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Baader MK-IV zoom eyepiece question

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#1 Thomas Marshall

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Posted 03 April 2020 - 03:16 AM

This is probably a dumb question, - I just ordered a 2" Diagonal for my AT102ED refractor, and want to know, if I remove the 1 1/4" barrel and use the 2" barrel, will the zoom get Full 2" capabilities and the wider fov that 2" eyepieces give? It is only the other way, stepping Down from 2" to 1 1/4" sleeve, that restricts full use of this zoom, - right??      I am hoping to keep from spending a bunch more $ getting 2" eyepieces. 


Edited by Thomas Marshall, 03 April 2020 - 03:23 AM.


#2 Jon Isaacs

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Posted 03 April 2020 - 03:23 AM

The Baader zoom is a 1.25 inch eyepiece that has a barrel extender that allows it to be used in 2 inch focusers without an adapter.

 

There is no difference in it's capabilities without or with the barrel extender.

 

Jon


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#3 emilslomi

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Posted 03 April 2020 - 03:23 AM

No, you'll see as much or as little as you are when using the the 1.25" configuration. The max focal length stays 24 mm and the size of the field stop remains unchanged, and the field stop was not maxing out the 1.25" barrel.

 

Different for the 31 and 36 mm Hyperion aspherics. The field stop is larger that the 1.25" barrel and you'll only get full illumination if you use them in the 2" configuration. But their fields of view do not get wider either.

 

Emil


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#4 Thomas Marshall

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Posted 03 April 2020 - 03:43 AM

That's disappointing. An Orion Q70-26mm 2" eyepiece, then would give me wider field than say my TeleVue 32mm Plossl 1 1/4" - correct?@ a higher power? 



#5 Jon Isaacs

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Posted 03 April 2020 - 04:41 AM

That's disappointing. An Orion Q70-26mm 2" eyepiece, then would give me wider field than say my TeleVue 32mm Plossl 1 1/4" - correct?@ a higher power? 

Yes:

 

The true field of view is determined by the field stop. The field stop is the dark edge that defines the field of view.  Physically, it's a ring at the focal plane of the eyepiece and you can see it if you look down the barrel of the eyepiece.  For a 1.25 inch eyepiece, it's limited to about 27 mm by the diameter of the barrel.

 

A 2 inch eyepiece has a larger barrel so it can have a larger field stop.  

 

The 32mm TV Plossl has a 27.0 mm field stop, the AgenaAstro/Orion Q70 has a 32.3 mm field stop.  

 

In your AT-102ED, the field of view looks like this:

 

TFoV = 57.3 deg/radian  x Field stop/focal length scope

 

TFoV = 57.3 deg/rad x 27.0/714 = 2.17 degrees  (TeleVue 32mm Plossl)

 

TFoV = 573 deg/rad x 32.3/714 = 2.59 deg (26mm Q-70)

 

Jon

 

T


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#6 jaraxx

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Posted 03 April 2020 - 06:04 AM

That's disappointing. An Orion Q70-26mm 2" eyepiece, then would give me wider field than say my TeleVue 32mm Plossl 1 1/4" - correct?@ a higher power? 

It is disappointing! The rules of optics have disappointed me a lot, especially when it comes to spending money on eyepieces. And when I explain how those rules require more eyepiece purchases, my wife seems even more disappointed than I am.

Then there's physics, that whole limit to light speed thing, that's a major disappointment and I might add more than a little inconvenient in a universe this size! And don't get me started on the ways I've been disappointed by chemistry...


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#7 Observateur

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Posted 03 April 2020 - 06:11 AM

This is probably a dumb question, - I just ordered a 2" Diagonal for my AT102ED refractor, and want to know, if I remove the 1 1/4" barrel and use the 2" barrel, will the zoom get Full 2" capabilities and the wider fov that 2" eyepieces give? It is only the other way, stepping Down from 2" to 1 1/4" sleeve, that restricts full use of this zoom, - right??      I am hoping to keep from spending a bunch more $ getting 2" eyepieces. 

Well, if it's a dumb question I can tell you I wish I asked it before buying a Mark-IV last Christmas. I misunderstood the design (newbie mistake I guess) and thought that I was getting an hybrid eyepiece that would be both 1 1/4" and 2", but realized once received that it's really a 1 1/4".

