Am I right to be confident? ...... spacing (!!)

[swag72]

2 nights ago, I thought I had pretty much nailed my spacing between the 314L and the SW 120ED. The reducer required 55mm. I hadn't measured it at this time as when I bought the Atik, it was supplied as having the right spacing. I was pretty happy with things, but just needed a little tweak in the one corner

Fast forward to last night, when I'd decided that I needed to get the camera even closer to sort out that corner - Everything was tighter than a sharks bottom and still things just seemed to be getting a little worse I thought it was my guiding playing up and so I fiddled with the settings in Maxim until 0200 when I just gave up Graph nice and flat, but stars just not round, even with 3s subs. That should have told me to rule out guiding errors, but I was fixated that was the problem.

This morning, a few more minutes ( ..... hours really!) spent in the obs and the imaging train taken off and the digital caliper came out - This was getting serious! I only had 53mm spacing when I measured it and no where left to turn, tighten or loosen. Perhaps it was no wonder things were getting worse the night before (I was continually lowering the spacing further!)

Head scratching and I remembered that filters add 1mm (quick search, check and dumb post on here....) Result, one more mm gained, only one more to go. Then I found a washer and put that between the reducer and filter wheel and tightened it all back up. The result is ...................... 55mm!!!

So, I ask you do I have a right to be confident for testing tonight? Is this going to be right? Is there really a world of difference between 53mm and 55mm?

P.S - For anyone brave enough to click on my posts and read them, I salute you!! They are pretty 'samey' and usually make me look rather silly

[ollypenrice]

2 nights ago, I thought I had pretty much nailed my spacing between the 314L and the SW 120ED. The reducer required 55mm. I hadn't measured it at this time as when I bought the Atik, it was supplied as having the right spacing. I was pretty happy with things, but just needed a little tweak in the one corner

Fast forward to last night, when I'd decided that I needed to get the camera even closer to sort out that corner - Everything was tighter than a sharks bottom and still things just seemed to be getting a little worse I thought it was my guiding playing up and so I fiddled with the settings in Maxim until 0200 when I just gave up Graph nice and flat, but stars just not round, even with 3s subs. That should have told me to rule out guiding errors, but I was fixated that was the problem.

This morning, a few more minutes ( ..... hours really!) spent in the obs and the imaging train taken off and the digital caliper came out - This was getting serious! I only had 53mm spacing when I measured it and no where left to turn, tighten or loosen. Perhaps it was no wonder things were getting worse the night before (I was continually lowering the spacing further!)

Head scratching and I remembered that filters add 1mm (quick search, check and dumb post on here....) Result, one more mm gained, only one more to go. Then I found a washer and put that between the reducer and filter wheel and tightened it all back up. The result is ...................... 55mm!!!

So, I ask you do I have a right to be confident for testing tonight? Is this going to be right? Is there really a world of difference between 53mm and 55mm?

P.S - For anyone brave enough to click on my posts and read them, I salute you!! They are pretty 'samey' and usually make me look rather silly

Confident that imaging gear is going to work??? Are you mad? Did you ever know anyone whose imaging gear was so stable that they could go out at night and expect it to work????

Seriously your chip spacing sounds right but will that be the issue on a small 285 chip? Not sure... I'm surprized it's that critical.

Olly

[Stephen]

As per Ollys comment, expect failure, be suprised

If you've still got an issue in one corner after this, you're probably looking at something else other than the spacing. I think there's +/- 1mm tolerance in it, and the smaller the chip the less it matters at all!

[swag72]

................. And ......................... down to Earth with a bump

Thanks both!!!