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Night Vision- tried my new reducer and other stuff

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#1 Solar storm

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Posted 22 February 2017 - 09:00 AM

Greetings!  Last night I was out with my 11" f4.5 dob and my PVS-7.  It was an awesomely warm night in Iowa. I tried out a couple things and here are my thoughts.

 

1.  Antares .7x 2" focal reducer-  this effectively made my dob f3.15.  The filter attachment that I use with my PVS-7 is the one from Scope Stuff that has a 2" filter attachment and a recessed 1 1/4" filter attachment.  I was able to place my 1 1/4" 7nm Ha filter in the recessed portion and had enough space to completely screw in the 2" focal reducer without any contact between the filter and reducer that I could tell.  My target was the Orion Nebula. Now I did not go into this with much hope since I had previously tried a 1 1/4" .5x reducer which had spectacularly bad results.  What I found when using the 2" .7x reducer was a lack of noticeable coma.  This was a pleasant surprise.  I also found that I enjoyed the view of the Orion Nebula more with the reducer than without it.  The view is much wider with the reducer since I was going from 46.6x to 32.6x.  This really drove home the point of fast focal ratios and night vision being a happy marriage.  When coupling the fast focal ratio with my 11" light gathering capacity, you get a winning combination.  Kinda makes me want a 20" f3 scope now.  So the Antares 2" .7x focal reducer is a keeper.

 

2.  I got to try out my 32,000 step encoders.  Are 32,000 step encoders overkill?  Absolutely.   Is my accuracy increased especially since it is a wood frame push-to dob?  Likely not.  Does it drain my DSC battery faster? Yup!  Do I think it is cool that I can move my scope as fast as I want without skipping steps?  Heck ya!  Basically, I just cant stop myself from always tinkering and upgrading my scope.  I just wanted to say these work awesome.

 

3.  My other real treat was trying out for the first time my Nexus DSC.  I wish I had gotten this sooner.  It is awesome.  I have used Sky Commander and Argo Navis and they are very good.  But, I have not had a DSC nail it first try like this before.  And connecting it to my Sky Safari synced so well with it.  Being able to move the scope around from nebula to nebula by just looking at my phone to see where it is pointing was amazing!

 

My Ethos eyepieces have been sad and lonely for about 9 months now.  I don't see that changing soon.

scope.jpg


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#2 Knasal

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Posted 22 February 2017 - 09:22 AM

Congratulations on a great night! Sounds like you had a blast and that all the tinkering paid off.

 

Regarding that 20" scope, I bet Rob (Teeter) would be happy to help you out!

 

Thanks for the report - I bet we'll be seeing more "warm weather" observing reports in days to come. 

 

Kevin

 

P.S. If you're looking to unload those Ethos eyepieces at a discounted price, this visual observer  would be happy to oblige!


Edited by Knasal, 22 February 2017 - 09:26 AM.

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#3 Doug Culbertson

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Posted 22 February 2017 - 09:53 AM

Nice report! I agree with you regarding the Nexus DSC; what a complete change from the Sky Commander that I used since the 90's.  Have you downloaded the latest firmware to allow syncing to your current target? I did, but have not yet had a clear night to try it out.

 

The last two times that I observed I found myself wondering why I even bought the Ethos that I own. Once they got first light, I switched to the PVS-7 and never put the Ethos in the focuser again.

 

Looks like you have a great home observing site!


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#4 Jeff Morgan

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Posted 22 February 2017 - 11:10 AM

Nice report! Very encouraging on the focal reduction, I have been wanting to try focal reduction in my f/7 Newtonian. Hoping to use a 2" .5x to get down to f/3.5.

 

SkySafari is awesome, I use an iPad and effectively have a moving map. Once I do 2-star alignment, I just hit "connect" in SkySafari and don't touch Argo again until it is time to power down at the end of the night. Just awesome to move the scope and watch the reticle glide from target to target. Never even have to look at the sky!

 

My iPad is in a Pivot case, I need to find a ram ball adapter for my FTX mount. Right now it sits on the eyepiece tray or I hand hold it. Would like to suspend it near the eyepiece position.


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#5 bobhen

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Posted 22 February 2017 - 11:18 AM

I also use the 2” .7 reducer and like it. It works well with my Tak 120 and Mewlon 210 giving me a reduced 650mm and native 900mm FL in the Tak 120 and a reduced 1,700mm and native 2,400mm in the Mewlon 210 for a nice rage of image scales.

