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I am hoping someone might be able to help with a possible way to shoot dark and bias frames on a DSLR (canon 700D) without the need to cover the scope or camera, ideally using APT scripts
My thinking is that the camera, has a noise reduction mode where it will take the light shot, then with the shutter closed it will take a dark frame and subtract it from the light. So could you take a series of dark frames on ATP and lock the shutter down?
If anyone knows I would love to know. Would be great to automate the lights, park the scope and have it run darks and bias, without the need to go out to it and cap up at 3.-4 in the morn
I know, I know, this has been discussed endlessly here and elsewhere, but I've read lots and watched lots and some of it I understood and some of it I didn't. A lot of it I didn't, actually, mainly because every time I think I get it, someone else contradicts what I think I've 'got'.
I've reduced it all to this, regardless of the number of lights I take, assuming I'm using a DSLR, with all the below steps at the same ISO value as the shoot:
Bias - 50 frames with the cap on, exposure time=shortest
Darks - 50 with the cap on, exposure=as per shoot
Dark Flats - 25 with the cap on, exposure=AV mode
Flats - 25 with the cap off, diffuse white frames eg t-shirt with light behind it or morning sun, exposure=AV mode
I know everyone has their own take on this (which is kind of my problem understanding it) but, reducing this to the very, very, very basics, as a starting point for a total noob with calibration... would this work?
I own a polarscope from FLO for a couple of months now, however I have never been able to get a correct polar alignment.
When I screw in the polarscope in the mount completely then the 3 angle is at the top (see picture).
However with this polaris keeps moving out of the circle when I polar align it. (Polar alignment seems not to work)
When I loosen it I can get the reticule to 0, however the polarscope is very loosely in the mount.
How to best get the polarscope correctly into the mount and get an accurate polar alignment.
Hi All, I am posting what I suspect is a newbie mistake question but hoping that someone can assist with the issue of flats.
Although I have been fumbling around the sky, taking snaps at leisure, recently I became serious. I have read up about the different calibration files (flats, darks, bias) and they seemed to make sense; different ways to capture the image defects and extract those from the image of the sky. After a few weeks (months) of further fumbling I went back to the very first target to receive my attention, M42 Orion Nebula.
In short, I took 20x 30s exposures in LRGB and ran these along with 20x LRGB each of darks, bias and flats. To obtain the flats I used a diffuse sheet of perspex (lightbox material) and an LED video lamp that has 180 white LEDs, turned to its lowest setting. Attached below is the stacked Luminance flat and the light image. In the lights I am getting very strong marks from dust and I had thought that the flats would subtract this but looking at the flats the marks are completely different shapes and do nothing to remove them from the lights.
The attached has been further stretched to show the issue. Now, I am obviously doing something wrong but I have no idea what, any pointers from the vast pool of knowledge will be much appreciated.
First post here, and I'm pretty new to AP, just picked up a Star Adventurer mount a couple months ago and have been happily playing around with it with DSLR and various lenses and a 72mm Sky-Watcher refractor. I'm new to the whole setup process, and I'm trying to do a decent job of leveling the tripod/mount, polar alignment, and I should probably think more about balancing the weight of things. I've gotten some decent shots, like 60-120 second subs with up to 300mm lens. My last time out I was getting star trails at 200mm and 15 second exposures, which could have been just a sloppy polar alignment, but today out of curiosity I looked through the polar scope and rotated the RA axis 360 degrees, and I saw that the target circle jumped a few times. I'm guessing that the target circle should appear not to move while the numbers 3, 6, 9, 12 would rotate around as I rotate the RA axis. So my guess is that the polar scope would need to be calibrated?