Josef “Jeff” Sipek


OpenMCT — While I’m not a fan of web-based UIs, this is a rather neat “dashboard” framework by NASA.

Wideband spectrum received in JO32KF — Over 5 years of HF spectrum waterfall in Enschede, NL.

10 Most(ly dead) Influential Programming Languages

Wikipedia article: PACELC theorem — An extension of the Wikipedia article: CAP theorem.

Learn Rust the Dangerous Way — Finally a Rust tutorial that speaks to people comfortable in C.

Interferometry and Synthesis in Radio Astronomy — An open access book.

Aviation Formulary — Great circle math applied to various aviation problems for those too lazy to derive the formulas themselves.

Papírová platidla Československa 1918-1993, České republiky a Slovenské republiky 1993-2016 — Complete list of all bank notes used in Czechoslovakia, Czech Republic, and Slovak Republic.

NOAA GOES Image ViewerWikipedia article: GOES weather satellite imagery.

Stellafane (2016)

Last weekend we drove to Wikipedia article: Springfield, VT to attend the Stellafane Convention. In short, it’s two and a half days of camping, astronomy and telescope making talks, and of course observing. I brought my camera (D750), two lenses (24-70mm f/2.8 and 70-200mm f/2.8), and a tripod. Over the two and a half days, I ended up taking 400 shots of just about everything of some interest. I post processed about 60 and created a gallery. I’m going to include only some in this post, so make sure to check out the gallery for more shots that just didn’t fit the narrative here.


Thursday was mainly about arriving in the late afternoon, setting up the tent, and doing some observing once it got dark. Photography-wise, my primary goal for Thursday was to get some sky images at 24mm. I tried some long exposure (657 seconds) to get some star trails:

There was a decent number of people walking around with red lights (so as not to destroy night vision), so a number of my shots ended up with some red light trails near the ground. (That’s that wobbly red line.)

I also took a decent amount of short exposures (10-16 seconds). At 24mm on the D750, 13 seconds seems to be just about when stars start to turn into trails.

This is the only staged shot—I intentionally left one of our red flashlights on in the tent to provide something interesting in the foreground.

Here is our tent-neighbor and friend looking up at the sky. He didn’t actually know that I was taking a shot of the milky way, and I didn’t realize that he managed to sneak into the frame. The trees got lit up by some joker driving around with headlights on. I expected that to ruin the shot, but it actually worked out pretty well.


Friday is the first full day. I started it by hiking to the other side of the site, which not only sports a nice view, but also nonzero phone and data coverage:

The original club house is there as well in all its pink glory:

The last, but not least, building there is the turret solar telescope:

Right next to it is the location of the amateur telescope contest. Yes, people build their own telescopes and enter them into a competition to see whose is the best. This year, the most eye grabbing (in my opinion) was a pair of scaled down reconstructions of the 8-inch Alvan Clark refractor. Here’s one of them:

I couldn’t resist taking a couple of close-up shots:

Heading back toward the main site, I walked past the observatory set up in such a way as to be handicap accessible:

After a breakfast, it was time to go off to the mirror making tent. I think that every year, there is a series of talks and demos about how to make your own telescope mirror.

The speaker letting an attendee give mirror grinding a try:

And a close-up of the eventually-to-be-mirror on top of the grinding tool:

Fine grinding demo using a glass grinding tool instead of the plaster one:

After lunch, there was a series of talks about a lot of different topics—ranging from digital imaging, to “crowd-sourced” occultation timing.

Between talks, I noticed that one of the attendees erected Federation flags in front of his tent:

Once night rolled around, it was time for more observing. I took a number of milky way shots. They all look a bit similar, with the only real difference being what is in the foreground. Of all of them from this night, I think this is my favorite—there were a couple of people standing around a telescope talking with their flashlights on.


The second full day of the convention began with mechanical judging of the telescopes.

Somehow, I ended up drawn to the twin-scopes; here’s another detail shot. You can see a little bit of motion blur of the governor:

The day program was similar to Friday’s—the mirror making talks and after lunch a set of talks on various topics.

The evening program consisted of the keynote, raffles, competition results, and other customary presentations. The sky was completely covered with clouds till about 1am at which point it started to be conducive to stargazing. Oh well. Two clear nights out of three is pretty good.


