Jonesdee

Canon 100D if they are still available. Very light weight, 18Mpx and do everything that's needed for astro via Backyard EOS. These days I mainly use cooled ZWO cameras, but keep the 100Ds for use with my Star Adventurer (I have 2 - one is fully modded, the other has just the IR filter removed.) Dave

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As someone whose main interest is imaging, I share these concerns expressed in this and the earlier thread. My thoughts on the problem are as follows: Prior to the launch of the first SpaceX satellites, I would typically see satellite/aircraft trails in fewer than 5% of my subs and as Olly says above, these can be processed out. Where I live in Wiltshire, aircraft are a bigger problem than satellites, so probably only 2% of my subs have been impacted by satellites. I therefore hope that even a 10-fold increase in satellite density will still be manageable using my current processing methods. Again, echoing Olly's comments on CMOS sensors, in my sky-limited suburban location exposures are typically 1 to 2 minutes using an ASI294 OSC and 2 - 5 minutes with an ASI1600 Mono and RGB or NB Filters. To be honest, the UK weather is a far, far, bigger problem for me. It is almost 2 months since I had a clear enough night to get the kit out and even on a 'good' night, more subs are spoiled by passing cloud or rising mist than man-made objects moving through the fov. That said, it is frightening that, having polluted our planet close to the point of extinction, we are now starting to do the same with space . . . Dave

Steve - what mount do you use for your 120? I have a belt-modded HEQ5 but I suspect that with imaging and guiding kit on board the 120, the HEQ5 would struggle. Although I have just bought a 100ED DS Pro and am well impressed with it, I am sorely tempted by Jon's sale ! Dave

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That's way better Rob, well done Dave

As Bobby says above, communication via their Google Group definitely works better than email/telephone in my experience. I have had a couple of issues resolved through this route. Dave

Bobby I'm not an expert in this, but I suspect that the streaky noise is due to shooting a long sequence of short exposures without dithering. The mount will not have moved the scope substantially between subs and the noise pattern repeats itself from light frame to light frame. When stacked, this shows as the diagonal streaks across the image. Dithering will randomly move the scope a small amount between lights, effectively ensuring that the dithered frames are all slightly offset from each other. When stacked, this helps kill noise and hot pixels from the background. The disadvantage of DSLR imaging is exactly as you say, the sensor temperature varies from frame to frame and it is almost impossible to match darks to lights. That said, I got some very good images from my Canon 100D, often without using any Darks. My own experience suggested that Flats were more important with the DSLR and I made sure that I did these with the camera/scope in the same position as when imaging. I really think it is worth trying dithering - as mentioned by alacant, the internal dithering function in APT can do this without a guide scope. Dave

Some examples of the APP workflow (just screen shots using clipping tool): A typical sub, 16 bit raw data. Due to skyglow the exposure time is sub-optimal: After calibration, stacking and LP Removal in APP: Then star colour calibration: I then finished off in Star Tools and PS to get the image in my previous post.

APP is Astro Pixel Processor: https://www.astropixelprocessor.com/ It is a relatively new and evolving programme which I find very good indeed for calibrating and stacking images. I habitually use Star Tools and Photoshop for post-processing, but APP has some useful PP functionality also.

Good one Bobby If you are guiding, use dither to remove the 'walking noise'. I use a SX Lodestar guide cam through an OAG mounted in front of the main camera and it has improved my images significantly. I also imaged M51 this week using an ASI294 on a 6"R-C scope. This is a stack of 160 x 20s frames stacked in APP with 40 x Darks, 40 x Flats and 40 x Dark Flats. APP has an excellent light pollution removal tool which reveals a lot of colour in the target. I then tweaked it further in Star Tools and Photoshop. The poor sky quality limited exposure time and viewed any larger than this, it is a very noisy image

If you want to borrow my D-sub to RJ lead, let me know. There are lots of these available across the web in various flavours of RJ: https://www.canford.co.uk/Products/46-660_CUSTOM-ADAPTER-D-SUB-9-way-male-RJ45-red