Gina

There may be a small chance of testing the rig with the 28mm lens tonight but I'm not counting anything. With rain a possibility later I shall have to make sure I close up before I go to bed regardless. I haven't yet got my automatic ROR closing when rain detected though I have have a couple more bits for it delivered today.

I missed a setting in the camera setup 16bit rather than 8bit. I have now set up rough focus with aperture of f8.

28mm lens is back on and I'm just waiting for a bit less light to set up coarse focus - remote focussing is quite fine. Minimum exposure on the ASI1600MM is 32µs and even with a 3nm NB filter and aperture set to the smallest of f16 the camera still overloads on a daylight scene.

Both lenses are from the same "stable", Asahi Optical Co. of Japan but the 55mm is an earlier one called "Super Takumar" whereas the 28mm is "Super Multi Coated Takumar" and a later model. The 55mm lenses were the standard lens supplied with the Pentax Spotmatic SLR camera. Whether the later models are tat much better I don't know as the 105mm f2.8 lenses which I've found very good are just "Takumar". All these lenses with the exception of one of the 55mm were bought second hand from ebay with no knowledge of their provenance.

I was, to the point that I entered it into the 30s imaging competition. Just brought the rig indoors and taken the 28mm f3.5 lens out of my astro box ready to put back on the imaging rig. This will give a good FOV when Orion comes back into view as it will cover the lot, including the whole of Barnards Loop.

This is an image taken with the 28mm lens. It's clearly a lot sharper than anything I captured with the 55mm lens!

I wouldn't be at all surprised! This lens doesn't seem as good as the 28mm f3.5 I used when I started imaging again after the long break. I thought the greater aperture of the 55mm lens would give me better subs but maybe not. Having got a few other things sorted out I might go back to the 28mm lens. Trouble is, that lens gives rather too wide a FOV. OTOH if I can get sharp images with that I can crop out the part I want and no doubt do better than with the 55mm lens.

Both. Elongated towards the edges. Normally that would indicate a curved field but these lenses gave flat field over a 36mm x 24mm image plane on film - the ASI1600MM is considerably smaller.

Just checked the captured images in Blink in PixInsight and the sky was pretty clear for the whole run up to 02:30 this morning but seems the mount thought it had hit the horizon 50m earlier and stopped tracking. It hadn't though as the images continued. So that's something else to sort out. I have a lot to learn about this KStars/Ekos/INDI system! That's not to say I don't like it - it seems much more logical than the Windoze software collection and I know it's going to be much better once I get it sorted out.

I'm not happy about the star shapes either. In fact the whole image is rubbish!

Think I'll just leave it capturing 300 Ha subs of 30s binned 2x2 and see what I've got in the morning. Lots of dew on the observatory framework but none on the lens last time I looked. Too tired to stay up any longer so I'll goodnight folks and hope you have some success.

I see. I'm not satisfied with the image clarity. Whether it's focus or trying to use the lens at too wide an aperture I don't know. I might try a different lens another night. Best HFR I've achieved is around 4 pixels which is ridiculous - I might as well use 4x binning. I don't think I've used the 55mm f1.8 lens before. I know I got good results with the 105mm f2.8. I also have 135mm f2.5 which should be suitable for the Cygnus Loop. Not bad for some of the other Cygnus DSOs either. The NAN and Sadr region are very bright.

The image isn't all that bad considering the state of the sky. This is Ha 30s exposure at gain of 420. The framing could be better if my Park position had Polaris centred. Of course, plate solving of the live image should correct that.

No sign of MW here - very few stars and not many street and house lights so seems to be mist. At 600ft (200m) ASL here so that may be the difference.

Had a look at the sky with no.1 eyeball and not many stars showing so I guess trying to do anything much is a waste of time and effort.

Do you use darks when plate solving, James? What settings do you use?

Tried the online solver and that failed to solve the original so didn't even get to try the live image.

No I'm using offline.

As expected - not very good sky. Autofocus worked and adjusted the focus a small amount. It was satisfied after 12 iterations. Live image plate solving is still not working probably because of poor clarity. OTOH the star pattern looks clear enough to me. Maybe I'll try OIII rather than Ha.

I can see stars in the sky

No problem. If you didn't understand it probably others didn't also. My explanations sometimes leave something to be desired 😁

Rearranging the supplies :-

Now if you consider using these in a circuit where you want the current shunt in the 13.8v supply line to the load, the shunt is at 13.8v and the supply for the ammeter circuitry needs to be 4v above that (minimum). The 0v of the ammeter is at 13.8v. It doesn't matter that it is actually fractionally below this due to the volt drop in the shunt as the ammeter can be run from anything between 4v and 30v.

These digital ammeters have 4 connections though 2 are common (connected on the PCB). This is what I imagine is in the digital ammeter. They need a minimum of 4v to operate between the supply rail and the common 0v

We'll just about be acclimatised to the heat when the weather will change back to normal and we'll all be freezing!!! Haven't done much today myself. My usual walk up the hill before it got too hot this morning and a rest on the bed this afternoon.