When the sky is capped, a fellow's mind turns to the shop. . .

Jan 20-23. So I've turned an adapter for the ST2000XM, an extension for the G11, the micrometer focusing rig for the A-P, and an adapter for the Giro to fit the Linhof. Maybe it's time to get a little more ambitious...

Continue reading about
The SN10 Rebuild

Feb 22. Where was I? I put the 5-inch A-P back on the G11 with a new guidescope mounting arrangement. No DSBS. The guidescope rides in an inverted Losmandy clampblock originally intended to attach 3-point rings to a DMM plate -- it's a little trick I made up looking for a way to attach the guidescope to the SN10 without much weight.

I aligned everything on the Moon and then dialed in M81 and M82 using the G11's stock, old-fashioned setting circles. Why don't I use these more often? They made navigating the high polar sky a snap. Sure beats pining after goto and DSC's.

For variety's sake and because I want those polar streamers in M82 (and also because the night's imaging began with a waxing almost quarter Moon high in the sky), I shot with the H-a filter. Wind and truly dreadful seeing are problems tonight. The weather service says the wind is steady at 20mph with gusts to 40, and the pines roar accordingly. A few blasts make it to ground level. When I am outside, I feel them; when inside, I see their effects on the tracking plot. In the images, the wind and seeing look like poor focus.

For all its bluster, this is a balmy February evening. The ST2000XM wouldn't reach -35C, so I'm using -30C. Which means I need a dark frame, which means I didn't want to shoot 30 minute subs. (I shot a dark, but several of tonight's frames refuse to calibrate. I'll figure this out tomorrow. If they had, I could have processed the shot at right more aggressively.).

Compare this shot to the one on page 16. It's flipped left for right (no star diagonal this time) and the previous image shows more structure (but less H-a detail, naturally).

 

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Cameras behind Telescopes:
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26 | 27 | 28 | 29

Text & Photos by David Cortner
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get in touch for other uses.

 

The Parts Bench:
3-inch Unitron rebuild project on the left,
Meade 10-inch Schmidt-Newtonian on the right.

 

2 hours, 5-inch A-P at F4.3
ST2000XM, -30C, Schuler 10nm H-a.

I think you can look for a
10-inch comparison image soon.