Ad Astra Observatory

I had nothing but trouble the last time I tried H-alpha imaging with the D70. I bought a 2” Baader filter, and decided that the Astronomik filter slide system would be perfect.

In short, nothing worked.

I had no method of autofocus at the time, so focusing was a nightmare.

The filter drawers couldn’t attach to the camera properly (the camera’s flash unit overhangs the T-ring).

The filter wouldn’t fit in the filter drawers — Baader makes these extra-tall filter holders. I bought some empty 2” filter rings to fix that problem, and the filter rings wouldn’t fit.

Even if I got it to fit, it would throw off the focal distance of the MPCC.

In all, it was about 3 months of throwing good money after bad to get the thing working and never got it right. So I sold it all off and decided that I would revisit this if something changed.

…

Something changed.

Astronomik now has a line of T-threaded filters! So they are neatly between the 1.25” and 2” size, but best of all, they screw right into the T-ring. This means that my problems of getting the camera to be oriented properly between filter changes goes away (I hope). And, if focusing is still a problem (despite FocusMax, etc), there’s a parfocal T-threaded luminance filter for $80. Nice!

The new Ha filter showed up this afternoon.

I look forward to trying it out on the summer nebulae!

I will probably press Pumpkin into service for this task at first — bigger FOV means less chance of missing the target, plus most Ha regions are big. And if I miss focus a little, I can resize down a lot.