Recent astropics by Pitt


Robert Pitt
 

Howdy folks:
I have been trying to take some pics from my backyard observatory (currently using a C9.25 f/10 with a ASI 2600MC camera) to figure out combination of light pollution filters and exposure subs. Attached shows 3 from late last week (along with an earlier one from Chandler with my RASA11 no filters and also with the 2600):

https://www.flickr.com/photos/bobpittphotos/albums/72157682328334220/with/48589951732/

I confirmed some obvious issues: narrow band light pollution filters (such as Lumicon Ultra High Contrast, L-Extreme, and Optolong Triad plus) require loooong exposures. Even with 10 minute subs, had lots of stacking failures (not enough stars to align). The Triad worked well with bright Ha and/or O3 objects. In all cases, 3 to even 12 subs at 10 min each left lots of noise. Played with reducing noise, but much more exposure would be best. These narrow band filters also play havoc with the color balance (again Triad was best for classical emission neb subjects), but as expected, galaxies were poor. For galaxies, the Baader Moon and Skyglow (wide band) filter seemed to work well in my light polluted backyard. The Chandler M81/M82 pic shown was with no filter was probably reasonable. In all cases, please excuse my amateur processing skills (and a couple of my framings could be better!)....

In case you are bored, you can even look at some of my other pics at:

https://www.flickr.com/photos/bobpittphotos/albums/with/72157682328334220

Regards,

Bob





Steven Grunfeld
 

Thanks for sharing. Steve Grunfeld


On Jun 20, 2021, at 9:38 PM, Robert Pitt <rpittal@...> wrote:

Howdy folks:
I have been trying to take some pics from my backyard observatory (currently using a C9.25 f/10 with a ASI 2600MC camera) to figure out combination of light pollution filters and exposure subs. Attached shows 3 from late last week (along with an earlier one from Chandler with my RASA11 no filters and also with the 2600):

https://www.flickr.com/photos/bobpittphotos/albums/72157682328334220/with/48589951732/

I confirmed some obvious issues: narrow band light pollution filters (such as Lumicon Ultra High Contrast, L-Extreme, and Optolong Triad plus) require loooong exposures. Even with 10 minute subs, had lots of stacking failures (not enough stars to align). The Triad worked well with bright Ha and/or O3 objects. In all cases, 3 to even 12 subs at 10 min each left lots of noise. Played with reducing noise, but much more exposure would be best. These narrow band filters also play havoc with the color balance (again Triad was best for classical emission neb subjects), but as expected, galaxies were poor. For galaxies, the Baader Moon and Skyglow (wide band) filter seemed to work well in my light polluted backyard. The Chandler M81/M82 pic shown was with no filter was probably reasonable. In all cases, please excuse my amateur processing skills (and a couple of my framings could be better!)....

In case you are bored, you can even look at some of my other pics at:

https://www.flickr.com/photos/bobpittphotos/albums/with/72157682328334220

Regards,

Bob





Don Waters
 

Good job, Bob. Thanks for sharing.

How long were exposures with RASA11? I assume you could get much shorter.

Don


Robert Pitt
 

Hello Don:
Thanks! The M81/M82 RASA11 subexposures were 3 minutes. I seem to normally use 30sec to 3 min subs for the RASA. I try for the longest possible subs, and the most subs possible. The subexposure lengths are usually based on mount accuracy, but am worried about blowing out bright areas. Varies with filters too. The M81/M82 at Chandler did not have any filters as was trying for natural color balance. In the past, I have used narrowband Ha filters at Chandler in the RASA (using the special Baader high speed filters) with 60 sec subs for bright objects (helix, lagoon, eagle, etc.) with the ASI 1600MM.
Regards,
Bob

-----------------------------------------

From: "Don Waters"
To: main@bas-astro.groups.io
Cc:
Sent: Monday June 21 2021 7:45:58AM
Subject: Re: [bas-astro] Recent astropics by Pitt

Good job, Bob. Thanks for sharing.

How long were exposures with RASA11? I assume you could get much shorter.

Don