at65edq and 2" diagonals
Posted 17 October 2012 - 04:01 PM
This is my first post so new to forums. I am looking to purchase the AT65EDQ but its description says it may not work with most 2" diagonals. Does anyone have any experience with these and if so what diagonals will work? I am looking to purchase the AT2D diagonal with it and was advised to post here by astronomics as no one was on hand with hands on experience with this question. I want to use for visual and imaging. Additionally would anyone recommend the AT72ED or the AT65EDQ over the other for my needs? I like the case with the 72. I will have the field flattener so the built in one on the 65 although convenient is not a deal breaker. So much to consider. Thank you so much everyone.
Posted 18 October 2012 - 04:07 AM
As far as I understand you need to use a SCT diagonal with the AT66. I owned a AT72ED, and it was a nice scope, but I am not an imager so I can't help there. For visual, I would choose the AT72ED or even an 80ED f/7.5 (I think you can get a reducer to bring the f ratio to 6.3 for the ED80)
Here's a decent review of the AT65:
Welcome to Cloudy Nights!
Posted 18 October 2012 - 11:58 AM
Here's what the site says:
Most 2” star diagonals will not reach infinity focus with the AT65EDQ with either 1.25" or 2" eyepieces, so a 1.25” diagonal is recommended for visual use.
Posted 18 October 2012 - 10:07 PM
Posted 20 October 2012 - 06:18 PM
I am in Phoenix like you. I own the AT65EDQ and really like the little guy. Little but heavy with all that glass.
I use it for guiding mostly and just starting to image with it.
I have not tried it with a 2" diagonal and just bought a 1.25" with it after reading the specs. I believe there is not enough backfocus for a 2" diagonal, hence the recommendation for using a 1.25 diagonal.
I will see if I can try it with my 2" the next couple days.
Posted 21 October 2012 - 05:15 AM
Awesome to meet you. Wish we could turn off even just half of all these high pressure sodium street lights and take advantage of our mostly clear skies. The difference in visibility would be astronomical. Thanks for letting me know your thoughts on the scope. I am on the fence still between the AT65 and 72 but want to order Monday to hopefully have by Friday for some overnight camping away from all the lights. If you find out by Monday I will be extremely appreciative of your first hand testing results. It seems the AT72 gets very good praise but I'm really set on those clamshell rings the 65 has for piggybacking my camera when not connecting directly to the At65 of my AT6RC. Not to mention the better glass and built in flattener. Have a great weekend. I look forward to your evaluation details. Thank you.
Posted 21 October 2012 - 09:18 PM
As you know, the clouds are out. Only checked on the moon.
Here are my findings with a 2" W/O Quartz diagonal.
40mm Pentax XW almost came to focus, not enough in focus
31T5 no way
26T5 on loan, did not check
20T5 Great, easy focus but not much infocus left
17T4 Great as above
14 ES 100* Great, lots of room
11 ES 82* No focus
10 XW Pentax No Focus
8.5 XF Pentax No
7 XW Pentax No
5 XW Pentax No
3.5 XW Pentax Did not bother
So there you have it, a 1.25" diagonal is recommended for a reason. The lightpath on a 2" diagonal is too long to bring most EP's to focus.
I will still vouch for the AT65EDQ as a wonderful little scope. Nice optics and a good flat field for imaging. I also remember the nice view in a 24 Pan when I first recieved the scope and the 1.25" diagonal. That EP is not on the list as I sold it from non use.
Hope this helps your decision process, whatever that might be.
Posted 22 October 2012 - 01:07 AM
Posted 22 October 2012 - 11:10 AM
Just a couple pointers:
My supplied rings held the scope, but were loose enough that the ring could just slightly pivot. I added some strips of 1/8" hobby foam between the ring and scope body, cut from an 8 x 11 sheet I found at Michials Hobby. That put enough tension on the rings to stabilize them from any movement.
Keep in mind that the supplied rings only have center holes, sure wish they were wide enough to have bolt holes on the outer edges. They work OK as is.
I use Losmandy dovetail plate adapters to mount the scope onto another scope. http://www.losmandy....mages/DVA-1.jpg I also shim between the scope and adapter to raise the scope enough to get at the focus lock knob. I just use heavy ? nylon ? spacer bushings with longer screws. Picture down below, sorry for the focus, quick and dirty just to show you.
When I guide with it, I use a 2" extension with a 1.25" centering ring attached to hold my SSAG and set the focuser at 2.6 to 2.7.
DSLR imaging with a 2" barrel to camera adapter focuses around 5.25 on the focuser hash marks.
My QHY8 OSC comes to focus with a 2" extender, 2" nosepiece threaded to the T threads at about 2.4 on the hash marks.
My scope is from the second run, so I am not sure what they are shipping now, therefore YMMV.
Posted 22 October 2012 - 03:41 PM
I tried two 2" diagonals known to have short light path on AT65EDQ.
I can come to focus to infinity with all of my 2" eyepieces (including Nagler 31T5) with 2" Zeiss Prism Diagonal.
With Astro Physics MaxBright, N31T5 is border line, just running out of inward focus. N22T4 is about 1mm left to go. I would say 2" eyepiece with Televue Eyepiece spec F column positive number works with Astro Physics MaxBright 2" diagonal.
This is with 2" Zeiss Prism Diagonal, about 6mm to go when it focus to near infinity (a few miles away)
2" Zeiss Prism Diagonal may be hard to find but Astro Physics MaxBright Diagonal shouldn't be difficult to get. If you have particular eyepiece in mind and if I have it, I can test it out for you if you like.
PS: You would need to use longer dovetail to get the combo balanced when you use 2lb+ eyepiece.
Posted 23 October 2012 - 05:25 PM
Posted 30 October 2012 - 07:21 PM
So at the last moment I went with the AT65. It is great visually. Saw Orion Neb on Saturday night. Pinpoint stars so nice. Have it aligned with myAT6RC and finder. Using it with an AstroTech 1.25 Quartz Dielectric and a Celestron zoom eyepiece I already had for quick views at diff magnifications. So here's a shot of the gang (sorry for the low res I had to seriously downsize it for upload).