Adam@SheekGeek

My Current Astrophotography Astronomy Setup

by

This is a quick list of Equipment I have and what I want. I have yet to have the time to get any spectacular images yet, but I think I could get some good ones given some practice. This is mainly a list for myself, but in case anyone else is interested in what to get for starting out in astrophotography, here’s a reference point. My next post on this topic will likely be a description of how I plan to use this to take wicked pics of planets, nebulae, and hopefully some galaxies.

  • Meade LX-10 telescope with declination motor kit (no longer sold new, but check craigslist)
  • Hacked together arduino system for guidance
  • HD Webcam for guidance and tracking
  • Green laser pointer for pointing at stars and such to make show people what I’m talking about (pointing into the sky with your finger is useless…) Make sure there are NO aircraft in your entire field of view before using this! While they don’t make the exact one I have anymore, this one seems to be the closest I can find.
  • I have a set of spirit (bubble) levels. I like using the T-type level to level my tripod and the top of my tube when polar aligning, and I use a torpedo level to level my forks. I got all of mine at a discount hardware store and all together they costs like $8, and this included a line set level.
  • Meade 1.25″ diagonal prism
  • 26mm plossi lens
  • 2x barlow lens
  • Extension tube (Mine’s a meade, but they don’t seem to make them anymore)
  • Canon T-ring for my friend’s 5D
  • Nikon T-ring for my Fuji and Nikon
  • The book Nightwatch: A practical guide to viewing the Universe. I literally keep this in my telescope bag and bring it with me everywhere I go!
  • My Red head lamp is priceless out in the field! I love the ability to flip it up and down when I’m using it. Be aware though because it turns the white LED on first, the second time you push the button it turns on the red LEDs so hold your hand over it until the red LEDs come on to save your nightvision.
  • A must-have is this wireless shutter-release for my Nikon. It uses radio, not IR so I can literally be inside my car or house and set the thing to take an image. This is great for winter nights. It has other modes on it as well.
  • You can also use an android or iOS app called DSLRDashboard which controls your DSLR via a tablet or phone. It gives you control of pretty much all the camera settings (except manual settings such as the autofocus switches on the lenses) from a tablet or cell phone. With this, you’ll simply need a USB “On The Go” OTG cable and your camera’s USB cable. The OTG cable allows you to plug devices such as cameras, keyboards, mice, flash drives, etc. into your tablet or phone. I prefer using the 90-degree cables to keep all the cables clean and out of the way.
  • Though, I’ve really been considering getting this wireless adapter for my Nikon because it will replace the wired setup mentioned above. This will be mainly for if it is too cold for comfort.
    When I’m roughing it, and my wife won’t let me use the Nikon, I use my old Fuji DSLR. I have my manual cable release for it so I can do long exposures the old-fashioned way.
    My low-cost DIY Dew Sheild.
  • And since I mentioned it, my telescope bag didn’t cost me much.

My next purchases:

Xcarve updates and Passive Amplifiers

by

passiveAmpIn summer, I went to Woodcraft and grabbed a bunch of blocks of wood to make x-mas presents for some friends. I already had an idea of what I was going to make from a project video I saw on Inventables’s site. I wanted to make Passive Amplifiers that would double as a desk nameplate. Rather than use the pre-made file from Easel, I wanted to do my own in Fusion360 to get more practice.

Machine Upgrades:

Before I had any time to work on this at all, I ended up buying the new beefier gantry makerslide.  I also 3D printed an enclosure for my smoothieboard and an enclosure for my E-stop button, both from thingiverse.

E-stop box         smoothiebox

Literally at this point, I’ve got enough extra makerslide, plates, belts, ACME screw and nut set and gears to build a Shapeoko 2 (missing bolts, nuts, washers, V wheels, bearings, or idler wheels). Leave a comment if you are interested in purchasing my extra parts.

I also had beefed up my gantry motor to a NEMA 23.

