Guide Cameras

[Gina]

I suppose I know the answer to this really But would like confirmation

I'm currently using a QHY5 for guiding on an OAG with NM190 scope and PHD, and having a problem finding stars for guiding. I've just got AA5 and will be trying that when the weather permits but I'm also thinking further ahead.

I'm thinking about buying a Lodestar for guiding from many recommendations but they aren't cheap! I'm not really worried about the connectors - I shall only be using the USB and not the ST4. Anyway, if I think the USB socket is poorly fitted I can probably improve it

The Lodestar has a CCD sensor whereas the QHY5 is CMOS and I gather the Lodestar is very much more sensitive and will therefore pick up much fainter stars. So while I may get better guiding with AA compared with PHD I think there may still be a bit of difficulty finding stars with a QHY5.

I've also been considering other cameras but the Lodestar seems to be favourite by far. It's nice and small and light compared with other CCD cameras - there would be no problem with bumping into anything else. One thing I had in mind was that if I bought a mono CCD camera capable of both guiding and imaging I could use it in a dual-imaging rig with ED80 and camera lenses. I'd thought of the Atik Titan but it's size could be a problem on the OAG - otherwise I gather it's quite suitable as a guide camera and I could use the QHY5 on the ST80 as before when I'm using the ED80 rig rather than the MN190. OTOH would the Lodestar be suitable for imaging?

Any comments and suggestions would be most welcome

[Spikey]

Are you using darks with the QHY5 Gina? , that certainly improves things for me when I use mine.

I'm going to suggest an Atik16ic as thats once again my main guide camera. It's a lot more sensitive than the QHY5 and easier to get hold of than a lodestar.

Craig Stark did a guide camera comparison a while back, it must be on his website somewhere and the Atik came out very favourably against the lodestar.

[earth titan]

I agree with taking darks. Although I'm not using mine for OAG, I've found my tracking has improved tremendously by taking darks and locking onto fainter stars.

[Gina]

Are you using darks with the QHY5 Gina? , that certainly improves things for me when I use mine.

I'm going to suggest an Atik16ic as thats once again my main guide camera. It's a lot more sensitive than the QHY5 and easier to get hold of than a lodestar.

Craig Stark did a guide camera comparison a while back, it must be on his website somewhere and the Atik came out very favourably against the lodestar.

Thank you I have tried taking a dark frame but I found I had problems with it in PHD - maybe AA will work better.

The Atik 16ic sounds interesting - predecessor of the Titan I gather - must look out for one I'll search out Craig Stark's comparison too.

[Gina]

I agree with taking darks. Although I'm not using mine for OAG, I've found my tracking has improved tremendously by taking darks and locking onto fainter stars.

Do you mean you're using a QHY5 with guide scope or for imaging?

[Spikey]

Thank you I have tried taking a dark frame but I found I had problems with it in PHD - maybe AA will work better.

The Atik 16ic sounds interesting - predecessor of the Titan I gather - must look out for one I'll search out Craig Stark's comparison too.

Found it; http://www.stark-lab...Roundup_API.pdf

[Gina]

Yep, found it myself too Thank you anyway

[earth titan]

Do you mean you're using a QHY5 with guide scope or for imaging?

When guiding.

I found the guidance on Cloudy Nights here and copied it for future reference:

To take PHD Darks, you just cap the guidescope and press the Dark button on the bottom right of the PHD screen (at least in my version).

PHD will not (at least, in my experience) let you guide on a hot pixel - when doing the calibration, there is not only no centroid as such to compute, but there would also be no movement during the attempted calibration, so PHD would refuse to guide on it.

Taking the dark frame simply subtracts the levels detected in the dark, from the light frame each time it's taken. The net effect is to increase S/N, making "bright" stars stand out more and making previously-marginal stars now visible enough to guide on.

This may be especially useful in something like a nebulous area, provided you offset a little when taking your dark. The net effect would be to subtract the nebula before looking for stars to guide on.

[Gina]

I've read Craig Stark's "Guider Roundup" and the Lodestar comes out on top with the Atik 16IC a close second. Both these cameras seem to sell like hot cakes on the second hand market and very difficult to get. I chased after one of each on UK Astronomy Buy & Sell recently but they were sold when I enquired a couple of hours after the advert was published. May have already have been sold before the advert appeared, of course. The Atik 16IC is obsolete now AFAIK and only available second hand. So buying new is limited to the Lodestar out of the two.

[Gina]

When guiding.

I found the guidance on Cloudy Nights here and copied it for future reference:

To take PHD Darks, you just cap the guidescope and press the Dark button on the bottom right of the PHD screen (at least in my version).

PHD will not (at least, in my experience) let you guide on a hot pixel - when doing the calibration, there is not only no centroid as such to compute, but there would also be no movement during the attempted calibration, so PHD would refuse to guide on it.

Taking the dark frame simply subtracts the levels detected in the dark, from the light frame each time it's taken. The net effect is to increase S/N, making "bright" stars stand out more and making previously-marginal stars now visible enough to guide on.

This may be especially useful in something like a nebulous area, provided you offset a little when taking your dark. The net effect would be to subtract the nebula before looking for stars to guide on.

