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Mount against wind: AZ-EQ5, HEQ5, CEM26?

Astrophotography
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#1 GTom

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Posted 04 March 2024 - 06:02 PM

I am often battling with wind, any suggestions, which of these three are the least susceptible to wind gusts? More, the competition should take place at low latitudes, where the AZEQ5 needs its native mini-pier and the HEQ5 needs a pier-extension

 

AZ-EQ5 on the pier-tripod (GT-P variant)

HEQ5

ioptron CEM26?

 

The HEQ5 is far the heaviest of the bunch but needs a half-pier to cover very low latitudes (important for me). Am I wrong to assume, that the lightweight CEM26, that doeasn't need an extension pier with its low center of gravity might be still OK? Even a similar result to the heavyweight heq5 would be a win as it means half the mount head weight to carry...



#2 CharLakeAstro

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Posted 04 March 2024 - 06:48 PM

While it depends on the OTA size, the AZ-EQ5 is a great little mount, but it is not resilient to the wind. One of it's weaker points actually.


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#3 GTom

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Posted 04 March 2024 - 07:45 PM

While it depends on the OTA size, the AZ-EQ5 is a great little mount, but it is not resilient to the wind. One of it's weaker points actually.

I suspect I have to rethink that tripod thing. Right now, we got some usual 40kts light breeze outside, I wonder if those have anything to do with the fact that the pier-version disappeared from the UK marketthinking1.gif imawake.gif



#4 CharLakeAstro

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Posted 04 March 2024 - 08:15 PM

With a 400mm refractor it's not terrible. But anything larger / longer FL, a wind break would help.

Closer to the equator, not certain if it would be any more or less resilient. I have only used mine at 44.8N


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#5 GTom

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Posted 04 March 2024 - 08:27 PM

With a 400mm refractor it's not terrible. But anything larger / longer FL, a wind break would help.

Closer to the equator, not certain if it would be any more or less resilient. I have only used mine at 44.8N

If you are further from the Equator and not photographing Zenith, then you can skip the longish half-pier. That's a significant bit for windage/wind caused vibrations.


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#6 luxo II

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Posted 04 March 2024 - 09:18 PM

Your question is as indeterminate as "how long is a piece of string ?". Wind loading is entirely dependent on how big the OTA is, ie what cross-sectional area is exposed by the wind. Without knowing that its impossible to say.

 

And 40kts is a gale, I wouldn't consider setting up let alone observe in that !

 

NB a picture speaks a thousand words.


Edited by luxo II, 04 March 2024 - 09:20 PM.


#7 dcweaver

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Posted 05 March 2024 - 12:10 AM

I can understand why you would be thinking in terms of "wind resistance", but you might be better off thinking about a way to block the wind instead. You could spend a lot of money trying different mounts and still not solve the problem.

 

Mount control systems only "react" to disturbances like wind gusts. Once the gust happens, the damage is done. Some mounts react faster and more smoothly (encoders vs autoguider), but they all depart by some amount when the disturbance hits. That departure could be enough to ruin a sub exposure. The best way to prevent any departures is to avoid them.


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#8 Spaceman 56

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Posted 05 March 2024 - 04:20 AM

I use the mentioned AZ/EQ5 Pro with the optional Pier extension.

 

the Pier extension is actually reasonably heavy and I find it improves the mount greatly.

 

not banging the camera into the tripod is worth its weight in Gold.

 

as for the wind it has never effected my imaging at 448mm or 530mm.


Edited by Spaceman 56, 05 March 2024 - 04:20 AM.

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#9 GTom

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Posted 05 March 2024 - 06:04 AM

 Wind loading is entirely dependent on how big the OTA is...

OTA's come and go, my actual bigger scope is a 105/735 APO.

 

I can understand why you would be thinking in terms of "wind resistance", but you might be better off thinking about a way to block the wind instead. You could spend a lot of money trying different mounts and still not solve the problem.

 

Mount control systems only "react" to disturbances like wind gusts. Once the gust happens, the damage is done. Some mounts react faster and more smoothly (encoders vs autoguider), but they all depart by some amount when the disturbance hits. That departure could be enough to ruin a sub exposure. The best way to prevent any departures is to avoid them.

Shielding is definitely part of the picture. However, the flimsy, wide open "observatory tents" available nowadays don't take 100% of the wind away.

 

I use the mentioned AZ/EQ5 Pro with the optional Pier extension.

 

the Pier extension is actually reasonably heavy and I find it improves the mount greatly.

 

not banging the camera into the tripod is worth its weight in Gold.

 

as for the wind it has never effected my imaging at 448mm or 530mm.

Thank you! Others might use it with longer focals then. 

 

I'd be interested, how the CEM26 fares in the game.


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