Is it possible yet to preprogram a series of flats, where SGP will command the rotator to move to proper angle before starting the flats for that target? Right now I have to tell SGP to move the rotator before the flats for each target, so if I’m taking flats for, say, five different targets, I pretty much have to sit at the keyboard the whole time. Can it be automated?
Kevin
It is possible, but not in a great way… meaning that SGPro must have access to plate solving to do it right now… obviously not ideal unless you have a mechanized flat panel. We have this on our list for 4.0, but I am still not 100% sure how to expose it to the user without creating a confusing experience. I’ll need to think about it a bit. Right now I am leaning toward event options that allow a mechanical angle to be set prior to execution. The choices would be any number between 0 and 359, but also a list of targets that contain light frames where choosing one would use the mechanical angle that corresponds to that target’s sky angle.
Ken, thanks for looking into this. If the second option would pull the mechanical angle (and maybe the filters also) straight from the lights in the same sequence, so that the user doesn’t have to enter it, that would be fantastic. That eliminates yet another source of user error, which I always appreciate since I can break pretty much anything I touch. 
Kevin
I may be an idiot but as the flats are to eliminate sensor dust and dust close the focal plane the rotation angle is irrelevant but for lopsided vignetting issues and central obstructions, it does make sense: which I why I swore off complicated optics and stuck with refractors and a clean objective. I use a Pyxis rotator during acquisition and typically shoot sky flats the next day without changing the rotation angle but preserving the focus for each filter at acquisition time. Of course Pixinsight spoils me taking care of that during calibration with the bias and darks.
@astrovienna: I use an Alnitak Flip Flat and a NiteCrawler WR 25/35 RotatorFocuser and my workflow is like this: Slew and center Target, take Lights then Flats with same rotation angle, Slew and center/rotate the next target and again lights and flats. when everything is set up properly I can sleep whole night its all automatic. regards from vienna ; )
drcr: I image with a C11, and the dew shield has an inside diameter of about 14", so my only real option for flats (other than sky flats) is a large flat panel. As far as I know, there’s no way that can be operated by SGP.* If it could, I could basically do it the way you do it with your Flip Flat, which would be great.
Just checking back in on this. Is SGP4 now able to automatically read (or permit the user to manually enter) the mechanical rotator angle, so that we don’t have to platesolve before each set of flats?
I just made a list of all the targets I need flats for, and I’m looking at a couple hours of babysitting my setup to get through all these. (Yes, I’ve been neglecting my flat-taking duties!)
A related question: how do I know what mechanical rotator angle to use for flats? Right now, I set up my filenames so that SGP automatically writes that angle into them, so I just read that angle from the file names. But I’d prefer to shoot flats in advance. How can I know what angle to use?
Kevin
Checking in on this again. Is this feature in the plans for the next release? Once again, I’m looking at a long list of flats that I need to take, which again means that I’m going to have to have keep nudging my rotator for a couple hours.
Kevin
Another six months have passed, and I’m sitting with yet another long list of flats that I have to babysit SGP through. Anything in the works at all?
Possibly… I have not tested it for this exact purpose, but if you want to grab the 4.1 beta and give it a shot, I think any issues would be pretty easily corrected to make the new functionality work for this purpose. It’s not documented yet, but you should see a new section in the target settings that will allow for an “unverified” rotation analogous to “slew” vs “center”. They are both the same thing, but center is verified in a closed loop and and slew is just blind.
I think that I will add one more option here so it will work like:
I thought about this for a few minutes and I think it’s not possible to use a “sky angle” for a sequence dedicated to flats. There is no way for SGPro to know a sky angle with at least one solve. I think the current implementation in 4.1 needs to remain as is or SGPro will just be guessing. In any case, you want to use the positional angle for flats frame anyhow. The question is now, what is an easy way to say that a target should move to the last know positional angle of a paired “light event”? In any case, that will not be part of 4.1, but if you pull the PA out of the FITS headers before you start the flats sequence, at least you won’t need to babysit.
Hi Ken - I wasn’t clear enough about how I shoot flats. I can’t shoot flats at the end of a session because, even if SGP could handle the rotation issue, my C11 would probably need a flat panel like 4 feet across on the wall of my obs. I don’t need SGP to shoot flats automatically at the end of a session, so hopefully my problem is easier to solve.
I usually shoot flats for several different targets in one “flats shooting session.” I create a sequence in SGP with all my targets and the flats to be taken for each. But between each target, I have to stop SGP and manually run the rotator to the correct angle for the next target, then start SGP again. That’s the babysitting part that I’d like to avoid. If, while setting up the flats sequence, I could enter the rotator angle for each target, SGP could run the rotator to the correct angle by itself, without my manual intervention. Is that possible?
Kevin
I don’t understand why you care about the rotator angle for flats. Dust mots on the chamber cover glass or on the filters are in a fixed position with respect to the camera and don’t change based on the position of the rotator.
If you are taking flats because of dust mots on the mirror/lens/corrector, then that is probably not necessary. A dust mot at the distance of the mirror/lens/corrector would be so far out of focus as not to be visible on a flat (or on any image).
Charlie
I think my comments above are applicable to this unless we are just totally miscommunicating in new and fantastic ways. For this flats session, before you start it, set the positional rotation angle for each flats target. You can get the PA from any light frame of a target. Press run, come back later, no fussing with the rotator during the session. What am I missing?
That’s what I do, and SGP shoots the flats for each target, but the rotator doesn’t run. I thought the rotator won’t run unless a plate solve is done first? If it helps, here is a target settings window that I used for shooting flats. The rotator was at 48 degrees when I began this sequence, and it stayed there. There are five targets in this flats sequence, each one at a different angle.
I feel like maybe you missed my post above discussing the new 4.1 features for rotation
I get it now. I confess I saw your second post first, and since it seemed to say “never mind,” I didn’t pay close enough attention to the first one. Let me try that and I’ll let you know. It would be really nice if that solves it.
Is positional angle the same thing as mechanical angle? Positional is used in Target settings, but Mechanical angle is used in the Rotator Docking module. I just installed a Moonlite WR35 and trying to understand the terms. Thanks -Phil
I use Eagle3 Pro!
