Extreme Planet Hunters: Uranus Edition

Click for full size.

Click for full size.

My astronomy activity last night wasn’t intended to be about Aldebaran disappearing behind the Moon, as I flat out forgot about it.  Instead, earlier that evening I wanted to try out the technique written about at Scott’s Sky Watch to capture Uranus with a camera.  It was only after I was done searching for Uranus that I happened to notice the headline about Aldebaran on the side of my blog.

Scott took a remarkable picture, using Mars and Venus as a guide to find the obscure Uranus.  I wanted to try to duplicate what he did.  I don’t have a “real” camera though, only my smartphone, but the Samsung Galaxy S7’s is still pretty decent.  Following Scott’s explanation, I set my ISO to 400 and exposure to 10 seconds (the max the stock camera app will go).

The first image on this post is typical of the many I took about 45 minutes after sunset.  All of them seemed overly bright, but I could see “hidden” stars throughout.  Still, I feel the image qualities were sub-par.  One obvious explanation is the excessive light pollution in my front yard from every neighbor keeping their porch lights on.  Another may simply be the inferiority of my camera.  And in hindsight, I should have been storing the raw native images and not JPEGs.

(Trust me that in the top image, the “UFO” is nothing to worry about.  I live near a busy airport.  That bright dot was only in this one image out of the dozens I took, but it was the best image I have to show what I think I found.)

If you click the top image, you will get the full size image so you can scan and zoom in yourself.  Initially, I was very disappointed because I saw absolutely nothing where Uranus should have been.  Last night I chalked this up as a loss, and instead decided to blog about my cool success with Aldebaran.

But this Sunday afternoon I re-read Scott’s Uranus post, and in particular I studied his image.  Note that Scott’s image was taken a couple days prior to mine.  I hope he doesn’t mind, but I copied his Uranus discovery image to demonstrate what I noticed:

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I added in the orange arrows.  I took notice of those three stars.  Now, here is a closeup of my image above:

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Click for full size.

Wow, I thought, I have the same three stars!  Obviously, my image is much worse than Scott’s, but nonetheless the star pattern is definitely the same.  And by following that pattern towards Mars, I do believe that I captured an ever-so-small chuck of photons from our solar system’s seventh planet.

Here is the same image with the shadowing, contrast, and brightness altered to try to accentuate the three stars and Uranus:

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Click for full size.

So do you think I caught Uranus, or am I just imagining it?

Watch as Aldebaran Disappears Behind the Moon

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March 4th, 2017, 9:45 p.m. local time

I almost missed it, but earlier in the evening I remembered that the star Aldebaran was going to come close to the Moon.  It was also supposed to occult behind the Moon.  So looking from my window at about 8:15pm, I noticed that Aldebaran was in fact very close to the Moon, and that I would have an excellent chance tonight to photograph the two together!

Finally, I thought, I would use my telescope to capture the Moon plus one other famous object in the same picture.  It’s not Jupiter or Saturn, but I still think it was pretty cool.  And as a side note, this is a good reason to have a quick-setup telescope available.  I had everything readied outside within minutes, then giving the telescope’s mirror about 20 minutes to cool down to the frigid outside temperature (more than enough time for a 5-inch scope).

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And so I took well over 100 images for over an hour as Aldebaran slowly moved towards the Moon.  I created an animated .gif that you have already seen at the top.  Directly above is a still shot I took with my camera’s Auto mode.  For my Pro mode captures (which you see in the animated .gif) I used ISO 100 and an exposure of 1/90, and all with my 40mm eyepiece.

It was a little nerve wracking as Aldebaran was about to disappear, for though I was video taping it, I had to keep adjusting the telescope as the sky moved.  Fortunately, I did capture the few seconds when Aldebaran dimmed out as it went behind the Moon’s black disc (recommend muting the audio so you don’t keep hearing the ruffling of my coat):

A key benefit from tonight is that I now have a good frame of reference for how much extra space I can see around the Moon through this particular telescope setup, so that I will be well prepared for the next event.

Grinding a Telescope Mirror: The Non-DIY Project

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John Dobson

I did not know John Dobson, nor do I know someone who knew him, but I feel like I did from all the testimonials I have read.  At the least, my telescope build is an extremely distant branch of his legacy.

Mr. Dobson is the namesake for what is commonly referred to as the Dobsonian telescope.  He did not invent this type of telescope, but instead ingeniously brought together a number of amateur telescoping making (ATM) techniques.  This compilation is a method with general designs for how to build your own Newtonian reflector on an altazimuth (up/down left/right) swivel mount.  Sometimes you see references to only the mount as the Dobsonian part, but a true Dobsonian refers to the complete package, from the mount to the tube to even hand grinding the primary mirror.

This latter part, concerning the primary mirror, is what I stumbled on conceptually at the beginning of my telescope build journey.  When you start any type of project, and especially when you undertake what we call DIY projects today, you will have many “make or buy” decisions.  How much of the project will you, personally, create from raw materials, and how much will you rely on pre-built/pre-manufactured components?

Platonically speaking, there is no such thing as a true DIY project.  I am not going to grow my own forest to harvest trees for wood, nor start a lumber company to secure the requisite labor and machinery for my platonic lumber mill.  Nor would I obtain raw silicon to fabricate my own nano logic gates for a homemade CPU.  Still, there is a generally accepted boundary for raw materials – products that are not a specific end to themselves but are intended to be reshaped and combined with other raw materials into some form of finished component.

