Backyard Voyager
Lunar Calendars
Determining the best times for lunar observation, particularly with a telescope or binoculars, is much simpler wih a lunar calendar.
Astronomers have relied on various devices for hundreds of years, but to observe at optimal times you no longer have to master the use of zodiacal wheels or complicated calendar devices.
Wherever these moon phase modules appear throughout the site, you'll find current, real-time lunar phase information. Enjoy.
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Celestron 9.25" SCT (and a few extras)Next
After six months of research I decided on the C9.25 with Celestron's Advanced Series. This would give me the equatorial mount, a CG5 Vixen clone with go-to, at a manageable combined weight of 69 pounds. I would have plenty of aperture without being as seeing dependant as some of the larger models. I ordered mine from Astronomics, which still lists the AS9.25 for $1,779.00 .
Having read about the quality and size of the finder scopes often supplied by both Celestron and Meade, I ordered an 8x50 Anteres RACI along with the telescope. At the same time I ordered a set of Bob's Knobs, which are thumbscrews that replace the collimation screws on the secondary housing. Finally I ordered a William Optics 2” diagonal to replace the 1.25” diagonal that Celestron supplies.
C9.25 with William Optics 2" diagonal and
Starlight Insturments Feathertouch focuser.
Regarding the rumors, the truth about this telescope turned out to be pretty simple and not at all mysterious. In the days before CCD chips took over astrophotography and film was still king, Celestron simply tried their hand at making an SCT that was somewhat better suited for film photographers. Celestron and Meade had always used spherical primary mirrors with an f/2 focal ratio and a secondary with a negative focal ratio of f/5 giving the optical system an overall ratio of f/10.
This time Celestron tried something a little different. They made an f/2.3 primary, which would put less strain on the secondary, this time figured at f/4.3, creating wider collimation tolerances and, most importantly, producing a flatter field with less coma, at least in film and CCD images. It also resulted in a slight physical difference. A C9.25 has a proportionately longer optical tube than other SCTs. It is, for example, nearly the length of the C11.
C9.25 optical train for planetary imaging.
Feathertouch focuser/Meade Flip Mirror/
Phillips' ToUcam Pro. On top is an Anteres
8x50 finder scope.
Whether or not these focal length differences are visible at the eyepiece is a matter for debate. If there really is a difference, then it is slight. I'm unable to see it, and can't honestly report that it is visually superior to other Schmidt-Cassegrains. All I know for a certainty is that the C9.25 is an excellent telescope. It has great optics and, for my needs, it is as close to a perfect size as is possible. It has enough aperture to pull in the DSOs without being difficult to handle. The OTA only weighs 21 pounds.
By the time UPS dropped off three large packages on my doorstep, I had already downloaded and read the manual three or four times. To say that I'm not mechanically inclined is an understatement, but the setup process was a lot easier than I anticipated. It took no more than forty-five minutes. All of the components were well packed and survived the trip with no damage.