Tag Archives: moon

Easy (HDR) Blending with Stacking Software

I’ve been teaching a “Catching the Moon” webinar approximately monthly. The focus of that course is to teach how to properly expose for the moon, how to catch the moon aligned with your favorite landmark, and how to determine the optimum light scenarios.  The webinar is based on my Alignment 1 and Alignment 2 articles with a healthy dose of additional material including some private material for students only.

One of the most difficult aspects of getting a moon alignment is that there is a pretty small optimum time window for getting an exposure.  Shooting earlier or later makes the foreground illumination and the moon illumination all but impossible to get both exposed properly in a single shot.

Here is an example of a single shot where the lighting was pretty close to perfect (though you can see the moon is a bit over exposed).

A Perfect 10 [5_057646]

However later that evening the sunset occurred quite a while before moon rise, so the sky and foreground were much darker.  The photographer faces a conundrum. Expose for the foreground or expose to preserve moon features.

On the left is a 30 second exposure prior to moon rise (though a tiny bit of the moon is in fact visible). On the right a 1/25th of a second exposure. Both taken on a tripod at f/9, ISO 250, 444mm effective focal length.  The problem is that a longer exposure renders the moon as a white featureless blob or streak (see below for an example). However exposing for the moon as on the right renders the foreground all but invisible.

What to Do?

There are a couple of simple alternatives. One is to bring both images into Photoshop. Make both images layers, the moon on top of the background and combine the two images using “Lighten” blending mode.  That will work very well and it’s essentially what happens when using the StarCircleAcademy Stacking Action. But that action, and even Photoshop are overkill for this situation.

Free Solution!

Fortunately Markus Enzweiler offers a free solution called StarStax that runs on Windows, Linux and Mac that makes it trivially simple to combine these two exposures – assuming they were taken on a tripod and the zoom, focus and direction does not change between shots.  StarStax is tailored to stacking star trails, but it does the same operation that Photoshop (and Image Stacker and StarTrails.de do).

And fortunately you can make it do a little more with almost no extra effort… as in this example. When the first image was taken it was quite dark and required a long exposure to capture foreground details.  Then all the moon images were taken with identical settings using an intervalometer.  It’s interesting to note how the moon darkens and deepens in color as it sinks in the atmosphere.

Project Impact [5_057573-615br]

So how do you create the simple or “stacked” motion images?  Easy.

 And here is the result.

Obviously to create a descending or ascending moon sequence you merely need to combine exposures taken at the appropriate interval. What is that interval? The moon travels roughly its diameter in two minutes. About 2 minutes, 14 seconds to be more precise.  I recommend taking exposures twice or four times as often as that, however and just use every-other or every fourth shot.

Since I took a simple approach to blend the images I also elected to go simple in presentation. Rather than fight the many different colors inherent in urban night scenes, I used Picasa3 to convert to monochrome, crop and frame the combined image – here using an earlier shot than the “Golf Ball on a Tee” shot above.

In the Evening [5_057775+92]

Here is one last example of a descending crescent moon combined using Photoshop. Here I didn’t wait a full moon diameter time between images because it was a crescent moon:

Mamma Glows, Baby Shines

 This also illustrates why taking more frequent exposures gives more creative latitude.


ISS Predictions

Last Updated: May 2, 2021

I had set up a program to automatically compute the ISS transits for different places and upload the results once a day – at around 11:00 am each day. See Zoom-Zoom for the impetus for this as well as references. However, it grew difficult and cumbersome to keep it working since the behavior was to run a Java process on my home computer, compute the coordinates and up load to my website.

But, the good news is… I found two resources that you can use that are quite helpful.
One is an Android App called ISS Transit Prediction Pro by Ed Morana. There may be an IOS version as well. I find it a bit clunky, but it does help to have a portable source to do predictions.  For example, here is the result of running predictions for the San Jose, California Area. There is a Jupiter transit and a lunar transit depicted. You can adjust how far you’re willing to drive, as well as the altitude of the transit.  What you can’t do, at least I haven’t figured out how, is to fine tune the prediction for a specific location. I imagine you can literally go there, or use Google maps (or set the location using the location in the app), but those options are a bit tedious.  See the web based app below for a comparison. The ISS Transit Pro app does allow you to save and share predictions – a feature that doesn’t exist in the Transit-Finder web page below.  ISS Transit Prediction Pro ALSO calculates transits of planets like Jupiter (see below). I’m eager to try getting one of those!

