Stub Mandrel

1 hour ago, perdrix said:

Yes the main group can be empty

Brilliant - I may now disappear into a processing hole for several weeks right when I need to get some serious work done!

10 hours ago, SIDO said:

The tube I cut was 1/8" wall aluminum I don't know the grade but think a slow hot knife trough butter would sum it well at that thickness, the cutter was rented for a couple dollars and intended use was for steel pipe up to 1/4".

 

Ah, sorry, I didn't realise you meant those sort of heavy duty cutters.  Might struggle on such a short piece, plus the end would still need tidying up.

h thanks, does taht mean I can have a main group with nothing in it - or just a bias?

Some things I have learned:

Use a Barlow. x3 is not too much with a 1200mm scope.

It's definitely worth getting an ADC, set it using an eyepiece, also useful to get the planet well centred.

Use a proper planetary cam, even the cheapest will outperform a webcam because it will save RAW video.

Spend lots of time focusing. When you think you have it right, spend as much time again getting it even better.

Mono doesn't offer gains over one shot colour - you have to use Winjupos to derotate the RGB and it is hard to get decent results, especially if you have a moon or moon shadow moving faster than the rotation of the planet.

The 5000 frame 'quick capture' in Sharpcap is pretty much optimal for Jupiter.

Accept that with the planets so low down seeing, transparency and dispersion will all limit what you can achieve.

This is from my only session on Jupiter this year, with a 6" Newtonian, a 150PL.

I think a pipe cutter will struggle beyond about 1mm wall thickness.

A neat job could be done by wrapping a sheet of paper around the outside - this will give a very accurate cutting guide, go over the end of the paper with a sharpie to transfer the line to the tube. Cut witha hacksaw just shy of teh line, then file it until it is neatly on the line.

It would be a nice job to finish with anodising.

I can see the moon, but not Jupiter, in broken cloud.

K3WL!

My neighbour's leylandii do a good job of blocking out the closest streetlight for me!

Straight through finder and turn the map upside down. I can't get my head around the view through an ordinary diagonal.

Good job I only just noticed this - I've put in a good day's work today, but I would have been sorely tempted!

IF Barkis can't help for any reason, I've got a well-equipped workshop, if you want to mark on it what you want taken off with a sharpie and post it to me with the return postage, I'll shorten it for you.

PM me for address.

I could fit a couple of grub screws as well.

What's the best driver for a Touptek GMOS01200KMB mono cam?

In Sharpcap it shows as a GPCAMAR0130M the driver is OK, but the camera seems to be MUCH less bright/sensitive for any given exposure than my ASI120MC - which uses the same chip but with a bayer filter, so it should be LESS sensitive.

Hi David,

First, thanks for DSS!

Second, I have sometimes struggled to combine data from sessions months or even years apart and get better results than stacking the 'best' of the various nights.

I've noticed that if I have three file groups, each with its own master dark, flat and bias, the dialogue offers the median method of combining the flats. I'm guessing its also combining the other control frames across groups.

I think this is what's degrading the results.

Is there a way to force DSS to only use the darks, flats and bias in each group for the lights in that group?

Thanks

Neil

Strong tea...

1 hour ago, Gina said:

Look after yourself Neil - health is everything!

You too!

I felt faint after getting out of the bath this morning so I took my blood pressure. Some good news - 102 over 67, I may need to cut down on my pills - hard to believe it was over 190 six years ago!

3 hours ago, Gina said:

'll try online solving.  At least I have 50GBps both way BB

2.8 Mbs here 😢

Expecting solid cloud, I took my C90 Mak to the meeting this evening just as a 'talking point' - I only took a photo tripod.

It did clear at tea break so we looked at the moon in the blue sky, with only the 32mm ep it's about 40x magnification.

When I left I noticed the sky had cleared and Jupiter was shining bright.

Only a couple of minute to set up again and those of us still there enjoyed nice, but low mag, vies of Jupiter, Saturn and the Moon.

All four jovian moons and the two equatorial belts were very obvious, and every so often the seeing settled and the red spot would pop into view. Geoff and I agreed it was at bottom left then I lookedit up on the Sky and Telescope app and yes it was abut an hour away from transiting (the C90 has a 45-degree RACI diagonal).

Saturn's rings were really clear, if tiny.

The moon looked lovely, and it wasn't to hard to spot the crater Moltke between the upper arms of the three-pointed peninsula in the Sea of Tranquillity and identify the Apollo 11 landing site.

Everyone agreed that the C90 is a fantastic grab and go scope with lovely crisp views, plus its cool Celestron rucsack!

14 hours ago, MSammon said:

This is with a 12” F 5.3 dob and Myriad XWA 3.5mm eyepiece. Can I get much clearer with my scope? 

You should be able to get sharper by stacking and processing. I did this a year ago April, using a 6" f87 - my 150PL.

A good target is to aim to get Aldrin, Collins and Armstrong craters. CXoolins is 2.4km across so resolving it suggests this is pretty much at the theoretical limit for my scope.

1 minute ago, johninderby said:

All scopes should have lifting/carry handles. So much easier to fit to the mount.

I've fitted a length of  aluminium section to the 'far side' of the tube rings on mine, as well as providing a handy place to attach a guide scope it's an extra 'grab point' for handling.

Wont it be rather harder to carry the bike lift to the mount than lift the scope ?

very nice pitures Stu, I'm a sucker for pictures with blue sky in.

2 minutes ago, Gina said:

Darks were at -20°C whereas the lights were at -27°C.  Couldn't get the temperature lower for the darks - weather has been too hot.  Do you think this is the problem?

Not if those figures are accurate.

A 0.25mm hole lets through as much sunlight as the full aperture of a 76mm scope with Baader film on it, but it will be defocused by diffraction and won't come to a point of focus.

A typical pinhole will be much smaller. You would need 25 tiny pinpricks 0.05mm across to let as much light through.

And how can sticking a patch on your film be less safe than sticking your film into a frame?

How close are the temperatures for your darks?

And are you feeling better?

Comment so I can follow this thread 🙂