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AT 72ED Opinions?

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#1 steve-in-kville

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Posted 19 May 2013 - 10:03 AM

I am considering this scope for my GNG set up. I've read a lot of reviews both here and elsewhere. I do mostly planetary and lunar work at the moment.

For the money, would this scope be best? Or should I be looking at something else?

#2 PatHolland

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Posted 19 May 2013 - 10:51 AM

It's a bit smallish for planetary work but for lunar, it works well. I haven't been able to detect any CA in mine. For planetary, I would recommend a longer FL instrument. At 420mm (AT72), you'd have to barlow up to 5X to try to get any detail and most people's seeing conditions don't allow for that very well (mine sure doesn't). I would recommend a 4" achro or larger, preferably with F8 or higher. You can always get a fringe killer filter to get rid of the CA. A small CAT (including Maks) would be nice for planetary as well - a large CAT or DOB would be better but not for GNG. Just my :penny: :penny:

#3 steve-in-kville

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Posted 19 May 2013 - 10:59 AM

Thanks for the input. Not sure what direction I will take on this. I have a 90mm f/10 that I am using now. I should just up and buy the C6 SCT that I have been looking at. Then just use the 90mm for GNG work. But I am still on the fence over that one.

#4 herrointment

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Posted 19 May 2013 - 11:10 AM

At 430mm fl it's not your #1 choice for lunar/planetary. I will say that this winter I used my AT 72Ed with the WO binoviewers, the WO 1.5X barlow along with a 2X barlow and a pair of 17mm AT High Grades just to see what would happen. My fingers were froze by the time I tore myself away from the eyepieces. Ignoring the edge the view was very good especially considering the nature of the setup IMO. Jupiter was crisp and a half moon begged for more exploration.

So you can get some pretty good views of the moon and planets out of the little thing. I'll assume there are better options available....

#5 PatHolland

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Posted 19 May 2013 - 01:22 PM

a 6" SCT is a good choice for planetary. 8" would be even better but not as portable and convenient as carrying around the 6" SCT. There are some smaller Maks that would fit the bill as well, such as the Meade ETX line and they are inexpensive to get on the used market. If price were not a consideration, I would probably go with a 125mm MAK for planetary and lunar observing. They can be had for about $400 - $500 and get you into the sweet spot of F12-F15 or so, 1500-2000mm FL and weigh less than 10 pounds. The only drawback with a MAK is cooling time (takes about 2 times as long as an SCT). Orion and Meade make the smaller MAKs.

#6 stevew

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Posted 19 May 2013 - 02:30 PM

I should just up and buy the C6 SCT that I have been looking at. Then just use the 90mm for GNG work. But I am still on the fence over that one.

The AT72 will work best for low power wide field views.
I think your idea about the C6 is good.
It will be very portable and should out perform the AT72 and your 90mm on the planets.

Steve

#7 MRNUTTY

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Posted 19 May 2013 - 03:43 PM

My GnG is a AT72 and C6-SCT on a dual mount iOptron MultitowerII.

#8 herrointment

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Posted 19 May 2013 - 05:47 PM

I like that idea and that Multitower appears to be just the right size. Looks solid on the electronic page as well.

#9 jrbarnett

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Posted 20 May 2013 - 08:46 AM

The C6 will be more compact than your 90mm, and likely be a better G&G OTA, too, than the 90mm.

I have an AT72ED and a C6 and a bunch of long focus achromats from 60mm to 105mm (and a bunch of other OTAs). For your intended use (G&G planetary) you'll want a bit more aperture than 72mm (or 90mm for that matter).

The C6 is great. The C8 OTA isn't hugely larger. The C5 OTA is much more compact. Between those three you're likely to find something that suits both of your goals (lunar/planetary and G&G).

- Jim

#10 coutleef

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Posted 20 May 2013 - 11:43 AM

The C6 will be more compact than your 90mm, and likely be a better G&G OTA, too, than the 90mm.

I have an AT72ED and a C6 and a bunch of long focus achromats from 60mm to 105mm (and a bunch of other OTAs). For your intended use (G&G planetary) you'll want a bit more aperture than 72mm (or 90mm for that matter).

The C6 is great. The C8 OTA isn't hugely larger. The C5 OTA is much more compact. Between those three you're likely to find something that suits both of your goals (lunar/planetary and G&G).

- Jim


Jim are you becoming a SCT fan?

i agree with your suggestion especially that the cool down time of a C6 is not that long

#11 frito

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Posted 20 May 2013 - 05:36 PM

my WO 66SD does ok on jupiter and saturn, certinaly much better than i expected it to do but pushing it past 120x usually does not result in a better image. that being said it's about 10 times better than my club's Orion AV120 ST. that short tube was a blurry obviously out of collimation full of CA mess on planets and even the moon to an extent so there is something to be said about quality optics even if you're pushing them to their limits.

#12 jrbarnett

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Posted 20 May 2013 - 10:18 PM

For G&G over a 90mm of any design, I'd pick a C6 o C8. I currently have a C8, C6, C5 and C90 (MCT) so I'm not against SCTs. That said, for something in the 6" to 8" range where compactness was less of a requirement, I'd not pick any SCT, preferring either a refractor or Newtonian instead.

Every design has its virtues and vices. It's hard to beat an SCT for aperture per inch of tube length, so if G&G and compactness are among your primary wants, I think SCTs are probably best. I'm a fan of every design for what that design does well. I dislike every design for those things that design does poorly. Horses for courses.

Regards,

Jim






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