Sunday is all about packing up and heading home. During breakfast time, I ended up walking around a bit and I got this image—with the food tent in the foreground, the handicap accessible observatory near the background, and the McGregor observatory with a Schupmann telescope in the very background.

So, that’s how I spent the last weekend. I’m already plotting and scheming my next astrophotography adventure.

2015 Lunar Eclipse

You may remember that there was a lunar eclipse back on September 27th, 2015. That evening, I set up our 90mm refractor telescope (1000mm focal length, f/11) in the driveway and spend a fair amount of time sitting on the ground. I used a t-mount adapter to mount my Nikon D70 instead of an eyepiece—effectively using the telescope as a big lens. (This is called prime focus photography.) Every minute, I took a shot of the moon hoping to make a collage. It took me nine months, but I finally remembered to do it.

(4 MB full size image—8750 by 1750 pixels)

To keep the overall image aspect ratio reasonable, I ended up using every sixth image. Therefore, each step is six minutes apart and the whole sequence spans about 42 minutes. Each of the photos was taken at ISO 1600, which the D70’s CCD does not handle very well, hence the noise.

I am looking forward to the next total lunar eclipse. It should be a whole lot easier to do with a modern camera like the D750. Sadly, it will be a while before there is another total lunar eclipse on the east coast of United States.

D750 Star Trails

I have tried star trails photography once before—7 years ago. Back then I was using the D70 which was a good camera but there were two problems with it for astrophotography: first, its CCD sensor wasn’t the best at higher ISOs, and second, long exposures were not possible because of some interference (thermal or electric) which resulted in ugly purple fringing. That experience made me not really bother with astrophotography—hence the seven-year hiatus.

A week ago I decided that I should try again with my D750 and the 24-70mm f/2.8 lens. Since they are both significantly newer than my old setup and are superior in just about every way, I thought why not try again and see exactly how much better the results would be.

I ended up with only three shots worth sharing. As always, I made a gallery with them. The one difference from the other photo galleries I make is that I will continue to add star photos to this gallery until the end of the year (when I plan to make a 2017 gallery).

After setting up the camera in the general direction of Polaris, I needed to figure out the exposure. So, I cranked up the ISO to 10000 and took a 5 second test shot at f/2.8. The hope was to see how the sky exposed, and then “trade” the ISO for time to get the same exposure but less noisy and with star trails. (E.g., changing the ISO from 10000 to 160 is 6 stop difference, so the shutter speed needs to change 6 stops in the other direction to compensate. That is from 5 seconds to 320 seconds.) When I viewed the image on the back of the camera, I was blown away:

While there is certainly noise in the image (which you can’t see in the resized version) and the composition is not great, it’s cool how both the foreground and the sky are equally well exposed. The trees are essentially light-painted by the neighbor’s driveway lights which were on at the time. And before you ask, no, that’s not the milky way, that’s just a wispy cloud.

Then, I proceeded to take a back-to-back series of 15 second exposures. After five minutes (21 shots), I was sufficiently bored to try something else. After heading back inside, I stacked the 21 shots using StarStaX. Here is the resulting image (slightly tweaked in Lightroom):

The orange blur on the right of the image is a small cloud that moved across the frame during the five minutes without me noticing. Unfortunately, there is plenty of light pollution to the northeast of us because of the neighboring city of Wikipedia article: Nashua. I am definitely going to experiment with stacking.

The final couple of shots I took were all various long exposures—ranging from 8 to 20 minutes. This is one of the 20 minute exposures:

Again, the light pollution from Nashua is unfortunate.

The 74 degree horizontal field of view at 24mm is pretty good. Of course, a wider lens would provide for an even more interesting shot. For example, a 15mm focal length would produce a 100 degree horizontal field of view. With that said, I am certainly going to experiment more with star trail photography—even if I have “only” a 24mm focal length.

Venus Transit (2004)

The recent transit of Venus made me dig up some old photos. Specifically, those from the 2004 transit of the very same planet. The quality is pretty poor since we were just hand-holding the cameras (Canon Digital Rebel and a cheap point and shoot) near the telescope eyepiece. It was a pretty nice day…


…with the moon getting ready to set…


…and Venus moving in front of the Sun…

venus transit


From 3 days ago:

This morning in arctic Norway, onlookers were stunned when a gigantic luminous spiral formed in the northern sky. Veteran observers accustomed to the appearance of Northern Lights say they have never seen anything like it. It was neither a meteor nor any known form of atmospheric optics. Rumors that the spiral was caused by the botched launch of a Russian rocket have not yet been confirmed.


