bomberbaz

Yeah despite my previous posts, a very lot to be said. It's basically try before you buy.

Ok sorry for spamming this thread here but there is also a Ursa Major 8" scope on offer. It has a great focuser (better than the 150p), better finder and cooling fan for primary mirror. Another great option. The market is awash with offers! See this one Neil Ursa Major 8" f/6 Dobsonian | First Light Optics

Can't see the 200 Neil, is it this 150P Sky-Watcher Classic 150P Dobsonian | First Light Optics Bargain.

This is a very frequently asked question, there really isn't a one size that does all but some come close. @mikeDnight above has already mentioned my preferred option given your budget. I am a big admirer of this Sky-Watcher Classic 150P Dobsonian | First Light Optics For one it has good reviews for planetary mode. It is perfectly capable of high magnitude (250X) views of the planets, it would even push to x300 with the F7.8 focal ratio but it will capture and do well on many deep sky objects (DSO) such as andromeda, M81/82, most star clusters would be superb and there are many nebula that would give pleasing results although the fainter fuzzies as they are often known would be beyond its reach. A little more explanation on why this is good might help. Generally longer focal length scopes with a ratio F10 and up are often used for planetary as the targets are brighter and the lower F ratio just works better for these. Lower focal length scopes of F5 and lower are preferred for DSO viewing as it means you have more light hitting the retina of difficult to see things. My option above ^^ just sit inbetween and will give very a very good return in all areas but won't be best in either. What is also good is the low price leaves you with a very nice wedge to buy extras to embellish and improve the scopes performance. I would be looking at a decent zoom eyepiece Hyperflex 7.2mm-21.5mm Eyepiece | First Light Optics, a reasonable 2" eyepiece for larger DSO. PanaView 2" eyepieces | First Light Optics If you are wondering why you need more, if you read the forums it is generally accepted that the 25mm eyepiece provided is ok but the 10mm version is pretty naff. This clips at the heals of £500 but is definitely as close to all-round as it comes.

I have had this data for a while but only just got around to having a go. From the off I was struggling with the green in the image. tried several different methods but in the end came up with these two images. One a straight forward process in Gimp and the other a blend of images using Gimp and Siril Only 29 minutes data but still a bit disappointed at lack of colour in comet, however only using 50mm of aperture so maybe I shouldn't be that surprised. One thing I am happy about is managing to keep the stars fairly round. EDIT: Dropped the top version into siril and used remove green noise tool mask, this has improved the image quite a bit to my eyes.

Ok further to my previous posts I did some updating to the PC with day to day, imaging and gaming (yes still even at my age) in mind. I did obtain a NVME drive (1GB) to use primarily for processing and storing critical data (I now have three different drives for the latter) and also upgraded my processor from the Ryzen 5 2600 to the Ryzen 7 5800X. I have moved stuff around to hopefully make the best of the added drive and so far seems ok. Tested drive speeds and bearing in mind I am on 4th Gen not 5th, I am very happy with speeds obtained which rival any shown on here from same gen. The new processor though has speeded everything up dramatically. Programmes launch so much quicker and in general things are much more snappy, very pleased.

Try what he said below!

I have checked the how performance and ram was only up to about 14GB used and according to the AMD website, the latency is faster than the processor (at least that's what I think it means). Anyway, unlikely to be memory. The HDD was running at 100%!

You have got me thinking now! I'll set it going again tonight before I go to bed and see if it replicates overnight. It should otherwise there could be something awry.

You have a look at the read and write times of the Nvme vs HDD and the differentials then the time taken becomes a little easier to take in. Anyway, like I said I switched back to the nvme drive for processing and may add another yet.

I run 15 second subs from my garden due to the conditions, very light polluted, so even with 5 hours data it is an awful lot of space I need. The time is reflected too of this. On M97 I gathered 1450 subs at 39MB each (that is 55GB), thats a lot of registering, stacking then kappa clipping, takes forever. If I drizzle which I have had occasion to do then obviously even more space needed and time of course.

don't flip flop peter 😉

Exactly what he said and this one specifically StellaLyra 8" f/6 Dobsonian | First Light Optics There is a recent-ish thread about best 8" dobs and a lot of people were throwing their weight behind this scope, I was one of them.

Added another 45 minutes to the above and really am very pleased with the result. I am very aware of the saying, keep doing the same thing and expecting different result is the definition of stupidity/insanity. So I have been mixing up my approach a little, trying different approaches to different objects rather than a one size fits all. Anyway, it still feels a little painted to my eyes, as a result of trying to get more out of something where it isn't there. I am though wedded to the idea of sticking with optimised exposure and so we have 95% of 768x15 second exposures, roughly 3 hours.

