Allan kindly let me have a loan of his QHY8 and I gave it a first try last night from home in Brisbane. I must say I'm impressed at how easy it is to use and the quality of image I got in what was less than ideal imaging conditions with the moon and Brisbane sky glow.
Here's my first attempt on the Hamburger 12x5min lights with flats and bias frames but no darks through the 10" Newt. The other first was using my DSI II pro to guide through a F80 Stellarvue finder.
I realise there is coma at the edges from the Newt and have on order the T adaptor for my Paracorr to sort that out.
Nice shot Peter, colour is "different" to me, but that is a subjective thing.
The relevance of the finder/guider though? This is what we were discussing a while back, correct? If so, looks very good, you would have to be happy with that.
Gary
Good effort, focus looks good as does guiding, but it is hard to tell much as the image is so small.
Too much green and not enough blue perhaps. I used your image as an adjustment example for you, adjusting the individual colours with curves to tone out the green cast, which can be prevalant in QHY8 images as the chip is strong in the green. Green also could be light pollution.
Keep it up, the QHY8 is a wizz bang unit for its money!
Cheers Trevor. I thought I was going pretty well with 5min subs and that 1hr integrated would be enough but have definately seen improved results with more subs using the DSI. What do you recommend?
Quote:
Originally Posted by gbeal
Nice shot Peter, colour is "different" to me, but that is a subjective thing.
The relevance of the finder/guider though? This is what we were discussing a while back, correct? If so, looks very good, you would have to be happy with that.
Gary
Gary, I was going on the PS info on the sky background where the RGB channels seemed pretty well balanced however as you say it's a subjective thing. The finder guider is as we discussed - I've picked up an 80mm Stellarvue with a helical focuser and with the DSI I can find a guide star in pretty much any field without adjusting the rings. I haven't checked the drift properly yet but I'm pretty happy with the stars in the middle of this image given it is a five minute sub. I know the paracorr will take care of the coma as I've used it with my DSLR.
Quote:
Originally Posted by TheDecepticon
Good effort, focus looks good as does guiding, but it is hard to tell much as the image is so small.
Too much green and not enough blue perhaps. I used your image as an adjustment example for you, adjusting the individual colours with curves to tone out the green cast, which can be prevalant in QHY8 images as the chip is strong in the green. Green also could be light pollution.
Keep it up, the QHY8 is a wizz bang unit for its money!
That's the downside of these large format chips - you have to reduce the image size so much to get under the 200k limit to post or suffer JPEG artifacts if you keep the size and compress! The moon was >50% last night and I'm about 2km from Brisbane so the skyglow was pretty noticable however the QHY8 seems to cope with this a lot better than my 400D.
10 minute subs I think, I'm finding with my QHY8 unless the target is bright 5 minutes subs just don't cut it although I could be doing something wrong
10 minute subs I think, I'm finding with my QHY8 unless the target is bright 5 minutes subs just don't cut it although I could be doing something wrong
Trevor,
If you are imaging with the 8" RC I think the difference is I'm using a 10" f5 scope.
Thanks for the advice re the green cast, I've been studying colour bias and balancing this morning and now understand the issue. I've been focusing on getting the background balanced but have been neglecting the galaxy. Here's my latest attempt. I'm much happier with this one.
Very nice images Peter, The QHY8 will do a very nice job on your big scope but still nothing will replace exposure time. If I was to be critical with the images you have posted using the QHY8 it would be the exposure time or at least the length of your subs.
You have collected some very nice sharp detail, your guiding is , as usual very good just you need that bit more exposure to get the images to pop.
Thanks Doug - I'll be sure to try some longer subs however as this was the first time I used the camera I was reluctant to blow a whole night and find I captured nothing. I've also been working on improving my guiding so was unsure how long I could achieve without drift. I seem to be ok at 5 minutes so might try 10 next time. I notice the histogram is peaking at 65,000 at 5 minutes however there seems to be some headroom at the black end - I assume this means I need to reduce the offset. I was shooting with gain=1 and offset=110.
Marc - thanks for the link. I ended up using one of the PS functions and this seemed to work pretty well. Do you follow the colour/lum split workflow as recommended on that website?
Cheers Troy. I'm quite impressed with this camera - easy to use and pretty nice image for a burbs shot. I would like to get one but am wondering how it would go when the temperature gets lower (eg at Astrofest) with no control over the cooling?
