Saturday, September 17, 2016

Prime Focus vs 300mm Lens for DSLR Moon Photo

I don't have many prime focus attempts under my belt - in fact if you search for "prime focus" on this blog, you'll only come up with 3 posts of the moon at prime focus, and a couple Jupiter, and a couple double stars. In fact, I don't believe I've even attempted the moon at prime focus since I upgraded from the Canon Rebel XT to the Canon T5i. After some major issues a while back, at least now I have my go-to prime focus attachments using a T-ring --> T-thread to .965" --> .965" threaded collar setup.

As I've noted before, the hardest part of photographing the moon at prime focus with my Meade 285 refractor is the clunky focusing wheel on the telescope. The focuser is plastic, and there is no fine focus adjustment. So, as you can imagine, when looking at the LCD screen on the back of the camera and adjusting the focus, it's nearly impossible to tell when I'm actually in focus... Whenever I touch the telescope the image jumps all over.

With all that in mind, the advantages to prime focus are that you get a much larger image (and therefore higher number of pixels in the diameter of the moon) compared to just a 300mm camera lens. Prime focus definitely has the potential upper hand, but a major handicap when it comes to focusing - whereas the camera lens has incredible hands-free focus, but the moon is only projected onto a tiny area in the center of the image sensor and thus a smaller diameter in real pixels.

I took the images below on Sunday, September 11, 2016.

prime focus vs 300mm camera lens
Click to enlarge, prime focus vs 300mm camera lens
Now many it's not completely fair, the 300mm moon on the right is far from my best attempt. I only stacked 10 frames in Registax, which was having a rough go of it on Windows 10. When I finally got it to stack without crashing, I noticed the alignment wasn't quite right, but it still does a nice job showing the huge difference (3x the diameter) in relative size.

waxing gibbous moon at 300mm
Stack of 10 frames, Canon T5i at 300mm, ISO 100, f/9, 1/160 sec with High Pass layer in Photoshop

waxing gibbous moon at 900mm
Stack of 17 frames, Canon T5i prime on Meade 285, ISO 400, 1/250 sec, 900mm with High Pass layer in Photoshop and Exposure +1.0 in Adobe Camera RAW

canon t5i on meade 285
From my perspective on the patio

During my observing session, I also saw the rings of Saturn through the Meade 285, which is always a treat - even though it is insanely frustrating to try to position this old mount that doesn't want to stay put once you have your target. I also tried several times to get my iPhone mounted on the eyepiece to take a video of Saturn, but the mount is just too finicky and shifty.

Finally, I took this quick timelapse video of my prime setup using the app Hyperlapse, which is convenient when you don't know how much you will want to end up speeding up the final video. Unlike the other timelapse apps where you have to set the speed at the beginning.

Tuesday, September 13, 2016

New iPhone Red Screen Tint in iOS 10 to Preserve Night Vision

This new iOS 10 feature lets you filter your iPhone screen with different color tints. A red tint throughout the entire phone is a quick trick for astronomy and stargazing to preserve dark vision. Previously, individual astronomy and stargazing apps would let you tint the screen red for night mode, but now you can change the tint of the entire phone with a red filter using accessibility features that are brand new in the latest iOS update.

ios 10 iphone color filter to preserve night vision for astronomy
Red color tint accessibility feature in iOS 10

I'd love to show you a screenshot of the new feature, but it's actually a color overlay so the screenshots show up the original colors. This makes sense, because that's the only way it could work across all different apps without adjusting each individual app features. This also means that it's not necessarily optimized for all of the apps you might use, but it's a quick and dirty trick to make everything tinted red.

Go to General > Accessibility > Display Accommodations > Color Filters > Color Tint

ios 10 accessibility features
General: Accessibility: Display Accommodations

ios 10 color filters
Display Accommodations: Color Filters

ios 10 color tint
Color Filters: Color Tint: Hue all the way to the right: Intensity all the way to the right

Similar apps are available for Android devices, but like I said iOS apps were limited to the ones that already included a 'night mode' such as StarWalk.

star walk app in night mode
Night Mode was already available within certain apps, such as StarWalk.

Previously, iPhone users would get an evil glare if they pulled out their phone during a star party, camping trip, or meteor shower - even with the brightness turned all the way down, when your eyes are dilated the screen still appears rather bright. I'd suggest turning the brightness down AND tinting everything red just in case.

Items that were previously red might disappear completely!

You can see that it is a quick and dirty option and can actually make items disappear if they are normally red, like all the little badge icons. Oh well! Neat trick, I'll have to try it out sometime. The nice thing is that it lets you use red filter through the entire phone and not just in some apps. I know sometimes it's nice to just whip out the calculator or something while I'm observing, which involves leaving the apps that have red modes built in. 

Shout out to xt8dob on Instagram for tipping me off to this new trick!