 

That said, it's much better than my Celestron zoom, and I really enjoyed having a zoom during our cold Canadian winter nights when it's no fun to play with eyepieces, so it's not a bad purchase.


Edited by Observateur, 03 April 2020 - 06:36 AM.

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#8 Thomas Marshall

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Posted 03 April 2020 - 03:45 PM

It is disappointing! The rules of optics have disappointed me a lot, especially when it comes to spending money on eyepieces. And when I explain how those rules require more eyepiece purchases, my wife seems even more disappointed than I am.

Then there's physics, that whole limit to light speed thing, that's a major disappointment and I might add more than a little inconvenient in a universe this size! And don't get me started on the ways I've been disappointed by chemistry...

Lol. -- Also, Thanks to Jon Isaacs for the good rundown on the fov of those eyepieces, - and to Observateur, - Yes, I'm still glad to have the B/Zoom, as it is an excellent tool. 


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#9 Thomas Marshall

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Posted 05 April 2020 - 09:16 PM

So, - I ordered a Orion 2" Q70 eyepiece on Amazon, only $99. and tax, free delivery. I had a $16.+ credit, so total cost $89.+. I figure as good a deal as I could hope for.  Even WalMart had a Q70 for sale, - THAT really surprised me. 


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#10 Thomas Marshall

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Posted 08 April 2020 - 09:25 PM

So, - Both the new AT2" Diagonal and the Q70 2" 26mm Eyepiece arrived. I tested the 2" diagonal last night when weather was very good, and seems to perform very good. Used only my 80mm F5.6/448FL Master Birder and MK24-8mm zoom. Powers from 18+ to 56X. Trapezium very sharp and clear. Today, - only daytime test, as very cloudy w/rain. The Q70 seems to give a "little" wider view than my TV32mm Plossl, but is a little less sharp at edges. The 32mm seems to open slightly wider with the 2"diagonal and 1 1/4" reducer, than thru the WO 1 1/4" diagonal alone. It stays sharp throughout. Both of course are better than the BaaderMK-IV zoom, on afov. I'm thinking the fov increase will be even more apparent when Q70 is used with AT102/F7/714mmfl. and when used with my C8 at F10/2000. So probably my easy use toolbag will be the 2"diagonal/Q70-26 for wide search/alignment etc. and MK-IV zoom for quick power changes, as both can be used in 2" mode, without putting in 1 1/4" adapter. Looking forward for clear skies again.     I just checked, and don't think the 2"AT diagonal will work with my C8, unless there is a screw on adapter, - But I have an old Meade 2" Sct. diagonal that is of lesser quality than my new AT 2", but still good, - if I want to use the Q70 for that scope. I bought the AT 2" basically to open up the AT102mm a bit more, to get All of Pleiades, and maybe on stuff like M31, and scanning, so I will see how it plays. 


Edited by Thomas Marshall, 08 April 2020 - 09:40 PM.

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#11 clearwaterdave

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Posted 09 April 2020 - 04:29 AM

Hello Thomas.,I think you will enjoy the sweeping with a 2" set up in the 102.,I have the AT 2" diagonal and am really liking the ES,2",28/68ep in my 102.,I also like my Baader zoom in this scope.,zoomin on the moon is "wicked sharp".,best2all

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#12 Jon Isaacs

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Posted 09 April 2020 - 04:45 AM

So probably my easy use toolbag will be the 2"diagonal/Q70-26 for wide search/alignment etc. and MK-IV zoom for quick power changes, as both can be used in 2" mode, without putting in 1 1/4" adapter. Looking forward for clear skies again.     I just checked, and don't think the 2"AT diagonal will work with my C8, unless there is a screw on adapter, - But I have an old Meade 2" Sct. diagonal that is of lesser quality than my new AT 2", but still good, - if I want to use the Q70 for that scope.

 

With a 2 inch Visual Back, the AT Diagonal should work with your C-8.  The field will be sharper at F/10 than at F/7.  The 26mm Q-70 provides a 20% wider field than the 32mm Plossl, the 32mm Q-70 would provide a 48% wider TFoV. 

