NGC 3372 - EAA Version

[floyd_2 (Dean)]

I've been a visual astronomer for more than 30 years, but age and light pollution are starting to catch up with me so I recently turned to EAA to help me stay in the hobby that I love. I don't really have the time (or skills) to produce the amazing images that others here show, so I try to squeeze what I can into relatively short sessions of 2-3 hours including viewing a number of objects EAA-style in any one sitting.

We've all seen NGC 3372 before - sorry to do this to you all. It's taken a bit of courage to show anything here as the work I see from others is just stunning. I thought Id show what's possible with relatively short / few exposures for anyone losing interest in astronomy. EAA has lit a fire in my belly and I'm back big time. I've seen more using my current rig than averted vision has ever allowed under suburban skies.

This one was taken with a Sharpstar 94EDPH triplet with reducer / field flattener, AZ-EQ5 guided (perhaps not well but I'm working on that) , ASI533MC-PRO (gain 101, cooled to 0C and no calibration frames) and Sharpcap Pro. I just used an IR filter in the hopes of preserving colour. Being colour blind I'm not sure how well I went at that but I think it's possibly ok. It's only 12 x 40 second frames - just EAA astronomy and not further processed, but I'm loving how much more I can see in nearly real time with my gear. I should have done this a lot sooner.

[Dave882 (David)]

Great stuff Dean- yeah I’ve come to the same conclusion from the suburbs in Sydney. As much as I still crave a view through the eyepieces I tend to go EAA unless I’m somewhere dark. Opens up a whole new realm of possibilities when you’re livestacking! I often use a guided GEM for eaa as well (even though shorter exposures are quite acceptable on an alt-az) and when using a GEM I’ve found that increasing the individual sub lengths can expand the reach of the camera even more (as in, 5x 1min subs can sometimes reveal more than 10x 30sec subs) especially for the fainter stuff. I also find playing with the live histogram stretch is also a lot of fun, teasing out detail in the darker and brighter areas back and forth in real time.
Thanks for posting!

[floyd_2 (Dean)]

Thanks David. I really appreciate your comments mate. I started out with EAA using ALT-AZ and thought it was quite acceptable, but eventually started to get the feeling that field rotation was losing too much of my field. I had never done a polar alignment before and always avoided drift alignment because I'm fairly time constrained. I finally bit the bullet and used Sharpcap for my polar alignment in EQ mode and it was so easy. Why did I wait so long? What a chicken! I'm glad I finally took the plunge as I can now take longer exposures, and it's brought out so much more colour in my shots. Whether or not it's the right colour is another story. All of my previous ALT-AZ short exposures (15s and thereabouts) had a green cast that I just couldn't deal with. Longer exposures give results that are significantly better than what I was getting in terms of colour and detail. I guess there's a point of diminishing returns under my skies but so far so good.

I'm eyeing on the Optolong L-Extreme now but worry that I'm going to start fighting with colour again given that it's narrowband. My CLS and OIII filters give good results, but the colours are terrible with my OSC. Have you tried the L-Extreme for EAA before?

[Dave882 (David)]

Yes I found the same green cast with short exposures on my alt-az as well. Not sure what it is but it’s 100% better with longer exposures as you have noted.
Yes I use an l-extreme for eaa. It’s brilliant - absolutely brilliant!! Just pick your targets carefully as it doesn’t give nice star colours and cuts out reflection nebula. It’s great for shooting into the city light glow or during full moon. You do need to increase sub lengths by about 2x tho. Flats as highly recommended otherwise you can get some crazy effects over the field

[Startrek (Martin)]

In regard to green casts here’s my experience......
Here’s a comparison of subs with imaging NGC 3372 Carina under Bortle 7/8 in Sydney compared to Bortle 3 South coast NSW
Same camera 2600MC , same settings , same sub exposure time ( 180 sec ) and both using the Optolong L Extreme filter
Moon phase was waxing around 25 to 30%

My green cast on the Sydney sub is definitely Light Pollution with a bit of moon glare thrown in.

I never ever get a heavy green cast on my subs down south under Bortle 3
When the moon is heading towards full , there’s a slight cast but not heavy green

Hope the above and attached helps

Cheers
Martin

[floyd_2 (Dean)]

Interestingly I've never had much interest in open clusters as a visual observer over the years. Being colour blind has really held me back in that area as the colours are part of the beauty of open clusters. However, with EAA and medium exposures I've noticed that the colours are strong enough for me to be able to clearly distinguish them. Thanks to EAA I now have an interest in open clusters that's eluded me for the last 30 odd years with all manner of telescopes! It's a bold new world for me

I'm going to keep an eye out for an L-Extreme btw and will try my hand with one Thanks for the tips.

