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The AT72EDII is out!

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#251 John Miele

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Posted 24 November 2017 - 08:54 AM

@ John

 

My experience with flatteners is that the shorter the scope FL, the longer the spacing between flattener and camera.  I use  an AT2FF with a 600mm Vixen ED80 and I get the best field correction at about 65 mm of spacing.  Just throwing that out there as an idea on what kind of range you can try.  The best spacing may vary a lot from one FL scope to another of greatly different FL.  

Thanks Adam. I'll try some longer spacing too.

 

But to be clear, I bought this scope primarily as a grab and go visual scope. Imaging was only a secondary purpose. I figured it would make a fun to use wide field imager based on my previous ATED72 original model and I think it will perform that role nicely...John


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#252 Sarkikos

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Posted 24 November 2017 - 02:44 PM

I recently bought the AT72EDII.  I already had the AT72ED with the aluminum equipment box.  Now I want to sell the AT72ED.  But I like that box.  The inlay for the AT72EDII fits nicely in the box for the AT72ED.  Should I sell the AT72ED without the box?  :thinking:  What to do, what to do ...?

 

:grin:

Mike


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#253 tomykay12

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Posted 24 November 2017 - 05:38 PM

get an 8" dob


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#254 John Miele

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Posted 24 November 2017 - 08:48 PM

Yay! I had a semi-clear night tonight. I removed the camera and spent a half hour visual. This was in my suburban backyard.

 

Observations:

 

1. Clear diffraction ring pattern inside focus. More fuzzy but definitely not just a "blob" outside of focus. I could see rings.

2. Collimation looked dead on.

3. Clear split of the the double double with a 6mm TMB and a 2X barlow (144x)

4. Craters on the Moon were sharp at the same power. But the image was dim and I would definitely go no higher in power. Also saw some floaters...blah. But the detail was impressively sharp. I also saw no sigh of false color on the limb of the Moon. 

6. My 14mm Pentax XW is a perfect EP with this scope. Very sharp views. Stars are pinpoint. The ET cluster and double cluster looked cool with several stars showing some color. Panning all over Cassiopeia was quite enjoyable. 

7. I could not see any obvious CA in focus on anything I looked at with any of the above eyepieces. 

8. I can carry the tripod and scope around the yard with ease! Given all my trees, this is very important. Makes it a very easy to use scope.

9 M31 was large and bright. Also saw M32 faintly to the side and  glimpsed M110 with averted vision as well. All in the same FOV with the 14mm Pentax.

 

I'm now done "testing". It's clearly a keeper so I just plan to use it and have fun this Winter!...John


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#255 coopman

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Posted 24 November 2017 - 10:09 PM

Yes, there are a lot of reasons to like this little scope. I don't have a 14mm anything to use in it, but it does very well with my 12mm Nagler and 12mm Radian. I'd like to get out to a dark sky site and try it out sometime.
It should be great for bird/critter watching too if you like that sort of thing.

#256 jay.i

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Posted 24 November 2017 - 10:18 PM

Maybe you got an amazing unit John, or I got a subpar one, but there is always a ring of neon around the sun and moon for me, with my A-P mirror diagonal and 13Ethos, 7XW, and 5XW. I also see the faintest purple haze over the moon sometimes depending on seeing. It's not incredibly bothersome but it's there. Overall the CA doesn't bother me given what this scope is and is intended for.



#257 Sarkikos

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Posted 24 November 2017 - 11:06 PM

get an 8" dob

I had an 8" f/6 Dob but sold it over a year ago.  I have an 8" f/3.9 Newt OTA on order now.  Different tools for different jobs.  One scope can't do it all.

 

Mike


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#258 Sarkikos

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Posted 24 November 2017 - 11:09 PM

Yay! I had a semi-clear night tonight. I removed the camera and spent a half hour visual. This was in my suburban backyard.

 

Observations:

 

1. Clear diffraction ring pattern inside focus. More fuzzy but definitely not just a "blob" outside of focus. I could see rings.

