michael8554

"Pentax‘s Pixel Shift (Available on the K-1, K-3 II, KP, K-70) attempts to alleviate some of these problems through a novel approach of capturing four images quickly in succession and by moving the entire camera sensor a single pixel for each shot. This has the effect of capturing a full RGB value at each pixel location" If you have this option selected, the Bayer Pattern is anyone's guess.......... Michael

Despite the Dec warnings your Dec guiding is fine, it's the RA error that is the problem, nearly 3 times that of Dec. Looks like you have enough stars to tick the "Multi Star Guiding" option ? Your PHD2 settings are burnt out in your image - it's best to take a Screen Grab with the Prt Scrn button on your keyboard. If your exposure was 1 second, that would be "chasing the Seeing", which would account for the choppy RA result. Michael

Have a look at the "pixel scale" and "Binning", about 5 lines down in the PHD2 GuideLog Calibration section. If ithe image scale isn't the correct figure for 4.63um pixels, then try again with Bin = 2, if it was on Bin = 1. Michael

Or are too un-round for DSS to recognise as stars. Your Flickr link is to images of birds ?? Michael

I would post this in the "Beginners - Getting Started Equipment Help and Advice" Michael

You should make a comparison of the Image Scales (focal length and pixel size) of your Guiding and imaging setups, FL on its own is only a very rough guide. Michael

That would have been the cause of the "not enough movement" message - RA and Dec have to move to Calibrate and Guide. Michael

Read my edited previous post Michael

Look up each item in the index of the the camera Instruction Manual. Michael

Thread-lock : https://www.amazon.co.uk/Everbuild-EVBTHRED10-Threadlock-10-g/dp/B0012RCYAO/ref=sr_1_7?dchild=1&keywords=loctite+thread+lock&qid=1614012954&s=diy&sr=1-7 Remove the camera and focus the sun on a flat surface. Measure from that point to the rear of the C-Adapter and attach the camera at that spacing. Do that before applying the thread-lock, to leave your spacing options open. Michael

The Random Dither in PHD2 varies the size and direction of dithers, so many of the dithers will be less than 12 pixels. So a slightly higher setting than 5 = 12 pixels might be in order. Michael

Your understanding is Bang On ! Though a Dither of about 12pixels on the DSLR is more common. Michael

I was generalising, your Andy video is not at all spurious. Michael

I would have a look on the US "Cloudy Nights" forum, there are many CEM posts there. Michael

For the Horsehead I needed 4 minute exposures to get usable data with a modded DSLR. Michael

Try focusing on a distant landmark during the day. That will get you familiar with using that focuser, and will be close to the slightly different focus point for infinity objects such as the moon and stars. The Dual Crayford probably has a Coarse Focus and a Fine Focus knob. Try turning them and look for movement of the focuser tube. If there's no movement there is probably a handscrew that needs tightening. If it still doesn't come into focus, have a look for a picture in the Instruction Manual that shows the focuser with an eyepiece in it - do you have any spacers missing, or spacers inserted that aren't required ? Michael

The PHD2 site has many links to instructions and fault finding, but few people go there, instead they look at random videos on YouTube.......... https://github.com/OpenPHDGuiding/phd2/wiki/EQASCOM-Settings Michael

Most mounts are driven by a small Worm meshing a large Worm Wheel. With that design it's almost impossible to make the small Worm rotate by unbalancing the scope, but easy to drive the Worm to make the Worm Wheel. move The only movement you'll see will be small, due to Backlash between those two "gears". "I made up the name gear lock" An apt description. Michael

Hi Grant To me it looks like the camera is out of focus. Adjust for lowest HFD in the PHD2 Star Profile window, And/Or has Star Bloat due to lack of InfraRed filter ? Michael

Try taking some Darks indoors with just the camera connected. Michael

You're an experienced imager, but in your new PHD2 Profile have you forgotten the default Guide Rate in EQMOD is only 0.1 ? If not then post the GuideLog. Michael

You're right Craig. I original tried to show that if G was in focus, and R and B were a bit off, L might not be too bad. Off course he should strive to get RGB all in focus. I'll slink away now ! Michael

I'll remind you all again, it was a simple answer to "how is L derived from RGB" If you have a better answer, by which I don't mean more complicated, feel free, I haven't seen that yet. Michael

Exactly right ! The Luminance of a Blue image will be 10% of peak white ! And for some reason, the response of a DSLR seems to have been tailored to match the human eye........

So only on the Lights, so external to the scope and camera setup. Full Moon ? Michael