h1

The Oct. 8, 2014, full moon

October 13, 2014

Full moon 2014-10-08

A big motivator for me in digiscoping is to see how good of a result I can get from very modest equipment. This image of the full moon from just a couple of hours before the recent lunar eclipse is a good example. It’s my sharpest iPhone moon photo. When I imported it into GIMP to touch it up, I noticed that it wasn’t left-right reversed like all of the other photos I’d taken through my 4-inch refractor. I couldn’t figure out why that would be. Then I remembered that I had started the evening using the GalileoScope, which David DeLano had equipped with a diagonal and a helical focuser. The diagonal is a prism, which can be ghastly, but this one is from StellarVue and it holds its own against a mirror diagonal. So I actually got this photo with the camera on my phone, shooting through a 2-inch plastic telescope that initially sold for $15. I like that.

Here are my previous full moon photos:

Evidently photographing the perfectly full moon is roughly annual obsession of mine. I haven’t put the new photo against the older ones to see how it stacks up in terms of libration and limb features, but I’m sure I’ll get around to that sooner or later.

h1

The orientation of the moon as seen from Earth

October 12, 2014

LPI moon orientation graphic

A few months ago I was contacted by Dr. Debra Hurwitz, a postdoctoral fellow at the Lunar and Planetary Institute. She was interested in using my Mount Baldy moonrise photo in a graphic that would show how the moon appears from different latitutes. As a committed redneck astrophotographer, I was flattered to have one of my humble images chosen for the project. The finished graphic is above, and you can see it in its native habitat about halfway down this page of resources for International Observe the Moon Night. Thanks, Debra!

h1

Observing Report: Total lunar eclipse on Oct. 8, 2014

October 11, 2014

London watching the Oct 2014 lunar eclipse 1

It had been six and a half years since I had actually watched a lunar eclipse (back in February, 2008), so I stayed up late Tuesday night to watch the lunar eclipse early Wednesday morning.

London watching the Oct 2014 lunar eclipse 2

London didn’t stay up that late, he went to bed at the usual time and I got him up about 3:00 AM. We spent about half an hour together, watching the Earth’s shadow gradually overtake the moon until the moon was entirely eclipsed. I had set up my pimped-out GalileoScope (it’s on the second tripod in the background), but after a lot of scope- and eyepiece-swapping, the setup I settled on was my 4-inch refractor and 8-24mm zoom eyepiece.

Oct 2014 lunar eclipse composite

My Nikon Coolpix 4500 gave up the ghost last year. I got a Canon S100 to replace it, but I dropped it out in the field this spring, and I haven’t gotten it repaired yet. So other than the DSLR Vicki uses at work, my only camera is the one in my iPhone 5C, and I used it for all of my eclipse photos. For most point-and-shoot photo purposes, it’s all I need. As an astronomical camera, it leaves much to be desired. There are apps out there that let you control the exposure and shutter speed, but I haven’t investigated them much yet.

When you first hold the iPhone camera up to the eyepiece, all you will see of the moon is an undetailed spotlight. The trick is to tap and hold on the moon for a few seconds to kick in the exposure lock and focus lock. That will gear down the exposure to the point that you can start getting decent photos. The focus lock is a little squirrelly – sometimes one part of the image is better-focused than another (for example, because the camera is not perfectly parallel to the light beam coming through the scope), and the camera will seize on the out-of-focus portion for the focus lock. In that case, you can usually get things back to good by tweaking the focus of the telescope, using the image on the camera screen to tell when the image is best focused.

All of the photos above have been rotated, resized, and lightly sharpened in GIMP. Max eclipse was at 3:55. The moon was entirely in Earth’s umbra, but it wasn’t centered in the umbra, so the northern limb was definitely brighter than the southern one, and the photos record that.

In sum, it was a lot of fun. Even the fussing about with the camera was rewarding – the iPhone may not be a replacement for a decent point-and-shoot camera when it comes to digiscoping, but it was still satisfying to learn how to use it for that purpose.

Now we’re getting prepared for the solar eclipse in a couple of weeks, and keeping our fingers firmly crossed for clear skies. Stay tuned.

h1

October 2014: two eclipses and my favorite star party

October 5, 2014
Eclipse end 8x10 sharpened

The end of the February 2008 lunar eclipse, as seen from Merced, CA.

Some big things coming up this month, especially for observers in the western US and in SoCal and the Southwest specifically. In chronological order they are:

A total lunar eclipse early in the morning on Wednesday, Oct. 8. These are the PDT timings for Los Angeles, from TimeandDate.com.

  • 1:17 AM – penumbral eclipse beings
  • 2:18 AM – partial eclipse begins
  • 3:27 AM – total eclipse begins
  • 3:55 AM – maximum eclipse (moon is farthest inside Earth’s shadow)
  • 4:22 AM – total eclipse ends
  • 5:32 AM – partial eclipse ends
  • 6:32 AM – penumbral eclipse ends
DSCN7707

An early phase of the May 2012 annular eclipse, photographed at Page, Arizona.

A partial solar eclipse in the afternoon of Thursday, Oct. 23. Again, these are PDT timings for LA, from NASA’s eclipse website, especially this table.

