Friday, September 30, 2016

What does the 'rare' Black Moon look like? Nothing!

I've been seeing more and more articles about this 'rare' lunar event creeping into my newsfeed. The black moon! Rare black moon this Friday! A rare lunar event is happening tomorrow! What the heck is a black moon? Is it anything like a blue moon, a supermoon, or a strawberry moon? Let me explain...

what does the black moon look like?
What does the rare black moon look like? Nothing!

First of all, I'm not going to do what all the other black moon articles do, and I'll tell you the most important piece of information first: You can't see a black moon. No really, you can't see it, it's literally not going to be visible. A black moon is the 2nd new moon in the same month, and a new moon is not observable. For all intents and purposes it might as well be invisible. Don't worry about waiting up for the rare black moon to appear because it won't.

Also, since the black moon occurs at 8:11pm ET on Friday, September 30, 2016 the moon and the sun will both be below the western horizon (at least from my location here in Indiana). For those in other areas, the new moon is always right next to the sun so you can't see it anyway.

how to spot the black moon
Looking at this diagram from Stellarium, the black moon will be well below the horizon from Indiana at 8:11pm ET. In other areas, the moon will be obscured by the sun, and lit from behind so there's really nothing to see. 

A new moon happens when the moon and the sun are on the same side of the earth. The far side of the moon is lit, and the side facing Earth is completely dark. Not to mention, the Moon is so close to the Sun that the light will completely obscure the moon. The only way to see a new moon from Earth is during a solar eclipse where the moon passes in front of the disc of the sun.

black moon diagram
My rough diagram of a new moon (not even close to scale) but you get the idea

Now, the day before or the day after it might be possible to see a very very slim crescent moon, which is really cool, but this technically isn't a new moon anymore. Speaking of moon phases, check out my composite of moon phase photos that took me 3 months to photograph.

So what is a black moon anyway? Apparently it's the 2nd new moon in a calendar month (sort of like a blue moon's invisible friend). From what I can tell, it's another in a long line of terms local news anchors borrow from astrology or the Farmer's Almanac and report it as a rare celestial event - when in fact there is no such term in astronomy, nor do these events warrant special acclaim or attention.

Remember when Neil deGrasse Tyson ranted about how the Strawberry Moon is completely meaningless? In this clip from the Late Show, he admits the fun names are kind of charming, but offers an explanation of the special attention paid to not-so-special events:

"Most people want something in the sky to be special and unique to their lifetime on Earth, an Earth that has been here for 4 1/2 billion years, so this is evidence of a delusional state." Neil continues "Something can be rare but uninteresting, because of how common its rarity is."

At least with a Blue Moon or Hunter's Moon or Strawberry Moon you have something to look at! This is a new low for celebrating meaningless moon phenomena because you can't even observe it!

So there you have it! Enjoy the blackness of the night sky without light from the moon just like every other month, or any other night before the moon rises or after the moon sets.

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!

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