2. Collimation looked dead on.

3. Clear split of the the double double with a 6mm TMB and a 2X barlow (144x)

4. Craters on the Moon were sharp at the same power. But the image was dim and I would definitely go no higher in power. Also saw some floaters...blah. But the detail was impressively sharp. I also saw no sigh of false color on the limb of the Moon. 

6. My 14mm Pentax XW is a perfect EP with this scope. Very sharp views. Stars are pinpoint. The ET cluster and double cluster looked cool with several stars showing some color. Panning all over Cassiopeia was quite enjoyable. 

7. I could not see any obvious CA in focus on anything I looked at with any of the above eyepieces. 

8. I can carry the tripod and scope around the yard with ease! Given all my trees, this is very important. Makes it a very easy to use scope.

9 M31 was large and bright. Also saw M32 faintly to the side and  glimpsed M110 with averted vision as well. All in the same FOV with the 14mm Pentax.

 

I'm now done "testing". It's clearly a keeper so I just plan to use it and have fun this Winter!...John

What mount is the AT72EDII on?

 

Mike



#259 John Miele

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Posted 25 November 2017 - 08:53 AM

I have it on a Porta mount and that is plenty stable on my grass but the slo-mo controls are needed at higher powers. At lower powers I just grab it by the diagonal and move it around.

 

I was using a TMB 6mm and a televue 2x barlow and I panned around the Moon's limb and just could not see any blue or green fringing. But I am not super sensitive to color, so maybe others might notice some small amount that I am missing? 

 

I went back out a 2nd time last night and at 144X this scope is also an excellent double star splitter. Rigel's companion showed up very clearly and Castor presented a beautiful and clean split with stable diffraction rings. Seeing was good later last night.



#260 John Miele

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Posted 25 November 2017 - 09:21 AM

Here is how I mounted mine. I moved the rings to the front of the dovetail and the dovetail is slid as far forward as it can go on the mount. The OTA has to be rotated so the focuser can clear the dovetail and rear of the mount. I also found a laser finder works great. I attached one to the tube rings with a stick of wood with some holes drilled in it. I'll pretty that piece up later. The location of the laser also helps pull the cg forward a bit...John

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#261 John Miele

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Posted 25 November 2017 - 09:22 AM

pic 2...

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#262 coopman

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Posted 25 November 2017 - 11:22 AM

A laser finder is all you need with this scope, to just get you in the vicinity of what you want to look at. The scope has a wide enough FOV to be its own finder after that. It's hard to just sight down the tube because there isn't much tube to aim with.

Edited by coopman, 25 November 2017 - 11:23 AM.

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#263 jay.i

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Posted 25 November 2017 - 11:33 AM

John, it's weird... I see more CA at lower powers than I do at high powers. I have only gone up to 86x and that's a remarkably color-"free" experience, all things considered. (It's not entirely free but it might as well be) You should try between 30 and 60x. If you still don't see any on the rim of the bright moon or sun, I will have to go and get the exact eyepiece and diagonal you're using to test it for myself. This lens design should display some false color and I see it. If you say yours has none, I suspect it has been edge cases and/or less sensitivity to the color. However it's not hard to see a dancing neon rim of the moon with the seeing making it all fuzzy.

 

I will say again though, my seeing sucks, and I have to look over a few office buildings (in an urban area) to see both the sun and moon, so that is definitely a factor. I have noticed less color on nights with good seeing for sure. Last night was actually awesome for a few minutes, a nice smooth flow over the moon with no "boiling". There was definitely less visible CA around 62x and 86x. So who knows... maybe you just have good seeing, maybe a better objective, maybe both. But there should definitely be some color with this lens design so I'm surprised you haven't seen it yet.



#264 gwlee

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Posted 25 November 2017 - 12:20 PM

I recently bought the AT72EDII.  I already had the AT72ED with the aluminum equipment box.  Now I want to sell the AT72ED.  But I like that box.  The inlay for the AT72EDII fits nicely in the box for the AT72ED.  Should I sell the AT72ED without the box?  thinking1.gif  What to do, what to do ...?

