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Jack’s Kingdom | |||||
| astronomy 3/6/2023 typical construction of a Schmidt-Cassegrain | ||||||
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I did not need another telescope, but got a Seestar S50 smart telescope in February 2024. It has a 50mm APO triplet with a focal length of 250mm (f/5) - totally electronic without an eyepiece to look through. It has a Sony IMX462 sensor with 1080x1920 resolution that displays to a tablet or phone. At 5.6 x 5.1 x 10.1”, it is tiny. As I did not like the orange tint of the solar filter, the film was replaced with Baader AstroSolar Film for a more natural rendition. I saw the Horsehead Nebula IC 434 for the first time. You can see results of the Seestar stacking on the tablet. Brighter objects need less time to show upThis will not show any details on planets Field of view is somewhat narrow Built-in light pollution filter Sturdy short carbon fiber tripod Need better alignment to integrate at 20 seconds Did not get to dark skies, but caught a couple of views of Comet ZTF (C/2022 E3), which comes by every 50,000 years, through the 127mm Explore near Mars. It was just a dim hazy ball. Nancy and I viewed Comet NEOWISE in the early morning hours on July 13, 2020. 
Chris and I went to the Boise National Forest to view the August 21, 2017 total solar eclipse. We had the Celestron 80EDF 500mm focal length at f6.25 and the C90 1000mm FL at f10 with Baader solar filters. Some of the campers got their first look at the sun through the C90. I now know why there are many eclipse chasers. Finally after having canceled five nights over the last two year, we were greeted with some viewing time though clouds did obscure the San Miguel Star Party on February 11, 2015. The next evening at Lakewood Elementary was great with calm air. We were able to view Mars, Venus, Jupiter, Orion Nebula M42, star cluster M41, and Pleiades. The previous San Miguel Star Party was Wednesday, November 5, 2013. SJAA and I set up telescopes for viewing a crescent moon, Venus, open star clusters, globular clusters, and M57 Ring Nebula. Ellis had its viewing on November 25, but skies were a bit turbulent. Columbia High had it on May 30, 2013. My arsenal of equipment includes the following, so I gotta get rid of some of this gear: Having piggybacked the 80EDF on the C8, I’m viewing more wide field objects such as the Double Cluster in Perseus, Pleiades, Hyades, and even bright deep sky objects. I mounted my Explore Scientific 127mm f7.5 carbon fiber APO refractor onto a C8 Celestron dovetail with two M6-1.0 x 20mm bolts. If I tighten the saddle clamps too much, it will bend the dovetail thus loosening the tube ring connection. Made a dovetail with 1/2 x 3” 6061-T6 aluminum by running it through a used carbide blade on a table saw. I also made a shoe from aluminum channel, fiberglass circuit board, and epoxy to mount a 10x40 C11 finder onto the ES127.
Made a 5 pound counterweight with 1 1/2” copper pipe, aluminum venetian blind slats, hand moldable and steel epoxies, 1/4x20 stainless steel insert, and C14 lock screw.
A Hyperstar 11 was purchased used. This lens assembly converts the C11 into a 560mm f2 lens! I haven’t used this much. Got a new C11 Celestron dovetail and a used C8 Celestron dovetail. Celestron CGE Pro equatorial mount. This carries the C14 easily. Both axes are spring loaded so there is virtually no backlash. Problems are that the tripod is too high for the C14 so I took out the inner legs and modified the bottoms. The pier/head assembly is too heavy at 79 pounds. Though it’s not recommended, I removed the four M7-1.0 x 20mm socket cap screws to separate the DEC head from the RA. Cut some 7/16” OD aluminum tubing to go into the DEC head and M7-1.0 x 55mm SHCS so it would be easier to dismantle. The DEC head weighs 30.3 pounds and the RA head with pier weighs 49.3 pounds. Still quite heavy. There are other mounts that are lighter and also separate at the RA and DEC heads. I fashioned tools for the clutch knobs from PVC, aluminum, and oak.
CGE1400 - new mount with 2009 optical tube assembly. A Farpoint dovetail replaced the Celestron one. I just ventured into some astrophotography using the C11 optical tube on this mount. Even though the mount was not having problems with cabling, I decided to make it more robust a la Gary Bennett. The leads are soldered within the RA and DEC motor boxes and connectorized in the pier. Power is obtained with Anderson Powerpole connectors on a marine deep cycle battery. I neglected to maintain the battery by trickle charging and it eventually sulfated.
Onyx 80EDF - My first refractor to be used for astrophotography and guiding. Nexstar 8 GPS XLT circa 2003 has a removable secondary (Fastar) allowing imaging at f/2 with an additional lens assembly. It’s a computerized scope with a huge database. Align it on 2 stars and it will slew to objects of your choosing. I have modified the c11 wedge to equatorially mount this. Go here for pictures.. Celestron C11 circa 1985 redone at the factory in 1993, black sand cast fork mount on C11/C14 wedge with C11/C14 locked legged tripod. Vibrations damp out in under a second with a pad of stainless steel, rubber, and some polymer material under the tripod legs. The original C14 dovetail now is mounted on this tube. C90 circa early 1980s old, orange/brown die cast on die cast fork mount. This was used with Baader solar film for the August 21, 2017 total solar eclipse. C8 circa 1976, orange/brown die cast fork mount on sand cast wedge. Purchased adjustable leg tripod years later. Optically it is slightly better than the C11 but doesn’t grab enough light for deep sky objects. All of these are catadioptric meaning lenses and mirrors form the image. All are photographically slow at f/10 but allow the use of low power eyepieces with longer eye relief. Criterion Dynascope 6” f/8 Newtonian reflector on a 4¼” equatorial mount. Bought for $100 when approached by a gentleman when I was reading Sky & Telescope in the San Francisco Public Library during my high school years. Been thinking of making a Dobsonian mount for it. The views are sharp and contrasty with this scope.
