Need help on GPUSB

[Meng Lee]

Hi,

I am intending to do this:

Use Lumenera with K3CCDv3 and GPUSB to achieve autoguiding for EQ-6 pro mount.

The Lumenera is of such high sensitivity and low noise that choosing dim guide stars is very feasible.

My concern is that the corrections are done through GPUSB which could be slower then direct relay output to the mount. My question is, is the guiding corrections still fast enough when using GPUSB? (1 correction per second is the slowest I can tolerate.)

Cameras like ATIK 16IC have direct relay outputs but the image download is 3 sec, so its fastest correction is 1 correction per 3 secs.

The noise of the Nugget camera is getting on my nerves already, hehe.

Thanks for reading and helping me.

[kochu]

Hi Meng Lee,

I use K3CCD V3.1, with GPUSB and MEADE DSI to guide EQ-6 Pro. Guiding interval is normally set at 1000 ms and capture duration upto 2.5 sec depending on the brightness of Guide Stars. . No problem other than that Drift explorer takes a while to settle.

Kochu/24-7

[Meng Lee]

Hi ,

That's good news. Inititally I almost wanted to get ST402 for guiding dim stars. The nugget is so noisy that it is hardly possible to use 3rd mag guide stars with 66mm guidescope.

Then seeing the low noise of lumenera and it ability to get dim stars with short exposures. so i came up with the idea of using it instead.

I have a DSI also, so the other option is DSI with GPUSB and PhD guide.

I ordered the GPUSB already. Will try things out.

Thanks kochu.

[rcj]

actually 1 correction per 3 seconds may not be that bad depending on the focal length of guiding and and PEC error tolerance of the EQ mount used. Sometimes I am guiding with a cyclic period of 4 seconds, and it is not based on normal luminance or colour channels, rather it is on H-alpha where stars are tight and small. It is important to make sure the mount tracking behaviour is predictable at the least, and it will make the job of the autoguiding easier. It will be benefial to align the guiding camera to the DEC and RA axes as well. Guiding at too short a cyclic rate might lead to corrective guiding of seeing effects instead of the real tracking deviations of the mount, resulting in 'bloated' stars. It is interesting to note the noise issue of the NUGGET. Is it possible to post an capture image sample of it? You might like to try PHD for guiding if you have not, it does a pretty good job considering it is free as well.

[Meng Lee]

Oh, I didnt have a screen capture of the nugget. I will try to take it next time. But the noise is really quite bad. (Note my guidescope is only 66mm.) Higher noise than QHY5 and Lumenera.

If I use PhD guiding, I will need GPUSB or ASCOM to communicate with mount, hehe. QHY5 has rather terrible software support, so up now I havent got it to autoguide.

I am using nugget with guidemaster, which only has gain controls but no black/white points adjustments, so I don't have full adjustments. So I always end up with a pile of hot pixels on the screen.

Seeing the low noise of Lumenera, if it works well with GPUSB + K3CCDv3 and 66mm guidescope, then nugget will go to astromart, hehe.

Yah, true, too fast guiding is actually guiding on seeing. But I just hope to have fast guiding in case weather is not that good to have time do drift alignment then take images.

[Meng Lee]

To use QHY5 with PhD guiding, I need to change the vid number to CCDLABS, which somehow cannot be done. Quite fustrating.

So QHY5 may go to astromart soon also, hehe. It works with QGvideo for avi capture, with ROI feature as well. Note that it uses the same CMOS sensor as Starfish and Mightex.

[rcj]

out of curiosity, do u have any issues pertaining to DirectX with Guidemaster? hmm... get an SBIG self-guided camera la... i might want to sell soon...

[Meng Lee]

I don't have directX issues with guidemaster. Perhaps I didnt really use modified webcam to work with guidemaster. I am not sure.

Relax relax. SBIG in 2008 is on the plan. I want to learn first. Hehe.