Processing the Blocks:

Once I had made the changes to my machine (a never-ending project in itself) I got to work on the passive speakers.  I clamped my handheld belt sander upside down in my workmate bench (I do not condone this stupid behavior). I sanded down all the blocks until you could no longer see the bandsaw marks using 150 grit sand paper. I rolled the edges and ends to get nice rounded edges. This worked for the most part, but sometimes I got inconsistent results along the entire edge of the block which looked bad and wasn’t easy to fix.

blocks

After rough sanding, I hand-sanded the corners to remove the sharp point using 150 paper by hand, then used 220 paper on my orbital sander to remove the traces of the rougher sanding and smoothed out the overall faces. Due to time constraints (I was so busy that I waited until the last minute to do these) I went ahead and hit the blocks with Tung Oil every other day for about a week. This soaks in and if I had done it more would really bring out the luster int he wood. It smells a bit funny so I left the blocks in the garage to air out.  Tung oil is good because it won’t combust spontaneously like a lot of oil-based stains. Heck, the guy that sold it to me said he never even wears gloves and has been using it 20+years. I wore gloves anyway.

After the blocks were processed and thoroughly tunged, I went about using Fusion 360 to design the passive amplifier element. Unlike the inspiration project, I wanted a continuous spiral as my cone. I created a block approximately the size of these blocks, then I created a spring. It took a long time to figure out exactly how to get the spring to have the features and be be the size I wanted. I then had to merge this with a cone shape to create a single solid body that was a helical cone shape. I put it on the block and performed a difference operation to remove the helical cone shape from the block. Then I added the slot for the phone. I used my and Jess’s phones as tests using a block of scrap 2×4 to find a width that fit both of them.

model1

CAM Processing

I can’t say this was intuitive. When I ran simulations of the cut, I kept having weird errors that would break an endmill in the real world. For instance, the bit would circle the perimeter of the helical cone step by step, leaving a huge plug of wood in the middle 40mm high to be cut from the side at the very end of the job. In order to remove this weirdness, I had to get creative with the cuts. Firstly I used a plunge cut to cut the very center of the cone out in several passes. As you can see in the image at the top of this article, there’s a bit of an error at the right side near the top of the helical cone. This is due to the lead-in of the plunge cut. In later iterations, I removed that stupid lead-in. I have no clue why it would generate paths that would defile the user’s design, but it does…

Then I used a contour cut to remove material for the slot and helical cone in multiple passes. The Fusion 360 simulator said it’d take about 5 minutes for the whole shebang, but it took about 3 times longer in reality. I’m not sure how to reconcile this. CAM

Milling:

So I intentionally went against my best judgment on this one. Looking for a cheap engraving bit, I ended up at Harbor Freight. I found a pack of 5 HSS router bits that included an engraver for $8. Since an engraver bit is usually taking a bit more light duty use than other bits, this was a good deal. Other bits were like $25 just for the engraver elsewhere! My mistake happened when I considered using the half-inch  router bit as an endmill. I figured if I take off only 1.5mm at a time, then it couldn’t hurt to use this router bit slightly out of its specified application. So I went ahead.

Surprisingly, this worked beautifully for the first four blocks I milled. The last one had ragged edges though. Since I needed to make about 4 more, I went back and bought another Hazard Fraught bit set. This was enough to cut the bulk of the gifts I was making. I had another 2 blocks to mill, but I had a couple weeks to finish those while these first 8 were needed literally that night at a party.

After I milled them, I had Jess get one of her fancy fonts and make some SVGs of our friend’s names to engrave on the other face of the block so it could be used as a nameplate on their desks. This was easy to do in fusion in a new file. I simply created a block the size of the wood I was using, then imported the SVG onto the face of the block. The Z axis here is still setup so the tool comes from the top (ie. as if the block has been rotated so that the face is pointing upward). Simply go into CAM and do an engrave and it’s done. The results came out beautifully!

The problems started when I moved my CNC machine the garage form the office to avoid the dust. I used one of those half-inch bits and aligned everything and let ‘er rip. I was making a video when the failure happened…

 

I hit the E-stop immediately but it still screwed up stuff. The bit came loose and slipped down as the router continued to spin (likely screwing up my quarter-inch collet) The CNC kept moving for a short time as well until I could hit the E-stop. This  caused the bit itself to break. Luckily no chunks of it came loose or flew off at the 22,000RPM I was running at, but it came close as the pics below show.

bit1     bit2

After this error, I went ahead and redesigned the toolpaths to use a proper 0.25″ endmill and tried cutting another block.  I didn’t get to see the final result, BUt I’m pretty sure the lead-in screwed me on the first plunge cuts I did.  I didn’t finish the part because like a genius I stuck the vacuum cleaner hose in the way of the Z cart and ended usp causing my X axis motor to skip a bunch of steps as it wedged the vacuum hose into the block. I’ve yet to revisit this. even this short amount of exposure to the incredibly fine wood dust made my nose clog up again(even wearing a respirator). I had to go back to work after new years and haven’t had a chance to revisit (or document) and projects until now.