ISS Transit Finder (Web)

Another app is the Transit Finder (https://transit-finder.com). This web app is pretty slick. It combines Google maps click-ability with clear information, and it is pretty easy to fine tune something you’re interested in. It does have a problem in that as of this writing you will get warnings about trouble loading Google maps, probably because the authors would need to pay Google a fee to use the data Google offers. When you start this web page you can have it auto-detect your location, or select it on a google map. You then set your other options and eventually click CALCULATE to see predictions.

If it FINDs any transits (and it might not!) You see a page like this:

Transit Predictions within the starting Location up to the maximum selected distance from the “observer”

You’ll notice above that there are two predictions shown out of three, one crossing the sun (just grazing it) and another that is a “close pass”. The good news is, it’s very easy to turn that grazing hit into a centerline hit… and that close pass into a hit as well by moving to the correct location. Indeed, the grazing solar crossing shown is what I could have observed from my home! After fine tuning a bit, I discovered a public place with an open area from which to set up instead.

You fine tune the prediction by using “Show On Map”, then finding/zooming and clicking on the centerline in an area that may prove useful for observing. For example, here I’ve zoomed in and scrolled to the street just outside the Apple Campus in Cupertino, California. The first image shows the boundaries of visibility superimposed on the map. Red indicates solar transits, blue indicates lunar transits.

In the second image below the entire background is red because the area shown lies between the boundaries where the ISS grazes the sun. The center line is where the transit goes right through the middle of the object (sun/moon).

The map of predictions, zoomed in quite a bit.
It’s not easy to see here, but the Apple Park Duck Pond is near the middle of the Apple “Space Ship” office. The green dot reflects where I clicked. NOTE that it shows the exact time of the transit (here 09:32:32.60) and the length of the transit which is a teeny bit more than 1 second! You SHOULD RECALCULATE for the location.

Because of the (current) limitations in the Transit Finder map, it’s helpful to pull up a second window with Google maps zoomed into the same area. I find a satellite view is helpful. Note a couple of other things… the window shows the exact time, the direction to face (Azimuth: 100.1 degrees which is 10 degrees south of East), and how high in the sky to look (Altitude: 38.5 degrees). HIGHER is better because it means the ISS will be closer to you and thus appear larger.

Using Satellite view in Google Maps (and Google Street view), you can get a good idea if there are likely to be impediments to your view in the desired direction. Here you’re looking at the Apple Campus in Cupertino. The place I picked earlier was N. Tantau Avenue.. given all the trees, you may have to find a parking lot with a view East-South-East.

After inspecting the map all along the center line, I chose the PruneYard shopping center parking lot as the go-to place because it’s a large flat lot. I originally planned to be closer to the street, but discovered that tall trees made that impractical.

Some Final Thoughts and Caveats

Remember that the International Space Station (ISS) is an in-use craft. As such it is subject to orbital changes – both of the routine kind and for special operations like adjusting for docking, or moving to a higher orbit. Because the orbit is changed fairly often, predictions longer than a few days in advance may be in accurate. It is a good idea to recalculate a few days before, and even a few hours before a planned event. In the case of the May 2nd event, for example, the centerline of transit went through the middle of a local park 24 hours before the actual event, but recalculation on the morning of the event showed a change large enough to affect the quality of the image (it still would have been a grazing hit, but not a center hit).

It is MUCH easier to catch the ISS traveling across the face of the moon (when it is lit by sunlight) because you can easily follow it with your eyes. Catching the ISS crossing the sun is MUCH, MUCH more difficult. You literally need time that is accurate to 1/10 of a second or less. Fortunately there are apps for that, too. I use Atomic Clock on my Android. I use a shutter release cable, set the camera to high speed capture and try to hit and hold down the shutter button 1/2 second before the scheduled time. Much sooner and I risk filling up my frame buffer before the event starts. I plan to try this all again but instead of shooting still images, I’m going to capture 8K video (and use a higher magnification)

Interestingly, rough aligning your telephoto/telescope in the daylight with the sun is pretty easy to do by paying attention to the shadow that is cast on the ground.

