gilesco

I do this (ST120), you can see some results on my website. I find it difficult to focus Blue in particular, the stars are always larger than in say the Red and Green wavelengths. It is partly because the focuser isn't particularly good on this scope, and the motorised focuser only pairs with a DC motor, not a stepper motor, you can get a replacement focuser for the ST120, but to be honest I am saving up for an apo and I'm not now going to continue the investment in the ST120, but I will still use it until I can afford an apo (and a stepper focuser etc...)

Well it's been a pleasure trying to get something more out of it, look forward to the results of something with 60s or higher exposures.

Go with the 130PDS... or hold the money and go for something in the future...

oh and, here are the master flats, darks, bias + a bad pixel map for your Canon EOS 80d https://drive.google.com/open?id=15qrX-pL9jPcUsLsA2vvk1Iudd_ki-s5q The Bad Pixel Map might come in handy if you haven't one already.

So dug myself into a ditch here, the "red rain" as you put it, still remained after integration, despite various methods to try and remove it. I can only suggest that you increase exposures to maybe 60s, or if your guiding can take it, even longer (I love my 180s exposures on a CMOS camera, when I get the chance), what we are battling with here is noise in the sensor - and, less noise, or more signal will definitely bring better quality to the show. I've not been able to improve upon the overall integration result that I've already posted before. It is always worth keeping old raw data though, as new techniques do come up all the time, and sometimes you wonder - "I wish I had put that through that"

Starting first integration, I took a note of some of these though, here are the worst frames in each of the categories, if the Integration doesn't produce anything better then I will manually exclude these and repeat it: Lowest Quality Images: 5137 5135 5053 5138 5131 5100 5107 5122 5066 5106 Noisest Images: 5137 5135 5053 5138 5131 5100 5107 5122 5100 5107 Most Poorly Registered: 4932 5041 5097 5006 5008 5019 4984 5075 4953 5137 Worst SNR: 5138 5100 5123 5107 5125 4983 4970 4936 5053 4995 Worst on Star Shape: 5019 5006 4953 5066 5122 5137 4093 5008 5053 5000

I might be able to identify it for you, on the next run I am going to omit outlier / low quality frames - I've also posted on the APP forum as to whether they could introduce a feature to export in CSV format the quality information that it calculates for each frame after they've been analysed, as this would help any third party to the software get an insight into the data.

By the way, your original assessment of longer subs, although resulting in less frames per hour, will really help here, as it will help your Signal-to-Noise ratio, I found it difficult to assess your subs individually as they are quite faint, and stretching brings in a lot of noise from which the source is difficult to discern. I'm taking another pass at your data, while adding algorithms to what I normally do, although if I add everything I will just goose-step all over your exposures! It is an interesting experiment for me!

Well, I have an integration result, on the registration at least one of your frames was way out of alignment with the others. I think I need to repeat this with a blur of some kind as there are some reddish artefacts appearing on the background.

OK, going to do a quick processing in the background with most of the defaults with APP. Might be able to post an initial result when that is done, then will look at using this dataset in a video with both Siril, perhaps Sirilic, and APP, would be a good comparison of the tools.

OK, well I am downloading a 7.5GB file, so it seems to be working, will take a while to download. I will take a look and try processing with APP which is what I'm more acquainted with. I think you were using Siril, so I may also try the same process with that, although I'm not so acquainted with that. Do you have any objections to me video'ing the processing session and posting it online on my website?

Just your RAW Lights and Calibration (Darks, Lights etc..) frames, prefer to have them in a ZIP archive as a single file.

You can do Astrophotography with the ST series, I do so with the 120. It is a cheap achromatic refractor, and I get a FOV of roughly 100' x 75' with an ASI1600 sensor. You should get a field flattenner, and to avoid achromatic aberrations (which you won't get rid of 100%) you will need to re-focus for each and every filter change. The newtonian seems like a better idea to avoid all this hassle. If you do want to go the cheap path and get the ST then look for a generic field flattenner, I use the Stellamira on my ST120 (https://www.firstlightoptics.com/stellamira-telescopes/stellamira-2-field-flattener-with-m48-adapter.html)

It looks like the flats should have done some compensation. Just looked like they hadn't been applied. I've not used any of the cloud file-sharing systems, but I'm sure that some cloud sharing system can host them temporarily, I guess they provide a link for others to download them. Maybe Google Drive can do this?