That is "almost" how it works on mine Mine will try to guide on on a hot pixel - produces a lovely flat line but doesn't actually do anything. It won't calibrate on a hot pixel. I found the main effect of taking a dark was to produce a white display

[Freddie]

Hi Gina, just got a lodestar for my OAG and MN190. All I can say is that it is nice and small so easy to fit and doesn't clash with anything. When it comes to guide stars, on the few targets I have looked at so far, LOTS to choose from!!!

[Gina]

Hi Gina, just got a lodestar for my OAG and MN190. All I can say is that it is nice and small so easy to fit and doesn't clash with anything. When it comes to guide stars, on the few targets I have looked at so far, LOTS to choose from!!!

Thank you Freddie I think I've pretty much decided to just go ahead and buy a Lodestar from FLO

[Gina]

I've "taken the plunge" and ordered a Lodestar from FLO together with a Baader focussing adapter http://www.firstlightoptics.com/adaptors/baader-t-thread-to-125-helical-focuser.html

[Freddie]

Was out tonight doing a bit of fine tuning (too much high level cloud and a big moon to do any imaging) and on a 3 sec exposure can clearly see M82. It's a sensitive little thing!! Is there enough focus travel to have room for that adaptor Gina? There wouldn't be on my setup which is why I screw the C mount adaptor onto the OAG stalk and Lodestar. It's all nice and tight that way as well.

[Gina]

Was out tonight doing a bit of fine tuning (too much high level cloud and a big moon to do any imaging) and on a 3 sec exposure can clearly see M82. It's a sensitive little thing!! Is there enough focus travel to have room for that adaptor Gina? There wouldn't be on my setup which is why I screw the C mount adaptor onto the OAG stalk and Lodestar. It's all nice and tight that way as well.

Great! The adapter/focuser I'm getting uses the barrel of the Lodestar rather than the thread which means it will actually get closer to the plate than a screw type adapter. The Baader adapter I've ordered is the recommended by Tim and Steve of FLO and is one of two FLO show for use with the OAG.

http://stargazerslounge.com/topic/178892-new-off-axis-guider/page__st__20 post #26

http://www.firstlightoptics.com/off-axis-guiders-oag/off-axis-guider.html

[Cath]

Oh to have a guide camera to play. One day!

[r3i]

From what I've read about Lodestar cameras, they sound superb so hopefully you'll now be spoilt for choice for guide stars.

I was going to suggest keeping an eye out for a secondhand Meade DSI - I've been using the V1 OSC variant for a few years now and it has worked a treat. But anyway, you're already sorted.

[Gina]

I got fed up with waiting for second hand things to become available - I NEED to get imaging again - I'm suffering withdrawal symptoms

[Freddie]

Great! The adapter/focuser I'm getting uses the barrel of the Lodestar rather than the thread which means it will actually get closer to the plate than a screw type adapter. The Baader adapter I've ordered is the recommended by Tim and Steve of FLO and is one of two FLO show for use with the OAG.

http://stargazerslou...er/page__st__20 post #26

http://www.firstligh...xis-guider.html

Oh yes, I see that now!! I think you will be very pleased with the cam when it arrives.

[x6gas]

Be interested to see how you get on, Gina.

As you know, I use a QHY IMG0H as my guidecam. I bought it as it has ST-4 guide switching and the Sony 618 chip so thought it would be good for planetary too.

Until recently I've never had a problem finding a guidestar - even with my HD11 at 2800mm f/l. However, the last time I tried to image M51 I couldn't find a guidestar any where (even though I'd been fine before when I'd imaged it) so not sure what is going on but wishing I had tried taking darks to see if it had improved things...

[Gina]

My order from FLO is out for delivery, so could arrive any time now Looking forward to that. Forecast is for clear sky tonight so should get a chance to try it May check my PA first and then try some imaging with guiding. With a bright moon I guess it'll be Ha as LRGB will be useless once the moon is up.

Be interested to see how you get on, Gina.

Hope to find out tonight and then I'll post the sesults

As you know, I use a QHY IMG0H as my guidecam. I bought it as it has ST-4 guide switching and the Sony 618 chip so thought it would be good for planetary too.

Until recently I've never had a problem finding a guidestar - even with my HD11 at 2800mm f/l. However, the last time I tried to image M51 I couldn't find a guidestar any where (even though I'd been fine before when I'd imaged it) so not sure what is going on but wishing I had tried taking darks to see if it had improved things...

Using the guide cam as planetary imager too sounds a good idea I might try planetary imaging again sometime now I have a longer focus scope - I have a x3 Barlow and a webcam or two.

[Gina]

Update :- It's arrived Looks nice

[Martin-Devon]

Gina, you'll love the Lodestar - rock solid reliable and sensitive. The connections admittedly could be a tad better, but as a guider, it's a very strong performer.

[Gina]

Thanks Martin I've had a look at the connectors - they're not too bad I will only want the USB. I'll probably loop the cable back and attach it to the camera body - anyway I'll sort it out, no problem

[sloz1664]

Hi Gina,

You will be amazed at the very clean & sharp image of the Lodestar. I purchased the Mammut L429, which has the same chip

as the Lodestar but has pec cooling. I had the same issues with a 1700 FL Tal 200K & guiding and have gone down the OAG route

But I am having problems with focal reducer/flat field issues.

cheers

Steve