Lessons Learned:

  • Never, ever, ever use tools the wrong way… especially if you get them from Harbor Freight. The half-inch router bit I used was intended only for routing (ie cutting sideways) and not designed for plunge cuts, even 1.5mm shallow ones.
  • Fusion 360 can’t fix stupid part 1. If you delete a shape’s reference, it’ll cause you trouble in Fusion. I don’t know how I did it, but somewhere in my timeline I deleted the helical coil. I get errors all over the place if I try to modify it. Yellows are warnings, reds are errors.
    timeline
  • Fusion 360 can’t fix stupid part duex. If you don’t know what you are doing as far as feeds and speeds, making sure your lead ins and outs don’t screw up your part, and don’t try to cut off too much at once, then there’s nothing Fusion 360 can do to help you.
  • Even with a respirator on during the sanding and milling, I still ingested a lot of dust through my nose (ended up with one hell of a sinus infection requiring a shot on Christmas Eve). It was a loud and dusty process. I need to build an enclosure. The never-ending project continues…

My Humble Telescope Case

by

scopeIncase1You can find them for as high as $600 for a hard-shell case or for a soft-shell case, about $300. We’ve had a set of luggage my mother gave us like 10 years ago and I repurposed the largest one to carry my OTA (telescope tube). It’s dimensions were perfect. 13″deep x 18″wide x 28″ tall. I went to a craft store and got some 1.5″ foam, wrapped it in a circle and smushed it into the bag. Then I cut off the excess which left me with enough to do a top and bottom and a sliver to set on the face of the tube after I lay it in there.

insideCase1

I did have to carefully cut a slot and hole in the top piece of foam to make a pathway for the focuser knob on the scope. This is the only thing I really worry about with this setup.

insideCase4

insideCase3

 

To make it look nicer and more finished, I got about 3 yards of shiny-satiny black soft fabric that I thought would be good to use and stuffed it along all the edges of the foam. I made sure to form the fabric into  the slot and hole for the focuser knob. I don’t want that snagging or to have any weight on it at all. There’s no sewing involved, simply tuck in about 1 foot of material around every edge, leaving a long extra piece hanging out the bottom.

insideCase2

Once the tube is set in place, bring this excess fabric up, fold in the sliver of left-over foam and set it on top of the OTA. Then zip up and you are ready to go. The bag has plenty of storage for accessories, although I do not keep my lenses in this bag.

pocket1pocket2

I would like to get a hard-shell case for it, but with the types of luggage available, the hard shell is very thin and I worry that it won’t hold up over time, but something like this looks a little more beefy. I’ve been looking at Ross and TJ Maxx when I happen to go to those stores, but nothing there seems to be big enough.

case1

My Introduction to Astrophotography

by

I’ve been interested in astonomy my whole life, and a few years back, I got a second-hand Meade LX-10 telescope. This is a 8″ diameter scope… definitely not a toy. It is great for planetary viewing and can even track the planets as the Earth turns. I have used it from time to time to try to take some pictures of celestial objects, but not very good ones. Astrophotography is a growing interest of mine now and I found the learning curve quite steep. I’m throwing together everything I’ve learned over the past couple of years including links to software and such into a few posts. There are multiple steps involved in this project and it took me a long time, working here and there and amongst about 1000 other projects, to finally get everything together for this.

To take amazing amateur astrophotography images you need to decide whether you want to look at deep space objects (DSO) like galaxies or nebulae, or if you want to focus on planetary viewing (within our own solar system). You don’t really want to zoom very much if you want DSO images because zooming narrows your field of view and most DSOs you want to get are very dim so you don’t want to zoom in to make their light spread out across your eye or camera sensor too much, you want bright pictures. You can take some amazingly cool pictures with just a DSLR and a “barn door” tracker. (This is just a device that rotates counter to the Earth’s rotation so your camera will continue pointing at the same object for minutes or hours at a time, meaning it moves a full 360 degrees in 24 hours).

