Imaging by Constellation

[Pat Curran]

Hi All,

New to imaging, so I'm wondering if I might start a project to give myself some practice using the  Comet Hunter and ZWO 533MM combo.

This book, 'Annals of the Deep Sky'

has given me an idea...why not image all the objects of all types within a constellation boundary. 🤔

The 731mm focal length of the Comet Hunter should yield a good compromise AoV when paired with the 533MM.

Anyone done this before?

I don't have NINA in front of me, but AFAIR, you can search for multiple objects within a constellation, but am unsure if you can search for individual stars.

Regards,

Pat

[JeremyS]

Good idea 👍🏻 

[Pat Curran]

Might be better to have a colour camera...Andromeda seems to have quite a few two colour double stars...

Any 533MC's on sale at FLO guys😉

[AstroMuni]

1 hour ago, Pat Curran said:

I don't have NINA in front of me, but AFAIR, you can search for multiple objects within a constellation, but am unsure if you can search for individual stars.

You could use a tool like Telescopius.com to get a list of objects in a particular constellation and then work your way through them.

[Elp]

How much imaging time have you got available, what sort of quality do you want, when do you want it done by?

The issue is, there just isn't enough time to do it reasonably quickly, it takes years. Some of the best sky surveys I've seen like this they have close to bortle 1 skies and climates which allow the majority of nights to image throughout the year, not once or twice a month like we get here. It all depends on your expectations as per my first paragraph.

[Elp]

It would also take an absolute age attempting it at long focal length if you want good quality, low noise, deep results.

[Pat Curran]

It's just a backdrop project to get experience imaging different types of objects...and hone equipment handling skills at the same time.

Not to be taken too seriousely with Irish weather to contend with...definately not going down the route of RGB filters on mono 533!

[Elp]

It's doable, you just need a lot of timescale. Doing it RGB/OSC with a widefield lens say 50mm or less it becomes more practical. If doing mono you'll be surprised what you can pick up in ha with a 14-24mm lens in one session.

[Pat Curran]

Think Messier Marathon confined to best place constellation during a month or so of fair weather.

Not looking for APODs at all...well maybe after a while.

[Pat Curran]

While waiting to see if I get approval from the boss to buy the 533MC, can anyone recommend a luminance/light pollution filter for mono only?

Thinking about this one...

https://www.firstlightoptics.com/narrowband/baader-uhc-l-ultra-l-booster-filter.html

Thanks,

Pat

[AstroMuni]

14 minutes ago, Pat Curran said:

While waiting to see if I get approval from the boss to buy the 533MC

Have you checked the 2nd hand market?

[Pat Curran]

Will do.

Been told to finance it by saving beer money! 🤔

[Elp]

18 hours ago, Pat Curran said:

can anyone recommend a luminance/light pollution filter for mono only?

Generally unless youre targeting narrowband emission gasses the best filter to use is any UV/IR or luminence filter. Most LP filters block out signal too, most forums I've looked at suggest as I have. I've owned a CLS and l-pro and didn't use them after an initial first trial, both of these were for OSC though.

[Pat Curran]

Thanks Elp,

Will certainly keep your comments in mind.

What's attracting me to the Baader filter is that in addition to it providing luminance, it also passes the two C2 lines to improve contrast of some comet tails. 

BTW, am I correct in thinking any luminence/LP filter cannot do anything to hold back glow from moonlight?

Thanks,

Pat

[Elp]

13 minutes ago, Pat Curran said:

BTW, am I correct in thinking any luminence/LP filter cannot do anything to hold back glow from moonlight?

Generally no as it's reflecting sunlight which is broadband light plus. LP filters reduce light transmission overall (so you'll see LP reduction too) but also hence the impact it has on signal passing through. Only narrowband filters reduce it significantly, the tighter the bandpass the better but O3 signal still gets affected, but you need to be imaging or viewing a strong narrowband emission target with said filter.

I generally rarely image true RGB in my bortle 7, it's extremely difficult post processing the results to the point it's usually not worth it. Only if the target is sufficiently high enough does it work okay. If it's an emission target I can use the lextreme with my OSC cameras, but if I want true star colour (and target signal) the only filter in use is a UV/IR cut or luminence, they're essentially the same thing.

[Pat Curran]

Thanks again  Elp,

I have tried imaging C/2023 A3 (Tsuchinshan–ATLAS) whenever the weather was good recently, but whilst I am in a bortal 4, the local town lies 4 miles to the south and has significant LP affecting any imaging in that part of the sky.

To date, I have no filters in use so a luminence/LP filter is my next FLO order. 

Do you see anything wrong with the Baader for a mono only imaging run on the Comet?

Link again...

https://www.firstlightoptics.com/narrowband/baader-uhc-l-ultra-l-booster-filter.html

Thanks,

Pat

[Elp]

I don't think that filter will work as it's a wide bandpass narrowband filter concentrated on HA (plus overlap with S2) and O3. It won't work well on a broadband signal object like a comet. There's many discussions about LED light pollution filters. They don't work, well. Hence why I suggested to use a luminence filter only. Don't confuse a lum filter with a LP filter as they are different. We only use UV/IR cut or lum filters to reduce IR bloat around stars, they otherwise allow all visible light through. I've imaged comets reasonably well from a Bortle 7, and I'm surrounded by LED lampposts and industrial light.

[Pat Curran]

Thanks again Elp,

What luminence filter would you recommend in order to end up with the best possible black and white image of a comet from a bortal 4 sky?

Pat

[Elp]

Any really, I've got three different ones, one made for Optolong, an actual Optolong one and an Astronomik (L2 I think), they all pretty much perform the same.

[Pat Curran]

The FLO description of the Astronomil L1 UV+IR Blocling Luminance Filter reads in part:

"L1, L2 or L3?

If you use an optical system that is completely free of any chromatic aberration you should get an L1 filter for your setup."

If I am correct in thinking the Comet Hunter, being a Mak-Newt design, it has  little or no chromatic aberration... then therefore the L1 variant is best suited to my setup?

...or is there any real improvement to be had in using the L1 variant over the L2?

Thanks,

Pat

[Elp]

If the optics are well corrected already I think they'd be minimal difference between them. They have the range more for refractors I believe.

[Pat Curran]

OK, L1 it is so.

Here is my first attempt at Comet C2023 A3 (Tsuchinshan-ATLAS).

Comet Hunter (731mm FL @ f4.8) + ZWO 533MM: 26x 60sec subs with no calibration frames taken. Sensor cooled to -10C.

Date 10th May 2024

The field is 53' 11'' square (0.89 x 0.89 Degrees)

[Pat Curran]

...I am very open to criticism! 😮‍💨

[Elp]

Looks like you've stacked it fine and captured the subject, just wondering why the image is so dark and lacks contrast, the stars at least should be bright.

[Pat Curran]

Are my subs too short and too few?