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FF/Reducer for AT72EDII alternative

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#1 Starblind

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Posted 10 March 2019 - 09:03 AM

Waiting for Astronomics to get these in stock for three months now.  Is anyone aware of a flattener/reducer I can use on the AT72EDII that will work and that I can actually buy?  I have an FF already but some targets are just too big as it is.  

 

Bob



#2 kolsen

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Posted 10 March 2019 - 09:17 AM

I'm in the same boat Bob,  I hope someone has an answer.  The AT72EDII with the flattener would be a great combo for wide field.

 

BTW I live close by in McHenry. 


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#3 bridgman

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Posted 10 March 2019 - 09:23 AM

I'm probably in the same boat - just ordered an AT72EDII with flattener & EOS adapter then realized the flattener was out of stock.

 

At first glance the following (locally available and in stock, of course) seems like the same thing except for the knurling on the top. It's possible that this one is 48mm T by default with a 48mm to 42mm adapter threaded on, but that doesn't fit with the pricing (48mm more expensive):

 

https://www.ontariot...ner_p_1431.html

 

EDIT - LOL... I did *not* see kolsen's post before typing my "in the same boat" comment smile.gif

 

FURTHER EDIT - looks like the back of the flattener/reducer has some other thread on it and accepts either 42mm or 48mm backs. Guessing the extra $$ gets you 42mm *and* 48mm backs. The Astro-tech, on the other hand, seems to have a fixed 42mm back.


Edited by bridgman, 10 March 2019 - 09:28 AM.

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#4 Starblind

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Posted 10 March 2019 - 09:47 AM

I'm in the same boat Bob,  I hope someone has an answer.  The AT72EDII with the flattener would be a great combo for wide field.

 

BTW I live close by in McHenry. 

We need to get together.  I don't know anyone locally that does AP.  There are not too many people into this hobby around Algonquin so I'm on my own unless I drive out to Dixon for a meet, the only really good dark site id Green River State park.  I love the AT scope, I'm really impressed with the images I get out of it but I'm in the market for a triplet now, likely with a longer FL.  I have the flattener on the scope but can't fit Andromeda into the field of view with the ZWO ASI183MM Pro.  This hobby can be frustrating at times.....

 

Bob


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#5 Starblind

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Posted 10 March 2019 - 09:50 AM

I'm probably in the same boat - just ordered an AT72EDII with flattener & EOS adapter then realized the flattener was out of stock.

 

At first glance the following (locally available and in stock, of course) seems like the same thing except for the knurling on the top. It's possible that this one is 48mm T by default with a 48mm to 42mm adapter threaded on, but that doesn't fit with the pricing (48mm more expensive):

 

https://www.ontariot...ner_p_1431.html

 

EDIT - LOL... I did *not* see kolsen's post before typing my "in the same boat" comment smile.gif

 

FURTHER EDIT - looks like the back of the flattener/reducer has some other thread on it and accepts either 42mm or 48mm backs. Guessing the extra $$ gets you 42mm *and* 48mm backs. The Astro-tech, on the other hand, seems to have a fixed 42mm back.

If you get the scope delivered I'll sell you my flattener.  I'm tired of waiting for the reducer to come in, it's been back ordered since last November.

 

Bob.



#6 AlienRatDog

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Posted 10 March 2019 - 01:54 PM

I have a dumb question, the Astro Tech field flattener/reducer says there is an image circle of 42mm, does this mean I can use an AT72 with a full frame DSLR (Nikon D750). I was looking at the AT60 and Redcat to use with an iOptron Skyguider Pro but the AT72 would also work well for a grab n go visual scope...

#7 kolsen

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Posted 11 March 2019 - 11:44 AM

We need to get together.  I don't know anyone locally that does AP.  There are not too many people into this hobby around Algonquin so I'm on my own unless I drive out to Dixon for a meet, the only really good dark site id Green River State park.  I love the AT scope, I'm really impressed with the images I get out of it but I'm in the market for a triplet now, likely with a longer FL.  I have the flattener on the scope but can't fit Andromeda into the field of view with the ZWO ASI183MM Pro.  This hobby can be frustrating at times.....

