Archive for the ‘Digiscoping’ Category

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Observing Report: Total lunar eclipse on January 31, 2018

February 2, 2018

Man, only the second post in six months, and we’re back to another eclipse! Oh well, that’s how it goes sometimes.

This is also going to a short post. I have more photos from the eclipse, and I’m hoping to get them processed soon and put into a composite like I did for the October, 2014 (link), and April, 2015 (link), lunar eclipses. But those photos are still lurking in a raw state on my hard drive. You’re getting the only two I’ve processed so far: the above shot of the full moon at 12:20 AM, before the eclipse started, taken with a Nikon Coolpix 4500, and the below shot from the start of max eclipse, around 5:00 AM, taken with an iPhone 7. Both shots taken afocally through London’s XT4.5 dob and a 32mm Plossl.

Hope you got to see it. Stand by for more shots…at some point. Hopefully. What can I say? Fossil season came early this year…as I knew it eventually would.

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Impromptu binocular digiscoping

January 18, 2017

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I grew up in Oklahoma, on the Great Plains. The plains have a wild, forlorn beauty, but I have always craved seeing mountains. When I was a kid, that meant waiting for a family vacation to the Rockies or the Black Hills of South Dakota. I have been very fortunate that since moving to California in 2001, I have essentially always lived within view of mountains. In Santa Cruz and Berkeley it was the coast ranges, which are really more like ambitious hills. In Merced it was the Sierra Nevadas, which are legit, but not particularly close to Merced. The mountains were only visible as a low line on the eastern horizon, and only when the air quality was good, which was not often. Fortunately that was just one year.

Since 2008, I’ve had the privilege of living at the feet of the San Gabriels and especially Mount Baldy (formally Mount San Antonio, but universally ‘Baldy’ to locals), which looms directly north of Claremont like a slumbering god. So I get to see proper mountains – the San Gabriels are still rising fast so they are impressively steep, and Baldy tops out at 10,064 feet (3068 m) – pretty much every day that it’s not raining and there are no nearby wildfires. In the winter the mountains are often snowcapped, although never continuously so, it’s just too warm here.

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A couple of days ago I was out running errands and the mountains looked so good that I had to drive up to the top of the First Street parking garage downtown to get some unobstructed photos. Off to the northwest, 22 miles distant, I could just make out the gleaming white domes on Mount Wilson. Then I remembered that I had my 10×50 binos in the car, so I got them out and spent a few pleasant minutes scanning the whole northern skyline, from Mount Wilson in the west to mount San Gorgonio, above Big Bear, 51 miles due east.

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Then I got to wondering – if I held my iPhone up to the binos, would I be able to get a recognizable photo of Mount Wilson? It was worth a try. I had to prop the binos on my sunglasses to get the angle right, and the raw shot is vignetted because getting the camera-to-eyepiece distance correct is a little hairy, but hey, there are the domes.

mt-wilson-from-claremont

Here’s a cropped, tweaked, and labeled shot. Except for the CHARA Array, an optical interferometer using six 1-meter telescopes in small domes that started work in 2002, all of the historically important installations are visible from 22 miles out.

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I also got some shots of the nearby peaks, especially the higher foothills of Mount Baldy. This shot is a pretty good match for the last photo in this post, which was taken through a different instrument at a different time of day in a different season, but focused on the same peak. This peak is 10.5 miles from my house, as the crow flies, so about 10.25 miles from the Claremont parking garage where the photos in this post were taken.

snowy-trees-on-mt-baldy-foothills

Cropped and tweaked. Not too bad for 10×50 binos that cost less than $30.

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Observing report: the transit of Mercury from western Colorado

May 19, 2016

Mercury transit 9 May 2016 - telescope setup

I was in Utah from May 4 to May 15, chasing dinosaurs with Mike Taylor, a colleague of mine from England. I took a telescope along in hopes of getting some dark-sky time, and to hopefully catch the transit of Mercury on May 9.

Things did not look promising at dawn on the 9th. I was in Fruita, Colorado, and when I got out of bed, the sky was completely overcast. Mike and I decided to head out west of town to visit Rabbit Valley, where a nearly complete skeleton of the long-necked dinosaur Camarasaurus is visible in a hard sandstone ledge. (Why is no-one excavating this dinosaur? Because we already have many nice specimens of Camarasaurus, and the sandstone around this one is like concrete. It would be a mountain of work for very little payoff.)

We spent about two hours measuring and photographing the skeleton, and as we did so, the clouds started to break up a bit. By the time we got back to Fruita, a little after 11:00 AM, the sky was clear except for a few scattered wisps of cloud. I set up my telescope in front of the Dinosaur Journey museum and started watching and photographing the transit.

