I was recently thinking about how I had been finding a “best fit” compromise in technique for capturing and processing both stars and the DSO target object in a single capture and a single-threaded processing workflow to produce a single image. I realized that what I was actually doing was suboptimizing both the stars and the DSO components of the final image. A higher level of thinking was required to conceive that there might be a way to optimize both, which led to the other day’s Monkey Head star field image.

I realized today that I had done the same thing yesterday when I split the problem of siting the camper and the scopes separately at Winter Star Party would be an easier problem to solve than trying to come up with a single site solution for both.

Resolving a problem into multiple components to look for optimal component-level solutions is probably a way to do what Kevin Johnson asked me to do many times when the solution set looked binary – look for the third way. I had to think harder, but learned to look for the third way on my own instead of stopping at what might be two obvious solutions so consider.

I want to be mindful to this thinking technique whenever I am solving multi-component problems in the future.

I am exploring a new processing technique that started out to be about getting better stars in my DSO images. As I thought more deeply about it, I realized that there is also an opportunity to get better target objects in my DSO images as well. For this reason, the objective has morphed into being better DSO images. While there are other opportunities to improve DSO images, the present technique that I am pursuing is based on separate handling of an image’s star field and the target object, and then combining the fully process stars and target object images at the end.

My traditional exposure durations for DSO images in a light polluted sky have been about 60s, which seemed to be a good balance between getting the skyfog peak above the noise while minimizing clipping of bright star centers. At first I saw suboptimizing (by clipping) star data as a necessity for getting good DSO target object data. And, I was pretty happy with my slightly blown out stars in a recent Monkey Head image and last year’s Veil Nebula images. I was also pretty happy with the target objects in those images as well.

Recently knowing that tools exist that permit me to remove stars from a DSO image, I read up to see what could be done to improve star data in processing. What I learned surprised me. There is an even bigger opportunity to improve star data by starting earlier in the value chain and collecting data for the stars component of an image separately from the longer capture for the DSO image. Essentially, 20s light frames is all that is necessary to get the an image skyfog peak out of the noise, with only the very brightes stars being clipped. I was also suprised to learn that only about 30 to 60 minutes of integration time is necessary to produce a good quality star image. After completing the separate processing for star data and target DSO data, the two images are combined.

Here’s the epiphany that fell on me: With separate capture of star data and DSO target data, there is no longer any need to foreshorten my main DSO capture to just 60s for the sake of stars, which I intend to remove from the DSO component image anyway. With longer exposures, I can accumulate weak DSO signal at a faster rate than with shorter exposures. For example, given a choice between an hour’s worth of 60s exposures (1 hour integration time), and an hour’s worth of 120s exposures (again, 1 hour integration time), 120s is a better choice because my data will have a better SNR in the longer exposure.

I don’t know what the longer exposure duration number will be until I experiment, but in principle,  I can get better DSO data by exposing longer, and I can expose longer because I am not worried about the star component of the long-duration images.

At this point I have captured short exposures, removed the nebula, and processed it as stars only. The star color is great. I think that it can be better if I add luminance. The background seems too smooth. I want to play with processing parameters that might allow a little noise to make the background more realistic.

The next step in my exploration is to capture and process long duration images for the DSO component of a final image. I am thinking something on the order of three or four minute light frames. Experimentation is required. Click image below to see in Flickr.

According to Give a Mouse a Telescope, my need for new equipment would be neverending. But I think that a narrowband filter set might be among the last things that I need to buy.

There are two reasons that I would like to pursue narrowband imaging. First is that I like narrowband images. Some of them are absolutely stunning. The second reason is that narrowband filters block out all but the wanted wavelengths, thereby extending DSO imaging opportunities into moonlit and bright suburban skies.

These filters are expensive. A 3nm SHO set costs about $1500, and I am willing to pay that, but I have some boxes to check off first.

To me it makes no sense to send money on narrowband imaging until first I have mastered wideband imaging. But I am not that far off.