 

As I wrote in another thread, the other night I observed 41, wide-ranging objects from Barnard’s Loop to the Rosette and the nearby 2, faint Sh objects to the Monkey Head Nebula to open cluster M35 and a “bright” 2158 and detail in galaxy M82 to a “better than photo-like” view of the core of M42 and MANY more, and all in heavy light pollution.

 

For the year that I’ve had the Micro, I too have not really used an eyepiece for Deep Sky observing.

 

Bob


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#6 Rickster

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Posted 22 February 2017 - 12:27 PM

Did you notice if there was any difference in the amount of coma with and without the 7nm filter?  In my f4 imaging Newt I get strong coma with a .63 reducer and no filter, but almost no coma when using a 12nm ha filter with the same reducer.



#7 Eddgie

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Posted 22 February 2017 - 12:44 PM

Very happy to hear that you got a reduced configuration to work for you and delighted that you think coma was not a problem.  Due to the long focal length of the eyepieces and the narrow 18mm circle, coma is not as intrusive as it would be using an eyepiece with higher power and a 36mm field stop would would show.  I would have thought though that at f/3.5, coma would start to show, but I am pleased to here that it was not intrusive!

 

As for eyepieces, I sold a bunch because I could tell early on that I would not use them.

 

Now, I have to say this.  I have the Boren Simon 6" f/2.8 on order, and I would love to try that scope with a 17mm Ethos!

While we can get a great boost form the image intensifier, we don't get reflection nebula, and we don't get color!  I think the 4 degree true field and 100 degree apparent field with a 6" Scope on a target like Pleiades would be everything Mel Bartel writes about.  I am sure there are many other targets like this as well, where there is reflection nebula and color stars waiting to be seen!

 

I would not sell any Ethos eyepieces yet.  As Mel's page makes clear, an Ethos in a very fast telescope probably makes a pretty dazzling wide field instrument!

This is one of the reasons I went with the Boren Simon.   I can use the ASA corrector in a wide variety of refractors and when you get into the f/3 range, you start to really open up the sky for very big scale nebula and reflection nebula.    

 

It will probably be another month before I get the scope (they said 3-4 weeks but there is also shipping) and when I do, I want to find someone in Central Texas with a 17mm Ethos and give it a try for visual.  Will report here of course, but I think this will be a very interesting scope to use visually. 

 

Happy to hear though that your reducer worked well with the f/4.5 mirror!    That is great news!


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#8 Solar storm

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Posted 22 February 2017 - 01:57 PM

I bet the Boren Simon scope would be really cool.  I did not use the reducer without the 7nm Ha filter, which probably explains the lack of apparent coma.  I am assuming it will be more obvious without a filter.  Since I really only see myself using the reducer with nebula, I probably wont use it without a filter.  When I galaxy hunt, I like the extra mag on board.    



#9 Solar storm

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Posted 22 February 2017 - 10:02 PM

ROUND 2 TONIGHT:  I found my second favorite use for my .7x reducer tonight.  This thing is great on Open Clusters combined with my 680 longpass filter.  With the filter there was again no discernible coma :).  It was great fitting wide clusters all in one view with the reducer. The Nexus and Sky Saffari allowed me to hop from cluster to cluster. The PVS 7 really made the clusters come alive.  I never really appreciated them as much until now.

 

 

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.


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#10 Starman81

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Posted 22 February 2017 - 11:39 PM

ROUND 2 TONIGHT:  I found my second favorite use for my .7x reducer tonight.  This thing is great on Open Clusters combined with my 680 longpass filter.  With the filter there was again no discernible coma :).  It was great fitting wide clusters all in one view with the reducer. The Nexus and Sky Saffari allowed me to hop from cluster to cluster. The PVS 7 really made the clusters come alive.  I never really appreciated them as much until now.

 

 

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.

 

I love open clusters too. I don't hear that much about NV being used for open clusters, so this report is appreciated. Mostly, you hear about nebulae and galaxies, of course, as they are more difficult to see visually and really helped with NV.

 

I also have a STS 11... Already a fast f/4.3... Is this 0.7x reducer the same as can be found here? I worry about coma in a fast reflector  and how best to achieve coma correction and it is a nice surprise to find out that filtering you would do anyways suppresses coma. 