Mercury transit 9 May 2016 - Mercury crossing the sun

I was using the same setup as in the last post: my Celestron C80ED refractor, a Celestron 8-24mm zoom eyepiece, and a GoSky full aperture solar film filter. For photography, I used a Nikon Coolpix 4500 for still photos and my iPhone 5c for video.

I caught about the last hour of the transit, and I got to share the view with about a dozen museum staff and passersby. A few light clouds drifted through the field of view, which looked pretty cool and didn’t obscure the view at all.

At 12:42 Mercury finished exiting the disk of the sun. The next Mercury transit will be in 2019 – I hope I’m as lucky then as I was this time.

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New scope: Bresser Spektar 15-45×60 spotting scope

December 9, 2015

Bresser Spektar 15-45x60 6 - side view

Thanks to this thread on CN, I recently learned about Optical Instruments, a sort of online clearing house for optical gear from Explore Scientific, Explore ONE, Bresser, and a few other instrument makers and resellers. In particular I was taken by the screaming deal on the 60mm Bresser spotting scope. I’ve had a lot of fun scoping birds with my telescopes (most recently with the C80ED), but I thought it would be nice to have a light, rugged all-in-one spotter for camping and hiking. And at $39.99 with free shipping, the price was certainly right – normally the scope lists for over $100. I placed my order on November 25, got a shipping notice on December 3, and the scope came in today (well, yesterday, December 8 – I’m up late).

Bresser Spektar 15-45x60 4 - on L-bar

I got the scope out for a few minutes late this afternoon for a test drive. It’s solid. The eye lens is nice and big and the objective has purplish anti-reflection coatings. Optically okay – the image does go soft in the outer 10-15% of the field, and there’s a bit of chromatic aberration, but neither problem is severe enough to put me off. The eyepiece is not quite parfocal across the zoom range, but it’s close enough that I just need to touch up the focus a bit after changing magnification. Fit and finish are merely serviceable, about on par with inexpensive Celestron binoculars. It certainly doesn’t have the feeling of machined perfection that you get from a nice telescope, but part of that may be the rubber armor (which I’m more happy about than not, as I intend to use this scope).

Here are a couple of unboxing photos with the scope still in its case.

Bresser Spektar 15-45x60 1 - in box

Bresser Spektar 15-45x60 2 - in case

Five features I really like:

  1. Padded view-through case – this has cutouts for the mounting foot and focus knob, and the covers for the objective lens and eyepiece snap off, so in bad weather you can leave the case on while viewing.
  2. Sliding dewshield for the objective lens – I’ve only had my scope out on a cloudy day just before sunset, but I’m sure this will come in handy for cutting down glare on sunny days. This is extended in the first picture at the top of the post, collapsed in the second one.
  3. Twist-up eyecup on the eyepiece – nice for visual, great for digiscoping as it helps get the distance from the camera to the eye lens just right.
  4. Mounting foot on a rotating collar – super useful for side-mounting. The focus knob is on the right side of the scope, so it’s better to put the mount on the left if possible. I used a Universal Astronomics DwarfStar mount for testing, first with the scope upright on an L-adapter (second photo above), and then later on side-mounted using a spare footplate from a Manfrotto ball-head as a makeshift dovetail bar (see next photo below). One thing to be aware of – the cutouts in the case for the focus knob and mounting foot are fixed, so you can’t have the view-through case on if you side mount the scope.
  5. Side-mounted focus knob – most spotting scopes have a little knob in front of the eyepiece that you roll side-to-side to focus. I’ve never gotten the hang of that; I’m always struggling to find the right amount of pressure to turn the focus knob precisely without pushing the scope off-target or shaking the view. The side-mounted focus knob on the Spektar makes it feel just like using any other refractor, in that I’m reaching my right hand forward and rolling a focus knob. Lefties may not be so wild about this.

Here’s a photo showing the scope side-mounted, with the mounting foot facing left from the eyepiece and the Manfrotto footplate ‘dovetail’ (lighter grey metal) serving as a dovetail bar. The lock knob for the rotating collar with the mounting foot is facing straight up here, and the larger, right-mounted focus knob is also visible.