I have my mount working well, and autoguiding is almost where I want it to be. The NP101is is a great telescope for narrowband. The ASI6200MM is a great camera for the task. My equipment and software are integrated and working well together. So what’s next.

I have some more work to do with the guiding system. I can see the path forward, but I just need some clear skies to work in.

Then I need to re-learn how to take Flats. This shouldn’t be a problem since I have done it before and have good notes. I just need to regain the ability to do it confidently.

And finally, I need to work through image processing in Pixinsight.

These steps, coincidentally, are the same ones that I need to work through to prepare for Winter Star Party, which is just seven weeks away. As there will be a learning curve for narrowband imaging, and because my focus will be on getting to the Keys, I will defer the filter set acquisition until after I return.

This is one star party that I have always wanted to do, because it has it all. It has warm weather in the dead of winter, it is a souther location that provides access to southern objects that cannot be seen at my 39 degrees north, and it has laminar airflows off of the Gulf of Mexico.

The event lasts a week, so there will be pleny of visual observing and photography opportunities. I’ll be traveling with Doug, but some of my long-time HAL friends will be there.

The plan is to divide the driving into two legs, stopping near the half-way point near Savannah GA. We’re taking the camper, because we’re not living like savages. But really, for a week long trip, having a shelter in which we can sit out a major rain event will be nice.

The reason that I want a camper is two-fold. First is to be able to comfortably survive at a dark site well into the cold season. Second is to be able to exist comfortably and stay dry during a rain event. I have chosesn a pop-up camper for this purpose. It is plenty large enough for two people, it has a small towing foot print, and in the scheme of things it doesn’t cost that much. I have traveled down a long and winding road to get to this decision, and that is an interesting story.

I started learning about shelter really quickly during a one-night stay at York County Star Party in 2016. I ended up sleeping on the ground with no shelter and I woke up soaked. I vowed that this would never happen to me again. A fellow HAL member was there stayed one day longer than me. She sat out a day-long rain event in a very small tent. I vowed that this would never happen to me.

Shelter for my next star party, AHSP 2016, was a large tent, and I had a large double cot for Lisa and me. I knew before leaving that the weather was going to be perfect, or I would not have gone to this event. Shelter for this event was perfect.

Doug and I returned to ASHP in 2018, and planned to stay for all four days. Not being able to predict the weather, I rented an A-liner pop-up camper. we were subject to high winds and nearly constant rain. Tent campers were miserable, but we survived comfortably.

Doug and I returned to the ASHP site in 2019 for a two-night stay in mid summer. After staying up observing until the wee hours, we really wanted to get some high-quality daytime sleeping in. We knew that rain was not in the forecast, so the large tent seemed perfect for this. The sun, it turns out, made an oven of the inside of the tent as soon as its direct rays came over the ridge to our east.

The next learning event was our first trip to Harney, MD. Doug and I planned to stay just one night. We were to observe for as long as we could hold out, and crash for a couple of hours before heading home. Based on the York experience, and the short amount of time that we expected to sleep, we elected to put up a pop-up awning for shelter. It turns out that heavy dew condensing on the inside of the awning made its own rain weather system right over our heads. We brought the large tent for the next two visits to Harney.

Meeting Victor at Little Orleans MD was a learning experience. I brought a small tent for a one-night stay. The temps dropped into the upper 30s, and I woke up very cold several times. I did not want to experience this again.

So, taking everything that I learnd about shelter over the past six years, it seemed that a pop up with an air conditioner and a furnaces was the right solution for getting out into the field more, and for extending the season for trips to dark sky sites.

After having a wonderful experience and being awed by the 2017 solar eclipse, I started looking forward to the next one On April 8, 2024. I have started making preliminary plans. So far it looks like Doug will be traveling with me, and that my daugter will likely meet up with us. As it stands, somewhere near central Ohio will be our initial destination, with options to move to a clear sky location if necessary.

We intend to select a campground in Ohio for our initial desitionation, and visit that campground in April 2023.

