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Over the past few days i've been gathering data on M31 due to the battery not lasting long and andomeda dissapearing behind a tree, therefore the mulitple imaging sessions. So far i've been out and me being me, only took dark, bias and light frames for the first 2 sessions but for the last one i also included flats... (The lights all have very slightly different settings cause i have been experimenting slightly... that being 45sec @ ISO 400, 45sec @ ISO 200 and 50sec @ ISO 100) Now DSS assinged all the correct bias and dark frames to the corresponding light frames but because i only have flats for my last imaging session it applied those to all the different light frames and not just to the last set...(and due to me moving the telescope / taking the camera off, the dust spots have obviously been moving around and that therefor dont work at all for the other light frames...) So my question: Is there any way in DSS to apply flats to only one set of light frames and if not are there any other apps with which i can do this with?
when applying the flats taken in my last session (to find out what is causing the strange diffraction spikes) with Siril, the final stacked result still shows the vignetting and the dust spots. I also did the whole preprocessing with Nebulosity, same result.
I took the flats as follows:
same iso as my subs camera and focus not touched I use a homemade flatbox combined with the a white t-shirt with Ekos took test shots till the histogram was half-way to the left checked all my flats, they all show vignetting and the same dust spots as in my subs I tried using them with and without using a bias frame, same result, the final result looks as if no flats were used.
Anybody any idea what is going on? An other question I have, will the vignetting and dust spots also show in the master flat (flats stacked)?
Thanks for your help,
I've created my own darks library for my ASI1600mm Pro. Various gains and various exposure times all at -10 Celsius.
I'm just wondering what people do with them? Once you've taken darks and processed an image you get your master darks.
Do you guys just keep the master dark, in a master darks library, or do you process your darks again each time you stack a new image?
I'm just thinking to save storage, could I discard the dark sub frames and just keep the masters? I don't want to throw them away if that is wrong though.
Also, with this camera I take dark flats rather than bias frames. Because the scope is covered, do I need to do dark flats each time I take flats?
I have an even illuminated flat box which I always use at the same exposure lengths. I guess the only thing that could vary is the gain value.
I understand the need for flats every time you change focus, for each filter etc., but if I'm using the same exposure time can I just use a previous set of dark flats as long as the camera settings are the same?
If this is possible, can I then create a dark flats library for any difference in gain values? Not sure if I gain values affect dark flats though.
I've read that back, and that's a lot of questions! All help greatly received.
I've finally got around to making my flats box.
I decided to go for a cylinder rather than the normal square as I thought it would maximize the amount of reflected light and limit any 'dead' areas. I could also use the Celestrons dust cap retaining pins to lock the flats box onto the 'scope.
I purchased some of the craft board that has a thin foam sheet sandwiched between two sheets of thick paper/thin card. In order to bend the card into a cylinder, I creased the board every 20 mm by pressing the edge of a steel ruler into the board. It took two of the sheets to make a cylinder big enough to fit my C9.25, with only a couple of cm trimmed off.
I then made a reinforcing ring/defuser holder from two strips of the foam board; this time creasing them at 15mm intervals. I stuck these level to the bottom edge so the joins were 90° to the main cylinder joins. These strips were cut wide enough to ensure that the diffuser cleared the secondary housing.
The cylinder was designed to lock into the C9.25s dust cap retaining pins so next I cut two keyways into the bottom outer side. They looked a little weak so I reinforced them with some Christmas chocolate reindeer plastic packaging!
Although the foamboard is quite shiny, I wasn't happy with all the grooves, so I lined the inside with white A4 paper. The Perspex sheet was cut to shape and hot glued into place onto the ledge.
Next, starting at the top, I notched the edge of the cylinder to run the LED string lights cable through and then started to spiral the LEDs around and down the cylinder.
The top cap/reflector was made from two discs of foamboard. One to go inside the cylinder and one to sit proud of the edge. They were glued together before being hot glued onto the top of the cylinder. The LED light string that I bought has an integrated on/off button as well as both up and down brightness buttons with a 3M sticky pad on the back, so I stuck this to the top cap.
As I had previously made myself a 'scope mounted power distribution box with aircraft sockets for power, I removed the 3 pin UK plug/ac-dc converter and soldered on an aircraft plug to match my 12 volt DC supply socket.
The lightbox illuminated.
i am having so many difficulties as far as i remember to make some nice flats to match my images.For some reason it it impossible for me to find the secret spot in time and adu for my Flats.
This is my equipment :
Telescope: Redcat 51
Camera: Atik 383l+ mono (i know the shutter problem that's why i always aim for 3sec and above for taking my flats)
Filter Wheel: Atik EFW2 (36mm)
Filters: Astrodon Ha & Oiii 36mm 3nm
FlatBox: Geoptic flat field generator 164mm (dimmable)
Image aquire software: APT Tool v3.71
Software: Astro Pixel Processor
This is what i get...i am uploading some images converted in jpeg for the site...
Photo A is a MASTER FLAT Ha (Bin 1x1) created with 30 Darks, 50 FLats (3.7sec adu 22000), 50 Dark Flats, 100 Bias
Photo B is a MASTER FLAT Oiii (Bin 2x2) created with 30 Darks, 50 FLats (5sec adu 46000), 50 Dark FLats, 100 Bias
Photo C is an example result of stacking my fits of Helix Nebula at Bin 2x2 , with the above calibration master frames (this is the Oiii in this case)
Are my calibration frames Over correcting ? if yes what can i do ?
Is the Optical path problematic ? as i can see at photo A ? what can i do , what to check ?
I have checked also the filter wheel position related to filter change , but it comes centered...i couldn't see a fault on it.
i Believe i have a problem also finding the correct ADU value....i made any experiments by changing the adu value and i have tried at 22000, 32000, 47000 by using the CCD Flats Aid.......but nothing all come out the same.
I hope someone can help cause i am loosing my mind and my fits 😥