 

You will be having some fun.. :whee: 

 

Jon


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#13 cupton

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Posted 09 April 2020 - 08:21 AM

Thats really (for the most part) my typical set up with my ED80. I use the 2" diagonal and my ES68 28mm for the wide views and then I drop in the zoom (Vixen with a 2"-1.25" adapter) for the rest of my viewing. I'll also drop a barlow in occasionally to get a higher power view. Your setup is nice in that your Baader has that 2" adapter already on it, so no need to fumble in the dark trying to fit it in the diagonal. And its also a nice zoom!  waytogo.gif


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#14 Thomas Marshall

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Posted 10 April 2020 - 01:43 AM

With a 2 inch Visual Back, the AT Diagonal should work with your C-8.  The field will be sharper at F/10 than at F/7.  The 26mm Q-70 provides a 20% wider field than the 32mm Plossl, the 32mm Q-70 would provide a 48% wider TFoV. 

 

You will be having some fun.. whee.gif

 

Jon

Thanks, - You are right, - had some fun tonight. The Q70 does indeed give a wider view than the TV32mm, but the TV32 is a bit sharper. I was able for the first time to get all of the Pleiades in FOV and view was very good. The Q70 does better in the AT102/F7, than in the F5.6/Birder scope, and though I have not used it in the C8, - I figure you are right about that, and it will do better than in the 4" scope. I checked out M42/M35 and companion cluster/M37/M36, and earlier some bird watching. I'm happy with both purchases, - the AT2" diagonal and the Q70. As a bonus, - tonight I was able to get momentary glimpses of both the E and F stars in trapezium with the 4" scope and Baader MK-IV zoom with 2X barlow. A first for me as only the E star before, except both in the C8 are easy on a good night.  



#15 star2020

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Posted 10 May 2020 - 02:20 PM

I had a question about using the Hyperion MK-IV zoom with the Hyperion Barlow on a 2" diagonal.

 

The instructions say to attach the barlow onto the 1.25" nosepiece. I've done this but also kept the 2" nosepiece on so that I can use the 2" diagonal. In this case the bottom of the eyepiece makes contact with the diagonal mirror.

 

Am I attaching the barlow incorrectly to the zoom? Or should a 1.25" diagonal adapter be used to seat it? I was hoping to avoid the latter as it's one extra step when using with a set of 2" eyepieces.

 

Thanks!



#16 Thomas Marshall

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Posted 10 May 2020 - 05:48 PM

I had a question about using the Hyperion MK-IV zoom with the Hyperion Barlow on a 2" diagonal.

 

The instructions say to attach the barlow onto the 1.25" nosepiece. I've done this but also kept the 2" nosepiece on so that I can use the 2" diagonal. In this case the bottom of the eyepiece makes contact with the diagonal mirror.

 

Am I attaching the barlow incorrectly to the zoom? Or should a 1.25" diagonal adapter be used to seat it? I was hoping to avoid the latter as it's one extra step when using with a set of 2" eyepieces.

 

Thanks!

Can you just insert the 2" barrel a little shallower, to avoid mirror contact? I don't have the Hyperion Barlow, I use the small screw on nose piece that came with my StellarVue binoviewers, or one of the other 2 short screw on barlows (1.4X and 1.9X), but I am being careful, as my old Meade 2" Sct. diagonal came used with a contact blemish that appears from this very issue, and I don't want to damage my new AT2" diagonal too. These barlows I am using are not the quality of your Hyperion, but seem pretty good. I don't need to barlow the 8-24 zoom with my C8, as I don't usually have seeing conditions that allow more power than what 8 mm would give (approx. 250X). But I think the 1.4X may end up useful, - we'll see. I haven't actually used the new AT2" diagonal on my C8 yet, as I was waiting on a new adapter. It came, and I will test soon. I Did test my 2"Q70 26mm on C8 with Meade 2" diagonal, and am pleased with extended fov. The AT2" diagonal is better quality, so I'm looking forward to that combo.  



#17 wrnchhead

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Posted 10 May 2020 - 07:12 PM

Weird to hear that barlows etc can contact diagonal optical surfaces. My Celestron 1.25”s have stops in them and my Meade 5000 has one also. Even with the 1.25 adapter it would take a looooong barrel to hit the mirror.