 

Bob

That would be great Bob.  I also don't know anybody locally(except astro-physics lol), I came into this hobby by myself and it would be nice to share it with somebody else. 

 

The reason I also started looking into a reducer is because of Andromeda. I have the Atik 460EX which will just barely fit the galaxy with the reducer.  Bridgman, that Starfield reducer looks great too, if the delay is much longer I might might go for it.


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#8 Starblind

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Posted 11 March 2019 - 11:48 AM

I have a dumb question, the Astro Tech field flattener/reducer says there is an image circle of 42mm, does this mean I can use an AT72 with a full frame DSLR (Nikon D750). I was looking at the AT60 and Redcat to use with an iOptron Skyguider Pro but the AT72 would also work well for a grab n go visual scope...

I don't know for sure.  I don't think the image circle will be big enough but it's still a 2" focuser so in theory...  I have a ZWO 183MM Pro on mine, and I did use an APSC sized sensor with no issues, but I think the WO would be better suited for full frame.  I would check Astrobin and see if there are any examples of full frame images on there for a 72mm AT.  I will have a look later.  As for the Redcat, that may well be my next scope.  I will be trying out a 200mm Petzval lens with both full frame and the 183MM in the next couple of weeks (Mitol 200mm I picked up brand new for $175) which works REALLY well with a Nikon D610 in daylight and at F4 it's pretty fast.  However, budget permitting, I will likely sell a few bits of gear and go for the new 8" RASA instead.  And pick up a ZWO 294 or 071 cooled color to go with it.  I like the idea of imaging at F2 instead of F6 or F5.

 

Bob.


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#9 Starblind

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Posted 11 March 2019 - 11:52 AM

That would be great Bob.  I also don't know anybody locally(except astro-physics lol), I came into this hobby by myself and it would be nice to share it with somebody else. 

 

The reason I also started looking into a reducer is because of Andromeda. I have the Atik 460EX which will just barely fit the galaxy with the reducer.  Bridgman, that Starfield reducer looks great too, if the delay is much longer I might might go for it.

I have a few friends down south but it's tough to meet up and time is key, along with the weather.  I'll try contacting Astronomics again to see if there is an ETA on the reducer.  If not, I'll stick with what I have for now on the AT, and I'll be trying out a 200mm lens, and I'm SERIOUSLY considering the 8" RASA for everything wide field.  If I can't swing the budget a WO Redcat will be the next scope purchase, the GSO will do for galaxy season since I have the CCDT67 already set up.

 

Bob.



#10 bridgman

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Posted 13 March 2019 - 03:41 AM

After discovering that the AT72EDII seems to have the same M63 focuser drawtube thread as the Z73 I was thinking hard about going with a WO Flat73a instead (wider field, possibly better performance but hard to be sure) but in the end decided to stay with a 2" barrel flattener/reducer instead.

 

https://www.cloudyni...cuser-drawtube/

 

If I lived in the US I probably would have waited for the ATR8 to come in, but it didn't seem to make sense to have a separate shipment up to Canada once the reducer arrived. I ended up going with the Starfield 42mm version above, rather than the 48mm. My rationale was:

 

- my biggest sensor (Canon T3i) is APS-C so 42mm T-ring is big enough

- I had ordered a 42mm EOS T adapter with the AT72EDII and it had already shipped

- like Bob I wanted a reducer... otherwise the Flat73a would have been pretty attractive

- I didn't find a lot of reviews on the Starfield (hardly anything compared to ATR8) but enough to take a chance

- the Orion 0.8x may or may not be a flattener as well depending on who you ask

 

After all that was decided, I was digging through the basement and found a 2" barrel with 42mm T threads on the back (probably from the SV AT1010) that I could have used in the AT72EDII without a flattener so I wouldn't have been totally dead in the water for imaging after all.

 

More interestingly, I found a WO Flat6A II that was still in stock at a number of dealers (including my local one):

 

https://agenaastro.c...p-flat6aii.html

 

It's only a doublet vs the triplet design of the Flat73a (1:1) and there are more reports of people having trouble finding focus than I would have expected statistically, but on the positive side it does have the same M63 threads which apparently fit the AT72EDII focuser drawtube, giving an all-threaded imaging path.. but the 2" barrel reducer/flatteners all seem to have enough bevel to make sure nothing is going to fall out anyways.

