22.08.2022 Lunt 60MT imaging trials continue: AR3085

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Monday 22nd 61F bright but very cloudy from the SW.  A few "teaser" gaps between the clouds. Early trials suggested I change to the 2.6x GPC to capture AR3085. A double spot with flaring mid northeastern quadrant.

09.49 First [half] decent image today. Pressure tuning the 60MT etalon for detail then focusing. 

  Yet again ImPPG is hardening and sharpening the imported, stacked image from AS!3. I am having to reduce L-R to minimum 0.5.

 

 

 

 

10.08  I have changed to the 2x Orion Shorty Barlow but was blocked from viewing by a huge cumulus cloud.

 Interesting curved filament over the lower left spot's umbra.

10.15 The seeing is too poor for the 2x Barlow but fun anyway.

 I have changed to 1000 frames instead of my usual 500. Still only stacking 50 frames.

10.31 This one opened in ImPPG without the
heavy sharpening.

 

 

 

 

 

 

 

11.00 It became progressively more cloudy. So I gave up. Hoping to return later if the cloud clears.

 Here is the complete image train with 2" Orion Shorty Barlow.. You can understand why I tried using a 2" diagonal to avoid having such a foolishly long assembly. The diagonal was quickly abandoned as too unstable and dangerous.

A long assembly is very prone to sag. Making collimation of the camera's optical axis impossible without external support. Tilting of the camera sensor could lead to all sorts of optical problems in the image.

 I can't just enclose the entire filter filter stack in a closed tube. It has to be fully accessible along its length for tuning and focusing adjustment in the middle. With the likely insertion/removal of further components along the length. This is vital when changing GPCs or fitting the Barlow. Some sort of external, tubular truss would work. Provided it was large enough and open enough for easy hand access. 

 Then some means has to be found to support the camera within the truss. The camera does have a rear, threaded screw hole. So it could be supported from a plate at the extreme end of the truss. The back plate would have to be adjustable along the length of the truss. So parallel tubes make much more sense than a tapered arrangement of tubes. 

 An open truss with baffle mounted components risks stray light entering the camera. Though the truss could be sleeved with a black, cloth sock. The truss must resist flexure in all planes. Because it rotates around its axis as the telescope tracks across the sky.  Ideally the truss wants to be as light as possible. To avoid a severe imbalance of the telescope. It must be stiff at the same time to avoid adding its own flexure.

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