Explore Scientific FirstLight 254mm f/5 Alt-Az Dobsonian Telescope

Explore Scientific FirstLight 254mm f/5 Alt-Az Dobsonian Telescope

Explore Scientific FirstLight 254mm f/5 Alt-Az Dobsonian Telescope

B&H # EXFL10STD MFR # FL-DOB1005-01
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Value: $35.00

Product Highlights

  • Large 254mm Aperture
  • 1270mm Focal Length, f/5 Focal Ratio
  • Low-Expansion Glass Primary Mirror
  • Borosilicate Glass Secondary Mirror
  • 2.5" Focuser with Reducer Adapters
  • 1.25" 25mm Super Plossl Eyepiece
  • Wide-Field 6x30 Finderscope
  • Large, Smooth-Movement Altitude Wheels
  • Floor-Based Manual Alt-Az Mount
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Aperture: 254mm (10")

203mm (8") esdtbzwz 254mm (10")
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  • 1Description

Sporting a distinctive large aperture and deep light bucket, the Explore Scientific FirstLight 254mm f/5 Alt-Az Dobsonian Telescope gives users powerful performance at a reasonable price. Its large parabolic primary and smaller secondary mirrors are made from low-expansion glass to eliminate distortion across the entire field of view, especially at the edges, while allowing sharp resolution of star clusters and nebulae that smaller apertures cannot achieve.

The fast f/5 focal ratio and hexagonal rack-and-pinion focuser make this an ideal choice for imaging, by enabling shorter exposure times with the ability to achieve tack-sharp focusing with the strength to handle large imaging rigs and eyepieces. This 2.5" focuser is designed to eliminate vignetting when using large wide-field eyepieces when observing, and when using large imaging sensors for astrophotography. Reducer adapters are included allowing the use of both 1.25" and larger 2" eyepieces and accessories.

The heavy base provides a rock-steady platform with very low vibrations. This alt-az rocker mount features Teflon pads on the ground plate, and large altitude wheels for smooth and easy movement along both axes with little vibration. Dual mounting rings allow the OTA to be precisely balanced for even smoother movement, and the altitude wheels can be removed and replaced with a Losmandy-style dovetail plate so the OTA can be used with EQ and GoTo mounts mounted on large tripods or piers.

