B&W M42 from backward


Robert Pitt
 

Howdy folks: attached is an M42 pic from last night from my backyard (B&W no filters). Working on collimation, close but no cigar yet, but reasonably pleased with this one.

Regards,

Bob

 

Robert Pitt, Ph.D., P.E., BCEE, D.WRE

Emeritus Cudworth Professor of Urban Water Systems

Department of Civil, Construction, and Environmental Engineering

The University of Alabama

Tuscaloosa, AL 35487

Rpitt at eng dot ua dot edu

http://unix.eng.ua.edu/~rpitt/

 


Mark Copper
 

Hi Bob,

Thanks for sharing. It's fun to see you work.

Can you say more what you're thinking about regarding collimation? Seems like there is more coma in the stars on the left, esp. lower left than on the right hand side. It is something that you are working to eliminate? Or is it something you have to tolerate with a 1 degree wide target with your aperture?

Mark


Robert Pitt
 

Hello Mark:

My main home scope is an early 12.5 inch Hyperion (from Starizona, of Harmer-Wynne optical design, parabolic main mirror, spherical secondary, and corrector) that I’ve had for many years (replaced the C14 that is currently in the Chandler rolloff dome). My early photo use was with a large CCD but very low resolution, recently started using high resolution large field camera, hence my attempts to tweak the obvious collimation issues (probably fine before I started to mess with it!). I used a sight-tube approach to visually center everything (secondary adjustments). All the mirrors are fixed but all can be tilted. Sounds like a newt for adjustments, but not as straight forward… Got CCD Inspector, but as I found over the past few nights, need much better seeing for that to be effective. Hopefully better seeing coming up! Will also try MetaGuide (free) as it can handle any seeing. https://www.bing.com/videos/search?q=MetaGuide&docid=608019257482871016&mid=C49D3BEAD5CD2A7C340EC49D3BEAD5CD2A7C340E&view=detail&FORM=VIRE interesting video by the MG developer and his philosophy on collimation and guiding. Working on getting it to talk to camera and mount this afternoon and will keep trying collimation tonight. Yes, I am trying to eliminate the uneven star shapes, as this scope should produce well across the full field… Just felt like shooting M42 the other night, which looks ok, if small on screen!

Regards,

Bob

 

From: main@bas-astro.groups.io <main@bas-astro.groups.io> On Behalf Of Mark Copper
Sent: Sunday, November 15, 2020 9:43 AM
To: main@bas-astro.groups.io
Subject: Re: [bas-astro] B&W M42 from backward

 

Hi Bob,

Thanks for sharing. It's fun to see you work.

Can you say more what you're thinking about regarding collimation? Seems like there is more coma in the stars on the left, esp. lower left than on the right hand side. It is something that you are working to eliminate? Or is it something you have to tolerate with a 1 degree wide target with your aperture?

Mark