The primary mirror of a Newtonian reflector is indeed the main component of the telescope.  Its aperture determines everything else about the telescope’s dimensions and how “powerful” the final instrument will be.  The creation of primary mirrors is a deep step into the peculiar world of optics.  Remember the Hubble Telescope’s original blunder of having the wrong curve on its mirror?  That’s optics.  Whether we are talking big or small mirrors and lenses, the universe of optics and optical creations are not really an end-consumer endeavor.  There is a level of precision required unique to that industry.

If you follow any guide on John Dobson’s telescope build strategy, you will quickly learn that construction of the primary mirror was the core task of his method.  Below is what I assume was an old VHS era documentary on Mr. Dobson’s step-by-step approach, and most of it (a little over half) is about grinding and finishing the primary mirror.

If you watch this, or follow another guide on the Internet for grinding your primary mirror, it seems to be truly a daunting task.  It is beyond hard work and effort and closer to a stint in a hard labor camp.  Why would anyone do this to themselves?

I am in no way criticizing the method John Dobson laid out.  Too often, we judge the past by our perspectives grounded in our present.  60 years ago, the nature of amateur telescope making was very different.  There were no online guides, no easily searchable list of vendors to purchase obscure products from.  If you wanted a big telescope, I’m guessing the overall costs were too prohibitive for anyone except established institutions.  If you wanted to build a nice big telescope of your own to see the universe, you had to build your own, even scavenging for your raw materials at times.  This, I surmise, was the world of John Dobson and the source motivation for what would become the Dobsonian design.

I asked myself, “could I grind my own primary mirror?”  My weak answer was…maybe.  I have completed DIY projects before, but the grinding of a primary mirror seemed beyond my need to satisfactorily say that I could build my own telescope.  There is so much more to it than just the primary mirror – the tube, the many proper measurements, the mount wood cutting, the secondary mirror’s spider, the swivel construction, to name a few.  I decided that acquisition of the primary mirror, and all the optics in general, would be a firm “buy” decision for my telescope project.

There are other reasons to refrain from a homemade primary mirror as well.  I concluded, after all the investigations I did into the task, that there is no such thing as a true homemade primary mirror.  A DIY build means you can run to your local hardware store, buy the parts, and then construct what you need in your garage or other appropriate home venue.  Construction of a primary mirror requires, as a final step, the aluminization of the mirror’s surface.  This critical step is not a home DIY task.  You would need to find an industrial optics company willing to perform the aluminization for you.  You can spend weeks of your life grinding the mirror, then be lost because you cannot find an aluminizer.  Unless you know someone, you are going to be left having to ship your precious near-finished glass to an unknown company, somewhere and at great cost, hoping it will eventually be returned as the desired finished product.  I’m not saying it couldn’t be done, but I safely believe it is too much of a risk of both effort and money, especially when you can buy a finished primary mirror relatively easily today.

I say “relatively” easily to buy a primary mirror, because even that was a challenge, although nowhere near as hard as grinding one yourself.  For what I call consumer high-range optics, it can be very hard to find a supplier for this type of work.  Only a few online merchants offer shopping-cart style access for primary mirrors, and their supplies are limited.  Many companies post that they will make custom mirrors, but usually at a high cost, or only make very large custom mirrors, like 16″ and above.

We live in a much different world today from when John Dobson started building telescopes.  The bottom line is that, unlike most DIY projects, it is going to cost you more to build your own Dobsonian, regardless of make-vs-buy for the primary mirror, over purchasing a commercial Dobsonian or general reflector from one of the big established merchants.  So from the DIY perspective, your best route is to find one of the vendors or re-sellers of the commercial primary mirrors supplied to the Meades, Celestrons, and Orions of the market.

Who should attempt to grind their own primary mirror?  For one, masochists, and I mean this in all seriousness.  Another group that could reasonably give it a shot are those involved with any type of materials shop, from wood to metal, where building anything is just part of your routine.  And those connected to building components for the optics industry could certainly do this as well.

For the rest of us, if you really enjoy a challenge, then grinding a mirror is for you.  But for nearly all stargazers contemplating building their own telescope, I recommend purchasing all your optics, including the primary and secondary mirrors, focuser, eyepieces, and finder scopes.  Your homemade telescope will be so much more than a few specific components.  It is the journey, the knowledge you will gain, and the final satisfaction garnered from creating something far greater than the sum of its individual parts.

Mars and Venus Play Peekaboo

Click to enlarge.

Click to enlarge.

March 2nd, 2017, 6:20 p.m. local time

It’s a cold, chilly night, with cloud cover breaking every so often.  Our thin crescent Moon was able to penetrate most everything Mother Nature threw at it tonight.  But distance Venus, despite its still-glaring brightness, struggled to keep up.

And then I almost forget about their other solar system neighbor hanging around – Mars.  Faint but still distinct, it could only punch through those fast-moving clouds in the best of moments.  Mars is not pictured here, but was about halfway between the Moon and Venus.

Nothing to see here, move along…

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February 28th, 2017, 10:00 p.m. local time

Due to inclement weather, I think it is safe to say my stargazing is officially on hiatus for the next several days.  Storms and rain and even snow are ahead.  The forecast shows a break in the clouds throughout the weekend, so it’ll be anyone’s guess how generous the skies look in three-to-four days.

This is a bummer, as I always enjoy watching the Moon’s very thin waxing crescent emerge in the West, night after night.

Here’s hoping that wherever you are on the planet, your gateway to the cosmos is unimpeded.