QHY8L First light- Frustrating!

[Zakalwe]

It was very gusty last night, but the sky was sooo clear I didnt hit the sack until dawn was breaking.

It was first light time with this wee beasty:

Nice big sensor

I used EZCAP to capture the files, which seemed to work well.

Now the frustrating part. Does anyone have a workflow, or walkthrough for handling the FITS files. Preferably using cheap software?

I seem to be struggling to Debayer the images. I have the FITS Liberator and when I open the file, I can clearly see the Bayer matrix. loading it into Photoshop, and then applying the FITS actions to split the channels gives me a massively Blue image.

I have tried the trial of Nebulosity (Open the image, then File>Save Colour Components) but it does nothing.

I am clearly doing something really daft, and am missing a simple step. Some of the workflows that I have seen say things like "Demosaic each image" but do not explain how to:BangHead:

[blinky]

get Deep Sky Stacker - It's free, and works wonders for stacking images.

[Zakalwe]

get Deep Sky Stacker - It's free, and works wonders for stacking images.

Thanks for the response.

I have DSS. In the FITS section I have selected QHY8 as the camera (same bayer matrix, I believe).

When I load the FITS into DSS, it is showing them as 16 bit Grey files.

Here's a crop of a test stack of a few lights (no darks or stretching)...the matrix is clearly visible.

[blinky]

I have a QHY8 (Not the L Version, whats the difference?) and here are my DSS Settings:

[Zakalwe]

Similar to mine, except I used AHD.

I'll give Bayer Drizzle a go now.

What do you use to capture the images?

[ollypenrice]

I use AstroArt with the OSC.

1) Calibrate the images with darks and flats but DO NOT COMBINE THEM. This produces a list of lights with the suffix _P.FIT

2) in a second pass combine the images having set the CCD Colour Synthesis box to the right offset for your matrix. (Just trial and error because the software does not know what colour filter is on your top left hand pixel, say. Try it on a daytime image to set that up.) Run a hot pixel filter at this time but I keep away from any high pass etc. That comes in post processing.

A note on flats: these need debayering so shoot and stack them as usual then in AA go to Image-shift and set both axes to 0.5. The matrix will disappear from the flats.

Olly

[Zakalwe]

Right, I think I have worked it out.

Selecting the QHY8 Camera id DSS seems incorrect. I have tried Generic GBRG and that seems to work.

Olly,

I am baulking at buying any software just yet, as I am unsure which one will suit. I'll give the trial version a whiz.

[MikeWilson]

Zakalwe,

I can see in your picture that the chip appears to be covered over with some form of glass. Do you know if this glass is IR-blocking or not?

(Is it possible to remove the nosepiece with the glass in it in order to test that it blocks IR from a remote control, say?).

I'm getting one, and would like to know if we can save cash by purchasing "Visual" (non IR blocking) filters instead of imaging ones.

Best,

Mike

[Zakalwe]

Zakalwe,

I can see in your picture that the chip appears to be covered over with some form of glass. Do you know if this glass is IR-blocking or not?

(Is it possible to remove the nosepiece with the glass in it in order to test that it blocks IR from a remote control, say?).

I'm getting one, and would like to know if we can save cash by purchasing "Visual" (non IR blocking) filters instead of imaging ones.

Best,

Mike

Hi Mike,

Yes, it is fitted with a 3mm thick IR blocking glass front.

Regards

Stephen J

[MikeWilson]

Hi Stephen,

<trumpets>

Hallelujah!

</trumpets>

This means that one can use an Astronomik CLS (non blocking) filter, and the huge swathes of visual filters (e.g. Baader OIII visual, various UHC filters) and so on to really take advantage of the cheaper non-blocking filters.

[r3i]

If you want to have another try with Nebulosity, you'll need to do the following (assuming the QHY8L operates the same as my QHY8):

1. Set the Manually Override the Colour Ceconstruction setting in the Preferences (see section 17.3 of the manual).

2. For a single image: from the menu bar, use the Image - Demosaic RAW function (whichever of the two you fancy). A popup will appear (see section 8 of the manual). You need to ensure that in the Matrix Offset section, the X and Y values are both set to 1.