Tag celestron

Planetary camera first light

Photonstopper

Still working without a dome, our setups are outdoors and temporary so we try and keep them fairly simple. Solar observing and imaging generally lend themselves well to brief observations due to the extreme amount of light available and resultant short photographic exposures. With a couple of clear days and nights available, we took advantage and made some experiments and observations with several successive setups on a single Skywatcher EQ6-R Pro mount.

Southern hemisphere of Sun — First Light image from ZWO ASI678MM planetary camera, via Baader Herschel-Prism, and Askar 103 APO telescope. False color applied.

We began with the Askar 103 APO telescope and its 700mm focal length, attaching our Baader Herschel-Prism, and the new ASI678MM monochrome camera. The setup worked well but for one issue: focus was only just achieved with the focuser racked all the way in with no latitude for adjustment. Image quality was very good but probably would have been better if we’d have had a bit more inward travel. Note: It was only later that we realized we might gain the needed travel if we had switched the camera’s nosepiece from the 1.25-inch to the 2-inch, allowing removal of the thick 1.25-inch adapter ring from the Herschel. A well, duh, moment!

By the way, we continue to be impressed by the build quality and optical excellence of the Askar refractor. It’s a solid instrument with great features, delivering superb results.

Askar 103 APO telescope, Baader Herschel-Prism, ASI678MM camera, on the Skywatcher mount makes an excellent combination. A Herschel wedge-style optical device does not require a filter be attached in front of the telescope’s objective lens — deflecting, absorbing, and ejecting the bulk of sunlight energy. Internal filters in the Baader apparatus reduce brightness and increase contrast.
The Meade 6-inch refractor atop the Skywatcher mount and tripod. Visually, very effective, but the setup did not work with the Herschel-Prism and camera. The circular paved area is to form the floor of the observatory structure, the gray conduit to deliver power to a permanent mounting pier. Yes, the sky really was that blue that day!

The second experiment involved installing our massive Meade 6-inch telescope on the mount. The Skywatcher has a retractable rod for holding counterweights and is, therefore, a bit shorter than it might otherwise be, resulting in less leverage. It took nearly all of our available counterweights to balance the big scope. We installed the Herschel-Prism and a nice eyepiece and got beautiful views of the spotted face of our star. Attaching the ASI678MM, however, we could not reach focus — that inward focuser travel limit again — but we don’t believe the switch to the 2-inch nosepiece will help. That’s a shame! The Meade’s 1,250mm focal length would have provided amazing closeups!

The 11-inch Celestron SCT set up for a nighttime trial. This OTA was part of an integrated mount system that had failed so we “deforked” the telescope and attached a mounting rail for use on an equatorial mount.

With the mount set up we decided to try out the 11-inch Celestron SCT at night. Herschel wedge accessories are not to be used on reflecting telescopes as the concentrated unfiltered incoming sunlight can damage the scope’s secondary mirror. To our disappointment the telescope, which has set in storage for months since we attempted collumnation, displayed rather severe image distortions — comma-shaped stars. After a good bit of frustration we dismounted the telescope and planned to come out the next night with the Vixen Cassegrain telescope.

All good things… A series of clear days and nights came to an end with clouds rolling in to cover Saturn as it emerged from behind neighboring trees.

The following evening looked very promising; the sky was actually more transparent than it had been for the Celestron effort. Saturn would rise from behind trees neighboring our site some time after 11 p.m. so, at the appointed hour, we stepped outdoors and looked. Clouds, heralding a day or two of rain showers, were rolling in — broken at first but rapidly obscuring the entire sky. We tore down the setup, stowed the gear, and called it a night.

Tight crop on sunspots from the planetary camera’s First Light image of September 4. Sunspot umbra, penumbra, details are visible as are faculae and the granulated texture of the solar photosphere. Askar telescope, Baader Herschel-Prism, ZWO ASI678MM camera.

Over the period of a couple of days and nights, much was learned and the new planetary camera proved itself to be an excellent performer. We’ll continue to use the camera and telescope for solar and, probably, lunar views. Next we’ll likely try installing the focal reducer to achieve full-disk images.

Trials were trying

Photonstopper
Crater Tycho is featured here, its web of light-colored ejecta radiating in all directions. Celestron C11 telescope with ZWO ASI 294MC Pro camera.

Taking advantage of what seem to be rare clear skies, last night (September 1, 2023) I ran first light trials on the Celestron C11 I was given, in combination with my ZWO ASI color astronomy camera. The telescope, with its decent aperture and long focal length, may become the primary observatory instrument. The results were largely disappointing with no good deep sky results, terrible results from Saturn, and not-so-good images of Jupiter. Even Earth’s Moon, usually an easy target, was barely in focus. It didn’t occur to me to use my Bahtinov mask focus aid — my gear is spread across two buildings and three or four locations! Once built, the observatory should help with organization. I hope to try again this coming week when mild, clear nights are forecast and I hope it is only a matter of technique and not an optical issue.

On the positive side, polar alignment was excellent as was goto control alignment so telescope sky tracking was very good during my efforts — until something caused an unexpected reboot of the telescope controller. I don’t know if dew short circuited a connector or if the connector pulled loose from the handbox but it was disconcerting!

The images shown here are simply interesting to look at, though not the quality I’d normally want to show. The first is youngish Crater Tycho showing off its extensive web of ejecta rays. The second picture includes several lunar “seas” including the “C” shaped Sea of Crisis. Two craters are seen near the left edge of the circle; the lower of those craters is named Picard. No, Star Trekkers, not THAT Picard. Still, a fun fact.

Several lunar seas are shown in this image with the Sea of Crisis, the C-shaped feature, on the right. Within the Sea of Crisis are seen two small dots and the lower of the two is Crater Picard. Celestron C11 telecope with ZWO ASI 294MC Pro camera.

Cool old lens looks at hot old Sun

Photonstopper
Full disk image of Sun as it appeared at 14:45 UTC, Saturday, July 22, 2023. Color was added to make the image appear orange. Dark sunspots are scattered across the disk.

I hauled out the 1970s vintage Celestron C90 telephoto lens this morning, attached my AstroZap Baader film solar filter, and my Canon EOS 7D to quickly image Sun. I’m hoping to be able to use the compact mirror lens for quick shots such as this and for images of the Moon; trials have thus far met with mixed results. It’s a cool old lens but not as good as other gear in my current collection. The setup was mounted on a simple photographic tripod and, astro-folk will note, Sun’s orientation here is cockeyed. Once the observatory is set up and a mounted telescope put into use, we expect to see improved resolution/magnification, and won’t have to struggle with gear too heavy for the tripod! There’s a smattering of sunspots to be seen in this image along with a few other, more subtle features in the solar photosphere. Clouds rolled in soon after this image was made.