Remote telescope operation is an idea that I got from Gene during one of HAL’s virtual star parties during the COVID pandemic. While I was sitting alone, cold and in the complete dark in my back yard, Gene was sitting in his warm, well lit study, commanding the telescope in his back yard to do as he wished.

I have spent a lot of nights sitting in the dark trying to make my imaging setup work. I no longer wish to do this, and I think that if I can make remote imaging work, I will be more likely to get out to the telescope and more likely to image in colder weather.

Thinking about how to do this, and looking at what solutions are available, I have settled on a mini-computer (sometimes call a NUC, or next unit of computing) that will sit on or near the telescope. This computer will run the software and drivers that operated the telescope mount, focuser, cameras, and filter wheel devices. The devices to be operated will be connectd to USB ports in the mini comptuter. The mini computer will run Win10 Pro so that that it can host remote access sessions.

It has been a while since I have written in Jim’s AstroLog, but I have been busy. Here’s a brief run down what what I have been up to. Maybe I’ll add more to fill in the blanks as time permits. I should say that I am enjoying writing again, even after these few words.

Federal Employee

Work and a long commute consumed just about every minute that I could have otherwise had to pursue my own interests.  The last two years with my former agency were among my best, but even that  (not to mention myself) was getting old. So I moved on.

Retiree

Big news – I retired (again) at the end of April, 2017, and I have been busy getting used to that. I kinda like it. I am probably working harder that I’ve ever worked, but with the difference being that I am doing the things that I have always wanted to do, which is especially nice.

HAL Officer

I was elected to the Howard Astronomical League as secretary for the Boards’ 2015 term, and served in that capacity again for the 2016 term. I was elected president for the 2017 term, and I am now in my second term in that capacity. Big news for the club during my tenure as president is accepting a Takahashi TOA 150 and an Astro-Physics 1200GTO mount from David Illig, and embarking on a project to upgrade the club’s observatory. This equipment is installed in the observatory and is being readied for the club’s members use. I expect to write more about this.

www.howardastro.org

Professor

In the last few days before I was retired, the opportunity to teach and I found each other – I have taught three semesters of astronomy at Howard Community College. I had absolutely no interest in working after retirement, but this has been a dream job that I never thought that I could find. I am really enjoying this gig! The SET department and I have been discussing the addition of an honors section to the course, and I am looking forward to bringing it on line and teaching it. Definitely more to write about here.

Master Gardener

Gardening is my other hobby. I enrolled in the Montgomery County Master Gardener Program with the 2018 class of interns. Still serving as an intern for the rest of this year.

Astronomer

With the exception of a trip to the Almost Heaven Star Party in West Virginia in September 2016, and to Kentucky/Tennessee to view the total eclipse in August 2017, I have doing very little of my own astronomy since I last wrote.

I finally cleared the decks and put my own personal astronomy ahead of just about everything else.  The impetus was signing up for the Almost Heaven Star Party 2018. Much to write about here, so expect another article.

I have written about my bout with aperture fever on this site, and how I overcame the affliction – at least temporarily. To be fair to myself, I did a through assessment of why I bought the Televue NP101 (4″ apochromatic refractor), and I came to terms with why it is a fine instrument. I am by no means abandoning this telescope. It has a place in my collection, and it can do things that the light bucket that I am about to describe could never dream of doing. I expect to use it often for as long as I am able to engage in my hobby.

Please indulge me for one more paragraph before I describe what I am buying. I have also written here about why I bought the NP101 in the first place – I am preparing to enjoy my life-long love of astronomy in my retirement. The acquisition that I am presently pursuing will add another dimension to my enjoyment of my hobby, and to my ability to share my hobby with others. And to be sure, this new instrument can do things that the NP101 can never dream of doing. There is plenty of room for both instruments in my collection.

