C8 Edge HD vs 120 mm apo

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Kanadalainen
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C8 Edge HD vs 120 mm apo

#1

Post by Kanadalainen »


Hello to all,

I typically use my 70mm apo for astro work - its my only AP scope and I have been gathering images for about 8 months. I have about 6 months of guiding under my belt, and the rig works fine.

My rig -
Mount: NEQ6
Camera: Canon 60D and a new 2600MC pro (3.76 uM pixel size).

At this point, galaxy season is coming. I want to get a scope with more reach for DSOs - anywhere from 750mm to 1500mm. A friend of mine has a c8 edge HD (6 months old) and the dedicated reducer for sale for a good price. My friend bought a larger scope. Thus 2000mm x 0.7 = 1400mm.

I have no experience using SCTs, I have been a refractor and newtonian person up to now. I am not necessarily limited by the higher cost of an apo frac.

Before this deal came along, I was thinking to buy a 120 mm SW Esprit, but this new offer is literally 40% of the price. Would the Celestron 8 edge HD be OK for DSOs? Anyone with experience with the edge HD for galaxies or thoughts on this is appreciated.

Thanks,
Ian
Ian

Fracs: Stellarvue 70T f6; SW 120mm Esprit f7; "Mark Mk. II" - 60 mm Tasco f6; C80 frac f 11.4
SCT: C8 Edge f10 or f7 with reducer
Dob: 14.5" homebuilt strut dob (f4.5 ZOC mirror), Nexus II, Moonlite focuser
Mounts - Ioptron Skyguider pro, Astro Physics GTO900
Cameras and lenses - ZWO 2600 mc, 290 mm mini, Canon 60D modded with Rokinon 10mm 2.8; Rokinon 135mm f2

Skysafari 6 Pro, Astro Pixel Processor, Pixinsight - using Mac tablet and ASIair pro to run the AP rig.

"Mothers! It is there!" - Rafael Gonzales-Acuna, 2018.
Voyageur
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Re: C8 Edge HD vs 120 mm apo

#2

Post by Voyageur »


It sounds to me like the primary attraction to the C8 is the price. A good deal is NOT a good deal if it isn't what you really want. Especially if it may not be the best tool for the job.

You can't really justify the "deal" on the basis of utility. As you already know, there is a lot of advice online to the effect that an SCT is not the best way to do DSO AP. I know it can be done, and there are people doing it and making beautiful exposures, etc., but... given the choice, don't you really want a nice refractor? A good deal is NOT a good deal if it isn't what you really want. Oh, I said that already, but it is pretty important!
Scopes: Vixen VMC200L, D=200mm, F=1950, f/9.75; Televue 2" Everbright diagonal. Coronado PST; AstroTech EDT 80mm, F=480, f/6.
Mounts: Vixen SXW/Starbook (original); Stellarvue M2C alt-az.
Eyepieces: Televue: 55mm Plossl, 22mm Panoptic, 17.3mm Delos, 13mm Nagler, c. 1980, 11mm Plossl, 7mm Nagler, 5mm Radian; Meade 15mm Super Plossl; VERNONSCOPE 2.4X BARLOW
Binoculars: Leica 8x32 Trinovids, circa 1997; Orion Megaview 20x80, Orion Paragon Plus mount.
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sdbodin United States of America
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Re: C8 Edge HD vs 120 mm apo

#3

Post by sdbodin »


I don't have an edge HD, but just from a personal point of view, the more plate scale the better for galaxies. I usually image at 2500mm with the BigDog 16 and all, but a small number, of galaxies fit that scale, so 1400mm is not too much and the native 2000mm would be fine also. A few cautions should be noted, guiding becomes the most important variable when imaging these small subjects, so you will probably need an off-axis rig. The SCT thread backplate of an SCT becomes a choke point for the light cone, so expect some vignetting especially at 0.7 reduction, FOV reduces the same as the focal length. The ASI2600MC is only just slightly oversampled at the 1400mm focal length, so should work fine.

That's all I can come up with for now, but should work OK, go for it.
Steve
Scopes; Meade 16 LX200, AT80LE, plus bunch just sitting around gathering dust
Cameras; Atik 460ex mono, Zwo ASI1600MC-cool, QHY5L-II color and mono
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