Do not be afraid to play with adjusting off the center line. If you are shooting against a half full moon, for example, you may prefer the ISS to cross over the shadowed portion of the moon (or the lit side). You do get the most TIME to capture if you hit the center, however… but we are talking a difference of about 1/4 of a second or so!

Zoom Zoom

Last Updated: May 2, 2021

Phil McGrew had an out of this world idea. Capture the International Space Station as it hurtled across the face of the pre-dawn moon.  Great Idea – because it worked! How we figured out when and where to be to make this happen is described in the references below.

We agreed to meet at a spot that fell near the “blue line” (centerline) of the event: Muir Beach Overlook.  I woke up at 3:00 AM and arrived there at 4:45 AM. Everyone showed up on time at 5:00 am and we lugged our equipment into the conveniently located World War Two era machine gun bunkers which kept us out of the wind. There were 3 such bunkers and I took up residence in the closest one since I had the most gear to haul (and am the most lazy).

Bunkered Down for the Morning…

My companions picked two other bunkers, while Rick headed further North along the coast highway.  Note: Don’t let the term Highway confuse you it is a tortuous winding road hanging on sheer cliffs above the Pacific Ocean.


Resources and References

Notes about the Event

Before we left we had some discussions about whether the ISS would be visible and how to prevent it from “streaking” and smearing. The ISS is moving at  17,800 miles per hour. At its altitude from our location, that means it crosses the ½ a degree wide moon in under two seconds! At minimum I needed to select an fast enough shutter speed to max out the camera’s frames per second (more chances to get at least ONE hit) which on the Canon 50D is about 5.3 fps.  However we weren’t sure about the comparative brightness of the ISS compared to the moon.  If it were sufficiently dimmer then the moon brightness would overwhelm the ISS.

It’s interesting to try to get the ISS against both the lit and unlit portion of the moon – and we indeed got both.  The ISS trajectory and where you choose to go affects what you will see.  One of our group went farther north and got the ISS brushing the lit edge of the moon, though not crossing it.  This proved to be a quite interesting shot as it is definitely true that the ISS does not stand out well against the moon.

I went with about f/9. This is a rough calculation factoring the f/7.5 refractor  [80mm aperture with 600mm focal length], and a 1.4 teleconverter.  I had to tape over the pins on the camera-teleconverter or it would not let me take the shot “cannot communicate with lens” well – duh, the lens in this case is a TELESCOPE.  ISO 800, speed 1/500th of a second and the camera in BURST (continuous high speed exposure) mode.

We were not expecting a whole lot but were all high fives and thumbs up afterward.  Now that I’m groggy from sleep deprivation I’m wondering if driving about 4 hours round trip was worth 3 seconds of glory.  Yeah, I think so.

If you’re interested in catching the moon near your favorite STATIONARY object, I’ve got a well reviewed, well attended webinar on that.  Want to try some Astrophotography? I’ve got webinars and field shoots for that, too.  Join me and let’s do something unusual with night and low light shots.

For the latest predictions for the San Francisco Bay Area, Yosemite National Park, and Research Triangle North Carolina see this page.

Washington Landmark + Penumbral Eclipse

If you took my course “Night Photography 111: Catching The Moon” then perhaps you’ve managed to calculate where and when to capture the eclipsed moon over one of our National Landmarks.  Which one?  Let me keep you in suspense for just a little bit longer.

Normally I’d love to share this information widely, but I fear that a large number of photographers might not only attract unwanted attention, it appears that when we published the information about the prime location for the eclipse over the Golden Gate Bridge over 200 people showed up!

Weekend Schedule

Saturday, December 10, 2011:  5:30 AM Meet at Eastern Market Metro Station (don’t be late). Address: 8th Street and Pennsylvania Avenue, SE, Washington, DC end shooting around 7:30 AM, end of the event around 9:00 AM. See below for maps and more details.

