tooth_dr

Very much so and will hold a lot more than that. I quite like mine but I do find I have to careful getting the camera flat against the rim when tightening to keep all square.

Sorry to bother you again! I'm trying to figure out the spread sheet. The 2600 high low gain conversion is 100, and 56 for the QHY. But then I read below and it says when using mode #0, the gain conversion is 26? **EDITED - I am now not sure what mode I've been using lol* What effect is there on the figures in the spreadsheet for the QHY camera if the gain conversion point is different to the ZWO? " #0 Photographic Mode This is the standard “default” capture mode. There is a high/low conversion gain cutoff point between gain 25 and 26 where you will see the read noise drop from about 5.2e- at gain 25 to around 2.5e- at gain 26. The read noise response is quite constant from gain 0 to gain 25, and again from gain 26 to about 60. Due to this, most users will probably want to use either gain 0 or gain 26 and nothing in between, as you would only be losing fullwell capacity and dynamic range in the middle. I mainly image at fast focal ratios of f/2.2 so for me it makes more sense to use gain 0. Users of slower focal ratio telescopes, or in dark skies, will most likely want to use gain 26 to take advantage of the lowered read noise. Increased exposure time is going to be recommended over increasing the gain into the “middle ranges.” #1 – High Gain Mode This mode features a consistently lower read noise throughout its response, with the tradeoff of a slightly lowered fullwell capacity. Like #0 Photographic Mode, there is high/low conversion gain cutoff point. For this mode the cutoff is between gain 55 and gain 56, where the read noise drops from approximately 3e- to 1.5e-. I like this mode the most for narrowband imaging as you can take advantage of the extremely low read noise at gain 56 without having to worry much about fullwell capacity. For most of my standard broadband imaging, I also prefer the lower read noise of gain 0 and still relatively high fullwell of 60ke-. Unless I am shooting a field with very bright stars in it where the higher fullwell capacity of Photographic Mode may be a better choice, this mode is my main choice for imaging with my RASA. This mode also features the best dynamic range at 14.26 stops. "

I’ve never thought of calculating the correct exposure time properly. Thanks very much for that link

To clarify the 1200s subs were with a CCD, not this camera.

No I was just wondering about you saying about the need for pixel rejection. I thought maybe you had a very small number of frames to work with. But even at 600s, you would still have 25 subs, I would have assumed that was plenty for the rejection algorithm to work effectively.

Cheers. I'll try the mode 1 tonight, and will go with 600s. In the past I've been using 1200s subs along with calibration data, and this removed the bad pixels etc and dithering cleaned up what even was left. Maybe you arent taking many frames in the mosaic? You need at least 16 for the sigma clipping to work isnt that right?

I'll set up a sequence of 300+600s subs, and run a dither every other sub.

Thanks for the reply. I was shooting in photographic mode (I think yes that is mode 0). I am not used to the modes. Previously I used a CCD, and the only thing you could change was time I'm using a 250px, which is a 10" reflector with a focal length of 1200mm at F4.7. Tonight is looking clear too. I will try mode 1.

@rnobleeddy First night using narrownband with my QHY268, and low and behold, a big bright circle in the middle. It immediately got me thinking about this thread, so many thanks for coming back and providing your solution. I havent had a chance to take flats yet as I was only imaging late last night. Here are my images from last night, 7nm Ha filter, and MPCC (mark i or possibly ii, it's about 12-14 years old, not sure when the mark ii came out) Integration: Sub: Sub:

Those both look better, smoother than mine - are those calibrated integrations or just raw stacks? I was using a 7nm filter, and it last night so a slightly bigger moon. Maybe 600s subs are the way to go?

Hi guys Any suggestions for gain/mode/exposure time for H-alpha imaging. I grabbed a handful of H-alpha subs last night 300s/gain 56/photographic mode and thought they looked a bit noisy. Are these the right settings for narrowband? I’ve attached an uncalibrated stack of 11x300s Thank you! Adam

Class job, really great FOV.

I’ve cut the M42 portion off mine as it was interfering with the prism in a previous oag. I bought mine in 2007-2009. It came with this box and ring too.

Great to see you imaging again. Superb FOV for this target 👍🏼👍🏼

49 hours well spent Rodd. That’s very nice indeed.

If it’s half as good to use as it looks I’ll be happy.

Did see this the other day whilst browsing for targets! That is looking good so far.

Mine has the M42 and M48 threads both cast into the holder, the M42 bit doesn’t screw off.

I’ve trying work out what model I have, but I can’t find product archive. I’m getting a bit of CA, and so am wondering could I upgrade my CC? Im using it with a 250px and don’t want to alter the focal length. TIA Adam.

Personally wouldn’t be my choice of model Paul, but aside from that, I’ve owned QHY products for several years and found them to be no more problematic than any other brand. In fact my least reliable camera is my ZWO120.

Looks really good Carole. Has a nice 3D feel about it.

What a fantastic image Lee.

It does look good on paper. Visually there is a fair amount of curvature. I don’t think this scope is particularly well suited to visual?

It definitely didn’t look as big in the for sale photos, this scope is well put together for a 4” 😂🥰 Beside the ED80 for scale

Really nice image Tristan, you have a really strong processing skills. The background is smooth but yet doesnt look overdone or forced. Would you mind sharing an outline of what you do?