The telescope that I have ordered is a Meade LX200 12-inch f/8 Schmidt-Cassegrain reflecting telescope. Unlike others I know who have purchased Meade or Celestron Schmidt-Cassegrain reflectors, I chose to forgo the Meade fork-style mount, and chose instead the Losmandy G-11 German equatorial mount (GEM) with the Gemini II goto system.

This telescope weighs 56 pounds, which exceeds the capacity of my Losmandy GM-8. I chose Losmandy mount over a Meade fork-style mount, because I intend to do astrophotography. A fork style mount is simple to use and is great for visual astronomy. It is, however, completely inadequate for astrophotography. This, and my familiarity with Losmandy made the G-11 a natural choice. And since finding objects with an instrument of this focal length (much narrower field of view) will be exceedingly more difficult than with my NP101, I ordered the Gemini II goto system to reduce the amount of time time required for find the object that I might be trying to visually observe or photograph.

I expect to take delivery of the telescope and mount in six to eight weeks. I will not be sharing the news of my telescope’s arrival with my amateur astronomer friends, because they will most undoubtedly hold me accountable for the many cloudy nights that are sure to follow its arrival. Meanwhile, I must maintain my sanity by being calm and forgetting that I have a new telescope on order.

© James R. Johnson, 2016
jim@jrjohnson.net.

I have written about my bout with aperture fever on this site, and how I overcame the affliction – at least temporarily. To be fair to myself, I did a through assessment of why I bought the Televue NP101 (4″ apochromatic refractor), and I came to terms with why it is a fine instrument. I am by no means abandoning this telescope. It has a place in my collection, and it can do things that the light bucket that I am about to describe could never dream of doing. I expect to use it often for as long as I am able to engage in my hobby.

Please indulge me for one more paragraph before I describe what I am buying. I have also written here about why I bought the NP101 in the first place – I am preparing to enjoy my life-long love of astronomy in my retirement. The acquisition that I am presently pursuing will add another dimension to my enjoyment of my hobby, and to my ability to share my hobby with others. And to be sure, this new instrument can do things that the NP101 can never dream of doing. There is plenty of room for both instruments in my collection.

The telescope that I have ordered is a Meade LX850 12-inch f/8 Schmidt-Cassegrain reflecting telescope. Unlike others I know who have purchased Meade or Celestron Schmidt-Cassegrain reflectors, I chose to forgo the Meade fork-style mount, and chose instead the Losmandy G-11 German equatorial mount (GEM) with the Gemini II goto system.

This telescope weighs 56 pounds, which exceeds the capacity of my Losmandy GM-8. I chose Losmandy mount over a Meade fork-style mount, because I intend to do astrophotography. A fork style mount is simple to use and is great for visual astronomy. It is, however, completely inadequate for astrophotography. This, and my familiarity with Losmandy made the G-11 a natural choice. And since finding objects with an instrument of this focal length (much narrower field of view) will be exceedingly more difficult than with MY NP101, I ordered the Gemini II goto system to reduce the amount of time time required for find the object that I might be trying to visually observe or photograph.

I expect to take delivery of the telescope and mount in six to eight weeks. I will not be sharing the news of my telescope’s arrival with my amateur astronomer friends, because they will most undoubtedly hold me accountable for the many cloudy nights that are sure to follow its arrival. Meanwhile, I must maintain my sanity by being calm and forgetting that I have a new telescope on order.

© James R. Johnson, 2015.

I was speaking with Kevin some months ago about astrophotography, and he mentioned that his camera, an Orion StarShoot Solar System IV, did not seem to be working correctly. The two problems that he mentioned were that he could not see the entirety of the moon in a single frame, and that he could not see Jupiter at all. I surmised that there was nothing wrong with the camera, and I explained that video-type planetary imagers like this had notoriously small sensors that have a very narrow field of view. Precisely aligning the telescope to cause Jupiter’s image to fall on the small sensor would therefore be difficult, and this would explain why only a small portion of the moon would be visible. He loaned me his camera for testing, and I have concluded that I was correct about the nature of his problem.