 

grin.gif

Mike

I found that never used the aluminum box that came with the AT72ED, so I sold it with the scope. Prefer a box that allows the diagonal to remain attached to the scope.



#265 Sarkikos

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Posted 25 November 2017 - 12:45 PM

The only time I would ever use the aluminum box is to store the telescope at home or when driving to a dark site.  When I carry small telescopes like this to observing sites within walking distance of my house, I put the scope in a small side bag.  So the aluminum box would have limited use for me.  I really don't need it.

 

Likewise, the aluminum box that came with my SW120ED sits in the downstairs closet.  It only comes out when I take the scope to a dark site.  I store the scope in a plastic bag on a bookcase shelf.  I could do the same thing for my AT72EDII.  

 

Mike


Edited by Sarkikos, 25 November 2017 - 12:45 PM.


#266 John Miele

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Posted 25 November 2017 - 01:42 PM

John, it's weird... I see more CA at lower powers than I do at high powers. I have only gone up to 86x and that's a remarkably color-"free" experience, all things considered. (It's not entirely free but it might as well be) You should try between 30 and 60x. If you still don't see any on the rim of the bright moon or sun, I will have to go and get the exact eyepiece and diagonal you're using to test it for myself. This lens design should display some false color and I see it. If you say yours has none, I suspect it has been edge cases and/or less sensitivity to the color. However it's not hard to see a dancing neon rim of the moon with the seeing making it all fuzzy.

 

I will say again though, my seeing sucks, and I have to look over a few office buildings (in an urban area) to see both the sun and moon, so that is definitely a factor. I have noticed less color on nights with good seeing for sure. Last night was actually awesome for a few minutes, a nice smooth flow over the moon with no "boiling". There was definitely less visible CA around 62x and 86x. So who knows... maybe you just have good seeing, maybe a better objective, maybe both. But there should definitely be some color with this lens design so I'm surprised you haven't seen it yet.

Yes. I did not search for CA at low power. I assumed high power would be worse. But maybe that's just the opposite! I had good seeing last night. I'll look again tonight at the Moon and use my 14mm. That may be a little different story.



#267 jay.i

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Posted 25 November 2017 - 02:32 PM

Definitely check out bright stars like Sirius or Rigel. If those aren't twinkling rainbows I'll be surprised.



#268 Moondust

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Posted 25 November 2017 - 02:48 PM

PB250796ab.jpg

Here is how I mounted mine. I moved the rings to the front of the dovetail and the dovetail is slid as far forward as it can go on the mount. The OTA has to be rotated so the focuser can clear the dovetail and rear of the mount. I also found a laser finder works great. I attached one to the tube rings with a stick of wood with some holes drilled in it. I'll pretty that piece up later. The location of the laser also helps pull the cg forward a bit...John

Mine is mounted like this. No need to rotate the focuser to clear the dovetail.  Had really gusty winds last night and it was rock solid, I'm sure the home made tripod helped. I get concentric rings on one side of focus and definite but less defined rings on the other side but not a blob. There is CA but its very minor and the optics are very sharp and well collimated. Had mine up to 162x and everything held together nicely although a bit dim as expected. Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.


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#269 jay.i

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Posted 25 November 2017 - 04:12 PM

Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.

I thought about this as well, and I still think 60mm is just too small. The AT72EDII is fairly small but it's as small as I want to go. I feel like it could be quite capable under dark skies and isn't entirely useless under bad light pollution. The 60mm can't go anywhere or do anything that my 72 can't. The 72 really is in a sweet spot I think - bigger than a finder, much better optics than a finder, but still quite small and portable.


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#270 PXR-5

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Posted 25 November 2017 - 05:17 PM


Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.

I thought about this as well, and I still think 60mm is just too small. The AT72EDII is fairly small but it's as small as I want to go. I feel like it could be quite capable under dark skies and isn't entirely useless under bad light pollution. The 60mm can't go anywhere or do anything that my 72 can't. The 72 really is in a sweet spot I think - bigger than a finder, much better optics than a finder, but still quite small and portable.