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#11 Jeff Morgan

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Posted 22 February 2017 - 11:46 PM

Eddgie, when is the BS (excuse me, Boren Simon  :grin: ) arriving?



#12 Solar storm

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Posted 23 February 2017 - 07:37 AM

 

ROUND 2 TONIGHT:  I found my second favorite use for my .7x reducer tonight.  This thing is great on Open Clusters combined with my 680 longpass filter.  With the filter there was again no discernible coma :).  It was great fitting wide clusters all in one view with the reducer. The Nexus and Sky Saffari allowed me to hop from cluster to cluster. The PVS 7 really made the clusters come alive.  I never really appreciated them as much until now.

 

 

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.

 

I love open clusters too. I don't hear that much about NV being used for open clusters, so this report is appreciated. Mostly, you hear about nebulae and galaxies, of course, as they are more difficult to see visually and really helped with NV.

 

I also have a STS 11... Already a fast f/4.3... Is this 0.7x reducer the same as can be found here? I worry about coma in a fast reflector  and how best to achieve coma correction and it is a nice surprise to find out that filtering you would do anyways suppresses coma. 

 

 

That is the reducer I use from Antares.  My scope is native f4.5 so it should work well with yours I would assume since they are not too different.  I have yet to try the reducer without a filter since I have only used it in an area of heavier light pollution.  Reducing my scope to f3.15 looks great all the way to the edge of view.  I use the reducer with this C-mounted attachement:

 

http://www.scopestuff.com/ss_c2bf.htm

 

This one allows me to fit very nicely my filters inside it while having the reducer on top.  Works perfect.



#13 bobhen

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Posted 23 February 2017 - 08:08 AM

ROUND 2 TONIGHT:  I found my second favorite use for my .7x reducer tonight.  This thing is great on Open Clusters combined with my 680 longpass filter.  With the filter there was again no discernible coma :).  It was great fitting wide clusters all in one view with the reducer. The Nexus and Sky Saffari allowed me to hop from cluster to cluster. The PVS 7 really made the clusters come alive.  I never really appreciated them as much until now.

 

 

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.

I also had some fantastic (best) views of open clusters with the reducer and 685 pass filter the other night.  M46, M38 and 1907, M37, and M35 with 2158 bright and in the same filed were just a few. Just sweeping around you come across many uncharted asterisms and star groupings that are also interesting.

 

Absolutely the best view of these objects I've had, and in any scope.

 

Bob



#14 Eddgie

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Posted 23 February 2017 - 09:15 AM

Eddgie, when is the BS (excuse me, Boren Simon  :grin: ) arriving?

They said about 4 weeks and that was about a week and a half ago, but my experience with these kinds of things is that they often take much longer than the vendors suggest.



#15 Eddgie

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Posted 23 February 2017 - 09:27 AM

 

ROUND 2 TONIGHT:  I found my second favorite use for my .7x reducer tonight.  This thing is great on Open Clusters combined with my 680 longpass filter.  With the filter there was again no discernible coma :).  It was great fitting wide clusters all in one view with the reducer. The Nexus and Sky Saffari allowed me to hop from cluster to cluster. The PVS 7 really made the clusters come alive.  I never really appreciated them as much until now.

 

 

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.

I also had some fantastic (best) views of open clusters with the reducer and 685 pass filter the other night.  M46, M38 and 1907, M37, and M35 with 2158 bright and in the same filed were just a few. Just sweeping around you come across many uncharted asterisms and star groupings that are also interesting.

 

Absolutely the best view of these objects I've had, and in any scope.

 

Bob

 

 

Yes, some seem to believe that they are not as useful on clusters, but I think they totally rip on clusters.  I could see as many stars in my Comet Catcher with NV as I could see in my 12" dob without it.

 

Clusters also bear magnification very well!  I can go easily to f/10 and the view remains excellent.

 

There is this though.  I live in light polluted  skies and I have done a lot of viewing lately with different filters and compared to the view with no filters.   Among the filters I have tried are simple red "Planetary" type filters.  More and more, especially when using scopes f/5 and slower, I am leaning away from long pass filters.     

 

A long pass filter will blacken the sky, but it will also increase the noise level and I have come to believe that I can see fainter limiting magnitude with no filter or with a mild filter than I can see with even 650nm filter, which makes the sky dark, but makes the very faintest stars harder for me to see..