Bresser Spektar 15-45x60 5 - side mounted

Now, five things I don’t like:

  1. No pictures in the so-called instruction manual. Until now, I’ve always gotten a chuckle out of the labelled photo of the assembled scope in most telescope instruction manuals – sheesh, who doesn’t know what the eyepiece is? But now the shoe’s on the other foot, and I’m not laughing anymore. This scope has some non-standard features and you’re basically left to figure them out by trial and error. I did that, mostly successfully (but see below), but it’s still an irritating oversight.
  2. Just below the eyepiece is a knurled ring that rotates. I don’t know what it’s for – maybe it’s a lock ring to hold the zoom eyepiece in place? I haven’t had the courage to unscrew it and find out.
  3. The rotating collar and lock knob feel very plastic-y, and the lock knob does not come to an authoritative stop. Instead it sort of oozes into tightness. I’m worried I’m going to overtighten it and either strip the threads or break the knob.
  4. As people on CN have noted, the soft rubber dust cap for the objective lens is a loose, floppy joke. At one point while I was unboxing the scope I happened to point the objective end downward and the dust cap just fell off. And most frustratingly, while I was packing the scope up at the end of the day my hand hit the dust cap and it bent in and left a smudge on the objective lens. Grrrrr. I have a cheap Meade spotting scope from back when and it has spring-loaded dust cap that locks in place, like the dust caps on most DSLR cameras and lenses. If the dust cap on the Spektar was at least hard plastic, I could shim it with felt (I’ve done this with countless telescope dust caps). Feels like they really cheaped out here.
  5. The padded view-through case is nice but it leaves the focus knob exposed. In my book that’s okay for day use but not for something you’re going to store the scope in. If there’s one place you don’t want moisture or dust getting inside the case, it’s at the focus mechanism. Something like a velcro flap over the focus knob would be easy enough to install, but it feels like something that should have been addressed at the design end. Maybe it’s mean to pick on this one thing – I buy scopes all the time that come in padded boxes with no case, so the padded case here is definitely a step up. The Telescope Warehouse on eBay sells locking and waterproof cases that fit spotting scopes – I’ll probably be picking one up shortly.

Verdict? The scope has some quirks and some outright deficits. Fortunately they are with the mechanics and accessories rather than the optics. It also has some very nice features that make it easier and more convenient to use, compared with most spotters I’ve used in the past. At the list price of $130 it’s probably possible to do at least as well or better with something from Alpen, Barska, Bushnell, or Celestron. But for $40 it’s a steal.

The rest of the photos are quick digiscoping pix from this afternoon’s test run. It was overcast, I didn’t get outside until just before sunset, and I didn’t put on the camera adapter but instead shot everything handheld. So some of the problems with the photos are not the fault of the scope – the low light levels meant low contrast, uneven field illumination was mostly my inability to get the iPhone’s camera lens centered in the spotting scope’s exit pupil, most of the CA and almost all of the spherical aberration are from the iPhone, and I couldn’t hold the camera as still as the adapter so the detail in the photos does not nearly match the view through the eyepiece. I need to get out and play with the scope under better conditions, but for now, this is what I have. Other than the unmagnified reference image, none of these are processed at all, partly for versimilitude and partly because I’m lazy.

With all of those caveats in mind, here we go. Captions are below photos.

Telephone pole at 1x

Here’s an unmagnified iPhone pic of the utility pole and the mountain shown in the close-ups below. The utility pole is about 300 feet away, the mountaintop is 10.5 miles according to Google Earth.

Telephone pole at 15x

Utility pole at 15x. Darkening around the outside is me not getting the camera in the right spot – it was not visible visually. See the woodpecker?

Telephone pole at 45x

Utility pole at 45x. Woodpecker had moved on by this point. I could see a lot more detail visually, including growth rings in the wood and the twisted wires that make up the power lines.

Mountains at 45x

Those trees on the ridgeline admittedly do not look brilliant. But considering that they’re 10.5 miles away and being imaged handheld through a couple of intermediate layers of branches, I’m pretty impressed. We’re in the glidepath for airliners going to LAX and Ontario, and for small private planes out of Cable Airport, and I had fun this afternoon chasing airplanes with this scope. The next clear night, I’ll probably be out chasing satellites instead.

As of right now (early in the morning of December 9, 2015) the spotting scope is still available at $39.99 with free ground shipping. Optical Instruments has a bunch of other stuff on sale right now, including some binoculars and small telescopes. If you’re interested enough to get this far, you owe it to yourself to give ’em a look.

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Digiscoping with the GoSky universal cell phone adapter

October 30, 2015

Bird on a stick - 50x

As I mentioned in the moon video post, I recently got a GoSky universal cell phone/eyepiece adapter. So far I’ve tested it on some birds during the daytime, and on the moon after dark. Here’s a Northern mockingbird at 50x, about 125 feet away.

