Jonesdee

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

Seems that RJ12 is 6P6C: https://www.leadsdirect.co.uk/technical-library/pinouts-wiring-diagrams/what-is-the-difference-between-rj10-rj11-rj12-and-rj45-connectors/ 9, 10 and 22 are 4P4C. I got a D-Sub to RJ cable with my HEQ5 but it is more than 4 connectors on the RJ end (never used it or the handset as I prefer EQMOD).

Think I have answered my own question - looks like it needs an RJ45 connector, not a D-Sub as sold by TE

Hi Bobby It isn't one of these is it? https://www.teleskop-express.de/shop/product_info.php/info/p439_TS-Optics-Adapter-from-USB-to-RS232.html Cheers Dave

Yes, ASICAP is a capture program from ZWO/ASI which offers full control over all functionality of their cameras. I use it if I need to image through my scopes in daytime as it is the easiest method I have found to use short exposures on the 1600 MM Pro (for setting back-focus, setting up OAGs, occasional bird watching, etc). It does not, however, offer the full astro image acquisition functionality that APT, Sharpcap, or SGP provide within a single application. By that, I mean integrated focus aids, plate solving, Polar Alignment tools, guiding, etc which make those programs so convenient. Possibly, if I had experimented with different gain/offset settings I may have recognised the impact of minimal camera gain before worrying that the camera was faulty, but with so much to learn and so few opportunities to see a clear night sky in UK, I had only ever used unity gain/50 offset until this was inadvertently changed. If my weather conditions matched the Met Office forecast, I would be testing the camera again right now, but once again cloud is covering my bit of North Wiltshire. Dave

Cheers Dave, about to get the kit outside in anticipation. I do hope that it is not a camera issue - the gain setting would certainly explain away most ofthe issues I have seen - not sure a bout the trailing, but some images tonight should prove it one way or another Dave

Update - I think I have found the cause of this phenomenon. The guys at ASI responded very quickly and asked me to send some files for examination, including a Flat Frame shot at a Gain setting of 300. I have always used unity gain (139) so opened the camera ASCOM driver to change this. I was surprised to see that the gain had defaulted to 1 and could not be altered. A quick check of the FITS headers of recent images showed that the change from 139 to 1 had happened between late October and early November, during which time I had upgraded APT to the latest version. I uploaded my stored configuration settings without paying sufficient attention to the changes in functionality and completely overlooked the fact that CCD Camera Gain is now controlled by default from the Camera Control panel. To allow the Driver settings to take priority as was previously the case, requires a configuration change which I did not make Given the low S/N resulting from such a low Gain setting with an Ha filter, I think this explains my issue - hopefully will be able to confirm that tonight if the clouds part for a while. Also explains why the seeing has seemed particularly bad lately! Wiping egg off face . . . . .

Thanks Dave, I have also seen similar reports on the Astro Pixel Processor Forum - several cameras were replaced, it seems. I sent the details of my problem to Zoltan at 365 Astronomy (very helpful guy) as I bought the kit from him and he has passed that on to ASI already. Hopefully will hear back from them soon. Will Google the threads you mentioned also Cheers Dave

Same issue after stacking with DSS - a quick stretch of the Autosave file in PS: I also tried (in APP) stacking random sets of subs, 4 at a time, and the phenomenon is visible in all stacks. It is not, however, visible in single subs as far as I can see. Many of the strange trails seem to be better focused than the rest of the image - I'm wondering if there is a clue there? Cheers Dave