 

I also found galaxies to be a bit easier without a filter in the 12" dob!   I have lived and observed from Austin for 16 years, and never before have I seen so many galaxies, and when I say "See" them, I mean see something more than a tiny suggestion of a smudge!

 

Point though is to try using different filters (and no filter) on clusters. I am feeling that the light red or 610nm actually produce better results than 690nm and in fact, I think that I see the most stars unfiltered.   The background is not as pleasingly dark, but seeing more stars for me is the name of the game.

 

(And the filter wheel has been amazing because it allows me to make these comparisons quickly by flipping back and forth.  I will try to never view though a telescope without a filter wheel again!  Here is my home made T2 diagonal/filter wheel setup. 

 

Filter wheel on T2 Diagonal.jpg

 

And the built in Barlow Rocks!  The great news about the Boren Simon is that it has enough back focus that I will be able to use my filter wheel!  This would be my higest recommendation for people using NV with a dob.   Get the back focus required to run a filter wheel!)


Edited by Eddgie, 23 February 2017 - 09:30 AM.


#16 Solar storm

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Posted 23 February 2017 - 12:24 PM

Ed have you been able to make the filter wheel work with your 12" dob?  I would love to use one with my 11" one.  I am just not sure I could get focus, but I would be willing to try.   I could install a filter slide, but buying a bunch of 2" filters for it doesn't sound fun economically.



#17 The Ardent

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Posted 23 February 2017 - 12:49 PM

Im in the same situation as Edgie but going in a different direction. I'm going to try the Earthwin single eyepiece Power/filter switch for my dob. It holds two 2" filters that can be moved quickly by thumb. Only one at time in use. Bill at Earthwin said he has adapters to hold 1.25" filters in these.  I'm trying this mainly for normal visual use (OIII blinking).  NV use looks promising too. Extra filter holders are available and swap out easy. 

 

http://www.earthwino...com/single.html

 

Why? My current filter slide is inside the tube. Reaching in to slide filters is a little inconvenient. Also they are farther up the light path than desired. 

 

This is unit can be customized for different scopes. From our phone conversation, I understand that adapters can be made for any purpose, and that he's willing to meet customers needs. I'm thinking a c-mount thread instead of the 2" eyepiece holder shown. Phone call will get quick answers. 


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#18 Eddgie

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Posted 23 February 2017 - 01:35 PM

Ed have you been able to make the filter wheel work with your 12" dob?  I would love to use one with my 11" one.  I am just not sure I could get focus, but I would be willing to try.   I could install a filter slide, but buying a bunch of 2" filters for it doesn't sound fun economically.

 

I have not gotten around to trying it, but I can tell you how much back focus you need.

 

The key is to use an adapter to couple the C mount of the device to the top of the filter wheel directly.   This will give the shortest possible light path (though it will make the built in Barlow not worth using). 

 

The filter wheel I bought came from Amazon and was something like $50.  This model has T2 female threads on both sides. Now the great news about this is that the Baader MPCC has male T threads so it will screw right on the front and act as a zero light path length nose piece (rather than having to use a 2" to 1.25" adapter which almost always has some light path length).

 

Now the top has a female T2, so what I did was bought a T2 male to male and put it in the top, then used a T2 female to C mount, so I could screw the PVS-7 right on.   The light path length could be reduced if I could find a T2 male to C mount male and I found one in Europe, but they are out of stock.  I considered having RAF make me one.

 

Anyway, for this to work, you need the light path though the filter, which is about 25mm and the flange to photocathode on the C mount (usually about 15mm) plus the light path length of the T2 male to C mount connection about 4.5mm in my case.  So this means you need about 43mm of back focus.

 

I do not think most dobs have this much but if you do, you should be good to go.   

 

This is what it looks like.  Baader says that the MPCC can actually require you to rack out, and I am very close where I am now, so if the MPCC does extend the light cone some, I should be good to go, though at this config the spacing is not correct.  With the Boren Simon 6" f/2.8, I should be able to get it perfect.  I can hardly see coma now though so I don't consider it a problem. 

 

Filter wheel for dob.jpg


Edited by Eddgie, 23 February 2017 - 01:42 PM.

