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| The initial FR reduced image of the Moon, white portion, is obstructed by the secondary, black circle. The gray area represent the EP. |
Making the Fastest Telescope Alive FTA
Breaking News - Wednesday, March 27, 2019, by Humanoido
Radical Experiment: Create a spectacular mind numbing speed so fast that the imagination could conjure up burn holes in the detectors!
Speed in a telescope is basically the same as speed with an optical camera lens. As the focal length becomes shorter, the images smaller and brighter.
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| Showing the full FOV with 2-FR & EP. The FRs image is corrected to eliminate the secondary obstruction using mechanical and image processing means. The test took place during the early morning hours of Wednesday, March 27, 2019. Imaged with an iPhone Xs MAX at f1.8 Telescope at f1.6. |
Telescopes with long focal lengths, such SCTs and Aplanatics are usually native F11 making the telescopes slow and not conducive to deep sky imaging. However the long FL with large image scale is ideal for planets. But what if you have a long FL slow telescope and want speed for DSO explorations?
Some telescopes, such as the Celestron EdgeHD, can transform with a very expensive third party lens that attaches to the front of the corrector plate, in which some view as a delicate and time consuming operation. It transforms the telescope from f11 to f2.
— this is the greatest thing to come along for owners of EdgeHD telescopes who want to inexpensively do deep sky imaging and conduct wide field surveys of selected objects —
Humanoido has taken some simple lenses and created the ultimate fast telescope from f11 to f1.6 speed. The trick is to find focal reducers without optical corrections figured in for making a more flat FOV. This is because the mentioned telescope is already corrected for a flat FOV.
In this case, two FRs were stacked in one direction after the visual back and before a Star Diagonal, and coupled to a 55mm EP with a two inch barrel. This initially resulted in an obstruction by the image of the secondary. Through special iPhone imaging at 1x, the obstruction was negated to create a lunar image. However, the 14" f1.6 combination is so incredibly fast, the Moon is hopelessly overexposed and even the new iPhone camera could not exposure correct it.
However, the focus was at the one end limit of the telescope and the good news is the iPhone made up the focus distance automatically. This makes the process fully useable although the secondary obstruction must be negated by one method or another and in the case of the Moon - the exposure regulated by neutral density filters. More experiments show the focus is sharp all the way to the edge of the FOV making the experiment very successful and usable for deep sky imaging with a converted f11 to f1.6 telescope. The experiment can be applied to large sky areas, the changing positions of Jupiter moons, deep sky, asteroids, comets, and other objects.
Experimental Hardware FTA
1 - Celestron 14" EdgeHD
1 - Stock Visual Back 2"
2 - FR Coated wo Correction
1 - Stock Star Diagonal
1 - 55mm Coated EP w/2" Barrel
1 - iPhone Xs MAX
1 - iPhone Built-in f1.8 Wide Angle Lens
Cost Savings
The commercial F2 Hyperstar is $1,400 for a 14-inch telescope. How does this compare to Humanoido's FTA approach? Numbers show the FTA cost is over three times less expensive which is $996 less money.
2 - FR = $80 ea. = $160, 1 - 55mm EP = $244, Total $404
Hyperstar 1400 - FTA 404 = Total $996