C80ED set up for digiscoping

I did most of the digiscoping with my C80ED and a 12mm Plossl (50x). I tried other eyepieces but for my purposes the 12mm Plossl delivered the best balance of magnification, true field, and image brightness.

C80ED digiscoping business end

If you haven’t seen one of these cell phone adapters, it has a diamond-shaped, padded clamp that screws down around the eyepiece, and another padded clamp to hold the phone. The bracket for the phone can slide up and down and rotate relative to the eyepiece clamp, so you can get the phone’s camera centered over the exit pupil of the eyepiece. As you can see here, the phone bracket is wide enough to hold an iPhone 5 with a heavy Otterbox case. I prefer to leave the case on while shooting – it’s rubber, so I can crank down the adapter bracket and make sure the phone is truly secure. Plus, it’s one less thing to do during setup and teardown.

iPhone earbuds remote shutter release

You may be wondering why I have earbuds hooked up to the phone. It’s because of a very nice feature with the iPhone 5 and 6 (don’t know about other iPhone models or other brands of smartphones) – the volume buttons work as shutter release buttons, which is often handier than trying to press the button on the screen, AND this functionality extends to plug-in volume buttons like those on the earbud cords. So you can plug in your came-with Apple earbuds and use the volume control there as a remote shutter release for hands-free, no-shake photography.

Fanned tail feathers - 50x

That mockingbird again, fluffing its tail feathers.

Waning gibbous moon 2015-10-28

Here’s one of the moon. The seeing was punk last night so I know the system was not performing anywhere near its limits. I’ve done far better holding the phone by hand on nights with better seeing, but only by dumb luck, taking loads of pictures, and throwing away all but the best. Using the adapter I get much more consistent results, even if the seeing makes them all consistently lousy on a given night.

The biggest problem with this setup so far is that the lens of the iPhone camera is bit fish-eyed and that introduces some kind spherical distortion (I believe it is positive or pincushion distortion – feel free to educate me in the comments) in the image. It’s not so bad in this cropped picture:

European Starling x4 - 50x

But check out the diverging power lines – which are parallel in real life – in the unmodified original:

European Starling x4 - raw shot

These are European starlings at 50x, again with the 12mm Plossl, from about 250 feet.

I did lots of back-and-forthing between camera and the various eyepieces to confirm that the distortion was in the camera and not in the telescope or eyepieces. It’s a fairly minor annoyance for me – I’m not expecting world-class results out of my smartphone camera. Just something to be aware of.

European Starling - 100x

I tried going up to 100x with the 6mm Expanse on this starling. It caused a lot of vignetting – even in this severely cropped photo, you can see that the corners are dark. I’ve had this problem with using too much magnification with handheld afocal photography as well. I think that as magnification goes up and the exit pupil goes down, it’s progressively harder to fully illuminate the camera’s CCD.

This may seem like a lot of caveats and complaints – distortion, vignetting, etc. – but they’re all problems that come along with doing afocal photography with a phone. The adapter itself is dandy. It holds the phone and eyepiece securely and without stressing either one or leaving a mark, it’s easy to put on or remove, and it adjusts easily. I wish now I’d gotten one a lot sooner. There are lots of interchangeable brands on these things – if you want the GoSky verison, it’s here.

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Video: Moon and clouds

October 29, 2015

After much helpful prodding by Doug, I finally broke down and got a cell phone/eyepiece adapter. I had some Amazon credit and I was looking at some cheap astro gear by VITE. In particular I was checking out their cell phone adapter when I saw the link for a similar piece of gear by GoSky. The GoSky model cost a little more but the build quality looked more substantial and the reviews were better, so I bit. Got it out after work this evening for some digibirding and then some moon shots. More about that, and about the mount, in another post.

Shot this video from my driveway using the C80ED, a 12mm Plossl, the GoSky camera adapter, and my iPhone 5C. I know a horizontal aspect ratio works better on most computer screens, but I deliberately wanted it vertical to catch as much of the moon rising as possible without moving the scope. These were the last clouds of the evening, so at least for now, the New Gear curse has lifted.

 

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Guest post: Photographing the moon with the Celestron 102GT

October 21, 2013

Here’s the first guest post by frequent commenter and sometime observing buddy Doug Rennie. He’s using the same OTA I’ve been using recently–the Celestron 102GT achromatic refractor–but the rest of his setup is different from mine: different mount, diagonal, eyepiece, and camera. Just goes to show that this scope plays well with lots of other gear. I flipped some of the photos to match the orientation of the moon in the sky, but otherwise they are as Doug sent them. The captions and any errors therein are mine. Enjoy!

