Planetary Getcomics

[Ambra Piszczek]

PIPPis a program for the pre-processing of planetary images before stacking them with applications such as Registax. You can load a sequence of images from supported video files, SER video files, etc. Image editing operations include cropping, centering the planet, calibrate frames, applying noise/gamma, and splitting color frames into R, G, and B frames.

I've been following this too and intend to try it when the sun gets higher and clears the house. I tried a few time lapse captures last summer and despite having decent PA (fixed pier) I was getting some drift over a couple of hours.

I tried Sharpcap's solar guiding several times and gave up, I couldn't even get a consistent calibration. I considered a dedicated solar guider but they cost a ridiculous amount of money for what they are.

Thanks to @Starflyer for bringing this new thread to my attention. For beginners, I highly recommend familiarizing yourselves with the basics and accumulating experience using the standard and well-regarded PHD2. I have developed an extension for the open-source PHD2 project to enable Solar and Lunar guiding, which I've named the Planetary Tracking tool. The aim of this new tool is to enhance PHD2's capabilities, allowing it to lock onto larger celestial objects with circular edges by identifying their center and using it as a "virtual star." This enables PHD2 to maintain its position locked on not only full round disks but also any crescent shape, such as the Moon in its various phases or the Sun during an eclipse.

The tool is in the advanced stages of development and has so far received positive feedback from a few beta testers (including my own limited testing). I have created some initial documentation; however, due to numerous developments and changes to the UI, I've fallen behind in updating the user manual. Instead, I've been issuing periodic updates on the FB forum with instructions for the proper workflow and tuning some of the detection parameters. Currently, the tool is maintained in a separate branch within the forked GitHub repository, and, as of now, binaries are available only for the Windows platform. I'll share more useful information later, but for now, here is the download link for the latest beta

I hope the following post will be beneficial to this community and clarify the recommended workflow. Yesterday, I managed to test the PHD2 planetary module for solar imaging with my rig, which includes an APM107/700 APO, Rainbow RST135-E mount, DayStar Quark Chromosphere, and a Player One Apollo-M Max camera for imaging. I also used a 162mm guide scope with a Player One Mars II Mono camera for guiding. The main imaging scope is equipped with a Baader ERF rejection filter, and in front of the guiding camera, I have a stack of Player One 1.25" ERF with a couple of ND1000 filters mounted.

After roughly focusing, I tuned the planetary detection parameters by setting the min/max radii to closely match the solar disk's size, setting the min radius about 10 pixels less and the max radius about 10 pixels more than the actual solar radius. I used the Eclipse mode for detection, which will soon be the sole option in my software for full planetary disk detection (surface feature detection will remain unaffected). Tuning the Edge Detection Threshold is a two-step process: I start with a value that allows the disk to be detected and show the green circle - a good starting point is a middle value. When PHD2 finds the solar disk, it displays its radius, and with the correct guide scope focal length setting, the radius in arcsec should be around 900-1000 (shown next to the radius in the star profile window).

To fine-tune focusing, I toggle from radius display to 'SHARPNESS' in the star profile window by clicking the 'RADIUS' label. I adjusted the focuser knob in small increments and observed the sharpness value peak in the Star Profile window. At this point, the sunspots were distinctly visible. Once the focus was set, I went back to fine-tuning the 'Edge Detection Threshold' by enabling the 'Display internal edges/features' checkbox, which shows the internal contour edges used by the detection algorithm. When set correctly, the red contour should closely follow the solar limb and remain stable without showing random artifacts or jumping 'hairs.' It's best to set this value close to its maximum and ensure that detection remains stable. Lower values may be necessary when the signal is weakened by clouds or when the object becomes thin due to an eclipse or crescent phases.

