Post by Chicago Astronomer - Astro Joe on Jun 30, 2011 23:46:11 GMT -6
Chicago Astronomer member Ray and his families Telescope
At our June 29th very successful star party...
( astronomer.proboards.com/index.cgi?board=StarParty&action=display&thread=3266 )....
I had the pleasure to meet Ray and his nice family. he receives the Chicago Astronomer email notices and decided to come down to join the crew on that warm and clear evening.
He brought with him a telescope and wondered if we could assist in setting it up.
Of course.
But with all of our visitors to attend to that session, I was quite busy and had asked Chicago Astronomer Steve to work with Ray to get it up and running....and they did.
In my short time looking over the scope I found some problems that needed to be addressed.
First, the telescope...
Bushnell 612 x 3" motorized GoTo reflector telescope
Focal length: 700 mm
Eyepieces: 20 mm, 4 mm
3x Barlow lens
Telescope Objective lens: 76mm diameter
Red dot LED
1x wide-angle, red dot finderscope: Lets you quickly locate the object to be viewed by the high-magnification main telescope
Telescope Magnifications: 525, 175, 105, 35
20,000-object onboard starfinding built-in computer
Remote controller with illuminated display and buttons
Kinematic mount
Quick-release adjustable aluminum tripod
Accessory tray
Easy 2-step assembly takes approximately 5-10 minutes
Telescope Dimensions (approximate, including tripod): 30" L x 60" H (tripod adjusts down to 42"H)
Telescope Weight: 20 lbs.
It's a decent first scope for a young budding astronomer, but limited on what it can display.
We were able to manually slew the scope around without engaging the electronics, which is good. But the telescope was incomplete.
Ray's scope only has a sub-standard 4mm and a 3x Barlow - that's it....!
With only a 3" aperture, a 4mm is practically useless, more so the 3X barlow. I advised ray to get some 1.25" low powered eyepieces and showed him the view with a 25mm I have. Focusing on top of the Sears Tower antennae array, I demonstrated what the lower powered eyepiece displayed in comparison with the 4mm.
We all agreed that some new eyepieces are in order. What Ray needs, are low powered 1.25" eyepieces to replace the single 4mm he now has.
One could buy a single eyepiece at a time, and nothing wrong with that...for example....
Bushnell 1.25" Format 25mm Kellner Telescope Eyepiece 780102
This single 25mm 1.25" basic eyepiece goes for $25.00. Various vendors sell single eyepieces like this.
.... but I like these kits ....
Celestron 1.25" kit -
Five superior-grade, 1.25-inch Plossl eyepieces - 4-element design with a 52-degree AFOV (32mm has 44 degrees ) - superb color resolution, edge sharpness and clarity. All eyepieces are fully multi-coated for maximum contrast and resolution. Included are 6mm, 8mm, 13mm, 17mm and 32mm focal lengths.
2X Barlow lens - complements Plossl eyepieces in this kit and gives you a total of 10 magnification combinations. High-grade glass optics with fully multi-coated lenses are used to avoid image degradation.
Six 1.25-inch, colored, lunar and planetary eyepiece filters - Included are Kodak Wratten #12, #21, #25, #56, #58A, and #80A. These filters will greatly enhance your enjoyment of our solar system.
1.25-inch moon filter - A neutral density filter that allows maximum enjoyment of moon-viewing, especially during the brighter phases.
Aluminum carrying case - This sturdy case accommodates all of the other items in its die-cut foam interior and even offers room for additional accessories. The dimensions of the case are 12.5 x 10.25 x 4.5 inches.
Astronomy Technologies Astro-Tech 1.25" -
This Astro-Tech 1.25" accessory kit includes ten 1.25" Astro-Tech visual accessories specially chosen to get the most out of small to medium size telescopes – from a 66mm refractor to an 8" to 9.25" catadioptric.