In my case, I want to do a little of both planetary and DSO. So I have my LX-10 telescope, which has an 8″ diameter mirror, meaning it can collect a lot of light, and it has a tracker so I can point a camera at one point in the sky as long as I want. However, unless you perfectly align the scope with true celestial north, the scope will still drift a bit over the night. This is because it is an open control system. You just point it at a star, turn it on and hope you aligned it well when you started. The best images are taken with closed-loop control systems. That is, they continuously look to see if it is drifting off target, then takes actions to move back on target when needed. This guy has my telescope and has taken some amazing pictures of planets, sunspots, and DSOs. Some are mindlbowingly good!  To be fair, he’s using some reducer lenses like this one to change his F-stop to make it much quicker (for example F/3.75 and F/4.6 in some images), oh and he’s using a 4x Powermate lens  a lot which costs as much as I spent on my entire telescope… But what is great about his site is that he tells all the settings he used for the images. This is similar to Reddit’s astrophotography subreddit.

My scope is what they call “slow,” “long,” or “dark.” This refers to the F-stop number. This is also called the focal ratio or relative aperture. It is a ratio of the len’s focal length and the diameter of the scope. THe focal length of my telescope is 2000mm. And the aperture is 8″ or 203mm. The F-stop of this would be about 2000mm / 200mm = 10. So this means my scope is a F/10 lens. The higher the f-stop number is, the darker the image will be (all other things being equal) when compared to a lens with a smaller f-stop number. For example an F/4 is considered a pretty “fast” telescope. My F/10 number basically means that to take a nice bright picture of Jupiter for instance, I need to play with the “sensitivity” or ISO number of the camera sensor (used to be film) as well as the duration I leave the shutter open on the camera.

You might say, “Well I can just crank up the sensitivity then. Higher sensitivity will make the image come out brighter, right?” The answer is yes and no. You can raise the sensitivity, but then a lot of other things (such as heat) can trigger a pixel to register a value in a digital camera. This will increase the noise in the image, making it staticy.

You might then think “Ok, the other option is to just open the shutter for a long time, exposing the camera sensor to more light over a longer time period.” yeah… not really. This can work as well, however you will increase the overall light pollution in your images and worse, you risk blurring the image. Since the Earth keeps on spinning, objects in a fixed telescope’s field of view move. Without tracking perfectly, long exposures will be blurred.

Even if you can fix all that, there’s blurring you simply cannot fix. This is due to heat inversion in the air column between you and the object you are viewing. The Hubble space telescope was designed to fix this problem… by simply being above all the air on earth orbiting in a pretty high orbital plane (at the farthest reach that the space shuttles could fly). Air at different temperatures has different densities. This acts like a prism to bend the shape of a beam of light. Look at a straw or pencil in a glass of water. Notice how it looks like it’s broken in half at the interface of the water and the air? That’s an example of the different densities acting like a prism. Since air is, well, air… it is gaseous and mixes and moves around a lot. It is in constant motion (unlike the water in your glass compared to the air sitting on top of it.) Hot air rises and cool air falls, making all sorts of weird prism effects in our viewfinder. In the column of air between you and the top of the atmosphere where Hubble is, there’s also a lot of dust. The dust as well as the temperature inversions is what makes starts look like they are twinkling.

Side note: Planets don’t twinkle in the sky when viewed by eye. This is because a star is so far away, you are only seeing it as a point light. This makes it easy for dust or temperature inversion to affect your view of it. But planets are much closer, and their light is spread slightly wider across the retina in your eye. This means there much less of a chance that a mote of dust will block it, or temperature inversion will guide the light too far from your retina.

So how do you fix the problem of having a dark image from the telescope without getting errors from too high of a sensitivity setting or blurring from too long an exposure and temperature inversions? You can thank Woz for the home computer! Using a laptop, I’m going to connect a closed-loop control system to my computer to track the objects I want to image very closely, reducing blur of long exposure images. I’m also going to take multiple images of the same object, then do a process called “stacking” where a computer algorithm will take the sharpest views of different parts of the planet, for instance, and stitch them together into a composite image that is overall much sharper. Then I’ll be able to do some image processing on the composite image to get some great results. Stay tuned for more posts on this theme!