Daytime PHD2?

[Les]

Hello, 

I have an Altair Guide Camera and am trying to get it set up for guiding in the evening.  I have been using the Altair software to focus the camera and to get some of the back focus issues taken care of.  

My problem occurs when I try to use PHD2.  I am trying to make sure I am getting the same image in PHD2 during daylight hours.  I set the gain down to 1 and drop the exposure time to 0.4 ms.  All I am trying to do is confirm that there is an image so I hopefully can get PHD2 to work in the evening.  All I get is a grey/white noisy screen.  No matter what settings I change, nothing works

What am I doing wrong?

Thanks in advance.

Les

[Nelson Viegas]

Hi Les,

Probably too much light. These cameras are very light sensitive. You have one, try to insert a neutral density moon filter before the camera, or any other narrow pass band filter. Anything that might reduce the quantity of light reaching the detector should work. The filter itself slightly changes the focus point, but it's no big deal.

Good luck!

Best regards,

Nelson

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[Les]

Thanks Nelson, 

I thought about that, but I do get a good image in the Altair capture software...it just goes away when I use the PHD2

[Nelson Viegas]

Hi Les,

Ops, sorry, didn't got that part quite right. Maybe someone else has an idea of what's going on. I'm very curious too.  :)

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[wave...@talktalk.net]

I reckon there's a big sensitivity difference between how PHD2 displays an image and how an imaging application displays the same light input. I use an OAG so maybe it's more obvious, I don't know. I saw it when setting up the cameras to get them co-focused. As the daylight fades, the guidecam image 'darkens' much more slowly than the imager, though both have similar exposures. So, if you get an image OK in the daytime using an imaging app, you should get a starfield image in the dark using PHD2. It's an issue that's very relevant to OAG users. For this, I found the simplest way to focus the guidecam in daytime is to swap the camera connection to something like SharpCap. You can then easily focus on a distant target to get things set up. I found this approach useful for co-focusing the two cameras attached to the OAG. A second laptop, also running SharpCap allows you to see what both cameras are seeing symultaneously. I guess this might work by running two instances of SharpCal on the same laptop, I haven't tried.

Hope this helps.

- Jack

[chris oneill]

Hey les iv got an altair gpcam and tried the same thing but couldn't get phd to work in the day light I guess the phd software is just set for low light. But for now I'd say just find focus on the furthest object you can find to make it easier to focus on the stars. You might find you need to crank the exposure and gain up in altair capture when doing the precise focus of stars depending on your guide scope. Just remember to make tiny focus adjustments then stop to wait for the exposure to catch up. 

Good luck

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[mj.w...@gmail.com]

To cut down the light to the camera, secure some "tin foil" over the scope with an elastic band, and make a pin hole in the foil.

Don't forget the big Contrast slider on the PHD2 toolbar.

Michael

Wiltshire UK

[Bryan]

PHD2 automatically applies a stretch to the displayed image.  If the gamma slider is to the far right and there is insufficient light (very short exposure), the stretch will result in a speckled pattern (see attached 2ms.jpg).  OTOH, with the slider to the right and there is too much light (long exposure), then the image will be smooth (see attached 15s.jpg). 

You can play around with the exposure, however, you may never get an image in daylight that answers the question 'is the camera working in PHD2?"  That may be a night time only test.

Bryan