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#19 Eddgie

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Posted 23 February 2017 - 01:44 PM

And Binoviewers made me crazy good at milking out light path length.   The fact that this filter wheel was T2 was great because the Boren Simon is also T2 male on top, so the filter wheel will screw right on, and with the 1.25" eyepiece holder on the Filter Wheel, my back space will be almost exactly what the ASA reducer calls for.



#20 outofsight

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Posted 23 February 2017 - 01:48 PM

Solar storm, you want to have some more fun of the type you've been having? Wait until this summer or so and take your setup and stare into Sagittarius and its surroundings. Link is to map, all the yellow stuff.

 

http://www.constella...ier-Objects.png

 

There's so much "stuff" there that you don't have to know where anything is, you'll see cluster after cluster, and then you can use your Nexus to backtrack and tell you what you're looking at. You should be able to do the same thing with all the galaxies in Coma Berenices. (I'd tell you to have fun, but you already are.)

 

(Eddgie, nice going with the "BS," we look forward to your report!)


Edited by outofsight, 23 February 2017 - 01:49 PM.

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#21 bandhunter

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Posted 23 February 2017 - 01:55 PM

NIGHT VISION ASTRONOMY IS JUST FREAKIN AWESOME.

 Definitely have to agree.  Wish I haven't been so busy.



#22 Jeff Morgan

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Posted 23 February 2017 - 07:57 PM

They said about 4 weeks and that was about a week and a half ago, but my experience with these kinds of things is that they often take much longer than the vendors suggest.

 

 

I look forward to hearing your first (and second and third) light reports. I'm wanting to press the trigger on something sub f/3, don't know if the PowerNewt is the ticket, or go all out for an Epsilon.

 

One thing I am concerned about - the focal length of the AB Nightvision ModC (indeed, most of the NV eyepieces out there). Being somewhere around 27mm, aren't you worried about getting an exit pupil that will reveal the shadow of the secondary mirror?

 

Or do you not get the same effect as a conventional eyepiece would?



#23 The Ardent

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Posted 23 February 2017 - 08:31 PM

I'm guessing here- NV acts as an imaging device more than an optical ep, so the large secondaries are not a drawback .

#24 The Ardent

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Posted 24 February 2017 - 03:57 AM

First light with Earthwin went very well. For normal visual no coma seen with my f/3.5 dob, power and filter switch work better than expected. Each increase in magnification requires racking out the focus. With the 2x lens ran out of travel. A little adjusting the spacer fixed that.  My trial targets were the Leo Trio: M65, 66, and NGC 3628. Faint in my city skies, the last almost invisible. 

 

Pop in the PVS-7. M65 has its bright core , 66 the bar, and 3628 the dust lane. The power and filter switches worked excellently. The only caveat : Baader filters won't fit. Too tall retaining ring. 

 

Its possible to replace one of the powerswitch lenses with a focal reducer. I don't know if that would work. 

 

Next target, a first time observation. Frosty Leo nebula. A bright protoplanetary easily seen visually but not much detail. 

Very bright with NV. Appears as two flattened ellipses stacked, with a dark lane separating. 

https://en.wikipedia...osty_Leo_Nebula

 

 

Im in the same situation as Edgie but going in a different direction. I'm going to try the Earthwin single eyepiece Power/filter switch for my dob. It holds two 2" filters that can be moved quickly by thumb. Only one at time in use. Bill at Earthwin said he has adapters to hold 1.25" filters in these.  I'm trying this mainly for normal visual use (OIII blinking).  NV use looks promising too. Extra filter holders are available and swap out easy. 

 

http://www.earthwino...com/single.html

 

Why? My current filter slide is inside the tube. Reaching in to slide filters is a little inconvenient. Also they are farther up the light path than desired. 

 

This is unit can be customized for different scopes. From our phone conversation, I understand that adapters can be made for any purpose, and that he's willing to meet customers needs. I'm thinking a c-mount thread instead of the 2" eyepiece holder shown. Phone call will get quick answers. 


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#25 Eddgie

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Posted 24 February 2017 - 12:09 PM

I'm guessing here- NV acts as an imaging device more than an optical ep, so the large secondaries are not a drawback .

 

Yes, exactly.  Purpose designed lenses often have a secondary in excess of 50%. NV Eliminates this concern. 


Edited by Eddgie, 24 February 2017 - 12:10 PM.



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