Star Trails

It was a dark and stormy night…wait a minute…it was a clear and calm night; the night sky glistened with the light from thousands of streetlights releasing billions upon billions of photons, only to be scattered by the atmosphere and to rain down upon Ann Arbor — to pollute the otherwise perfect night sky. So, Jeff, a twenty-odd year old who can be best described using Dungeons & Dragons character alignment as "chaotic good," decided that it was time to escape the particle bombardment to attempt the astronomically difficult, and equally arcane, task known as astrophotography…

Anyway…Here are the exposure details and the photos (from February 24, 2009):

826 seconds
ISO 800
Nikon D70
18—70mm @ 18mm (35mm equiv: 27mm)
Location: McCollum Rd, MI


Here’s the same photo, but with a very well known constallation outlined.

Ursa Major


This is essentially a follow up to a previous post.

As it turns out, the big gray-ish blob commonly referred to as Luna, or even more commonly referred to as the Moon, is still there. As always, it seems to hide about once every 4 weeks.

The other day, I read somewhere that the moon was going to appear bigger than usual. When I got home, I ran outside, saw that it wasn’t cloudy, and took a bunch of photos of the moon. I spend a grand total of about 4 minutes outside before the -8C air got too much for my fingers to control the camera well.

Here are the spoils of war. Just as in the earlier post, these are taken at the 300mm end of my 70-300 zoom, which on my D70 is equivalent to 450mm on 35mm film.

They were all taken at f/5.6, with either 1/640 or 1/800 second exposure.

I should try to use a tripod one day, take a burst of 1/800 exposures, and then try to stack them in software. (I know people use webcams though telescopes and hundreds of exposures to get decent images, so it should work just as well with an SLR.)

Luna Luna Luna

Lunar Eclipse - photos

As I have mentioned earlier, there was a lunar eclipse. Unfortunately, I was unable to get away from the light poluted skies of New York, and so I spend the 4 hours in the backyard. Here are some highlights…

It was quite cloudy during the first half of the eclipse, so the “darkening” shots look pretty bad.


Something eating the moon!


I got a little bored, so I tried to take a photo of the Orion Nebula. Not quite all that good :) Even the 30 second exposure shows noticable amount of rotation of the Earth.



It was quite difficult to get a good shot of the part of the moon still in the shadow. This was a 1 second exposure, f/5.6. From the noise, I guess it was at least ISO 800…I’m a bit too lazy to check :)

The moon is coming back!


But I tried again….

Ewww…ugly noise


…and again.

Ewww…ugly noise - again!

But, if I resize the image to  50% of the original size, it doesn’t look all that bad!

Ewww…ugly noise


Aaaaand, here’s what the moon looked like after the whole thing. Back to normal :) 1/500 second exposure at f/9 with ISO 200.

Yay! Back to normal

International Space Station flyover

Few days ago, I decided that it would be fun to try to take a photo of the Internation Space Station (ISS) flying over. I marked my calendar to go outside today for the 18:16-18:22 pass over NYC-area. I used my Nikon D70, with a 18-70mm lens at 18mm (equivalent to 27mm on 35mm format), 15 second exposure, f/13. I used RAW file format. Unfortunately, I didn’t get to experiment with the exposure at all.

After I got myself back inside, I used UFRaw (a Gimp plugin) to convert from raw to jpeg for your viewing pleasure. There I used a custom curve which you can get for yourself - but it’s probably going to be completely useless.

First, I got some clouds; it was quite windy and the clouds were moving fast enough that in some of the shots they look quite…scary.


And soon after…ISS! The big light source is the moon…

ISS, take 1

…more ISS…

ISS, take 2

And the best for last…

The bright star is actually Mars. The reason the moon doesn’t look like a circle is because the camera shook a little bit at the beginning of the exposure (take a look at the ISS trail - the beginning is wobbly too).

ISS, take 3

And here we have the ISS about to disappear behind the trees…

ISS, take 4

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