 

If I find any other interesting alternatives will post back - in the meantime hope the ATR8 comes through for you.

 

John

 

P.S. I haven't taken a thread off topic for months so I'm overdue... does anyone happen to know what the threads in the AT72EDII scope rings are ? Guessing M6 is most likely but I guess there's a chance they could be 1/4-20. AFAIK the Vixen rail includes a 1/4-20 tapped hole for tripod mounting but that doesn't mean the ring bolts are 1/4-20. Tx.


Edited by bridgman, 13 March 2019 - 03:49 AM.


#11 bridgman

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Posted 14 March 2019 - 12:22 PM

OK, the AT72EDII and reducer both arrived today. The scope is a little gem - I was pleasantly surprised even after enjoying all the pics others have posted.

 

The threads in the AT72EDII rings appear to be M6 as expected. Looks like the ring base is a bit thicker on the bottom (where the main rail attaches) than the top (where an accessory rail or rings can be mounted) so at first glance a screw that fits the bottom OK could be too long for the top and hit the scope tube.

 

On the Starfield reducer, the camera end of the reducer has an M54 thread with an M42 adapter threaded onto it. I'll try to get scope + reducer + GEM set up over the weekend and get some images. At the moment there is a thick layer of clouds between me and first light (right on schedule, it was sunny yesterday laugh.gif).

 

Discovered another interesting possibility for a reducer - the Stellarvue reducer for the SV70T has threads on the telescope end of the reducer that look like M54 at first glance. If so then the reducer should be able to thread into the camera end of the AT72EDII rotator which I (crudely) measured as M54 as well (M63 from rotator to drawtube).

 

https://www.stellarv...ener-for-sv70t/

 

The SV reducer is intended for use with a different objective (triplet vs doublet) so I don't know how well it would work with the AT72EDII, although all indications are that it does work very well with the SV70T. I haven't found any records of anyone testing it with AT72EDII or similar yet, but haven't searched very hard either.

 

John


Edited by bridgman, 14 March 2019 - 12:46 PM.

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#12 ghostboo

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Posted 14 March 2019 - 03:22 PM

OK, the AT72EDII and reducer both arrived today. The scope is a little gem - I was pleasantly surprised even after enjoying all the pics others have posted.

 

The threads in the AT72EDII rings appear to be M6 as expected. Looks like the ring base is a bit thicker on the bottom (where the main rail attaches) than the top (where an accessory rail or rings can be mounted) so at first glance a screw that fits the bottom OK could be too long for the top and hit the scope tube.

 

On the Starfield reducer, the camera end of the reducer has an M54 thread with an M42 adapter threaded onto it. I'll try to get scope + reducer + GEM set up over the weekend and get some images. At the moment there is a thick layer of clouds between me and first light (right on schedule, it was sunny yesterday laugh.gif).

 

Discovered another interesting possibility for a reducer - the Stellarvue reducer for the SV70T has threads on the telescope end of the reducer that look like M54 at first glance. If so then the reducer should be able to thread into the camera end of the AT72EDII rotator which I (crudely) measured as M54 as well (M63 from rotator to drawtube).

 

https://www.stellarv...ener-for-sv70t/

 

The SV reducer is intended for use with a different objective (triplet vs doublet) so I don't know how well it would work with the AT72EDII, although all indications are that it does work very well with the SV70T. I haven't found any records of anyone testing it with AT72EDII or similar yet, but haven't searched very hard either.

 

John

Congrats on your new AT72EDII. I love imaging with mine. After a while, the dew shield got a little sloppy but I put a rubber band or my dew heater behind it and it stays up now. That's the only issue I've had with mine. 



#13 SkipG

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Posted 01 May 2019 - 02:49 PM

FYI, I called Astronomics and asked about their 0.8x reducer that was listed for the previous model. They said more are on the way, arriving perhaps mid-Summer, and that the reducer was a generic 0.8x reducer--no scope specific changes had been made for the new design. Orion sells an 0.8x generic reducer for $150, and it's in stock.



