JamesF

27 minutes ago, JeremyS said:

I’ve no idea who he is talking about 

🤔

Nor me.  I barely have enough for a different one each month, and that hardly seems excessive.

James

I'd agree with jambouk that it won't necessarily increase the field of view because there may be other limitations of the optics that prevent doing so in any useful manner.

It must reduce the effective focal length of the entire optical train when compared to not having a reducer however, because of the way focal length is defined.  If it didn't then it wouldn't be acting as a reducer.

James

6 hours ago, randomic said:

Although I can't find a reference I've read that, for an SCT, the focal length changes by approximately 3mm for each 1mm of backfocus

I'd have thought that's dependent upon the focal ratios of the primary and secondary?

James

I recall Steve (from FLO) posted a while back saying that supplies are very unreliable.  As an example I think he said that they'd been waiting for one shipment to fulfil a number of orders for the Skywatcher ED80 and when it arrived there was only one ED80 with the shipment, to share between all of the UK vendors.  It all sounds like a bit of a nightmare really.

James

4 hours ago, paul mc c said:

Maybe its a conspiracy against all the good looking astronomers....😁

Could be.  It's been working fine for me.

James

"mc" is presumably "multi-coated", if that helps with a search.

James

Something about it just screams old-school Baader to me, but I don't even know if they made such an eyepiece.

James

17 minutes ago, wimvb said:

To bring out the colour, I used arcsinh stretch, which is also available for photoshop

Is this available natively?  I have one that is allegedly a "fair" approximation done as actions, but if it can be done directly please tell me more.

James

18 minutes ago, Padraic M said:

It eventually occurs to you that you have been collecting lots of expensive equipment but you haven't actually taken a photography in years.

Crazy!

Hey, if it makes you happy, who is to say that it's wrong?

James

Adding the barlow moves the focal plane "further out" of the focuser, diverging the light cone from the primary mirror to the point where it will reach the image sensor in the camera, which is why it now works.  The problem without the barlow is that the focuser doesn't allow the camera to be moved inwards far enough to reach the un-barlowed focal plane.  That's why shortening the tube, thereby moving the primary mirror closer to the camera worked for Art Gecko -- effectively it moves the focal plane out of the focuser by the same amount as the mirror is moved upwards.  It's not a perfect solution however, because the secondary mirror may not be large enough to capture the entire image reflected from the primary, so you can end up "throwing away" part of the image.

Replacing the focuser with one that allows the camera to be moved in further would probably help, but quite possibly it would be cheaper to buy a 130P-DS than to replace the focuser.

If you're happy with what you're achieving with the barlow for the time being however, then just crack on and enjoy yourself

James

I shan't be at the star camp -- opposite end of the country to me, but the homebrew comments caught my eye   That looks like a very pale brew.  I was expecting more red colour from something called "copper".

This is my glass at the moment:

Made to a recipe for Old Speckled Hen.

James

12 minutes ago, rnobleeddy said:

Interesting. I've been looking to get a cheap second hand Canon with an 18MP sensor because somewhere I read they were less noisy, but I don't think I've seen anywhere that tries to quantify that. Also because I want to try astromodding on something cheap!

Have a search for Gary Honis's website.  He did quite a few comparisons of Canon DSLR models that might be useful.  As I recall, there are cameras that are better than the 450D in terms of noise, but not that many.

James

12 minutes ago, rnobleeddy said:

a better, less noisy sensor than the 450D.

I believe, for what it's worth, that the 450D sensor is actually one of the better ones in terms of noise, though more modern cameras may have other advantages for some people, such as the flip-out screen.

If you're on a budget, second hand is definitely the way to go.

James

Ah.  Bit more of a problem then

James

I find myself wondering if it even needs to be there at all?  Or does the camera report a fault if it isn't?

James

I still use Windows for processing because that's what my copy of Photoshop is for, but I have been meaning to give this a try at some point:

https://github.com/Rolf-Hempel/PlanetarySystemStacker

James

Someone reported that there was a problem with Quicktime a couple of days back.  That definitely used to work, so I'm wondering if Apple have dropped support for some codecs.  I wasn't aware that VLC didn't work though.  There's a setting to write Windows-style AVI files.  You could try enabling that (or disabling it should it already be set).  I don't know it will work, but it's worth a go.  Really useful feedback anyhow, so thank you.  The project has become something of a beast and testing everything has got a bit beyond me with the last couple of releases.

Personally I prefer SER format for planetary imaging these days, but it does generate larger files.

James

4 minutes ago, laudropb said:

Can I ask where you got the thumb screws John ?

ye-olde-torture-shoppe.com ?

Oh, not those kinds of thumbscrews

James

I'll pull in the latest SDK with the next release, so that should support the 269C by default.

James

1 hour ago, Ouroboros said:

@JamesF   OK Progress so far ....  I've downloaded oaCapture 1.7.0. onto my MacBook.

 At present I'm just using a QHY 5-II-M  mono camera to test it with. 

oaCapture finds the camera as:  (QHY) QHY5 (no firmware).  Can I assume from this that I don't have the right drivers installed?  Interestingly KStars has no problem finding the camera.  

When I click on the camera oaCapture closes and I get an error message saying "oaCapture quit unexpectedly" 

Sorry to trouble you. 

I'll check on that.  I have a QHY5-IIm I think.  If it says "no firmware" it means the camera does not have the firmware loaded, but it should load automagically so I don't know why you're seeing that.

James

Oh, I see.  One of them is the Sun.  That's definitely a unique planet

James

"you get 10 unique planets"

I wasn't expecting that.

James

17 minutes ago, Ouroboros said:

I’m slightly concerned about a thread on SGL which seems to refer to an issue between oacapture and KStars/ekos/INDI. I don’t want to muck up my KStars set up I use for  imaging. 

That should be a Linux-specific problem.

James

Have a play with it.  See how you get on.  Once I'm relieved of the opportunity to work at the end of the month I shall be spending more time on it, too.

James

1 minute ago, Ouroboros said:

Thanks. Quick response. Is it good? 

Of course.  I wrote it

James