I was also so impressed with the FOV of the supplied 30mm 2” GSO that I went 2” whenever I could, but didn’t take long to learn that MOST EP focal lengths aren’t really gaining that much from 2” furniture and the added FL/aperture loss from light path increases on my SCT weren’t worth it. So I have a 2” complete setup for my Schmidt that is collecting dust.
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#18 Schurke

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Posted 10 May 2020 - 10:59 PM

The barlow is thought to be used in your 1,25" adapter. I asked baader about it because they even have a picture on their site with the barlow attached to a mk3 zoom in a 2" diagonal. But they said the barlow is not meant to be used in 2" mode, sadly...

#19 Thomas Marshall

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Posted 11 May 2020 - 02:13 AM

Weird to hear that barlows etc can contact diagonal optical surfaces. My Celestron 1.25”s have stops in them and my Meade 5000 has one also. Even with the 1.25 adapter it would take a looooong barrel to hit the mirror.

I was also so impressed with the FOV of the supplied 30mm 2” GSO that I went 2” whenever I could, but didn’t take long to learn that MOST EP focal lengths aren’t really gaining that much from 2” furniture and the added FL/aperture loss from light path increases on my SCT weren’t worth it. So I have a 2” complete setup for my Schmidt that is collecting dust.

That's good to know. My new Q70 2" 26mm makes finding things for alignment easier, - last time, I didn't even use my laser finder as I could pretty much eye ball it close with my AT102ED, and align on 2 stars and use goto from there. I've been fighting the urge to spring for 2 or 3 more 2" eyepieces, but your post has given me pause, to not get carried away. 



#20 lionel

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Posted 11 May 2020 - 11:41 AM

I had a question about using the Hyperion MK-IV zoom with the Hyperion Barlow on a 2" diagonal.

 

The instructions say to attach the barlow onto the 1.25" nosepiece. I've done this but also kept the 2" nosepiece on so that I can use the 2" diagonal. In this case the bottom of the eyepiece makes contact with the diagonal mirror.

 

Am I attaching the barlow incorrectly to the zoom? Or should a 1.25" diagonal adapter be used to seat it? I was hoping to avoid the latter as it's one extra step when using with a set of 2" eyepieces.

 

Use the 1.25" diagonal adapter and keep it attached to the Barlowed zoom for the session. Then when you want to switch to a 2" eyepiece just remove the adapter/zoom/Barlow from the diagonal as a single unit. Saves the extra step.

 

Lionel


Edited by lionel, 11 May 2020 - 11:53 AM.


#21 star2020

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Posted 11 May 2020 - 12:00 PM

Can you just insert the 2" barrel a little shallower, to avoid mirror contact? I don't have the Hyperion Barlow, I use the small screw on nose piece that came with my StellarVue binoviewers, or one of the other 2 short screw on barlows (1.4X and 1.9X), but I am being careful, as my old Meade 2" Sct. diagonal came used with a contact blemish that appears from this very issue, and I don't want to damage my new AT2" diagonal too. These barlows I am using are not the quality of your Hyperion, but seem pretty good. I don't need to barlow the 8-24 zoom with my C8, as I don't usually have seeing conditions that allow more power than what 8 mm would give (approx. 250X). But I think the 1.4X may end up useful, - we'll see. I haven't actually used the new AT2" diagonal on my C8 yet, as I was waiting on a new adapter. It came, and I will test soon. I Did test my 2"Q70 26mm on C8 with Meade 2" diagonal, and am pleased with extended fov. The AT2" diagonal is better quality, so I'm looking forward to that combo.  

 

 

The barlow is thought to be used in your 1,25" adapter. I asked baader about it because they even have a picture on their site with the barlow attached to a mk3 zoom in a 2" diagonal. But they said the barlow is not meant to be used in 2" mode, sadly...

 

 

Keep the 1.25" diagonal adapter attached to the Barlowed zoom for the session. Then when you want to switch to a 2" eyepiece just remove the adapter/zoom/Barlow from the diagonal as a single unit. Saves the extra step.

 

Lionel

 

Thank you all for the helpful responses!