I'm thinking the same thing, I actually ordered, then cancelled the AT60ED, (thanks Pete) I'm going to spring for the 72 :)

I'm currently using a ST80 for wide field and feel the 60 may be a let down in my semi suburban skies. YMMV of course.
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#271 John Miele

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Posted 25 November 2017 - 07:44 PM

attachicon.gifPB250796ab.jpg

Here is how I mounted mine. I moved the rings to the front of the dovetail and the dovetail is slid as far forward as it can go on the mount. The OTA has to be rotated so the focuser can clear the dovetail and rear of the mount. I also found a laser finder works great. I attached one to the tube rings with a stick of wood with some holes drilled in it. I'll pretty that piece up later. The location of the laser also helps pull the cg forward a bit...John

Mine is mounted like this. No need to rotate the focuser to clear the dovetail.  Had really gusty winds last night and it was rock solid, I'm sure the home made tripod helped. I get concentric rings on one side of focus and definite but less defined rings on the other side but not a blob. There is CA but its very minor and the optics are very sharp and well collimated. Had mine up to 162x and everything held together nicely although a bit dim as expected. Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.

 

I'll have to give your arrangement a try. Can you balance that with a heavier EP? I have to rack my drawtube out about 2 inches to achieve focus with my 14 Pentax and that really moves my balance point backwards. I keep my Porta altitude friction setting very light, so balance has to be real close.

 

Well, I looked at the Moon again this time at lower powers and I do see just a hint of sort of yellowish-greenish glow around the limb. But it is extremely subtle. The color becomes more pronounced if I move the Moon right to the edge of the field but in the center of the field its a ghost. I cant say there is any kind of color smeared over the field at all. The Moon looks pretty neutral and the contrast is excellent. I am very impressed with the lens design and execution. I'mot really a CA peeper so this feels very close to a true APO to me!


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#272 John Miele

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Posted 25 November 2017 - 07:46 PM

attachicon.gifPB250796ab.jpg

Here is how I mounted mine. I moved the rings to the front of the dovetail and the dovetail is slid as far forward as it can go on the mount. The OTA has to be rotated so the focuser can clear the dovetail and rear of the mount. I also found a laser finder works great. I attached one to the tube rings with a stick of wood with some holes drilled in it. I'll pretty that piece up later. The location of the laser also helps pull the cg forward a bit...John

Mine is mounted like this. No need to rotate the focuser to clear the dovetail.  Had really gusty winds last night and it was rock solid, I'm sure the home made tripod helped. I get concentric rings on one side of focus and definite but less defined rings on the other side but not a blob. There is CA but its very minor and the optics are very sharp and well collimated. Had mine up to 162x and everything held together nicely although a bit dim as expected. Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.

Forgot to say I really like your homebuilt tripod. It looks beautiful and solid!...John



#273 jay.i

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Posted 25 November 2017 - 08:08 PM

I do really like looking at the moon at lower powers with this scope. The contrast is just right. Higher powers look good too for sure, but it looks great at 30-60x.


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#274 Sarkikos

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Posted 25 November 2017 - 08:30 PM

 

Is there any good reason to get the AT60 if you already have the AT72? Someone talk me out of it.

I thought about this as well, and I still think 60mm is just too small. The AT72EDII is fairly small but it's as small as I want to go. I feel like it could be quite capable under dark skies and isn't entirely useless under bad light pollution. The 60mm can't go anywhere or do anything that my 72 can't. The 72 really is in a sweet spot I think - bigger than a finder, much better optics than a finder, but still quite small and portable.

 

Well, if you want to walk to an observing site a mile away, the 60 will fit in a smaller side bag.

 

Mike



#275 jay.i

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Posted 25 November 2017 - 08:39 PM

Sure, you can fit it into a bag slightly smaller than the one needed for the 72. But it's not that much smaller, and it's not small enough to slip into a backpack without taking up a big chunk of space. I'd rather just carry a slightly bigger side bag with the extra 12mm of aperture inside, a 44% increase in light gathering area!




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