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QHY5 v DMK?


Psychobilly
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I'm looking to get a guide cam for the EQ3 Pro based widefield setup..

At the moment I have the DMK21AU04AS fitted and havent had a chance to try it yet.. I did test it as a guidecam on the 8" f10 SCT and it seemed to do the job.

On the widefield setup it's on an 80-200mm f3.6 two touch

I have always fancied a QHY5 how does is compare sensitivity wise to the DMK?

Peter...

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Peter,

I have both...

The DMK is used by the guys in Oz for guiding... which it does VERY well; never tried it (yet) myself...

The DMK is IMHO much better / more sensitive - you can check the datasheets QHY5=Micron,MT9m001, DMK = Sony,ICX098BL, than the QHY5 ( which is a very good general "dogsbody" and meets all my current guiding needs)

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I am wrestling with a guide cam choice too Peter. I am about to buy The TS OAG,and wondering whether to use a DSI 1 I already have, or get a QHY5. Indications from what I've read in SGL's imaging threads, indicate the DSI is a very capable guide camera.

Are you talking about a QHY5v camera though.? I believe it is a video cam similar to the DMK Isn't it?

Ron.

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Hi Ron,

it was the bog standard QHY5 I was thinking about as it has a larger chip that the 5V..

I use Color DSI I (on TS OAG) and II (on 500mm f8) cameras as my primary guidecams and they work a treat .. if you can pickup one of the Mono "Pro" ones they are even better...

I am trying to get to the stage where my setups are essentially fixed almost there...

The only issue I have with the DMK on PHD is its awkward to change the exposure time...

Peter...

Edited by Psychobilly
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The QHY5 cams are cmos based... the IS cams are CCD based...

Ron the QHY5 is a 1024x768 sensor, the QHY5v is 752x448. The 5 has a rolling shutter, and the 5v has a global shutter, making the 5v a better option for lunar/planetary.

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Thanks Peter/John. I suppose I'll make do with the DSIc for now. Why spend more money than necessary:D.

I had reservations regarding the Meade camera, regarding it having problems connecting via Maxim.

Ron.

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DSI is way way better and more sensitive...I have both and the QHY is only for star party rig use, where it needs more exposure time than the DSI just to pick up guide stars. Never failed to get a guide star with a 1s exposure on the DSI.. used with PHD it just works...flawlessly

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If you need a top-sensitive guider then try a webcam or Imaging Source D*K and change the CCD to ICX618 (or wait for Basler Ace / Point Grey Flea 3 to be available and supported by guiding software). ICX618 is more sensitive than ICX098 family (webcams, IS), ICX424 (Lumenera and others) and even ICX285 (Atik 314L+ etc.) :D

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Yes, a hacked 618 DMK once the software issues at 60fps will be good. The Fle 3 looks like a winner barring that it's IEEE1394/GigE (find that on a cheap netbook!), and will need power (4 pin doesn't do power with FW), so unless you have a macbook = not so easy..

But at what cost too...

Whilst the 424 etc are less sensitive, this is a guide camera...a MEade DSI on a 102mm or 80mm guide scope at F5-6 has in my 2 years almost of using it, never once failed to get a guide star anywhere... a QHY5 regularly does, and increasing the exposure time is the only way around this...not a big hassle, and the advantage of having on camera guide is nice...but for s/h typically around £80 a DSI and GPUSB (add another £50) is almost impossible to beat

Peter, I never used my DMK for guide duty, seemed like a waste to me to put a very very good 60fps imaging cam to do that.. but the 098BL is used by many for autoguiding..

All for new and cool products, which up the ante...but cost effective ones always shine through

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Ahh, but if you use a DMK as a guide camera and a excellent planetary/lunar imaging camera - then its even better value for money.

I had a QHY5 - had real trouble finding a guide star every time I tried (I just assumed that it was the scope that was at fault - as other had an easy time with it).

I have never failed to find a guide star with the DMK. Had plenty of issue with dodgy usb leads and hubs....

Ant

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Cheers Nick,

The DMK is effectively zero cost as I already have it and the C-M42 adaptors it also runs a dream from the Netbook and is a compact and lightweight... and I'll have it with me for when I can afford to add a PST ....

Thanks Ant...

Just the practical experience answer I was looking for :D

Peter...

Edited by Psychobilly
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You don't need 60FPS for guiding :D At 1-2 sec exposures at f/5 I'm able to get Hyperion near Saturn (and no big moon on the sky) with DMK21 - and that's about 14,5 mag. So you can guide on ~10mag stars if the focal ratio isn't to big.

As for the new cameras - Point Grey Flea 3 uses the 9-pin firewire. To connect it to 99% of laptops you need a smartcard adapter for the 9-pin firewire (or a smartcard adapter put in SmartCart to PCMCIA adapter). Basler Ace is Ethernet camera so you connect it to the ethernet slot - easy :p Ace is tagged to cost slightly more than DMK21, and will be supported by FireCapture (as well as Flea 3).

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You don't need 60FPS for guiding :D At 1-2 sec exposures at f/5 I'm able to get Hyperion near Saturn (and no big moon on the sky) with DMK21 - and that's about 14,5 mag. So you can guide on ~10mag stars if the focal ratio isn't to big.

As for the new cameras - Point Grey Flea 3 uses the 9-pin firewire. To connect it to 99% of laptops you need a smartcard adapter for the 9-pin firewire (or a smartcard adapter put in SmartCart to PCMCIA adapter). Basler Ace is Ethernet camera so you connect it to the ethernet slot - easy :p Ace is tagged to cost slightly more than DMK21, and will be supported by FireCapture (as well as Flea 3).

Never said you did need 60fps for guide.. I just have a kind of "one camera for one job" philiosophy...Nice...but costly..

.and 9 pin FW even rarer.. smartcard on a netbook? :-)

GigE and support from apps like PHD is still limited. I think Peter's right to stick on the DMK...

All good info though

Edited by NickH
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Good point on the VFM thing...and it seems like I missed out not using the DMK as a guide cam.. :-)... It's a souped up LX modded mono toucam, so no reason why it can't work well

And Mike's results speak for themselves...

Edited by NickH
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