Astronomy – A Darker View

A Changing Sky

Gazing up at the sky while reading the old texts one would not be amiss in believing that the stars never change. Indeed there are many who insist vehemently that the stars are eternal and unchanging. But the stars do indeed change, often quite visibly, sometimes within the span of a human lifetime.

VLT/SPHERE image of the star L2 Puppis and its surroundings — A VLT/SPHERE image of L² Puppis showing the enveloping cloud of gas and dust representing an early stage planetary nebula. Image credit ESO/P. Kervella used under Creative Commons 4.0

One such star is L₂ Puppis.

A bright star, one of the few naked eye variable stars that could be seen to fade and reappear without the aid of a telescope much like the far more famous stars Mira and Algol. On star charts the star is found prominently drawn at magnitude 4, buf if you attempt to locate it today you will not find it without the use of a telescope.

I first encountered this star quite recently while starhopping through southern Puppis with an 8″ telescope from the driveway. The chart showed two bright stars close together, L₁ Pup and L₂ Pup, while the view in the finder ‘scope showed only one bright star.

Solo Stars at Kaʻohe

The start of a dark night at Ka'ohe on the side of Mauna Kea — The start of a dark night at Kaʻohe on the side of Mauna Kea

Morning Observing

First quarter moon… Telescope time.

Observing Table — The observing table under red light.

I find myself reliably rising early, often around 4am, something that seemed to have begun during the pandemic. Those who knew me in my younger years may find this a bit unbeliveable, I used to hate mornings, but now?

The other factoid about island mornings. It is almost always clear. The afternoon and evening clouds have dissipated and clear skies are the rule.

Combine these bits with a love of the sky and the result is morning observing sessions, often half a dozen mornings will be spent out with a telescope in those couple weeks the Moon is absent from the morning sky.

Get up, shrug on some ratty old clothes, and wheel the telescope out of the garage. The ‘scope of choice is almost always the old Astrola, even with larger and more sophisticated telescopes available there is just something about using that old manual ‘scope that I find satisfying.

Perhaps the lack of computer or digital setting circles means it is my own skill enabling my path among the stars. The Astrola does have manual setting circles, but I rarely use those. A star chart, a finder, and starhopping allow me to wander through rather than jump about… I just see more, often stumbling across unexpected bits of beauty.

I have upgraded the Astrola a bit lately, adding a larger finder ‘scope with a wide field eyepiece. It is a 50mm 3D printed finder of my own design allowing me to see more sky at once with fainter stars.

There are a few more days until the bright Moon crosses into the morning sky, a few more mornings you will likely find me out with the ‘scope.

A Battery Caddy for the AM5

The ZWO AM5 telescope mount is a great piece of kit… It integrates very well with software allowing easy computer control, just click and go. The mount tracks wonderfully allowing excellent astrophotos. It is small, does not require a counterweight for smaller ‘scopes, and precise polar alignment is a breeze.

A 3D printed battery caddy on the side of a ZWO AM5 telescope mount

The mount is not without issues… Without a camera integrated into the system the GOTO accuracy is awful, using the mount as a visual mount is frustrating. You really need to have at least a guide camera and the ASI Air computer connected to allow to plate solving and automatic correction of the position at the end of each slew to a new target.

Another issue is that the mount has no concept of cord wrap. It will happily spin around and around as you wander across the sky. In equatorial mode this is not an issue, in alt-azimuth mode this runs the risk of damaging your equipment if you do not notice the power cord getting wrapped up on the mount in the dark.

Yes, I did that.

Awaiting Dark

A large dobsonian set up at Oregon Star Party 2023

Segment Exchange

Lifting segment 4-76 out of the Keck 2 primary mirror for re-coating and repair — Lifting segment 4-75 out of the Keck 2 primary mirror for re-coating and repair

Binocular Solar Filter

One of the things I brought back from Oregon Star Party was a set of solar filters for binoculars.

A simple set of solar filters for my Nikon binoculars

The filters were from DayStar Filters who had a booth at the star party. I spent a while chatting with the gal running the booth and enjoying the hydrogen alpha views through the ‘scope they had set-up. The Daystar SS60 Hydrogen alpha ‘scope they had on sale was rather tempting.

A Solo Night at Kaʻohe

A dark clear night at Kaʻohe, just the thing I needed. A telescope… A dark sky.

There had been plans of a few friends from work, but with a virus rampaging through the crew a social event did not seem like a great idea. Will have to do the invitations another time. This evening would be a solo run.

No big production… Toss the gear in the vehicle… The Nexstar 11″ ‘scope, a few munchies and a thermos of hot tea, a table, a notebook, and go.

The night was nearly perfect, no wind, not all that cold, a few wisps of cloud that dissipated after sunset.

I would work the southern horizon this night, as low as I can go from 20°N latitude. From the Kaʻohe site due south is right over the summit of Mauna Loa. Just above the shadowy outline of the caldera I would catch stars and galaxies as they transited. Constellations unknown and inaccessible to northern observers… Pavo, Grus, and Phoenix. Some of the objects I observed were in the lower -60° declinations…

φ2 Pav Pale yellow, no companion noted, φ1 Pav is visible 33′ west

NGC 7582 Bright and obvious, extended 5′ x 2′ northwest-southeast, brighter to the center without a notable core, NGC 7590 and NGC 7599 visible 10′ northeast, NGC 7552 visible 28′ southwest, the Grus Quartet makes an entrancing field with four bright galaxies

NGC 45 Quite faint and diffuse, difficult, about 5′ diameter, a slight brightening to the center, a 10th magnitude star in the southeast quadrant, the 7th magnitude star HD 941 is about 5′ southwest

NGC 7155 Small, faint, round with a stellar core, at the center of an east-west 15′ arc of 11th to 12th magnitude stars
Andrew Cooper, 7 Oct 2023

A good night out with a telescope, packing it in about midnight as to not totally wreck my sleep pattern. Still, I got in five hours of observing.

Battery Corrosion Again

Leaking alkaline batteries, the bane of our portable, battery powered existence. All too many times I have found myself repairing electronic devices damage by leaking batteries, or just junking the gear when the damage is too severe.

Corrosion damage in the base section of a Celestron 8SE mount

This time the device in question was just a bit too valuable to dispose of despite fairly extensive damage.

A Celestron Nexstar 8SE telescope.

Category: Astronomy