127 Mak M5 -- a second attempt

[JamesF]

Better than the last one, but still not as crisp as I'd like. Keep on trying...

20 subs of 45 seconds, 127 Mak & 450D, stacked in DSS.

James

[astro mick]

Hi James.What a shame,just a tweak on the focussing,and it would be an exerllent image.Your not too far away at all.

If its not the focussing,it just looks a little soft.

Mick.

[JamesF]

Focusing is quite tricky. I've never managed to get a Bahtinov mask to work to my satisfaction with this scope and without GOTO it's pretty much impossible to focus on one star and then slew to something you can't even see. Most targets don't show up in live view either, so I end up working entirely off APT's FWHM value and focus scores calculated from single subs which is tricky to say the least, especially when the mount is marginal at best. Sometimes I do make things hard for myself

James

[luigis]

I also own a Mak 127, I know your pains

I bought a Bahtinov mask from a UK seller via ebay for my Mak, it works really well. But why can't you focus on a bright star before anything and then do the alignment or whatever you do to image? Strange!

The Maks are really picky about temperature changes, I let mine out 2 hours before imaging and re-adjust the focus every 1 or 2 hours depending on the temperature changes. APT can help you do that

if you add the temperhum sensor, it's also good to monitor probable dew.

Finally I've found that at such long focal length the sharpness really depends on the seeing, some nights it just doesn't work at all.

Hope it helps, M5 looks nice!

[JamesF]

If I put the camera on and focus on a bright star with the mask, say, then I can't swap to find the target an eyepiece because that will disturb focus. Neither can I see the target in live view. I might be able to find the target with an optical finder, but not necessarily accurately enough to get it on the camera sensor.

How would you do it?

James

[luigis]

If I put the camera on and focus on a bright star with the mask, say, then I can't swap to find the target an eyepiece because that will disturb focus. Neither can I see the target in live view. I might be able to find the target with an optical finder, but not necessarily accurately enough to get it on the camera sensor.

How would you do it?

James

I understand now, you are using an eyepiece to find the target. Well without goto it is indeed a bit of a problem!

You may try centering your target, putting the DSLR on the scope and then unclutch the DECl or AR know but only that one and sweep to see if you can find a star that may be used to focus in live-view then you can return to your target as you only need to move back to the original position.