globular

Roughly speaking, when the exit pupil multiplied by secondary obstruction % is about half or greater than your dilated pupil then you'll see it. So in Louis examples; lets guess his secondary obstruction was 30%; and he started to see it around 5mm exit pupil; when secondary exit pupil was 30% * 5 = 1.5; so his dilated pupil when looking at the moon or sun was probably around 1.5 * 2 = 3mm. When dark adapted his dilated pupil is probably 6 or 7 (if he's lucky); so the exit pupil of the secondary would need to be 7 * .5 = 3.5; and the full exit pupil would, in that case, be 3.5 / 30% = 11.5mm; you'd be mad to create an 11.5mm exit pupil when your own pupil is only 7mm - seeing the shadow won't be the only problem you'd face. (And Louis isn't mad - hence why he's never seen it when dark adapted).

Very impressed. It looks like the filter screws into the slider (rather than just drop in)? So I'm guessing you'll make a slider for each of your filters for quicker, easier changes? And a nice storage box to slide them all in for safe keeping will be on the cards too no doubt?

Connecting an M54 into my train won't be an issue - I've accumulated lots of adapters over the years - but if you're modifying an existing rasa connecting plate to make this then you won't have a surplus of them to make more. No worries. Keep posting updates - can't wait to see the finished working version.

Looking very good If you're up for making more than just for yourself then I'd be interested in buying one or two. (Not for a RASA but for minimising back focus usage with binoviewers on an EdgeHD.)

Thanks both. I'm not scared of collimating (ok, I am a bit scared) but I'd rather spend the few opportunities I get to observe observing rather than fettling. Sounds like the Mewlon ticks that box.

Sorry to butt in momentarily but, for my future reference, how well does a Mewlon hold it's collimation once you get it right? If it's just on and off a mount and into and out of the house should it stay 'forever'? Or do they just naturally lose it over time - no matter how carefully it's handled? Many thanks

Stop. You'll have me in stitches.

Would Edward know? I think he would.

Friday at 10pm is my best forecast for I don't know how long... but something tells me I shouldn't be an amber gambler.

Have you considered the Pentax XW40? It's 700g so is heavier than the LVW's 550g - but not by 'that much'. And there are none of the distortions and varying magnification described by Michael in the LVW - and it's the same price. I love mine.

Where is the jealous emoji? Good luck with Triton

Fairies pinch the power to charge their 90s game boy consoles. In cold weather the fairies also use the power to heat their wing warmers.

The 8"CC has an 8.4% secondary obstruction ==> 7.4" effective aperture The 9.25" SCT has a 13.1% secondary obstruction ==> 8.0" effective aperture The 10" CC has an 10.9% secondary obstruction ==> 8.9" effective aperture The 11" SCT has a 11.6% secondary obstruction ==> 9.7" effective aperture Personally I'd make sure I was really getting everything possible out of the 8" CC before concluding I need more aperture. It should be capable of producing stunning planetary images - not that far behind a 9.25% SCT (non edge hd). Are you really sure it's lack of aperture that's holding you back? It could be a multitude of other things. But if you're adamant more aperture is what you need / want then I think you need a step up bigger than a 9.25" SCT to make the extra spend worth while.

Lovely

Wow, impressive.

Call your SSID "InternetFor£10perMinute" and no one will go near it 😉

Hiding SSIDs really doesn't provide any extra security. It might stop a casual attempt at joining your network - that will likely be kept out by the key and/or mac address security - but a real hack attempt won't bat an eye at a hidden ssid. I used to hide mine years ago - but I don't think it worth the hassle it causes when connecting new devices to bother any more.

Something for ZWO to fix then. Was worth a try - sorry it took up so much time.

I was going to reply to this thread earlier, but then I couldn't find it.

Again, you could temporarily disable mac authorisation while you add the seestar. You can then see the mac address on your router so you can turn authorisation back on and enter the correct mac address.

You could try temporarily unhiding your ssid so you can add it to the seestar. Then, once added and saved, hide it again. It should connect again once added even if hidden.

I find it very accurate and very reliable. The only time it fails to align is when I forget to take the lens cap off. Is it worth the money? Only you can decide that. It will cut your 10 minutes aligning down to zero. (It takes a minute or two - but you can be doing something else while it does it... I go and get my eyepiece case and it's done when I get back). So how much is 10 minutes worth to you? How long does your CPC take to cool - maybe the few minutes you've saved won't actually get you any more quality observing time? Do I think it's worth it for me? YES. I love it and wouldn't have a driven goto mount without it. I use my scope much more often because there is no lengthy set-up process that would to put me off bothering on those all to common iffy partly cloudy nights. It's like a grab and go manual experience with goto and tracking.

You are doing the right thing - get the scope and see how your existing EPs work in it. I will repeat my earlier comment on exit pupil though. Your 40mm plossl will give you an idea of the FOV you can get - but I suspect the way the FOV is presented will not be very good, and not representative of what a higher power but wider eyepiece would produce. With an exit pupil of over 8mm you will not be able to get all the light from your scope into your eye all at once. This means the image will be dimmer and is akin to losing some of your telescopes aperture. Your scopes aperture is already small at 102mm so I'm not sure you'll enjoy the view when giving up a significant proportion of it. If your eye's pupil size is, say 5mm, then you're losing about 22% of the light when using a 40mm eyepiece - so the brightness will be like that from an 80mm telescope (although the magnification and field of view will be that of your 102mm scope). My guess is that the best wide field views you'll get from that scope will be using a 20 to 25mm eyepiece.

Agreed. If I remember correctly, that part of the book is talking about the importance of aperture - so I think he couldn't help but put it first.

In the copy of Suiter's book that I have the 'wobbly stack' items are listed without numbers or an order of importance - rather they are roughly stacked in the order that light from the object travels through the 'system'. Read your list above with that in mind and you might agree that the same applies to Roger Vine's reproduction of the stack too.