Unlike competitive kits that supply only a 50° apparent field Plössl for their medium focal length eyepiece, this Astro-Tech kit gives you a fully multicoated 1.25" four-element Astro-Tech 15mm SuperView eyepiece with an apparent field of view of 68°. It provides an exceptionally wide and dramatic field for observing nebulas, open star clusters, and galaxies. The Astro-Tech 15mm SuperView weighs 3.4 ounces and has a good 11mm of usable eye relief.
The Astro-Tech SuperView has a soft rolldown rubber eyecup to shield your eye from ambient light and improve contrast. It has dust covers for both ends of the eyepiece. Its chrome barrel is threaded for 1.25" filters, and a safety groove is machined into the barrel. This engages the thumbscrew or compression ring of your star diagonal to keep the eyepiece from falling in the dark should the thumbscrew accidentally loosen during use.
You also get three fully multicoated 1.25" four-element Astro-Tech Plössl eyepieces, in focal lengths of 6, 9, and 40mm. Like the SuperView, each has a soft rolldown rubber eyecup and dust covers for both ends of the eyepiece. Their chrome barrels are threaded for 1.25" filters, and a safety groove is machined into each barrel.
The 40mm Astro-Tech Plössl has an apparent field of view of 45°. It provides the widest field and brightest image possible from a 1.25" eyepiece with any scope down to an f/6 focal ratio. Competitive kits usually provide a 32mm eyepiece, which has a smaller exit pupil and is only about two-thirds as bright on faint objects as the 40mm in this Astro-Tech kit. The Astro-Tech 40mm Plössl weighs 5 ounces and has a long 18mm of usable eye relief, for virtually unvignetted views when wearing eyeglasses.
The 6mm and 9mm Astro-Tech Plössls each have a 52° apparent field. They are designed for high contrast/high power lunar and planetary observing, resolving globular clusters, and splitting close binary stars. Each weighs 1.5 ounces. The 6mm eyepiece has a short but still very usable 3mm eye relief, while the 9mm has a longer 6mm eye relief.
The supplied fully multicoated 2x Astro-Tech 1.25" achromatic Barlow effectively doubles the power of each eyepiece without reducing its eye relief. The 6mm effectively becomes a 3mm, while the 9mm becomes a 4.5mm. The 15mm SuperView effectively becomes a 7.5mm, while the 40mm effectively becomes a 20mm. The 25mm or 26mm eyepiece normally supplied as standard equipment with a new telescope effectively becomes a 12.5mm or 13mm when used with the Astro-Tech Barlow. Note that there is no duplication of magnifications with any of these eyepiece/Barlow combinations. The Astro-Tech Barlow weighs 2 ounces.
To bring out surface structure and details in lunar and planetary observing, you get the following four 1.25" eyepiece color filters: #12 medium yellow, #23A light red, #56 light green, and #80A medium blue. A specification sheet provided with each kit describes the effect of each filter on the various planets.
You also get a 1.25" #ND-3 neutral density Moon filter to cut down the glare of our nearest celestial neighbor without affecting the color and increase the contrast of its features. The 50% light transmission filter is also useful for splitting close binary stars, as it will reduce the glare of the brighter star of the pair so that the dimmer component isn’t overwhelmed by the light of the brighter one.
Finally, all the accessories come in a locking aluminum-frame 12.5" x 10.25" x 4.75" hard carrying case with a die-cut foam interior to keep them conveniently handy in the dark. The case also has room to store three other optional 1.25" eyepieces (the standard eyepiece supplied with your scope, for example), plus three other optional 1.25" filters (such as nebula filters).
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This Astro-tech kit above is slightly cheaper, but both are fine eyepiece kits that won't disappoint.
There are various vendors that sell these kits for about $100.00 or so. These are decent 1.25" workhorse Plossl eyepieces. If Ray ever decides to upgrade his telescope to something more serious, he can still use these fine eyepieces with whatever telescope he upgrades to.
Ray, let us know what you decide on...