I tested the camera on my C11, and obtained the results seen in the images below, which seem so confirm that the camera was working. As I began to write up the test, I learned that the camera’s sensor format was 1/3-inch. To put this fact into perspective, 6 of these sensors arrayed side by side would be required to span the entire width of the 2-inch rear aperture of the telescope. In other words, the sensor is only 16% as wide as the aperture, which explains why Kevin would not have seen Jupiter in the sensor frame unless its image was almost perfectly centered in the rear aperture.

The focal length of the C11 with a 2x PowerMate is 5600mm. This results in a .14 x .14 arcsecond field of view on each of the camera’s 3.6 x 3.6 micron pixels. I set the camera to a 640 x 480 mode to improve the frame rate, thinking that I was selecting a smaller region of interest, or a subset of the sensor’s pixels at the center of the sensor. What I did not realize is that this binned the output into 2×2 arrays of pixels that would be output as a single 7.2 x 7.2 micron pixel.  This had the effect of halving the resolution that the camera was capable of producing. I would like to be able to repeat this test in the 1280 x 960 mode.

Before mounting the camera on the telescope, I wanted to make certain that Jupiter would be visible on the camera sensor by using eyepieces to center up Jupiter in the field of view. I started with a Panoptic 35mm, which I found very difficult to determine if Jupiter is centered. This is because this eyepiece’s exceptionally wide field of view made it impossible for me to see two opposite sides of the visible field at the same time, so centering at this stage was very much an estimation. Next, I replaced the 35mm with a 17mm Nagler, and repeated the process. It was better, but it was still somewhat difficult to determine if Jupiter was centered with this eyepiece. Next I put in a 12mm crosshair eyepiece, and was able to center up perfectly. When I replaced this eyepiece with the camera, and brought it up on the laptop screen, Jupiter was centered perfectly. Finally, I put the 2x PowerMate in the optical path, and only needed to adjust slightly.

On March 30, 2015, the night of the test, Jupiter’s apparent diameter was 41.6 arcseconds. I used PhotoShop to measure the diameter of the image produced by the combination of the optical configuration and the sensor. The measurement across the center of Jupiter’s white equatorial band was 142 pixels. This compared favorably to the computed prediction of 154 pixels. I attributed the difference between the computed and actual values to me being less than completely careful in taking the measurement and the limb darkening on the disk of Jupiter. Being able to predict the image size  increased my confidence that Kevin’s camera is working just fine.

Just a few words about the clarity of the images as I wrap this up. As I previously mentioned, the resolution of the images could have been improved by using a 1280 x 960 setting instead of 640 x 480, thus doubling the resolution. The night was fairly still and dry, so the “seeing” probably did not affect the image quality very much. Focus seems to be very difficult to achieve while watching video stream off of the sensor, so that could have been a factor affecting image clarity. I made no attempt to rule out focus as a problem by capturing several frame sets while slightly changing the focus each time. And lastly, I believe that the telescope might have some issues, which I believe can be ruled in or out by eliminating focus as an issue.

For good measure, I did a couple of captures on the moon. Clarity, seems to be an issue here too. This did demonstrate that the entirety of the moon’s surface is not likely to be visible in Kevin’s telescope. Note that in the Plato photos, adding the 2x PowerMate magnified the blurriness.

All of the images that follow were lightly processed. I stacked the frames in Registax, and then I adjusted the curve and levels in PhotoShop.

© James R. Johnson, 2015.
jim@jrjohnson.net

There will be a total eclipse of the Sun on August, 21, 2017 beginning in Oregon with the Moon’s shadow racing across a thin swath of the United States and ending in South Carolina.  The path of totality will not cross Maryland, so an expedition is required to go see it. I have a telescope, a camera, a Jeep, and a sense of adventure. Why wouldn’t I mount an expedition to see one of the most awe-inspiring astronomical events that humans have ever witnessed? Please check back to this post as I periodically update with specifics as my planning exercise progresses.

