produced more noise and less detail than 15 min with the Nikon. With the Nikon it takes generally 10 - 20 frames to reduce noise levels to acceptable levels. with the ZWO it takes at least 60 !

I guess companies like Canon and Nikon have huge resources and technology to achieve this.

4 hours ago, neil phillips said:

Nice detail in those Roy

Thanks Neil - glad you like them.

5 hours ago, BRADLEY 1953 said:

Some really lovely images there, i Particularly like Aristarchus.

Thank you Bradley, I think that is probably my favourite too.

Love it !  Great work.

Very nice - well done !