[floyd_2 (Dean)]

Originally Posted by Startrek

My green cast on the Sydney sub is definitely Light Pollution with a bit of moon glare thrown in.

I never ever get a heavy green cast on my subs down south under Bortle 3
When the moon is heading towards full , there’s a slight cast but not heavy green

Thanks Martin. That's a significant difference, and an excellent like-for-like comparison. Light pollution is the scourge of the skies for astronomers. My Bortle 5-6 skies aren't much chop but I'll take what I can get I have a lot of trouble balancing out the green when using my filters. I guess that they're rejecting most colours other than green, and the OSC camera being more sensitive to green isn't helping at all. My 12yo daughter likes viewing with me and has a better touch for balancing the image as it evolves.

Maybe part of the equation is the sub duration. Not sure on that score but I might experiment further. Certainly, only using an IR gives much better colour balance at the expense of exposing sky glow rather than rejecting it. What a tricky business this is!

I shot an image of the same nebula using my C9.25 at f/6.3 (a comparative zoom shot) using an OIII and there was so much more to see compared to not having a filter, but the colour was terrible

[Tinderboxsky (Steve)]

Great to see your post, Dean.

Definitely best not to worry about comparisons with other dedicated astrophotography images posted here. It is a “chalk and cheese” comparison. In my view, EAA observing is all about using technology to observe in almost “real time” and then moving onto the the next object. The techniques are quite different and will always lead to a different type of image outcome. It is not the quality of the image produced, but rather the significantly enhanced observation that is possible.

It is a shame there is not a separate EAA observing forum within IIS. I think there are now many more experienced “observers” such as yourself and David who are now predominately EAA observers. I, too am rapidly transitioning to predominantly EAA observing. I know this has been raised in the past to no avail. I have been thinking of experimenting with some EAA observation reports within the existing “Observation Reports” sub-forum. This of course, was the domain of visual observation reports, but is slowly "withering at the vine” because of lack of support and reports.

Originally Posted by floyd_2

I've been a visual astronomer for more than 30 years, but age and light pollution are starting to catch up with me so I recently turned to EAA to help me stay in the hobby that I love. I don't really have the time (or skills) to produce the amazing images that others here show, so I try to squeeze what I can into relatively short sessions of 2-3 hours including viewing a number of objects EAA-style in any one sitting.

We've all seen NGC 3372 before - sorry to do this to you all. It's taken a bit of courage to show anything here as the work I see from others is just stunning. I thought Id show what's possible with relatively short / few exposures for anyone losing interest in astronomy. EAA has lit a fire in my belly and I'm back big time. I've seen more using my current rig than averted vision has ever allowed under suburban skies.

This one was taken with a Sharpstar 94EDPH triplet with reducer / field flattener, AZ-EQ5 guided (perhaps not well but I'm working on that) , ASI533MC-PRO (gain 101, cooled to 0C and no calibration frames) and Sharpcap Pro. I just used an IR filter in the hopes of preserving colour. Being colour blind I'm not sure how well I went at that but I think it's possibly ok. It's only 12 x 40 second frames - just EAA astronomy and not further processed, but I'm loving how much more I can see in nearly real time with my gear. I should have done this a lot sooner.

[floyd_2 (Dean)]

Interestingly I recently found SkyTools 3 Pro in my software arsenal, which is an ok planning and logging tool. It's a bit antiquated now and has been replaced by v4 which I don't have. However, v3 is still decent for adding EAA pics to objects, adding notes to objects, and above all for generating observing plans for an evening. It does a whole lot more, but those functions are nice. I might start using it again to plan my evening sessions and perhaps start to take notes as an image builds in SharpCap Pro.

Originally Posted by Tinderboxsky

It is a shame there is not a separate EAA observing forum within IIS. I think there are now many more experienced “observers” such as yourself and David who are now predominately EAA observers. I, too am rapidly transitioning to predominantly EAA observing. I know this has been raised in the past to no avail. I have been thinking of experimenting with some EAA observation reports within the existing “Observation Reports” sub-forum. This of course, was the domain of visual observation reports, but is slowly "withering at the vine” because of lack of support and reports.