Seelive

I image from a Bortle 5/6 sky. All local street lighting is LED, but unfortunately due south of me is the local town and a very large industrial estate (and I've no idea what lighting they use!). Here's a couple of unprocessed single frame images of Orion taken a few days apart back in February this year when it was approximately due south. This was taken without any filters (60 sec with a 50 mm lens at F2.8): And this was taken using an IDAS D2 filter: The most obvious difference is the colour shift (which can be corrected in post processing) and I suspect that the local LED light pollution has been mostly removed by the filter leaving the more distant light pollution from the unknown sources. However. I don't think that the filter is particularly suited to be used at such wide apertures as reflections appeared on stretched images, so in the end I used the unfiltered images. This is the 75 x 60 sec unfiltered images with my unmodified Canon 200D at ISO1600.

Once the image has been debayered, most astroprocessing software should give you the means to bin the data to reduce the image size and still retain colour.

Normally, 2 x 2 binning of a colour camera results in a monochrome image since the RGB pixels are combined into a single pixel hence loosing the colour information.

I've never quite understood why guiding accuracy is referenced to arcsec on the guiding log. I would guess that PHD2 can only guide at best to within about +/- 0.1 PIXELS of the guide camera. What that results in +/- PIXELS on the imaging camera depends upon the focal length of the guide scope, the focal length of the imaging scope, the pixel size of the guide camera and the pixel size of the imaging camera. If you are getting round stars, then I wouldn't worry too much about the guide log, but if you're not and the guide log shows guiding errors of less than 0.2 pixels then I would suggest you need to consider your hardware setup.

Have you reported it on the DSS forum?

Their's also the newer EQM-35 Pro, it has a slightly higher load capacity than the EQ5 and benefits from a larger (180 tooth) RA wormwheel than the EQ5 and seems to use the same tripod, but is a few pounds cheaper. I've not had any problems using mine for astrophotography.

Yes.

How big is your existing PSU? This one is 180mm x 65mm x 40mm https://uk.farnell.com/powerpax/sw3477d/ac-adaptor-12v-10a-reg-3-pin-vi/dp/3375895 which seems to be typical for a 120W PSU.

The voltage drop with a 7m length of 20AWG twin core wire will be around 5V at 10A, so not much left out of the 12V you start with. You could use a 2.5mm flex cable (e.g. https://uk.farnell.com/pro-power/3182y-2-50mmblk100m/flex-cable-2core-black-2-5mm2/dp/2425457?st=Multicore cable) which at 7m would drop about 1V at 10A. Flexible cables above 2.5mm are about as rare as rocking horse **** but if flexibility is not a specific requirement you could use 4mm twin and earth which is readily available.

I would say it's drift due to polar alignment. It appears to be about 3 arcmin total over the total exposure time of 5.5 hours (assuming the scaling shown is correct). That drift could be achieved with a polar alignment error of less than 5 arcmin at that declination. At the end of the day, that's what stacking software is for.

Unfortunately, these days we seem to be reliant upon imports.

Both stainless steel and hi tensile steel are corrosion resistant and hi tensile steel is harder than stainless, but but you should be able to file either. At the end of the day, I would prefer stripping the thread on the bolt rather than on the mount so I would go for A2 stainless.

Have you tried asking the council to fit a screen on the light? I know they do it in my area to prevent lights illuminating bedrooms instead of the street.

INUWAAUITHTBEFTTBU! (I never understand why acronyms are used if they have to be expanded for them to be understood) 😆

For drizzle you need small movements of the image relative to the pixels. Whilst dithering is the ideal solution, polar alignment drift will get you part way there.

DSS will not stack images where the stars are out of focus or trailed or just too large. It also needs a minimum number of 'valid' common stars to be present in each image (I believe the number is 8). So counts of 5 or 7 are too low. When the threshold is reduced further and you get a sudden huge increase in the number of stars detected, you are infact just detecting noise so make sure the median filter is enabled.

My first real attempt at narrow band processing since I only use a DSLR for my own astro-photographs. Processed using IRIS and Starnet++. 1. Combine data as SHO 2. Equalise and offset sky background histograms peaks 3. Initial small stretch and remove stars using Starnet++ 4. Create stars only image 5. Apply curves to nebula image to equalise and offset histograms 6. Blend in stars only image 7. Apply minor RGB colour correction 8. Small ASINH stretch 9. Light wavelet filtering 10. Small application of CRISP filter The Ha still seems to be a bit too strong for my liking so I may try an alternative colour pallet.

With such a short a focal length lens, the image scale distortion can be quite large so any misalignment between images can cause stacking issues.

When I try to connect to my EQM-35, PHD2 complains that it can't find the com port and I have to click on the spanner button. PHD2 then finds the mount and then I can connect. For some reason, the com port for the mount changes from one session to the next (but the com port for the guide camera doesn't). The error message is probably obscuring the box that needs populating but if you need to supply a com port for the mount during the initial set up, you should be able to determine what it is through Windows Control Panel.

A bipolar stepper motor will only have 4 leads, a unipolar will have 5 or 6 leads.

No screws or obstructions, it's all plain tube between the front lens lip and the rear focuser lip.

That's what my PHD2 guide logs also say for my EQM35 but is working fine for me. However, PHD2 doesn't appear to the talking to the mount (no RA or DEC info). Are you ST4 guiding through the camera or direct mount guiding by connecting the PC to the handset USB port?

I'm having exactly the same problem, there are so many stars in the field. I can't get Starnet to produce a usable starless image either. A work in progress, I'll certainly be interested if you find a solution.

Finished for the night. The white tube section length is 107mm and 56.0mm diameter.

Mine's currently guiding, if you haven't had an answer by tomorrow I'll post the measurements.