Saturday, December 10, 2011: 4:30 PM (Optional) Catch the moon rising behind the Old Post Office Tower and/or the Washington Monument.  See below for details.

Sunday, December 11, 2011: 4:45 PM (Optional) Catch sunset over the city with great views from the 315 foot tall Old Post Office Tower. See the EVENT details on the Night and Low Light Photography Meetup of Stafford, VA for details.  (NOTE: I’ll give preference to anyone who is attending the Eclipse event with me).

What to Bring (all events)

  • Camera, memory cards, extra memory cards, batteries, extra batteries
  • small flashlight
  • Sturdy tripod
  • Release cable / intervalometer (recommended)
  • Telephoto lens (200mm or better recommended)
  • LAYERED clothing including a hat, gloves, scarf, parka
  • Rain-proof covering for yourself and your camera. A shower cap usually is enough for the camera. And emergency poncho may work for yourself.
  • Change/cash for bus/cab/metro fares + beverage or breakfast

Eclipse Event on December 10th, 5:30 AM

Meeting location: Eastern Market Metro station: 8th Street and Pennsylvania Avenue, SE, Washington, DC

NOTE: Trains will not be running until after 7 am. You must take a taxi, bus or other transportation to arrive on time. Maximum cab fare within the city is $19.  Could be much more from outside the city.

You’ll know it’s me ’cause I’ll have a red backpack and at least one tripod hanging like a sword on my side. If it’s dark enough I’ll also have a flashing green light hanging on me.

After meeting PROMPTLY at the Metro Station we will be walking one to four blocks south east (as far as 12th street). Exact location will depend on my scouting the day prior.

While walking to the final location, I’ll go over some important points on how to capture the moon and foreground. We begin shooting at about 6:15 AM and shoot until about 7:25 AM – after sunrise.  Then we’ll head to the Starbucks at 401 8th Street SE (1/2 block south from the Eastern Market Metro) – or possibly to Le Pain Quotidien which opens at 8:00 AM to discuss what we’ve done and enjoy a hot beverage and/or breakfast.  By 9:00 or so we’ll be finished and can either take metro from Eastern Market or whatever other arrangements you’ve made.  But don’t forget about the EVENING event!

SATURDAY PM: Moon Rise Behind the Washington Monument

If you attended the Night Photography 111 class you may have noticed that I provided the location for the evening shoot… the shore of the Potomac river on the Mount Vernon trail.

There are two possibilities here: at the waterfront in FRONT of a tree (not sure if there is room), or further away.


While using Google Street View, I noticed another building to the left of the Washington Monument… The Old Post Office Tower.  So it is possible to get the Post Office Tower with the moon behind it first:



Memorial Beacon [C_055580]

As it actually looked!

At 17:14 PM and stay put to catch the moon 4 diameters above the Washington Monument OR move south about 200 feet to catch the moon directly behind the Washington Monument at 17:33 PM.



The vantage point(s) are on Columbia Island along the George Washington Parkway. Easiest way to get the there is: Take Metro to the Arlington Cemetary Station (BLUE line). Exit the metro along Memorial drive east. Follow the pedestrian pathway turning south after crossing the bridge (before the Potomac Bridge).  There will be opportunities to photograph the Lincoln Memorial and other buildings while you’re on your way… so allow plenty of time.  The sun will be at your back so the buildings may look spectacular.

SUNDAY: Post Office Tower

If you hadn’t noticed, the following evening I’m planning to get some evening shots downtown from the Old Post Office Tower.  The group is limited to 12 attendees so join up soon if you’re interested.  It will be REALLY cool to get the moon rising behind it on the 10th and then photograph from it on the 11th.


QUESTIONS About the Eclipse Event

Q: I’ll be using a Canon 50D. I have the following lenses

Canon EF 300m f/4 L
Canon EF 70-200mm f/2.8 L
Both the 1.4 and 2X teleconvertors
Sigma 170-500mm f/5-6.3

Which one do you recommend?

A: Bring them all!  Ok, so that may be impractical in which case the 300mm + 1.4X would be my weapon of choice.  But I’d probably bring the 70-200mm also in case you want to shoot wider.