Yep, it is great to start to find yourself getting pleasing results, everyone here has been along this journey and appreciates how much of a time, energy and a learning curve we all have to go through to get to where we are now (and all the frustrations of failures here and there). Keep going!

To be honest, I found your TIF file didn't look like flats / darks and bias had been applied, so difficult to really get anything from it, once I tried to remove vignetting, remove light pollution, calibrate the background and calibrate the star colour I found a lot of anomalies that I would normally expect to have been removed with Darks / Flats & Bias. Actually, if you want to provide all data, darks, flats, bias & individual exposures, I will quite happily try and put them through an semi-automated process and see whether we get anything better? Not sure how much data that would be, probably a big download.

You definitely need the flats. I think your darks are adding future processing potential to the frames too. I'm not sure about the rest, I have a CMOS camera, and use bias, flats & darks myself.

Hi Steve, I've seen the Australian guy on his star stuff you tube channel apparently routinely cleaning his lens with a regular house dusting cloth, and his pictures seem to remain great. I would avoid chemical cleaners, or anything that has an abrasive feel to it, I tend to use compressed air cans from amazon, to get rid of dust on the imaging train, without an actual visual inspection it is difficult to give advice, if there is an obvious blemish on your optics through a visual inspection then you will need to remove it. But it might be best to consult with the manufacturer of the optics first to get an idea of the chemical concentrations of any fluid you might think of applying to clean it off.

Welcome to the journey, we're all on the same road here. About budget - take care here, as astrophotography is not a one-shot (excuse the pun) deal, you spend £500 today, and next week/month/year you want to spend another £500. You might want to think about how much you want to spend on this hobby over a certain amount of time, rather than have a one-off budget and think that it will tide you through for the remainder of your interest in this subject. You will want a DSO camera, you will want a good equatorial mount, and you will want some decent optics. Combining all three of those will take maybe all or more of your current budget. Once you have all three of those, you will get cold, and you will start to look at things like auto-focusers, controllers, and all those things that help you actually stay inside in the warmth while you operate the equipment. The flip side here, is if that if you skimp on the quality of any of the above requirements then it might impact your results, and hence, your enthusiasm. I would definitely look at second hand rigs that might be on sale out there, they are often a bargain, and you can augment your equipment with some top notch stuff at a later date, it is a journey.

The Apollo astronauts did not mange that quality of photographic detail during their descent and they were actually on their way there, you should be proud of those pictures, and also the fact that you can produce them with an ubiquitous device like a smartphone. You can see a blue chromatic aberration to the right of the exposures, you might be able to compensate for that with some processing, but great to see those and always inspiring to go further.

There is great central detail there, I'm not a fan of diffraction spikes on stars. Maybe concentrate on reducing what looks to be edge interference, perhaps just a bit of vignette reduction, or cropping.

I had never heard of Stellamira before buying a field-flatenner built by them, they've vastly improved my FOV overall-focus, so their triplet looks really intriguing to me now. I think an Esprit Pro, if you can afford the outlay, would be a good investment, I'm looking at the 120mm as a future purchase.

If you're getting quality shots like that, I wouldn't agonized about a few tints! Good job!

I appreciate your helpful comments: https://www.coochey.net/?p=286 PS - No images in view until around 31' to the video, so if not interested in anything other than than FF to 31'

I have siril installed, but tend to use APP. If I get time I will try and get the hang of it and use it with one of my datasets, record a video session, and post it to my website as a tutorial, but as I say, I have been so impressed with APP (paid product), that I stopped using it. I blog my progress: https://www.coochey.net