Simon Pepper

Hi all I am after some advice please (posted this one before never got to the bottom of it)! I decided to put away the widefield scope and use my ES127 to get an image of M13. However the reason I put the scope away has come back to haunt me. I cant get rid of this dark spot from my images and I don't even know what it is. Seems to dark to be a dust moat? Whats really odd with this is I use the same camera, filters and filter wheel on my widefield scope and I do not see this mark. I do shoot using NB on widefield and this is RGB, but clearly its not the filters as its on each one and as I shoot NB same camera it cant be the camera? I have looked down the ES127 and it looks clear. Yes there is some dust on the lens, but nothing that could make this mark? I see the master flats contain the same mark, but no matter what I try they will not remove it from the image. OTA where I have this: ES127, hotech field flattener (could it be that)?, ZWO1600mm Pro, EFW7x1.25, Baadar RGB filters OTA where I dont see this: Redcat51, ZWO1600mm Pro, EFW7x1.25, ZWEO NB filters Any ideas on what to try or where to clean even will be awesome. Also on a separate one I am still learning RGB imaging, but when I combine my images they are far from what I would call natural colour in the stars all the starts are one colour! Is this because I do not have matched amount of time on RGB? I had an hour on G and R and only 30 mins on R. (clouds)! This was a quick test to see how the scope performed on M13 and I was planning on a lot longer integration, but its going back in the box if I cant figure this one out! Thanks

You won’t regret it! Depends how much the wallet can stretch. If you get Sii and Oiii at a later date you will wish you got the 7/8 position EFW as it’s a pain opening it up and swapping out RGB. Also you will ideally want an EAF as well mono soon gets pricey! To save some dish you could always look on ABS or here for a second hand one that’s how I got mine and been a dream.

Hi I actually sold my 294MC pro and got the 1600mm bundle and gosh I am glad I did. The difference is image quality is very noticeable. That being said though it is a learning curve and it sounds like you are fully aware of this. I would definitely not go back to OSC now though. With the 294 I paired it with lextreme and got some good results and you won’t be disappointed but I put money on you going mono one day! Just need to save the pennies for a 16bit MM now!

Yep my exact setup 😂

Thanks Steve make it happen:) 1600mm pro

You won’t be disappointed!

Let me persuade you…

After a few years of imaging I decided to take a little dip into bino viewing with the possibility of getting some eye pieces for my scopes and after checking reviews on here these beginner cheapies seemed to be best buck for your dollar. Had a look through and they seem sharp to me! FLO great as usual with me a day later and clear night tonight will be binning the “may contain clouds” sticker 😂 the gin well as it’s Friday!

Thanks I missed this as well but will watch it on iPlayer. Great presenter

As expected astronomical events clashing with rainy terrestrial ones 😂 maybe next time

Thanks Stu I’ll get setup then 🙂

Hi all finally got a clear night tonight anyone know if this SN is still visible? Thanks

Reading this I wonder if all this imaging I am doing I miss the visual side to this hobby! I really need to sort this. Thanks for sharing!

This sounds awesome what bortle sky is this a 1 or a 2? Thanks

Hi you will need some capture software so either an ASI air pro, Nina or APT. Are you using one of these?

Well done all three awesome images there! Thanks to Martin as usual for putting together and the judges as well!

So I put the camera and filter wheel on another scope and got this so must be the camera sensor? Can’t be filters as it’s every filter so only leaves the camera? I will calibrate my new image on the other scope and see if they appear in the lights. Anyone got any other ideas or things I can try to fix? Thanks

Was this with a dslr or dedicated? Thanks

The focus may have changed on the NB filters as not used them for a while but certainly not on the LRGB ones as that’s what I used for M101. I keep seeing people mention darks are important as well in subtracting the flat I am using a dark library where the stack was taken through the Ha filter but fairly confident that should not impact this as it’s a dark? I’ll keep running some test here like trying to manually calibrate in PI. Not done that before so will have to check out a tutorial.

I took a flat for each filter and a simple stretch applied to each this is how they look don’t understand why they are not calibrating out. not sure why the vignette changes either per filter but probably a valid reason for that… L Ha S O R G B

Haha thanks Scotty yep tried that still there no idea what to do

I retook the flats and its made no difference. Just so I can rule most out what do flats not correct for? Could whatever this is not be dust and not being removed? Thanks

Hi Olly Thanks for this detailed answer and glad you are as confused (or almost) as I am. I have never had issues in the past with flats this is why I'm stumped. I only removed the camera after doing the flats as was concerned it was something on the sensor. however as noted nothing there and by the sounds of it you are too convinced they are further down the OTA. I have put the camera back and should be same orientation as it was to being tight so I will try running them again and see what happens here. I use PI that allows you to move a window over and to me it looked like they were matching up perfectly. As mentioned all the masters looked the same LRGB and FLATs but I assume they would as I was trying to match the ADUs vs exposure length. Thanks

Hi SGL I have been imaging for a few years now and always take my calibration frames, however the last couple times I have done this I cant see the flats are being subtracted/divided from the lights? The artefacts are present still in my master light as well as the master flat. I have not changed anything in my workflow and I cant get them to go.... A few additional details: The artefacts are present on all LRGB filters, so they must be on the sensor (I have checked cant see anything) or somewhere else in the OTA. I use the white tshirt method and AAP so set the ADU value around 27000. I was a bit lazy with this and didnt take the scope outside pointed it through a window but they look good I thought? I use WBPP in PI but OI have also tested in DSS and get the same issue so this must be an issue with how I am taking them I think? I have tried a million settings in WBPP and cant remove them. I will try taking them again but wanted to check to see if anyone had any other ideas? Thanks

Ok this makes sense and very interesting I didn’t know this existed so great Info. Next question which hopefully someone can answer how is that down in Pixinsight using the weighted pre batch processing? Thanks