Stub Mandrel

Caught nearly all fo last night's ISS pass by accident when I went out to wire the mount and scope to my laptop!

Don't forget you can adjust the tilt of the 130P-DS focuser tube

I didn't spot the ISS either, hazy cloud and not quite dark enough

Scrubbed.

Looking a bit shakey with the weather now...

It's raining in Florida!

Not one I've come across. This review is framed quite positively but suggests a wobbly vertical axis is an issue and there may be some compatibility issues with Cura. That said it's got some nice features like a mains heated bed and volcano-type extruder.

That's the second pass, quite a bit further south so less visible.

I think they cut off near sunset. I expect so. Stellarium has it overhead at 20:22 UTC (21:22 BST) and visible, just 8 minutes after sunset here. At mag -3.3 its 0.7 of a magnitude less bright than Venus but MUCH further away from the sun. May be tricky to spot but will be visible. Of course they should both be visible on the later pass.

People seem to think highly of the creality kits but reviews suggest some software hiccoughs.

I'll be watching on my laptop in the garden. Why? The ISS goes over at 9:30 followed by the Falcon at 9:45

Rats. Complete my Mk2 bearing block, the unpowered one with a 'top hat' roller. Offered it up - and realised it needs to be angled sideways by ten degrees. Now printing a 'tilted' version. The roller and the other combined roller/pulley have a shaped hole to suit a pin of 8mm precision bar with a flat milled on it. This lets them run in two skateboard bearings and means they can be assembled/disassembled in place if required by just lifting the pin (and unmilled section stops the pin dropping right through).

In my previous post I observed that my data for M13 could do with a bit more processing to make it 'sparkle' more. I adjusted the original RGB image as a colour layer, slightly increasing the saturation and softening it a bit as some yellow stars had become a bit posterised on close inspection. I went back to the original data and reprocess it it with a lot more effort on brining out faint stars while not blowing out the core. Then I applied some very gentle lucy-richardson deconvolution, basically kernel size and kurtosis set on 1 except strength at just 0.7. This was enough to make the stars in the core more prominent and lift up the fainter outer ones. Although this was now a nice RGB image, the colour wasn't as good as the original so I combined them with the new image as a 92% luminance layer. Finally I slightly blurred the cores of the two big stars to tone them down a touch.

I don't expect any of these images to win an award, basically I spent two nights trying to get as many globulars and open clusters as possible, given that those low down don't make much of an appearance here and I suffer from nearby LP low in the south west. One or two were replacements for disappointing earlier images, most were new targets for me. Unless otherwise explained , these are roughly 10 one-minute subs for each of RGB, no luminance. The ones where there was a shortage of subs are most interesting. all cropped down to 1200x900 and jpg to save space. M13, I wanted a half decent image to replace my 'nearly' ones, so 2.5 minute subs. The red wasn't excellent because the sky could have been darker, so I took extra subs to compensate. Something like 20 red, of which 6 or 7 discarded, 10 B & G. I think some more work on this would give a better looking result, it doesn't 'sparkle': M53, another one I wanted a better version of, but shorter exposures than M13: Then down to M80 - I got two red subs before it went behind a roof, shows how much more even a small number of subs (as above) brings: M107 - you can see there are plenty of stars in the core that would show better with longer exposures or less LP: M10 and M12; interesting to compare the colours. Does M12 really have more blue stars? M9, quite a small one: M23 - it's so hard to make open clusters look like anything other than a random pattern of dots... M18 - the last one, cloud came in and hid it before I could do more than 1 or 2 blue subs, and despite some playing I couldn't get the blue stars to show decent colour: Conclusion... a useful set of 'record' shots but the M13 shows the benefit of more integration time. It has the potential to be a much nicer image so I'll go back to the data.

Some progress: Pulley for 1.5mm timing belt, printed with 0.1mm nozzle: Upper platform with pivot and sectors: Jigged with platform horizontal to measure correct angle and height for rollers (rather than trying to calculate it):

I should have been clearer! Yes it's object size, and I should have said 'no change' with sensor size. I've edited the table to correct this.

This table might help. 'Image size at fixed dpi' is, for example, how large it will appear if displays at 100% on a computer monitor: FACTOR INCREASED Field of view Exposure Time Required Image Size at fixed dpi Aperture No change Reduced No change Focal length Reduced Increased Increased Focal Ratio Indeterminate* Reduced Indeterminate* Pixel size No change Reduced Reduced Sensor size Increased No change Increased Sensor quantum effciency No change Decreased No change *Change in field of view or image size will depend on whether or not focal length is changed, this is why focal ratio alone is unhelpful without further information

The problum with this issue is when people try and understand the issues when two variable are changed (e.g. scope aperture and sensor size). The easy way to understand each factor is to work through the effects of changing them one at a time.

There are theoretical arguments for the optimum shape for a given aperture/focal length. After trying a large array of random masks, I can confidently say that though the detail may affect brightness and spike contrast anything that looks like a bahtinov mask will work like one.

I don't know... I imagine the easest thing would be just to copy the design in your favourite drawing pogram, its pretty simple really. Nothing is critical - a Y-shaped twig works so anything vaguely right with slits at three angles will function.

Nicely captured and processed, Gina.

Stepper motor and furniture sliders for my EQ platform project.

I'd be tempted to bin, with an OAG and narrow field of view you may struggle to get something bright enough to use as a guide star. But try both and see what works best.

The Invision Community software allows anonymous voting, another site I'm on holds monthly photo and composition challlenges, but 'just for fun'.

If I settle for an alleged 1/4 way accuracy I could by 20 from China for a few tens of dollars, coating extra! At that price I could buy a batch and chuck any rejects. For making guidescopes it's literally cheaper than buying 'toy' scopes and throwing away everything but the lens. Grinding custom lenses isn't expensive these days with CNC machines. I would believe a couple of hundred pounds for a UK ground custom lens, but over two grand for a standard item?