After achieving focus and stable detection, I ran a PHD2 calibration using the same workflow as for nighttime astrophotography. The choice of guiding algorithms is up to personal preference and experience; some may prove more suitable for solar photography, which will be determined experimentally. My rudimentary polar alignment resulted in a 10.7-degree orthogonality error in PHD2 calibration results. Nonetheless, I started guiding and ran a 1-hour and 40-minute capture session using SharpCap. PHD2 maintained the Sun's center with a total RMS of 0.7 pixels or 2.6". Despite poor seeing and potential tuning needs for my Quark, the session served as proof of concept. I'm sharing the resulting video, which has been stabilized and processed for contrast.

After capturing the movie, I attempted to improve polar alignment by using PHD2's Guiding Assistant tool and manually adjusting my mount's azimuth/altitude. In about 10-15 minutes, I significantly improved the polar alignment (see attached image in the comments). If time allows, I recommend trying to improve polar alignment before your imaging session. A few iterations with the Guiding Assistant, minimizing both RA and DEC drift rates with small mount adjustments, can make a difference.

I hope sharing my experience proves useful to you. Happy imaging and clear skies!

Attached below are few screenshots showing PHD2 guiding in action, a screenshot of SharpCap and two different PHD2 calibration results - the worse one was actually used to create the timelapse, and the improved one - after using Guiding Assistant and attempt to tweak the Alt/Az of the mount.

Recalibration is not required during the tuning - the GA will turn off the guiding anyways. Just watch the slopes and trends to minimize the drift. Before adjusting the knobs, exit GA and stop guiding. Turning the knobs too far may push the Sun away from the frame, so be careful. This is an iterative procedure but with some patience it will be rewarding. But, at the end, when you reach low drift rates in both axes, you'll definitely need to recalibrate.

* Add pause/resume planetary detection button to enable handling brief periods of cloud cover and totality during eclipse. Still, if for any reason the object will drift away from field of view, PHD2 won't be able to locate and bring it back to center when resuming. The button is enabled only while guiding is active.

* Integrated UI controls for reviewing and setting the mount's tracking state and selecting tracking modes. Tracking rate should be select as the beginning of PHD2 session - before calibration and guiding.

* Implement logarithmic scaling for the Detection Sensitivity parameter in the Surface Features Detection algorithm. This modification provides a more intuitive and practical control over the algorithm's sensitivity.

I followed your instructions on the blog regarding STAC (Introduction to the STAC UI in ArcGIS Pro (esri.com)). However I get very confused in this part (please see pic below)where we are supposed to create a cloud storage connecton file. Can you elaborate on the this part? Does it mean I need to create my own Azure account first?

This documentation describes how to create the cloud storage connection files -app/latest/tool-reference/data-management/create-cloud-storage-connect... Be sure and change to the Python tab and the last python example you'll see is for creating the connection to Microsoft Planetary Computer (MPC) Landsat collection. The unique aspect here in CreateCloudStorageConnectionFile function is around the concept of connecting with "token vending service". For each collection in the MPC there is a different set of parameters that you'll name to make the connection. Specifically, accesskey, bucketname, and ARC_TOKEN_SERVICE_API will vary.

PLEASE NOTE: If you are intending to conduct any analysis at scale, do deploy a virtual machine with ArcGIS Pro in the Azure West Europe region right next to the data. You can do this manually or through the Azure Marketplace AMPC listing -4mpc-template?tab=Overview and take advantage of the options that you need for your particular workflow. More info on the AMPC here: -planetary-computer/latest/help/get-started-with-arcgis-for-micro...

I have one more question though, if I would like to access other collection listed in the MPC catalog(i.e. modis product), how could I get the parameters needed to create the connecton file(please see pic below)?

Thanks for the update. Glad it is working for you. To create ACS for other MPC datasets you'll need to first gather the parameter values from Microsoft's Planetary Computer Data Catalog. For example with MODIS Surface Reflectance 500m the dataset overview page provides a STAC Collection link. Use your browser to open it and search for the values of these three pieces of metadata:

3a8082e126