CraigT82

Here is a couple of threads with images of blooming.... https://www.cloudynights.com/topic/685884-blooming-with-kaf8300-sensor/ https://www.cloudynights.com/topic/486989-unusual-blooming/ The effect is much more noticeable un unstretched images and sort of gets lost in the glare during stretching, but is definitely still there. My plan going forward, is to shoot much shorter RGB frames and use the round, nicer coloured stars from those to replace the wonky stars in the long exposure narrowband stacks. Not sure if this will work or not, not even sure how to do it but there's bound to be a tutorial somewhere.

Very nice images, especially for the LP but your ED80 seems to have a diffraction problem 😉

I don't actually use the flats wizard in nina as I already know the exposures required for each filter from using the flats aid in APT (from before I switched to nina for it's autofocusing capability). I just set an empty target sequence in nina with the correct exposures for what I need for the filters used and run that. Sorry not much help!

Baader VIP barlow works as a T2 modular system. Very good barlow by all acounts

Someone should tell that to this 20 year old plywood dob still wearing its original varnish and working as well as the day it was made 😉

Yes the attachments are a bit of a fiddle with the ZWO one too to be honest. The back side of mine attached to the filterwheel using a T2 thread, this thread is a kind of three pronged dovetail ring (hard to describe!) which first screws onto the FW and then the body of the OAG goes onto that and secures using three thumbscrews. The prongs of the dovetail (being the thing which the screws bear against) are about 20mm wide so you have this amount of rotational adjustment for the body of the OAG. The front of the OAG has a 48mm thread, and it comes with a 48mm to 42mm step down adapter, which is what I use to attach to my M42-2" nosepiece (my moonlite focuser doesn't have any threads on the drawtube so I'm limited to using a 2" nosepiece). One thing I'd say is that I made good use of a set of Baader delrin M42 thread spacers, in order to fine tune the final position of the guide cam once everything is all screwed up tight (because of the FW the guide cam could only stick out one way (as pic below)). Oh one other thing with the ZWO unit, I had to file down the threads on both my T2 nosepiece and the M48-M42 step down ring, as when screwed up tight into the OAG the threads fouled the prism stalk.

I connect the camera and mount in PHD2, check right profile is selected, complete the calib and GA, run a test guide for a couple of mins to see if there is nay obvious issues and to check what guide exposures I want (if seeing looks poor I'll increase the exposure from my default 2s). Then I stop the guiding test and leave PDH2 open and go back to nina, when I start the sequence in nina it automatically selects the star and starts guiding, and the pauses/resumes guiding during autofocus routines, slewing etc. Would be awesome if NINA did all that but remember we are talking about a free application that one bloke built in his spare time.

I've just started using an OAG on my 1200mm fl newt (ZWO OAG), once set up it works very nicely with minimal fuss. Getting it set up can be tricky though, particularly finding focus with the guide cam. I did it at nighttime and lost precious hours faffing with it, I'd definitely recommend doing it in the day by pointing scope at something far off! Oh and be prepared for weird star shapes in the guide cam. Mine look like boomerangs but PHD2 seems to identify the centroid correctly and guides on it nicely. I tried moving the prism further in but didn't seem to make any difference to the star shapes.

My own workflow with NINA is: 1) Start Nina, connect camera, filter wheel, focuser, scope and guiding. Set camera to cool 2) Go to PHD2 (which opened when I connected guider in NINA) and run calibration and GA in there. 3) Back to NINA to set target, framing, sequence and start capture. NINA then starts, pauses and resumes guiding as and when necessary. Works perfectly so far. I agree it would be good if NINA ran the calibration and GA automatically but it it think that's a step too far for it currently

Wow the fine detail in both of these captures is outstanding. Those Redcats really punch above their weight

OK have been looking around on t'internet and have seen a lot of images showing the horizontal blooming of 8300 sensors and am now convinced that is the issue (with the bright stars at least). The dimmer stars are still not round but that is a different kind of 'not round', and is down to poor guiding the other night, so not overly concerned about that right now. Getting a 130pds should solve both issues 😂. Apparently something to do with the shift register... lot's of info over on CN.

Thanks Adam, I hope it is blooming actually as its the simplest to solve - buy a new scope (lol!) A 130pds was always my logical next step as the 200/1200 dob tube was just to get me going. I will just need to get one sooner than planned and stick to fields with faint stars in the meantime. Certainly not a fault with the sensor, more of a quirk!

I've been getting some funny star shapes over the last couple of nights when running my 383L binned 2x2 which I initially thought was either terrible guiding or pinched optics, but having a look at them closely I think it might be horizontal blooming as only the brightest stars are affected, which from googling is apparently something that can affect the KAF8300. Can anyone confirm if this is the case? Maybe you've seen it before? If it is horizontal blooming then I think will just have to place an order for a 130pds and stick to unbinned imaging. Image attached is a single 1200s sub (linear & uncalibrated). Star in the centre is mag 6.8. Star at upper left is mag 5.8. Cheers

Both really lovely images. First one for me as I prefer the star colours in that one.

That is stunning! How on earth do you get the stars so beautifully smooth and sharp?! I have so much to learn 😆

If you select tif or fits as the output file it will give you 16 bit images.

Excellent work Geof, well worth the effort.

Yes you can definitely set it to either average or sum in pipp, and you can load up and output fits files too. I just need to caveat this by saying I haven't tried it with deep sky images, but I was very pleased with the SNR boost using the sum method when I was trying to lucky image the minor components of the trapezium with my 290m recently.

You would prob be better off just collecting the data as normal and then binning the colour channels yourself in software later (pipp is pretty good for this) you can set the binning method , average/sum and it should approximate the same benifits you get from hardware binning a CCD. I've binned lucky imaging data from my 290mono like this before with decent results

That really is fabulous! I noticed from your Astrobin that you used to image with a 200/1200 newt, do you still use it at all? I've just started using mine for DSO imaging and it seems to work pretty well so far with not too much coma (for me anyway)

Have now combined the Ha (Bin1x1) with the S2 and O3 data I captured on the 28th (at bin2x2) to produce HOO and SHO images. There wasn't much data in the O3 and S2 and they had to be severely stretched. Will try again for more data when it's clear and without a full moon. I have no idea how to do these combinations properly, I believe you don't just assign one channel to a colour but rather you blend them in together for each channel in various proportions? These are just strap swaps - one NB channel to one RGB channel, and with a lot of tweaking of the colour balance to get it to resemble other SHO images online!

Also you don't really wanto to be trying to guide through NB filters? Or does that work ok?

I'm pretty new to long exposure imaging but I stacked two nights worth of images on the same target together and it worked really well

My god I hope you never get stopped by the police you will have some tough questions to answer

Yeah I know what you mean. The other night I came inside and went to bed then woke in the morning to find the laptop controlling everything in the middle of a forced update... luckily it started towards the end of the sequence and I didnt lose too many subs.