IMG_3393 - Northeast quadrant

The northeast quadrant of the moon. The landing sites for Apollo 11, 15, and 17 are all in this quadrant.

So I went out several nights last week with the waxing gibbous moon looming large and bright over our front courtyard, and took out the C 102 on a Porta II with my Celestron 8 x 24 zoom attached to my DSLR for some eyepiece projection AP. Took a lot of photos, most of them so-so to utter crap, but maybe 8 or so not half bad. I still need to focus more on . . . focus. Note in the photo that I insert the zoom/camera into a 2″ High Point Scientific 99% dielectric diagonal vs directly into the focuser as this is a lot easier to work with, and having done it both ways, I really see no image quality drop-off using the diag.

Scope and camera setup

The Celestron 8 x 24, as you can see from the photos, allows the removal of the rubber eye cup which exposes a threaded male connection; this allows the eyepiece to be mounted directly to the t-ring on my Canon T1i DSLR. Eyepiece projection photography. I found that to achieve focus using the LED LiveScreen at the back of the camera (which works well; my eyesight is the issue here) that I need to run the shutter speed up into the 3-4 second range so that the image is bright enough to both fill the screen and capture the necessary (for focusing) details. Once I have focused, I then move the shutter speed back to that which I will actually be shooting at, usually (depending on brightness and how much of the darker Mares fill the screen) anywhere from 1/30 to 1/160, the most common being around 1/60, ISO set at 800 for most.

Closeup on diagonal eyepiece and camera

I also use a remote shutter release cable (about 4 bucks through eBay) to cut camera movement/vibration down to next to nothing.

With the zoom, I can go everywhere from 42x to 125x magnification, and everywhere in between, with a quick quarter turn.

The north-central portion of the moon. The smooth dark crater on the lower left is Plato, and the deeply-shadowed crater with the bright rim far to the north is Philolaus.

The north-central portion of the moon. The smooth dark crater on the lower left is Plato, and the deeply-shadowed crater with the bright rim far to the north is Philolaus.

The C 102, as you pointed out in your report, serves up wonderfully bright, sharply-resolved images and much of this comes through in the photos. Any soft edges are more the result of my less-than-perfect focusing than with any of the optics involved.

Also, these are all single shots: focus, click, move on. Stacking? We don’t use no stinking stacking!

The prominent crater in the upper middle is Copernicus, with the Apennine mountains curving away to the northeast, marking the rim of Mare Imbrium, the Sea of Rains. Near the lower left are three craters making a backwards comma--these are Ptolemaeus, Alphonsus, and Arzachel (Arzachel has a prominent central peak).

The prominent crater in the upper middle is Copernicus, with the Apennine mountains curving away to the northeast, marking the rim of Mare Imbrium, the Sea of Rains. Farther down and to the right are three craters making a backwards comma–these are Ptolemaeus, Alphonsus, and Arzachel (Arzachel has a nice central peak).

I am now waiting until Jupiter and Saturn again appear in my observing window, along with M42, M45 and other brighter DSOs as I believe I can capture some decent images with my current set-up, as long as I don’t need to go longer than 12-15 seconds. We’ll see.

This shot is from a few nights previous to the last one. Now the backward comma formed by Ptolemaeus, Alphonsus, and Arzachel is right on the terminator, just slightly above and right of center.

This shot is from a few nights previous to the last one. Now the backward comma formed by Ptolemaeus, Alphonsus, and Arzachel is right on the terminator, just slightly above and right of center.

Frankly, I never see myself getting heavily into AP as the costs alone are prohibitive, plus all the technical stuff overwhelms me just thinking about it. That, and it seems to me that too many of these big time AP guys do little, if any, visual observing, that their views of the heavens mainly come after the fact when they look at the photos they took. Not me. My biggest joy is still what I see at the moment via the EP. But it’s still fun to screw around with modest gear/modest goals AP, especially when its Moony out and that’s about all there is to do. But I am eager to try my new eyepiece projection technique on Saturn and Jupiter when they next appear, and am optimistic that I can even score some good photos of brighter DSOs such as the Orion Nebula and the Pleiades, which won’t be long now.

The bright crater above and left of center is Tycho--note the rays of ejecta that point back to this young, well-defined crater. Below Tycho is the much larger, worn Clavius, with a nice arc of craterlets of decreasing size on its floor.

The bright crater above and left of center is Tycho–note the white rays of ejecta on the right that point back to this young, well-defined crater. Below Tycho is the much larger, worn Clavius, with a nice arc of craterlets of decreasing size on its floor.