Mike's Astrophotos

Here are my astronomy photos. Nothing exciting, mostly works in progress as I learn how to do this.


First, the good stuff: (click on them for larger versions)

M16

M16 - Eagle Nebula

M20

M20 - Trifid Nebula

M27

M27 - Dumbbell Nebula

Reprocessed 6/1/2019

M92

M92

M13

M13

Reprocessed 6/1/2019

M42 - Orion

M42 - Orion

Pleiades

Pleiades


Now, my rantings:


Fungus Eating Stars I was imaging the Trifid Nebula the other night. When I processed the subs in PixInsight, I got this crud that looks like some fungus eating the stars! Some weird artifact.

PixInsight's BatchPreprocessing script is using some unknown parameters for integrating the registered subs into the master lights for each channel. If I do the ImageIntegration by hand, I get a much better result.


Red Vignetting I keep getting red vignetting after doing flats and background neutralization. I'm not sure what I'm doing wrong. Time to reach out to the astrophotography community.

I forgot to do ABE (AutomaticBackgroundExtraction) before doing BackgroundNormalization!


M92 After doing M13, I had to do M92 since it was the next one in line.


M13 I reset the settings on my AVX's hand controller and realigned the Dec spur gears. That greatly improved the PHD2 guiding as can be seen here. A half pixel RMS error is about as good as I'm going to get from my currect setup. Unfortunately, that's a half pixel on the guide scope, which equates to about a pixel and a half on the main scope. Until I switch to off axis guiding, I'm going to have to live with it. Binning 3x3 should help make the two pixel scales match better, at a lose of resolution in the final images.

The better guiding allowed me to try to takes some images of actually astronomical objects. So I aimed for the tried and true M13 globular cluster. The data came out pretty fine but I had dust spots.

So I went thru the process of creating flats for each channel and used PixInsight's BatchPreproccessing script to generate all of the masters. I then combined them together using the LRGBCombination process. That image still has dust spots from the L filter! Argh! So then I recombined the masters, leaving the L channel out this time. The results are much better with more pleasing colors.

The concensus on CloudyNight's is that the filter wheel was not returnign to the exact same spot due to the wheel supporting bidirectional travel. The suggestion was to force it to use only a single direction. That helps about half the time. The same night that I took the M13 image, I also took one of NGC 6888 - the Crescent Nebula. It doesn't have a dust spots left from the L filter! Although if I leave the L channel out again, I do get more staturated colors.

And that brings me full circle. It was the Crescent Nebula that started me on this whole astrophotography journey!


More guiding In order to try to get better guiding result, I chnaged my guiding scope to an Orion CT-80 with a 400mm focal length. It's brighter and has alonger focal length than my old Orion 50mm with a 2X Barlow on it. It's a lot bigger scope than I had anticipated!

After doing a drift alignment on Friday night, I attempted to get PHD2 to calibrate my new setup. The calibration review looks good except all of the Dec return data points are stuck on the left end of the axis. And yes, PHD2 did give me an alert about no south movement being detected. It seems I have a severe backlash issue with my Declination axis. Everything points to this being a hardware issue with my Celestron AVX mount.

But despite the Dec issues, I went a head and did some 5 minute exposures of M101. The tracking in the subframes looked pretty good, especially in RA. The Dec history graph was showing too much jitter of up to 4 arc seconds on ocassion. It also appeared that PHD2 was having to work a lot harder to keep Dec under control with frequent corrections. A lot more frequent and more intense than what it needed for the RA axis. But despite all of that, this is some of the best and longest tracking I've attempted so far!


M104 Mono Here is a mono image of M104, also know as the Sombrero Nebula. This is thirty 90 second frames stacked together.


AVX Pier Adapter Here is a design for an adapter for my Celestron AVX mount to a permanent pier. There will be a bottom plate that this adapter bolts to thru the 4 outer 1/2" holes in this plate. Rev B is made out of two pieces.


My guiding typically sucks. It suffers from a sawtooth oscillation as shown here. After some discussions with the AZ-Observing crowd, I decided I needed to learn how to do "drift alignment" in PHD2 since I can't see Polaris from my backyard. I followed this PHD2 Drift Alignment Tool tutorial. After some false starts because I was trying to start guiding before invoking the tool, I got much better results.

I also decided to train the PEC (Periodic Error Correction) of my AVX mount to try to minimize the guiding error. I followed this CloudyNights post. That was straight forward other than finding PEC Tool on Celestron's website. Their search function wasn't able to find it no matter what I searched for. So I went to the Downloads page and use my browser's text search. It found PEC Tool right off the bat!

After doing the drift alignment and training the AVX mount's PEC, I got much better better. This is with a single PEC training run. One of these nights, I'll retrain it using PEC Tool to average 5 or 6 runs. That's reported to give a much better characterization of the worm gear's periodic error.


M42 Orion 20190227 - A reshot Orion with PHD2 guiding working. I think it's a much better image than last month's. This is composed of fifteen 90 seconds exposures for each RGB channel. Or increase the contrast a bit more.


M36 - The open cluster M36. I find open clusters to be kind of boring. But the tracking was good. Ten 60 second exposures for each RGB channel.


NGC2024 Flame Nebula - This is a pretty poor image. It's the one that suffered from "water spots" which were identified as dust by the AZ-Observing guys. Most of the dust spots were deminished in the normal PixInsight processing but the image still has a lot of "grain" in it. This is five 90 second exposures for each RGB channel. I don't know why Alnitak has a purple/green fringe.


M42 Orion 20190124 - My first attempt at doing separate RGB channels. I clibrated, registered, and integrated each channel seperately in PixInsight. Then I registered each of the channel masters and combined them together into a single RGB image. I probably should have calibrated and regsiters ALL of the images together in one operation. Then integrate each channel and finally combine them together into a single color image. I'll try that next. And yes, I have the blow out in the center of Orion that is common in simple images of it.


Pleiades-20181005 - Seven 3 minute subframes stacked, taken at the 2018 All Arizona Star Party.


What is it? - Old image I found. What is it? Is it real? The guys on AZ-Observing think it's lens flare. But the bright star doesn't show up in Stellarium. The two to the upper right of the bright center object are HIP 81754 and HIP 81632 according to Astrometry.net. So I'm still puzzled.

And this is where I think it is on Stellarium's star map.

One of the guys on AZ-Observing figured it out. That bright "star" is Saturn! And that explains the ring shaped reflection just to the left of it. I have to remember that static star maps don't show those "wanderers" unless you have the correct date entered.


Pleides-20161023 - Single frame 60s @ f2.8, ISO 800


Crescent2-20180623 - Better processing in PixInsight


Crescent2-20180623 - Decent, needs beter processing


M13-20180611-raw - Noisey


Crescent-20180610 - Bad focus!


Saturn-20180609 - Rings and a moon!