Optical Tube
  • 254mm (10") aperture
  • f/5 focal ratio
  • 1270mm focal length
  • Optical design: Dobsonian-variant of a Newtonian reflector
  • Low-expansion H-PZ33 glass primary mirror
  • 74mm low thermal-expansion Borosilicate glass secondary mirror resists expansion to limit aberrations
Mount
  • Alt-az rocker design
  • Large aluminum altitude wheels allow for smooth movement and tracking with reduced vibration
  • Teflon pads on ground plate enable smooth 360° rotation
  • Adjustable mounting rings enable precision balancing when using lighter or heavier accessories for smoother motion
  • Mounting rings allow the altitude wheels to be removed and replaced with a Losmandy-style dovetail for attachment to an EQ, alt-az, or GoTo mount head for tripod/pier use
Focuser
  • Large 2.5" hexagonal rack-and-pinion design
  • Provides strength and rigidity to handle heavy eyepieces and imaging rigs with little backlash, tilt, or shifting
  • Large drawtube prevents vignetting with wide-field eyepieces during observation, or when using large imaging sensors for astrophotography
  • Includes 2" and 1.25" eyepiece adapters to allow use of a variety of eyepieces and accessories
Included Accessories
    Super Plössl eyepiece:
  • 1.25" diameter barrel
  • 25mm yields 51x power
    Finderscope:
  • Conventional 6x30
  • Wide-field for fast subject acquisition and easy star hopping
UPC: 812257018284
In the Box
Explore Scientific FirstLight 254mm f/5 Alt-Az Dobsonian Telescope
  • 6x30 Finderscope
  • 25mm Plossl Eyepiece
  • 2" Eyepiece Reducer Adapter
  • 1.25" Eyepiece Reducer Adapter
  • Focuser Extension Shell
  • Rockerbox Assembly
  • 2 x Tube Clamps
  • 2 x Altitude Wheels
  • Limited 1-Year USA Warranty, Extendable to Transferrable Lifetime Warranty with Registration
  • Table of Contents
    • 1Description
    Optical Design Dobsonian reflector
    Aperture 254mm
    Focal Length 1270mm
    Focal Ratio f/5
    Eyepiece Barrel Diameter 2" or 1.25", with included adapters
    Diagonal N/A
    Finderscope 6x30
    Tripod None
    Mount Type Alt-az rocker mount
    Power Source None
    Optical Tube Dimensions Length: 47.2" / 120.0 cm
    Diameter: 11.8" / 30.0 cm
    Weight Tube: 28.7 lb / 13.0 kg
    Fully assembled: 61.5 lb / 27.9 kg
    Packaging Infoesdtbzwz
    Package Weight 82.0 lb
    Box Dimensions (LxWxH) 58.0 x 20.4 x 19.8"
    FirstLight 254mm f/5 Alt-Az Dobsonian Telescope is rated 5.0 out of 5 by 1.
    Rated 5 out of 5 by from A fine example of the principle of "good enough" I saw this on sale on the Explore Scientific (ES) website, but it was sold out. I waited until B&H matched it, which they did. Bought it right away. It arrived in 1 very big box. Everything was clean and well packed. There were a few noticeable things right off the bat. First; there were no real instructions. Not an issue as they are readily available on ES's website. If this is not your first scope, you probably wont need them anyway. 2nd; the base comes unassembled. If you ever bought furniture from IKEA then this is a non-issue. Otherwise, instructions on ES website. 3rd; it does NOT come with a "Wide-Field 6x30 Finderscope" as described in the B&H ad (c'mon guys!). Instead it has a rather cheap, and horrible to use red dot finder, as depicted in the ad pics. It works: good enough. No matter because I was putting my Telrad on it anyway. Included is a 25 mm Plossel eyepiece. Not sure if it is ES brand but I am sure it's not their premier brand. Just good enough. OK, time to assemble the base. Easy enough; I shop at IKEA. Just be careful not to over torque the screwlocks. The base is solid and not quite as heavy as I though. It is easy to carry and the rubber feet hold it firmly in place. Make sure you place it on a flat surface, as there is no way to level it. Now the scope. It comes with mounting rings already attached. I wish it came with a grab handle, but it does not. Simply attach the rockers to the rings with the 4 thumb screws. The rings will need to be loosened to allow fitting of the rockers. There is a certain way they have to be attached, making sure the plastic tab aligns to the outside of the cradle. (Instructions on ES website. LOL) The tube is metal. It has 1" spotting scope mounts permanently attached, 1 on each side of the focuser. It has a fast focal ratio at f 5, which makes the scope shorter than most dobs of this diameter. In other words, you wont need a ladder to use it. The scope simply drops into place on the base. That's it.....really. Now go outside and play! Right, but first comes collimation. Even though the factory promises alignment out of the box, any Newtonion owner knows better. Here is one of my first real issues. The primary is nice and clear. It is marked for center and the adjusting screws are like most other Newts. No problems. The secondary on the other hand is a PITA. The 3 alignment screws are very tight and require a very large screwdriver to turn them. Be careful because applying to much torque here causes the flimsy spider to flex. My secondary was out of center. The center screw, a #2 phillips , is frozen in place, and I can not turn it without over flexing the spider. Also, I'm afraid of stripping it, so ..... maybe it's not too out of center..... ah, it's good enough. Collimation complete. Took less than 5 minutes to move outside and set up. The teflon strips on the base provide good resistance. There are nylon pads that act as limiters and keep you from over tilting. They can easily be jumped if you need to point straight up, which we need to do at times. I found an issue with micro adjustments. These are hit or miss. Sometime you get lucky and the rockers slide nice. Sometimes they grip a bit too much. After using it a while you get used to it. It's not a deal breaker. Rotation is smooth. Vibration cleans up quickly. The focuser. I have heard a lot of good things about the 2,5" hex. I'm not impressed. It does not have a 10:1 fine focus adjust. The focus knobs are a bit loose, which is VERY noticeable at high power. I can live with it for now, but I am trying to find a 10:1 knob kit for it. Bottom line: Not a great scope, but it's good enough. Because of it's simplicity and ease of set-up, it has become my primary grab and go scope. Yeah, it's big for a grab and go, but did I mention how easy it is to use? For the first time in my 40 or so years of looking up, I have seen the great red spot as a very real big red colorful spot. Fuzzies are still, well, fuzzy. But there are so many more of them!! ( I finally upgraded from a 130mm reflector) Maybe a little better than good enough. Guess it depends on how critical you are and how deep your pockets are. At the current price it is an absolute must! First scope buyers: Don't be intimidated by the size or my negative findings. If you want an inexpensive way to see what's up there, this is it. Storing it takes very little room. Put it on the mount, angle it strait up-ish and it fills an area less than 3x3 feet. Going through the box before putting it away I found a black plastic thing with suction cups on it. Had no clue what it was until a few days later I figured out it was a cell phone adapter! OK, if you say so... And what's this? could it be? YES!! ES includes a dovetail adapter. This changes everything. Next night the scope was on my EQ-6. The joys of computer guidance. Another first for me, through any scope, I saw Pluto. Took comparing photos from 3 nights, but I found that 14th magnitude dot right there in Sagittarius. It may have it's issues, but boy, what fun! Including a few picks from my cell phone. Jupiter looks much better with the naked eye; cell doesn't do it justice.
    Date published: 2018-07-09
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