Homebuilt 4¼” f4 reflector with Edmund Scientific mirror. Accessories include an off-axis guider, telextender, T-mount, University Optics 0.6x reducer. 7x50 Celestron binoculars has more light gathering power than 7x35. March 2007 - Just acquired some Baader AstroSolar film from Astrophysics to replace my old aging SolarScreen material. Currently we are at a cycle of very low sunspot activity. I setup my C11 for the annual San Miguel Star Party and Solar Viewing. In November 2007, I trained it on the Ring Nebula, M57 as well as the moon. My binoculars were pointed toward either Comet Holmes or the Pleiades. The first time I participated in the Columbia Middle School Star Party was March 15, 2007. These schools arrange it with some members of the San Jose Astronomical Association annually. The air was quite calm and I aimed my scope at the Orion Nebula M42 and Saturn. Other objects included Venus and the Pleiades. Students and parents always have a wonderful time looking through the telescopes. In 2009, the Nexstar 8 was side by side looking at M37 with the C11 on Saturn and M42. |
This is the transit of Mercury on November 8, 2006. My C90 was setup at San Miguel Elementary. About 100 students got a chance to see something that will not occur again until May 9, 2016.
A special filter is used in front of the telescope to reduce the heat and light otherwise you will damage your eyes. Do not use only a filter at the eyepiece.
USNO forms to calculate
I bought a Phillips CCD webcam SPC900NC to do planetary imaging and the brighter deep sky objects. I was not able to achieve desired results and now using it with Skype on my homebuilt Mac. Have patience as seeing conditions vary night to night and during each night. Do not use too much magnification with the telescopes as brightness and contrast will decrease. I tend to use the 24mm and 18mm a lot yielding 117x and 156x respectively. While an excellent eyepiece, the 9mm (311x) is usable only in transparent skies when the stars twinkle at a minimum. I also have an ancient dual axis autoguider and RA/Dec drive corrector manufactured by AstroPhysics. It varies the DC voltage and polarity going to the DC declination motor and varies the AC frequency going to the synchronous right ascension motor. When used with a fairly bright guide star and fairly good polar alignment, this does better than manual guiding. It appears to work very well but I have not used for astrophotography. They do not make these anymore, however they make excellent refractor telescopes and mounts. What’s up in the sky - Sky & Telescope I am a member of the San Jose Astronomical Association TAC Observing Intents - who's where astrospotter Observer ReferencesSkippySky Astro-Weather forecast Other clubs:
Astromart - Buy & sell your gear click on Classifieds Cloudy Nights - everything rolled into one! Classifieds, forums, reviews, etc. This is run by Astronomics from Norman, OK How-to’s on Astromart Celestron Lawrence Hall of Science cam windfinder |
| Eyepieces and Accessories - 1¼” unless noted | |||
| 55mm eyepiece TeleVue Plossl 2” |
40mm TeleVue Wide Field 2” Meade MA (Kellner variant) Celestron Kellner (Circle T) Celestron Nexstar Plossl Celestron E-lux 2" Kellner |
32mm University Optics Konig 2” |
30mm Explore Scientific 82° 2” Celestron Kellner 0.96” |
| 25mm Celestron Kellner (Circle T)
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24mm Meade UWA 82° 2” University Optics Konig |
22mm TeleVue Nagler Type 4 82° 2" |
20mm Orion Sirius Plossl |
| 19mm Smart Astronomy Extra Flat Field 65° - two |
18mm Explore 82° 2” Celestron Ortho (Circle V) Celestron Kellner 0.96” |
16mm University Optics Konig |
14mm Explore 82° |
| 12.5mm Smart Astronomy Long Eye Relief University Optics Ortho (Circle T) |
12.5 mm Parks illuminated reticle Celestron CrossAim illuminated reticle Lumicon Ortho eyepiece |
11mm Explore 82° |
9mm TeleVue Nagler (2”- 1¼”) Ortho (Circle T) |
| 6.7mm Explore 82° |
6mm Smart Astronomy Long Eye Relief Ortho (Circle T) |
4.7mm Explore 82° |
diagonals 2” Meade & Explore dielectric 99% reflective Celestron SCT + 2” drawtube #93519 Televue diagonal 1¼” |
| telescope guidance, planetarium Southern Skies SkyFi with SkySafari 6 running on iPad |
barlow Televue 1.8x focal reducers Meade Series 4000 0.33x with #61 variable t-adapter |
Hyperstar 11
t-adapter Orion StarShoot autoguider |
cases Harbor Freight aluminum tool case #35777 for eyepieces Contico tool box, orange for accessories, tools |
