8 replies to this topic

[jeffz]

I currently own the AT 72mmED II and use it for visual astronomy. I was thinking of replacing it with the SV 80mm Access. Would the SV give me an improved imaged?

[KerryR]

I can't comment on those specific scopes, but I can say this: DSO's are noticeably brighter in my 80mm f4.3 achromat (Orion Thermos Bottle) than they are in my optically superior (to the Thermos) Pronto (using similar exit pupils). While the difference isn't "knock your socks off" significant, it's enough to make me want to get a better 80mm, even though I really like the images in the Pronto. So, I think you'd easily notice the increase in aperture, as long as you have realistic expectations.

If it were me, I'd keep the 72mm 'til I was certain I preferred the 80mm.

 

There are other considerations, too-- if the 80mm is significantly heavier, it might tax your existing mount, and larger aperture is largely wasted if you can't see the point of best focus due to focus wobbles...

[gwlee]

I currently own the AT 72mmED II and use it for visual astronomy. I was thinking of replacing it with the SV 80mm Access. Would the SV give me an improved imaged?

I have an AT72ED2, and have owned a fast 80mm scope, but haven’t used the Access 80mm f7. Expect the 8mm aperture advantage would be noticeable, but not “wow” noticeable. Being longer, the 80mm would be easier to balance than the AT, and have a bit less field curvature, but give up some portability. Doubt there’s much difference in the optical quality between these two scopes. Depending on the mount you are using for your 72mm, it’s possible that you might need a bigger mount or tripod to handle the longer and fatter 80mm.

 

For me, these two scopes are close enough in aperture that they would fill the same niche, so don’t think I would want to own both of them, but the 72mm will offer a bit more portability and the 80mm will offer a bit more performance. If your AT72ED2 mount is up to the task, and you don’t need the extra portability of the AT72ED2, I think replacing it with an 80mm f7 might be worthwhile. 

Edited by gwlee, 29 November 2019 - 02:19 PM.

[jeffz]

Thanks

[Don Allen]

The 80 has 23% more photon catching glass than the 72.

 

The ED elements are essentially equal. 

 

How much will your eyepieces adjust with the different F ratio? ..i.e., will you have to trade/purchase a new one to get the wide field available on the F/6 72?

 

Don

[russell23]

The next aperture jump that would be significant is the 102mm ... which would require a larger mount.

[gwlee]

The next aperture jump that would be significant is the 102mm ... which would require a larger mount.

If the OP is willing to wrangle a 4” scope and willing to buy a bigger mount, something like AT102ED f7 doublet that sells for $599 might be something to consider. It will definitely give more impressive views of anything that will fit within its FOV than an 80mm f7. 

[Don Allen]

A 102 will double the photon catching ability over his current scope.

[KerryR]

100mm scopes, and even many of the 90's, quickly get in to another level as far as grab and go. If a scope requires more than 1 trip out the door, I don't consider it grab and go, I consider it a normal scope. For me, that happens right around 90mm and up, because a heavier tripod and head are generally required, and things get awkward if the scope is carried out attached to the mount. 80's are nice because they're a great combination of aperture and, with a carefully selected mount, easy-one-trip-one-hand-out-the-door. While I can wrestle my 90, and even my 100, out the door, mounted, it's nowhere near as easy/comfy as my smaller scopes.