#14 Malachi7

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Posted 12 March 2020 - 04:05 PM

Wondering how long its takes for the 72EDII to arrive after ordering.  I ordered mine in Oct. 2019 and still nothing.  Is this typical of the wait time/list?



#15 bridgman

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Posted 13 March 2020 - 06:19 AM

There's no "typical wait time"... the scopes come in in big batches every so often, and your wait time is a function of when you ordered vs when the shipments arrive.

 

When I ordered my AT72 it was in stock and shipped immediately. I was really impressed with the AT72 and ordered an AT115 back in April 2019 and it arrived in Jan/Feb 2020. I believe that is a longer wait than normal though.

 

There were some AT72EDII's in the last big shipment (Jan 2020) but looks like there may not have been enough to clear the order backlog. Astronomics can tell you when they are expecting the next shipment to arrive, but that might slip a bit depending on how busy the factory is.


Edited by bridgman, 13 March 2020 - 06:21 AM.


#16 LPA

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Posted 13 March 2020 - 02:10 PM

I got the Apertura Adjustable Flattener for 60EDR and 72EDR - FFADJ from Highpoint. I've only been able to take a few test shots so far, but it seems to give good correction at the corners of my AT72EDII and APS-C dslr. This flattener has an adjustable back-focus which is nice. My camera adapter didn't screw all the way onto the threads, so I moved the bf to 0 from the recommended 1.5 to compensate for the additional distance to the sensor. That worked fine.

 

Larry


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#17 HaroldC3

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Posted 14 March 2020 - 11:27 PM

Wondering how long its takes for the 72EDII to arrive after ordering.  I ordered mine in Oct. 2019 and still nothing.  Is this typical of the wait time/list?

I was told they are getting a shipment some time in April.



#18 Don W

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Posted 15 March 2020 - 09:30 PM

I ordered mine last April.



#19 Fluke

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Posted 06 April 2020 - 04:44 PM

I was told they are getting a shipment some time in April.

 

I placed an order for an AT72EDII last week, and was told that the shipment scheduled for this April was delayed due to COVID-19, and that it would likely arrive at the end of May.  On the same shipment should be the ATRF72, an .8x reducer/flattener specifically for this scope.  I added that to my order, even though I hadn't heard anything about this flattener before.

 

https://www.astronom...ical-tubes.html


Edited by Fluke, 06 April 2020 - 04:44 PM.


#20 Don W

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Posted 07 April 2020 - 11:20 AM

Corrected to show that they are AT72EDs and not the II version.

 

I had one AT72ED that I purchased used about this time last year. I ordered the ATR8 in early April. Still waiting. I also have the new ATRF72 on order.

 

A couple months ago someone was selling an AT72ED with the ATR8 so I snapped it up, mainly just to get the ATR8. So now I have two AT72EDs (one black, one blue) and one reducer/flattener. I guess I'll use one for grab and go visual and the other for imaging.

 

Not going to cancel the orders for the reducer/flatteners yet.



#21 bridgman

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Posted 07 April 2020 - 11:48 AM

Nice... I have often thought that a second AT72EDII would be really useful :)



#22 Toddeo

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Posted 07 April 2020 - 12:02 PM

I had one AT72EDII that I purchased used about this time last year. I ordered the ATR8 in early April. Still waiting. I also have the new ATRF72 on order.

 

A couple months ago someone was selling an AT72EDII with the ATR8 so I snapped it up, mainly just to get the ATR8. So now I have two AT72EDIIs (one black, one blue) and one reducer/flattener. I guess I'll use one for grab and go visual and the other for imaging.

 

Not going to cancel the orders for the reducer/flatteners yet.

I thought that the newer version of the AT72EDII comes only in white. The older models of the AT72 come in various colors. They would not be the "EDII" version.



#23 Don W

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Posted 07 April 2020 - 01:10 PM

You are indeed correct. Just looked and they are both AT72EDs and not the II versions. My understanding is that there was very little difference between the two versions optically. Correct me if I'm wrong. (won't be the first time, lol)




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