  • 2:08 PM – eclipse begins
  • 3:28 PM – max eclipse
  • 4:40 PM – eclipse ends
AASP 03 London and Daddy at dusk

London and me at the 2010 AASP.

On the two days right after the solar eclipse, the 2014 All-Arizona Star Party will be taking place at the Hovatter Road airstrip in western Arizona. London and I have been three times now, in 2010, 2012, and 2013 (click on links for my observing reports), and we’ve always had a fantastic time. See the star party webpage for details.

 

h1

A birthday observing run at the Webb Schools Hefner Observatory

June 16, 2014
Spiral galaxy M81

Spiral galaxy M81

My birthday was June 3. That evening, fellow PVAA member Steve Sittig invited me up to the Hefner Observatory at the Webb Schools in north Claremont. Steve teaches science at the Webb Schools, and he has a particular interest in physics and astronomy. The dome at the Hefner Observatory houses an orange-tube C14 Schmidt-Cassegrain. Observing with us were two other Webb faculty members, Andy Farke (paleontologist, blogger) and science teacher Andrew Hamilton. Andrew Hamilton had brought along his DLSR, a Sony Alpha33—this would turn out to be important.

Starburst galaxy M82

Starburst galaxy M82

We got started a little after 9:00 PM with a look at Jupiter, which was low in the west. We noticed right away that the seeing was pretty darned good. We went on to the waxing crescent moon and then Mars and Saturn. After that we turned to the deep sky. M81 and M82 looked great, so we hooked up Andrew’s DSLR and attempted some photography. We didn’t have a remote shutter or computer control, so we were using only the camera’s native controls, and assessing the results on the LCD screen.

Planetary nebula M57, the Ring Nebula

Planetary nebula M57, the Ring Nebula

After the galaxies, we went on to the Ring Nebula, M57, and then the Great Globular Cluster in Hercules, M13. Even with the 30-second exposures that the camera was natively limited to, we were getting very respectable images. I am including a few here.

M13, the Great Globular Cluster in Hercules

M13, the Great Globular Cluster in Hercules

Our results were pretty primitive compared to what people can do with dedicated astro cameras and post-processing, but we still had a grand time, and the process was sufficiently rewarding that we stayed out until almost two in the morning. All in all, a pretty darned good birthday present. Hopefully we’ll be able to reconvene and shoot some more this summer. I’ll keep you posted.

Many thanks to Andrew Hamilton for permission to post these photos.

h1

Earth-moon distance and the diameters of the planets

June 15, 2014

A few days ago Mike sent me this:

Earth-moon distance and planetary diameters

I was surprised to see so many people calling BS on this–it’s simple enough to double-check. So I did. Here are the results.

Mean radii in km, from Wikipedia:

  • Mercury – 2400
  • Venus – 6100
  • Mars – 3400
  • Jupiter – 69,900
  • Saturn – 58,200
  • Uranus – 25,400
  • Neptune – 24,600
  • Total – 190,000

Doubled, to convert to diameters – 380,000 km

Average Earth-moon distance, also from Wikipedia: 384,000 km.

Yep, this checks out. With the proviso that the Earth-moon distance actually varies from 363,000 to 405,000 km, so sometimes you’d have to leave out Mars and Venus, and other times you’d have to clone them to fill the extra space.

If you want a remarkable coincidence, the moon formed maybe only 10,000 miles from Earth and has been gradually receding ever since. So we are living in the tiny slice of Earth history when the moon is at just the right distance to appear the same relative size as the sun, and thus produce total eclipses as we know them. Annular eclipses have only been around for a few tens of millions of years, and in another few tens of millions of years, they’re all we’ll ever get, because the moon will be too distant to completely block the sun.

Anyway, after I sent Mike this reply, he said, “That is a whole lot of awesome, which clearly ought to be a 10MA post”. And now it is.

UPDATE October 13, 2014: A much more detailed explanation of the end of total solar eclipses in the distant future can be found on this page, under the “Final Totality” heading.

h1

Guest post: David DeLano’s ultimate Galileoscope quest, Part 5 – SCT focuser notes

March 15, 2014

Well, our long journey is at an end (for now!). No new pictures, just some notes on how long the various bits are, should you want to add an SCT focuser to your GS (or just about anything else). For previous posts in this series, go here. Thanks, David!

IMG_1242

Yes, that is a 2-inch focuser on David’s Galileoscope. Why do you ask?

SCT Focuser – 90mm
Low Profile 2″ – 1.25″ adapter – 10mm
Tele Vue Low Profile SCT adapter – 38mm
SCT M-M – 10mm

For F/11 objective, need something close to 75mm + 50mm = 125mm
Above parts are 90mm + 10mm + 38mm + 10mm = 138mm
Need to cut down 23mm, though 20mm might be enough.

Could use a zero clearance 2″ – 1.25″ adapter or negative adapter (ScopeStuff) (negative won’t work, since the diag won’t slide into it).

From Agena

SCT Focuser – 90mm
Low Profile 2″ – 1.25″ adapter – 1mm
TV Low Profile SCT adapter – 40mm (probably a better figure than OPT)
SCT M-M – 1mm

Total – 90mm + 1mm + 40mm + 1mm = 132mm (5-7mm too much)

However……since not using the SV helical, there might be gain on the diag EP end.

Follow

Get every new post delivered to your Inbox.

Join 98 other followers