 

Good idea on inserting the barlow into the 2" diagonal a little shallow. However, there isn't much clearance even in doing that. I'd be scared of damaging the mirror if it slips a little.

 

So Baader has clarified that their barlow can't be used in the 2" diagonal. Until now I was wondering what I was doing wrong. With this information I think I'll go with the clever idea of keeping the 1.25" diagonal adapter attached to the barlowed zoom.


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#22 Thomas Marshall

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Posted 12 May 2020 - 08:05 PM

I had a question about using the Hyperion MK-IV zoom with the Hyperion Barlow on a 2" diagonal.

 

The instructions say to attach the barlow onto the 1.25" nosepiece. I've done this but also kept the 2" nosepiece on so that I can use the 2" diagonal. In this case the bottom of the eyepiece makes contact with the diagonal mirror.

 

Am I attaching the barlow incorrectly to the zoom? Or should a 1.25" diagonal adapter be used to seat it? I was hoping to avoid the latter as it's one extra step when using with a set of 2" eyepieces.

 

Thanks!

I double checked my 3 screw on barlows with the Baader Zoom today at the kitchen table w/flashlight, in conjunction with my new AT2" Diagonal. The 1.9X Burgess measures 12.5mm height, plus threads, - the 1.4X is 17mm, plus threads, the 2XSV nosepiece is 20mm, plus threads. All 3 stay clear of Mirror Contact, by the built in stop of the diagonal for the 2" barrel. So, it's a non-issue for me. I don't know the height of your Baader Barlow, but it must be around 25mm or more I would guess.     OR Your diagonal is of another kind, with a barrel stop that is closer to the mirror.  


Edited by Thomas Marshall, 12 May 2020 - 08:10 PM.


#23 Chuck2

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Posted 14 May 2020 - 01:33 AM

Using the Mark-IV Zoom mated with the Barlow in a 2" diagonal, I add a short, inexpensive 2"i.d. extention. Provides plenty of clearance so barlow does not hit the diagonal mirror. I have sufficient focus travel so I just leave the extension in all the time for all my 2" eyepieces.

 

https://agenaastro.c...-extension.html


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#24 star2020

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Posted 14 May 2020 - 06:30 PM

I double checked my 3 screw on barlows with the Baader Zoom today at the kitchen table w/flashlight, in conjunction with my new AT2" Diagonal. The 1.9X Burgess measures 12.5mm height, plus threads, - the 1.4X is 17mm, plus threads, the 2XSV nosepiece is 20mm, plus threads. All 3 stay clear of Mirror Contact, by the built in stop of the diagonal for the 2" barrel. So, it's a non-issue for me. I don't know the height of your Baader Barlow, but it must be around 25mm or more I would guess.     OR Your diagonal is of another kind, with a barrel stop that is closer to the mirror.  

 

The Hyperion Barlow plus the adapter to attach to the nosepiece together measures 37mm in height excluding threads. I think that explains why I have the issue and you don't.

 

 

Using the Mark-IV Zoom mated with the Barlow in a 2" diagonal, I add a short, inexpensive 2"i.d. extention. Provides plenty of clearance so barlow does not hit the diagonal mirror. I have sufficient focus travel so I just leave the extension in all the time for all my 2" eyepieces.

 

https://agenaastro.c...-extension.html

Good idea, thanks.


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#25 george tatsis

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Posted 14 May 2020 - 11:59 PM

I had a question about using the Hyperion MK-IV zoom with the Hyperion Barlow on a 2" diagonal.

 

The instructions say to attach the barlow onto the 1.25" nosepiece. I've done this but also kept the 2" nosepiece on so that I can use the 2" diagonal. In this case the bottom of the eyepiece makes contact with the diagonal mirror.

 

Am I attaching the barlow incorrectly to the zoom? Or should a 1.25" diagonal adapter be used to seat it? I was hoping to avoid the latter as it's one extra step when using with a set of 2" eyepieces.

 

Thanks!

Use O-rings on the 2" barrel to increase the height between the diagonal and the bottom of the barlow. I have both the Mark III and the MK-IV zooms and I can tell you for a fact that the Mark III is much better with that set up.

 

George


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