Clarkey

Processing is probably 75% of imaging. I have been imaging for 3 years and still consider myself a novice. Not only is it a learning curve, but the software is improving rapidly too. Give it a couple of years and we will just plug in the images and AI will do it all for us🤣😭

Have you downloaded the image and looked at the histogram on a PC? Does it give the same result? It does not look genuine so might just be a quirk of the Asiair.

I'm probably being a little pessimistic in terms of data needs, but I would rather have too much space than not enough. The site expects to get around 200 clear nights per year - which is a lot of data. I generally double what I need to give me a mirror copy. As a syndicate member I have no say on what other people image, or the sub lengths - however, the maximum for the scope would be 180 secs.

I already have two SSDs and an additional HDD in the PC giving me 8Tb total. I also have 2 associated external drives to back these up. I use the SSDs for the OS, programs and one is a 'working area'. The rest is just storage. I probably need a couple more 8Tb drives to keep enough space for a couple of years.

I think @vlaiv and @Fegato, you are sort of telling me what I already knew. I was rather hoping I had missed something obvious and there was a way round saving all my subs. I know I am probably going to get at least double the amount of data I have had over the last 3 years - that is a lot of disk space. I even avoided full frame sensors to keep the size down. I will potentially have the option of saving binned files which will help. The idea of grouping exposures might be a good one. I'll have a thing about the best way to automate the process.

I have recently started to image at a remote site and the amount of data I will be getting is going to be a lot more than I get currently. (Hooray - clear sky). However, the negative of this is that I will have a lot more data to process and store. To reduce the total amount of data, I could limit the flats / bias / darks etc. by saving the master frames only. However, currently I keep all of the original light frames. My question is this; when I have multiple data sets over a number of nights (or scopes), will I see any difference integrating the master light frames only over re-integrating all of the frames together? If there is no difference, I would only need to keep the masters, drastically reducing the overall amount of data stored. I realise that data storage is relatively cheap, but there is also the backing-up and management of all the data which adds to the time / cost. What is the general consensus? Do I need to keep everything, or just the master frames?

I need a visor to reduce the glare🤣

Great image and processing. Much as I love these subtle dusty images, I always seem to struggle to get the dust detail. (Not sure whether it is completely linked to my B6 skies). You have certainly nailed it on this one. What I do want to know - where did the clear nights come from?

The ZWO 120 mini is only USB2 so you will not get very high transfer rates. (Plenty for guiding though). The main thing is to make sure any cables and ports are backwards compatible to USB 2.0.

I know nothing about Macs - so this is my opinion for Windows PC only. (I am no expert so hopefully someone more knowledgeable will come along) Despite the PI website suggesting you need the greatest PC in the world, a reasonably decent PC will work. Obviously better ones will be quicker. I would say you definitely want and SSD for your working area of at least 1Tb. Use a standard drive for storage - but for PI you will need lots of it. I had 32Gb of Ram on my PC, which I upgraded to 64Gb - but this made no real difference in performance. I don't think PI uses the graphic cards to help in the processing, so spend the money on the main processor to give the best performance. (Obviously this may change in future releases). FWIW I use a Rysen 5600X which works fine, but a quicker processor with more cores would be better. (PI seems to run processes on a core-by-core basis). The other worthwhile investment is a decent monitor. I have a 27" 2560 x 1440, which I would say is the minimum specification you really want. I am no expert in PC's, but I built mine on line from PC Specialist about 18 months ago. I did a bit of research to get the best bang for my buck, but with hindsight a slightly better processer would have helped. However, at the time I was using other software that did take advantage of the graphics card capability, so the build was a compromise - largely on cost vs performance. So, in summary I would say 32+ Gb RAM, large SSD working area, plenty of drive space (or external) and the best multi core processor you can.

You could save some money and buy the Starwave 115mm. Yes, it is FPL-51, but the correction is excellent. I purchased one recently and I have been really impressed. I did wonder whether the FPL-51 would be an issue, but I am glad I saved my pennies. The £400 you saved could buy the new (second hand) mount😀

I have the JTD dual saddle from FLO, which costs £300. I could (and should) have bought a second hand mount, such as another HEQ5 instead. I could have picked one up for £500.

Having said this, there is no loss in running at -10 or -20. I have two sets of darks - one for -10 which I can achieve all year regardless of ambient temperature. I also have a set for 0 degrees which I use on battery to reduce the power requirements. I think sub length is probably more important once below zero, but as I do not want to be producing too many subs, I still run longer than technically necessary. Like most AP, it is a compromise.

This is the bit that stopped me using the dual rig. I now have two separate rigs imaging simultaneously - sometimes on the same target. I use NINA and PHD2 and there was no way of dithering 'intelligently'. As far as I could work out you needed to dither every frame of one rig which I felt wasted too much time.

I would have to agree. I started with mono and moved to OSC as well. Not only does mono allow full narrowband imaging, but undoubtedly gives better results. You also have the benefit of weighting the channels as you see fit. Personally, I find mono processing easier too. Obviously if you ever get a RASA things might be different......

Just for info there is a 200P dobsonian on Astro Buy and Sell for £200 in Wigton at the moment. It's a couple of hours away, but good value and it looks like the vendor will post if needed.

I'm sure I saw a broomstick too.....🧹

I have the AA Starwave 115mm refractor which is excellent. It's FPL51, but the colour correction is very good. It also makes an excellent visual scope. I also have an RC8 which is also very good. The RC8 binned has the extra aperture and is 'faster', but in terms of image quality there is very little in it. The RC8 is quicker to cool, but as they are permanently installed in an observatory it is not really an issue for me. For galaxies the RC8 is excellent value for money.

Just to add another possible option - what about a 6" classical cassegrain? More aperture and FL than a refractor, but quicker cool down than a SCT or Mak.

I'm not sure how much improvement you will see with a narrowband filter. You might reduce the background noise, but a stock DSLR will never give good results on an emission nebula. Another option would be to modify the camera and buy a filter to return the camera to 'normal' daytime use such as this; TKAstroservice OWB Clip Filter for Canon DSLR | First Light Optics .

I don't have a mono IMX571, but my darks look nothing like yours. The histogram looks very odd too. Personally, I would say there is clearly something wrong with the camera.

Yes, mine is one of the early V1's. I have seen some complaints regarding the CA - it is there certainly, but manageable. As you say - realistic expectations, especially at fast focal ratios.

A small mount probably draws no more than 1A tracking and a camera will be similar, probably less. If that is all you are using then that is 24 W at 12V. So if you want 4 hours run time it would be 4x24, or 96 Whr. Give yourself a bit more for slewing etc, but 200 Whr should give you at least 6 hours.

Carrying on with my PI learning journey, here is my latest image. I am starting to get the hang of the software now, so hopefully the results will start to improve! This is 12.5 hours of HO with the L-Extreme and 6 hours of RGB. Other than the stars, the RGB made very little difference as it was swamped by the Ha signal. Imaged using a Risingcam IMX571 and the FMA180. The FMA180 seems to get some bad press, but I must confess I quite like the images it has produced. Yes, there is a small amount of CA but this is easily removed in processing. Constructive comment welcome as always.

@Marvin Jenkins Oops. It was meant to be! I shall move.