Monday, August 29, 2016

Tippecanoe Indiana Milky Way at Camp Tecumseh

This past weekend I was in Tippecanoe, Indiana at Camp Tecumseh. I took advantage of the dark skies and brought along my camera. Just like previous years, I was at a Peer Education retreat, and went out later at night for some shots away from the light pollution in Indianapolis. Unfortunately, this year it was extremely humid and I had to wipe the lens every 30 seconds, re-focus, and try to get a quick photo before condensation would creep in again. All of this on top of the heat which adds to the image noise.

Nevertheless, it was worth a try, and I got a much better photo than I can achieve from my own back yard. I came away with ONE decent image out of the whole lot, but hey I can say I tried!

Milky Way from Camp Tecumseh
Milky Way from Camp Tecumseh, Indiana, single frame, Canon T5i at ISO 6400, 24mm, f/4, 13 seconds, heavily adjusted in Photoshop

I had my EyeFi memory card with me, and was able to Instagram the photo before I even got home! I transferred it from my camera to my iPhone, and edited it in Instagram - which actually wasn't too bad. EyeFi lets you transfer files over a short range WiFi connection that the card puts - no internet provider needed. It's not like you can surf the net on it though, haha, but you can get your photos to post them immediately. Note: RAW files don't transfer to switch to JPEG or do what I did and use the JPEG + RAW shooting to save both to the card at the same time.


Below is a comparison of the original file, my Photoshop edits, and the in-app edits in Instagram. I think Photoshop is still a lot better, but Instagram is definitely getting better especially for convenience of doing it all from a cabin in the woods.

instagram milky way edit
Side by side comparison with original file from camera (ISO 6400, 24mm, f/4, 13 seconds) edited in Photoshop vs. in-app edits in Instagram transferred to phone with EyeFi. 

Here are a few more photos from the night. I was only out for 15 minutes or so. You can tell the humidity was just unbearable.

night lens flare
Cool lens flare, but not what I was going for...

humid night sky photo

humid night sky photo
Big dipper and hazy humid parking lot

humid night sky photo
Weird color balance aiming the camera straight up

milky way north west indiana
Larger version of the original photo
camp tecumseh leadership center room interior
I had this whole room to myself at the training retreat!

Saturday, July 23, 2016

Full Moon Rising over Washington Monument

I've traveled to Washington DC four times this year for work, and I never thought I'd be doing this much traveling in my job in student affairs! I was in DC again this past week and decided to do some sight-seeing while grabbing dinner. I got a sushi burrito and water and walked over to the Washington Monument to enjoy the view as the sun set.

full moon washington monument


I knew the moon was getting fuller by the day, but I didn't realize it was the night of the full moon until I saw a bright orange sliver peeking over the clouds. Everyone around me stopped playing Pokemon GO for a minute to enjoy the bizarre and familiar sight.

Since the monument is positioned on a hill, there were plenty of great angles to view the moon juxtaposed alongside the flags and monument - but I didn't have my 'real' camera with me, so I was only able to grab this iPhone photo.

I reclined on the marble benches around the base of the monument and slowly watched the sky change colors and a few stars and planets slowly appear.

washington monument iphone

looking up at washington monument with hand

looking up at washington monument

Sunday, May 22, 2016

Milky Way Barely Visible in Noblesville

We had exceptional clear skies in Noblesville, IN on May 16 at 4am. I woke up to let the dogs out and it was like 40 degrees (F) with absolutely no wind. Perfectly clear skies. I saw Saturn and Mars blazing in the tail of Scorpius, and my favorite asterism the celestial teapot in Sagittarius.

I tried for a couple Milky Way shots and was surprised I actually could see some nebulosity even from my backyard. Noblesville is NE from downtown Indianapolis, so the light dome from the city is obvious - so seeing ANY part of the Milky Way is pretty cool.

backyard milky way before and after
Before (R) and After (L) processing in Adobe Camera RAW - not a lot to work with, but the fact that I caught it from my own backyard is pretty cool.

backyard milky way with light pollution
Single frame, Canon T5i, ISO 800, 18mm, f/3.5, 13 seconds on fixed tripod

backyard milky way with light pollution
Single frame, Canon T5i, ISO 1600, 18mm, f/3.5, 10 seconds on fixed tripod

backyard milky way with light pollution
Single frame, Canon T5i, ISO 1600, 18mm, f/3.5, 10 seconds on fixed tripod
As you can see, I didn't have much to work with - as soon as I turn the exposure and highlights up, the light pollution washes out the Milky Way. Still a cool piece of sky, and definitely reminds me of summer. Here is a screenshot from Stellarium showing the position of Saturn, Mars, and the stars in the constellations Scorpius and Sagittarius.

stellarium screenshot tea pot
Screenshot from Stellarium showing the southern sky at the time I took the photos on May 16, 2016. 
teapot asterism
Single frame, Canon T5i, ISO 800, 34mm, f/4.5, 6 sec - the Teapot Asterism and M7 globular cluster visible over the rooftops in the southern sky.

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