Powermate x 4/5 with a zwo 120mm camera

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denababy
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Powermate x 4/5 with a zwo 120mm camera

Post by denababy » Fri Feb 09, 2018 4:53 pm

I have tried at least five times to log onto the ZWO users page but since it moved servers all I get is a page telling me the site cannot be found. Anyway I would like to be able to get closer pics of everything specifically prominences, so I thought I would save up to buy a Powermate, but the question is, having just about managed to get focuss screwing the camera directly onto the blocking filter, how do I fit the camera onto a Powermate? Anyone help please. I have just fitted a Feathertouch focuser onto my Lunt 50ha scope, I’m just trying to get things right ready for the slightly warmer days when we should have some sunshine which seems to be in very short supply at the moment, it gives another meaning to ‘solar minimum’ !!!!

HansH
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Re: Powermate x 4/5 with a zwo 120mm camera

Post by HansH » Fri Feb 09, 2018 5:10 pm

The ZWO support forum can be found at: http://bbs.astronomy-imaging-camera.com

I am using ZWO ASI 174MM together with TV 2.5x powermate on Lunt 50 without focussing issues.
No idea though with 4 or 5x. Given my standard seeing, the 2.5x is sufficient for me. Do have cheap 3 and 5x barlow, but not giving me results I want to get.

The cam to go into powermate with nosepiece on.
C'est ca.

Regards
Hans

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Re: Powermate x 4/5 with a zwo 120mm camera

Post by FlankerOneTwo » Sat Feb 10, 2018 2:09 am

The PowerMates provide the stated magnification at the top of the eyepiece holder, I measure it at 52mm. You get less magnification closer, more further. The PowerMate has a 1.25" eyepiece holder on top, you can simply screw one on to the camera and plop it in there. I get Newton rings with pretty much any camera on the PowerMate, so I use TeleVue's T-ring adapter to screw a Daystar Interference Eliminator to the top of the PowerMate, and then T-ring spacers on top to reach the proper distance.

The PowerMates are stated to be parfocal, so you shouldn't have to change anything to reach focus as long as you can get the PowerMate right on top of the blocking filter. I had to change to a low profile eyepiece holder because the T threads on top of the stock Lunt one lifted some of my Barlows just enough that I could not reach focus. The LS50 is not ideal for imaging in this regard because of the limited inward focuser travel. Using a 1.25" form factor camera like the QHY/ASI 174 worked better than the ASI1600 that I otherwise use (the ASI120 would be similar I think) because of the ability to seat the sensor deeply in the eyepiece holder. I eventually went to the LS80 which is well set up for imaging.

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Re: Powermate x 4/5 with a zwo 120mm camera

Post by PDB » Sat Feb 10, 2018 8:39 am

Backfocus for ASI-120 is 12.5 mm and for the ASI-174 it is 17.5mm
If it works for the 174, it will for sure work with the 120 (sensor is closer to the BF)

Paul

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Re: Powermate x 4/5 with a zwo 120mm camera

Post by denababy » Sat Feb 10, 2018 9:58 am

Thanks guys for the very helpful replies, I am going to save my pennies as well as it is my birthday soon, to buy a Powermate.

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Re: Powermate x 4/5 with a zwo 120mm camera

Post by PDB » Sat Feb 10, 2018 10:53 am

Just one remark. Don't use too much Barlow. Given the pixelsize of the ASI-120MM (3,74 Micron) the minimun f/ratio (Nyquist 2x sampling) is f/13. With your Lunt 50 at f/7 you are indeed undersampling with the camera and not getting the maximum resolution. A 5x Barlow will get you at f/45 and you will be heavily oversampling with that camera, resulting in longer exposure times and no real benefit. I would go for a 2x or 2,5x Barlow (or maximum 3x with very good seeing) for the ASI-120. If you increase f/ratio, probably Newton rings will get worse as well.

(The ASI 174 has much larger pixels, so for that one a 3 to 4x Barlow would be my choice for that scope)

Rgrds,

Paul

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Re: Powermate x 4/5 with a zwo 120mm camera

Post by marktownley » Sat Feb 10, 2018 3:48 pm

Good advice Paul
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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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