March 1, 2015: I begin planning with a few parameters in mind: 1) view the eclipse at the point of the longest period of totality, 2) temper that with finding a point where the weather most likely to be clear, and 3) find a jumping off point where I can quickly shift east or west to avoid cloudy skies.  Of course, driving to Oregon is out of the question, so perhaps any point from say Missouri to South Carolina might be a reasonable target.

March 5, 2015: It is a snowy day in Maryland, which somehow seems an appropriate time to begin working in earnest on an expedition plan for a solar eclipse that will occur on a hot August afternoon almost two and a half years hence. I discovered a great information source: www.eclipse2017.org, and I recommend this Web site for anyone wanting to learn more about this eclipse, or stay current or related developments. Among the things that I learned that makes an expedition an imperative is that my location in Maryland will experience about 85% totality. This will never do!

The the ideal place to view the eclipse is at the longest point of totality (2m44s), which will be in Shawnee National Forest in southern Illinois. Coincidentally, the path of totality within a five-hour drive east or west of this point is in a zone that historically experiences 30% to 40% cloud cover in mid-August. This is much better odds than I can ever get in Maryland.

The initial plan that I have formulated is arrive in Louisville, KY the afternoon before the eclipse. This is a 9-hour/600 mile drive from Maryland, and Shawnee can be reached in another three hours the next morning. Also from Louisville, there are good routes for moving east or west along the path of totality to reach alternate viewing cites if Shawnee is predicted to be clouded over.

March 7, 2015: Looking at east-west options that are reasonably accessible from Louisville, I have selected St Louis, Missouri (4 hours, 250 miles) to the west, and Franklin, Tennessee (5 hours, 380 miles ) to the east the boundaries for selecting alternative viewing sites. I am fairly happy, at least for the moment, to have framed a coincidence of maximum totality, good weather, and accessibility from where I live. Before examining specific viewing sites, I will next work on a viewing plan that can be modified to account for any location that I may elect for viewing the eclipse.

 February 24, 2016: It has been almost a year since I added planning details, but that doesn’t mean that I have not given a considerable amount of thought to the matter. As I add this entry, it is a cold, blustery, and snowy winter’s day in Saint Louis, just over a two-hour drive to the point of the eclipse’s longest duration, just south of Carbondale, IL. I have formulated Eclipse Logistics Plans A and B. Plan A is a drive straight to Carbondale on the day before the eclipse if Carbondale’s weather is promising. I would either view the eclipse from the Southern Illinois University (SIU) campus where the duration is only four seconds less than the eclipse duration at the longest duration point, or drive the six to eight miles required to get exactly on the eclipse center line. Plan B, if Carbondale’s weather outlook is not so promising is to drive to Louisville, KY the day before the eclipse and bed down there. This would require that I wake up at zero-dark-thirty the next morning, assess the best weather prospects either east or west of Carbondale, and drive there leaving sufficient time to set up before the eclipse begins. In the next installment, I will capture my thinking on what equipment to take and how to observe and/or photograph the event.

Heretofore, I have been “hand coding” html pages for Scope Out, and for pretty much anything that I wanted to write and share with readers. Now I have discovered and learned how to use WordPress. It is incredibly easy to develop and publish content, so my limited writing time will be more productive. This post, for instance, took about two minutes to write, and I only need to click “Publish” to make it instantly available.

I decided that I will build a backyard observatory. My reason for wanting an observatory is pretty typical of why any amateur astronomer builds one. Having to set up in the field for every observing session consumes considerable time dragging equipment out, assembling and configuring it for the session, and getting a precise polar alignment for photography. At my skill level, this could take two hours, and I still might not be satisfied with the alignment when I finally throw in the towel. An observatory changes everything! I would be able to walk in, open the roof, turn things on, and I’m ready to observe or image in five or ten minutes. The equipment is always there, and only needs minor configuration before use, and an excruciatingly precise polar alignment is preserved from session to session.  Still researching piers…steel on concrete vs all concrete, building type, electrical considerations and several other details. I will probably settle, and break ground when it gets a little warmer.