After 5 month absence from imaging due to mostly bad weather and some personal things to take care of, last night I had a wonderful experience of 7 hours of uninterrupted sequence run including changing RGB filters, auto focusing, slew to DSO, plate solving, and automatic Meridian Flip including auto centering. My target DSO was NGC 2430. My image is at: NGC2430
Details including equipment are at my web site. It’s below the image so scroll down a bit. This was taken from high light pollution area of Reno, NV.
I have been imaging without Luminance filter lately. Lum with heavy LP just don’t work well together. So I take minimum of 2 hours unbinned for each RGB filter. Sometimes pseudo-Luminance can help by either extracting Lum from RGB combined or stack of RGB subs, process pseudo-Lum and blend or apply to RGB. I have done pseudo-Lum with varying success but lately I use PixInsight’s Curves Transformation using “S” tool to boost color saturation using only RGB and works well.
Great job Peter. Especially nice job preserving the star colors… IMO, it is one of the first things that gets destroyed as you focus on the DSO (and it adds so much depth when done right).
Let’s see if I can remember the exact procedure since I am currently at work.
I looked for reference image of NGC 2403. I use Astrobin and I found one that matches best for my setup.
Click on Gear icon next Target Settings. Copy the url address of Astrobin reference image and paste it to Reference Data.
Click on “Solve” or “Solve Blind” and if solve is successful, it will automatically fill in RA/Dec coordinates under “Location”. Close Target Settings.
I assume you already know how to fill in events for each filter so I will skip this.
After my mount is polar aligned using RAPAS, using hand controller slew to a known star next to target object. “RCAL” on that star.
Focus the star with Bahtinov mask.
Click on Gear icon next to Target Set (in my case "NGC 2403). Target Settings window will open.
Click on “Slew Now” button. It will slew to target DSO.
Click on “Center Now” button. It will center target DSO based on reference image from Astrobin image.
Run “Frame and Focus” to make sure the DSO is in the image and centered. I use binned 2x2 for 1 to 4 seconds.
Run PHD2, calibrate and start guiding. (May not be necessary but I feel safer this way).
Manually run Auto Focus to make sure AF will be successful.
Bring laptop indoors. I use 36ft active USB cable.
Run Sequence.
Watch TV and go to bed if tired.
Here are other settings:
AF every 2C or each filter change. I believe I set to 7 seconds for each RGB filter. I do not use filter offsets.
Flip Meridian 1 degrees past Meridian. Mount settling is 10 seconds. Enabled Auto Center after Meridian Flip.
Auto Guider: Settle at < 1.0 pixels for 8 seconds. High Dither. I use Baader 10x60 finder with Superstar guider and A-P bracket mounted to focuser’s body.
I use Optec’s ASCOM driver and FocusLynx software to set backlash compensation instead of SGP’s backlash compensation.
I hope I didn’t left out anything else. If I left out anything I will fill in other information when I get home from work. Feel free to ask questions in case I forgot other settings.
thank you! this is a great help - I’ll give it a whirl tonight.
A couple of questions:
-the autofocus that would occur due to temp changes or at filter changes… how does that happen? Does SGP slew to a nearby star of the correct intensity? Or does it uses the stars in the target frame itself?
any particular reason you use the handcontroller to do the first RCAL of the night, as opposed to a “plate solve and sync” via SGP itself?
what happens at the end of the sequence: is the guiding stopped? the mount parked? the camera cooler shut off?
1a) From Control Panel an under “Focus” tab, select “Use Auto Focus” and click on “Set” button next to it, it will display “Auto Focus Options” window. You will see “Auto Focus every “X” degrees change” and “Auto focus on filter change”.
1b) SGP uses the stars in the target frame itself. That’s what makes SGP so cool!!!
2) Using hand controller to do first RCAL is purely a personal preference. I park the mount to Ref-Park 1, then slew to the star with hand controller and from then on it’s SGP. I do it because I find it simpler and quicker. Use any method you preferred.
3) That depends how you set up when the sequence ends. SGP offers flexibilities and choices of what you want to do when the sequence ends. For example, under “Control Panel” and “Telescope” tab, you can select “Stop tracking when sequence completes”. Also under “Auto Guide” tab, you can select “Stop (guiding) when sequence completes”.
Please click on my avatar for my equipment list. Mine is Optec/Starlight Instruments Focus Boss II and Handy Stepper motor. I am not exactly sure of the accuracy of the stepper motor thermistor. For example, my last imaging session outside temperature started at about 38F (3.33C) and finished at about 28F (-2.22C). My first image FIT header said -0.8C and last image FIT header said -5C. Delta temperatures for ambient and motor’s thermistor appear to be close enough. I also noticed sometime during the imaging session, the stepper motor reported temperature actually got warmer but eventually reported getting colder, I am not sure if the ambient temperature also got warmer or motor’s temperature got warmer. Overall, I am pleased with my focuser motor setup.