The Visibility and Magnitude of M97's Central Star

[Scott Harrington]

Back in late 2023, when I was making last minute edits to Ronald Stoyan's Atlas of the Messier Objects (Second Edition), I didn't care for the magnitude he listed for the central star of M97. He called it +13.2 and wrote that "From 8 inches upwards, the faint central star can be seen. It lies on the bridge of brighter nebulosity, right between the two 'eyes.' Good seeing and high magnifications are required to achieve sufficient contrast between the nebula and the small diffraction disk of the central star (see M57."

I argued that it couldn't be nearly that bright since I had never seen it in my 10-inch (hadn't looked at M97 yet with my 16-inch), SIMBAD lists it as +15.77, and Steve Gottlieb's online notes state that only with his 24-inch "...the mag 16 central was readily visible using magnifications of 200x and higher." However, since it was too late in the season to reobserve M97 and too late in the editing process, Stoyan decided to leave it where I found it.

Well, I'm now working with Stoyan on another book project that will include M97 and have an observation of the central star to report. Using my 10-inch last night under skies that went from 21.5mpsas at 11pm to 21.35mpsas at 2am, I studied the planetary while it was almost directly overhead. At 260x and no filter, I saw the central star several times in the few minutes I looked at it. No doubt whatsoever. This means that it probably is around magnitude +15.8 and that only under world-class sky conditions could the central star be seen in an 8-inch. What really makes or breaks seeing it I would think is "seeing" since any blurring of it and it would probably disappear into the mist. Last night I had really good "seeing" and studied NGC 2440 at 400x.

Scott

[Mel Bartels]

I have a drawing of M97 though with a much larger 30".

Mel

[Uwe Glahn]

I could barely (not steadily), but clearly see the CS with 12" under 21.5 skies.

 

Uwe

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[Akarsh Simha]

I don’t think I’ve logged the central star of M97 before, but I do remember attempting AINTNO #47 on Jimi’s telescope: 

https://adventuresindeepspace.com/aintno.htm

I don’t think I succeeded seeing one star in each eye although someone else did I believe.

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[Steve Gottlieb]

Here's a link to the VIZIER page on a 2013 study.  It shows a B mag of 15.414 and a V mag of 15.777 for the central star.  That makes sense with our experiences.

Seve