Horsehead Nebula - imaging and processing

Dark skies during last Friday's moonless night gave me a chance to work on imaging.  I used my 127mm Explore Scientific APO refractor with the Moonlight focuser, the QHY5III174 monochrome imager, my SSAG guider on the 80mm piggyback scope, all mounted on the Losmandy G11 mount and driven by SkyX Pro via my MacBook running Parallels.  Filters were the Baader LRGB 1.25" set, mounted in a Skyris manual filter wheel.  A previous-night QHY Polemaster polar alignment proved to remain pretty tight.

This is the result of fifty images per color and fifty more for luminance, also incorporating my guide camera through SkyX.  Finished up with 25 images each for Flat, Dark and Bias calibration.

Only 20 second exposures for each science image... I chose 20 seconds due to some issues I've been having with the GHY5III174 monochrome camera reading-out early, before the duration is over, on occasions where I set the exposure length longer than about 30 seconds.  Still troubleshooting that issue.

I found that the guiding plot chart on SkyX showed what I assessed to be too much correction in Declination axis when I checked during the first set of images.  This settled down very well once I decreased the 'Aggressiveness' setting for SkyX guiding.  I did not reshoot the images though, so I know I can improve results in the future.  I will work on improving my guiding optimization next time too, since R.A. guiding looked a bit rough harsh as well.

Processing the approximately 300 images was done via PixInsight.  I'm a newbie on using the software for anything more than a quick histogram correction, but after all day Saturday working through book 'Inside PixInsight' by Warren Keller, I'm figuring out a workflow to integrate, calibrate and correct monochrome images... next time it will be a lot quicker.  I'll write more about that process  later.

Lots more to learn on processing, but I'm ready to call this image presentable.  The size and framing of this image make it difficult to tell what parts of the diffuse glow is from skyglow and what parts are part of the nebula, so I limited my processing so that I don't unnecessarily remove actual detail from the image.

I plan to come back to this target once I fix my camera readout issues so I can get longer exposures and bring more of the color that is clearly visible here.  Thats all for now.

Mark J.

Solar Eclipse retrospective

I began my interest in solar eclipses shortly before the 11 July 1991 eclipse which tracked across Hawaii before crossing Baja California and Central Mexico.  At the time I was working at the Lunar & Planetary Laboratory (LPL) in Tucson following my graduation from the University of Arizona two months earlier.  Some of my colleagues were involved in an eclipse observation trip to the totality in Hawaii, and just the day prior to totality I committed with a friend to drive down to Mexico to try to observe it via hand-built pin-hole projection.  We got close to the path, however we diverted to a beach we knew a bit shy of the 100% line due to fatigue and didn't go any further on the actual day.  No photos were taken, but the love of the event took hold.

More to follow...  meanwhile, here's a picture from the 17 August 2017 eclipse, taken in Casper Wyoming with my portable telescope rig:

5-6 May 18 (a short post)

Successful calibration of the Auto Guider / mount pulse-guiding arrangement  The key issue with all my failed calibration attempts was the hot pixels on the guide camera.

I had never done Dark images for the guider, so all previous guide calibration attempts still had hot pixels on the guide images.  When running those previous calibration cycles, TheSkyX appeared to use the hot pixels instead of a star for calculating tracking rates.

Choosing a star field with very few stars for guiding, it became clear which area of the guide image was being used for calibration, and it seemed to be a single pixel.  This highlighted several consistent pixels across multiple images and made it clear what was necessary.  I processed an auto guide image for dark subtraction and subsequently had my first successful calibration.

With the guider / mount tracking rates calibrated, I can now work to optimize the guider settings.  Current settings:

min move 0.010 seconds

max move 1.00 seconds

aggressiveness - all are 10

results:

M13 60 second clear, guided image

More Galaxies

A few recent updates to the rig...  Current imaging setup:

Explore Scientific 127 APO triplet
Explore Scientific 0.7 Focal Reducer / Field Flattener
Moonlite Crayford Focuser 2.5"

Celestron Five Position Skyris Filter Wheel

Losmandy G11GT Mount

Orion short-tube 80 (F/5) for guiding

Orion Starshoot Autoguider (SSAG)

Explore Scientific 50mm finder

Thunderbolt 2 dock

QHY Polemaster polar scope

QHY5IIIM174 (for imaging)

Skyshed

Next purchase:

Narrowing down my selection for a new imaging camera.

Galaxies:

Captured M51 on the evening of 16 April.  One 4 minute exposure, calibrated with 4 minute dark and a bias image.  Missed the opportunity to get flat field images, so I used some old ones for processing, still pretty satisfied with the result for this unguided image.

M51

Another session last night (20-21 April 18) to capture galaxies.  Also unguided, but this time I did record some flat field images:

NGC4535

M94

Also, here is m81 and m82 in a 240 second exposure, also unguided:

Next session will be focused optimizing my guider parameters.  Looking forward to successful imaging longer than four minutes...



PS: a gratuitous waxing crescent moon shot:

24 December 2017

Tried the Orion Bahtinov Focuser today, and I love it... more on that later

Imaged M33 using the QHY5III174M camera with the Orion 80mm f/5 scope and the Star Adventurer mount.

This is a two-minute capture, no filters, just a single monochrome image.

The three-minute capture was too saturated to provide much hope in the available sky-glow.

Tried capturing images using SharpCap 3.0 as well... Looks like a very promising technique, will develop that capability next time.

Also, a single attempt to image of M45 on my friend's 12" dobsonian...

Will work on the images, and edit this post if I can improve on this quick processing.

ISS Lunar Transit
On 20 Dec 17, the International Space Station transited the waxing crescent moon shortly after sunset, from the point of view of north-western Louisiana.  I found this from the very-handy ISS Transit Finder web app:
https://transit-finder.com/

The interface is very easy and the output makes it simple to optimize your selected location within the transit corridor.  Here's a re-calculated map for that transit...

Interestingly, it has changed by a couple miles today, versus the calculation I did prior to the actual transit.  I don't know if the orbital elements changed since Wednesday or the back-calculation introduces some error...

I used the Orion 80mm (f/5) scope and the QHY5III174M camera again.  Here's the video of the transit, at 10% speed, plus a few zoom-ins and a 4% speed playback:

Thanks to the professionals at Camp Minden and in particular, SFC Jowers for the support at the location.

Since this worked, I'll next plan for a solar transit as well as another with the big scope.

Northern Lights

My wife and I decided to travel the coast of Norway back in 2011 to view the aurora.  As March and October appeared to be the best months to view them, we chose March for a cruise on the Hurtigruten Ferry line from Kirkenes near the northern border southwestward to Bergen.  Six days and five nights aboard the MS Trollfjord visiting about 23 ports along the beautiful Norwegian coast provided us with a very memorable vacation.

We had armed ourselves with a Canon 16-35mm II f/2.8 L-series lens for our Canon 5D mark II and hoped the weather (terrestrial and space) would provide some opportunities, unlike the sailing immediately prior to ours which had been socked in with clouds the whole time.

Sure enough, dinner on the first night of the sailing was interrupted by the Captain announcing the presence of the aurora.

This kicked-off five nights of more and more auroral activity, which we did our best to capture on the usually-moving large ferry.  Varying the exposure lengths and taking as many as we could while docked at ferry ports produced some images I'm kinda proud of, but the next time we will definitely try to have opportunities by land to improve the chances of crisp image.



Also, here's an interview I did with KTBS on the aurora...

https://www.ktbs.com/news/arklatex-indepth/northern-lights/article_75208998-c11b-11e7-a182-b3aaac7c7335.html