I have an external hard drive. Documents, pictures etc which I deem extremely important are back up to that, nothing else is saved but I do keep my eye on things and luckily have always seen failing before it's got to a critical stage.

Ok so ran my own Diskspeed checks, results pretty much where I expected them to be although the 8TB mechanical quite a bit better than the other mechanicals on here. I am presuming the higher speed (7200rpm) and larger 256MB cache helped here. Top to bottom, 1TB NVME drive (partitioned to 250MB as disk C/750MB E), 250MB disk D SATA (this has PC games on it) and 8TB HDD

Ahead of you on this one vlaiv, I moved all the pictures, video and other media from the storage on the Nvme drive onto the 8TB mechanical drive last night and that leaves me a little over 600GB free. Should cover my needs I think. Thing is, I have checked my motherboard specs and it turns out it has two Nvme ports and I could have gotten a 1Tb drive which would have met my needs easily for far less than the 8TB mechanical drive Kingston 1TB NV2 PCIe 4.0 NVMe SSD | Ebuyer.com I think my board is 3rd generation so a super turbo boosted SSD (Read/write over 6GB/s) would be wasted on it. Going to speak to my PC man monday, I may just buy the drive for the sake of under 50 quid!

Very good point and the HD drive I installed does have a 256MB cache, however (and I am not sure exactly how DDS processes files) but at 39MB per file & 1250 of them, it will as you point out only get you so far.

I don't actually have a problem with the machine, just pointing out what to some might not be immediately obvious. The fast SSD is indeed a Nvme drive, I believe that is the reason for part of the huge differential. One of the reasons also for the differential is the spin speed. I purposely got a 7200rpm HDD but even so, it was running at 100% the whole time of stacking so almost certainly that is where the log jam is. I could happily run it overnight if needs be on a larger stack requiring more disk space. The processor is a Ryzen 5 - 6 core, but It has 12 threads so shows as 12 in device manager, sorry for mix up but DSS does pick up all 12. (I can see that being updated soon) EDIT. Just looked and a Zen3 R7 processors are £200-300 depending on model, tempting!

I decided to stick all my data processing / imaging stuff on one disk drive of my PC. It's high end is said PC, Ryzen (12 core) processor, 32GB memory, and only 2xSolid state drives (SSD) until yesterday. I had bought a 8TB (that's 8000 Gigabyte for the pc noobs) hard disk drive (HDD) with the intention of isolating imaging to help simplify things, seemed a rationale approach. I had considered speed but didn't think it would be as impacting as it actually was/is! So anyway I had also decided to use the 8TB HDD disk as the temporary folder for DSS, then I set a stacking operation going and 14 hours later it finished. I was a little surprised at that time and so decided to run a side by side with some other data comparing HDD and SSD speeds. M97 (not that it matters) was the data. I tried it again using the HDD and it was stacked in 7 hours and 40 minutes. I then simply switched the temporary folder in DSS to my SSD drive and ran the same stack, no changes. The time1 hour and 40 minutes 😲 So if you use a PC for processing (or similar updateable equipment), just bear this in mind next update you plan. A word of warning that SSD's are quite expensive but can offer some considerable advantages in terms of speed as I can testify too.

Agreed, I had a very quick look at it and first thing I noticed was what looks like dust related artefacts. I tried using Siril to extract them but wasn't really getting there. However i do agree some nice detail.

Further to all the above I have carried out the following procedures and I am far happier with what I have been able to achieve. first stacking in DSS. I have increased the number of calibration frames used and added 2x drizzle. Interesting to note that in doing this there was no sign of posterizing in the image prior to back ground extraction. The only Auto/semi auto process used in Siril was background extraction and green noise removal. In gimp nearly all other processing was manually done and I have to say, I felt more connected as it were to what I was doing. I do love that gimp now has the workflow running down the left side to allow you to look back easily without constantly having to add and name layers, far more intuitive. As always I know I am not there yet, it's a little overdone in some areas, notably the stars but happy to be making some kind of progress. The biggest plus is my stacking and processing appears to be in better control of the walking noise. (I will dither from now on)

Always learning they say, I would always agree with this statement and below is testament to this. I have altered my processes after picking up a little advice from a previous post on here. Slightly more involved but nothing significant. I have also been applying the "less is more" approach and the result of this can be seen below. I only have 75 minutes of data on the IRIS, no where near enough I know but 1 shows a result from using auto processes only. Number 2 is where I have rowed back on histogram, background extraction and other processes.

Thanks @Elp, that's quite impressive. What programme do you use for this and is there a walkthrough anywhere, I am all for learning new techniques.

Thanks for the reply, I think, given my last go this should be very helpful. I will let you know. It might be a few days as tomorrow my techy guy is installing a new 8TB hard drive. (Should future proof me for a few years at least. )