NGC 891 & Friends

[Davide Simonetti]

The galaxy NGC 891...a quick and easy target because we weren't sure what the weather was going to do and there was a full Moon and stronger than usual winds to contend with. After a cloudy evening, the night sky became beautifully clear and NGC 891 was well situated for imaging. The shot was framed in such a way as to show some of the other galaxies that are part of the Virgo Supercluster (I counted 27 in the image but there are probably more). Astrometry.net identified only a few of them. Those identified are, from left to right: NGC 914, NGC 913, NGC 911, NGC 912, NGC 910, NGC 909, NGC 906, NGC 898. Their approximate distances from us range from between 200 million to 250 million light years.

22/10/2021
030 x 300-second exposures at Unity Gain (139) cooled to -20°C 
050 x dark frames
040 x flat frames
100 x bias frames
Binning 1x1

Total integration time = 2 hours and 30 minutes

Captured with APT
Guided with PHD2
Processed in Nebulosity and Photoshop 

Equipment:
Telescope: Sky-Watcher Explorer-150PDS
Mount: Skywatcher EQ5
Guide Scope: Orion 50mm Mini
Guiding Camera: SVBONY SV105 with ZWO USBST4 guider adapter
Imaging Camera:  ZWO ASI1600MC Pro with anti-dew heater
Baader Mark-III MPCC Coma Corrector
Optolong L-Pro filter 

[rl]

Lovely shot. Illustrates the real power of simple kit in good hands. Where was it taken from? Was it London as per your signature? If so, the filter is proving its worth. 

[Paul M]

That's a great image.

I took the liberty of plate solving it in ASTAP and then annotated using the HyperLeda tool. It looks like you got some pixels for very nearly every one of them

[Davide Simonetti]

6 hours ago, rl said:

Lovely shot. Illustrates the real power of simple kit in good hands. Where was it taken from? Was it London as per your signature? If so, the filter is proving its worth. 

Thank you 😀. Yes, the shot was taken in north London under Bortle 8 skies...and with a full Moon. So the Optolong L-Pro filter is doing a splendid job. I'm kicking myself for not getting one years ago because it's a real game-changer when you're struggling with light pollution.

[Davide Simonetti]

7 hours ago, Paul M said:

That's a great image.

I took the liberty of plate solving it in ASTAP and then annotated using the HyperLeda tool. It looks like you got some pixels for very nearly every one of them

Thank you so much for that. That's a much better result than the one I got from Astrometry.net. I've been looking for a good open source astrometry program and up until now I've occasionally been using XParallax VIU but it isn't as good as ASTAP. I've just downloaded it with the HyperLeda database and I'm playing with it now and learning to use it and it seems to be just what I was looking for, so thanks again...and thanks also for your encouraging comment 😀

[Paul M]

I use ASTAP as the plate solver in APT too.  Just need to download a couple of catalogues and point APT to the executable in the Point Craft settings tab. It does a lot of things including live stacking. So as APT saves out individual subs ASTAP will monitor the selected folder and attempt to stack any images it sees there as soon as they arrive. It's a good tool for seeing whether an imaging session is heading the way you wanted.

 

[Davide Simonetti]

Wow, that's another bonus. I quite like using APT so having programs that interface with it is good news. I'm looking forward to trying that out next time we get a clear night (which, sadly, doesn't look like being anytime soon).

[adyj1]

50 minutes ago, Paul M said:

I use ASTAP as the plate solver in APT too.  Just need to download a couple of catalogues and point APT to the executable in the Point Craft settings tab. It does a lot of things including live stacking. So as APT saves out individual subs ASTAP will monitor the selected folder and attempt to stack any images it sees there as soon as they arrive. It's a good tool for seeing whether an imaging session is heading the way you wanted.

 

Switching to astap in APT produced a dramatic increase in speed and reliability of plate solving for me. I think it should be the default install now

[Paul M]

1 hour ago, Davide Simonetti said:

Wow, that's another bonus. I quite like using APT so having programs that interface with it is good news. I'm looking forward to trying that out next time we get a clear night (which, sadly, doesn't look like being anytime soon).

APT is actively developed and new features are introduced regularly.

You can test the functionality of plate solving with any images/subs you have to hand.

Just load one into the APT preview pane and then go to Point Craft and either blind solve or enter the approx RA/DEC and click solve. It won't read any fits header [Edit: it seems to now!] but here is your JPEG image, so I just selected that in the Object menu and its coords were input for me. It does help to have the details of the camera sensor and scope entered at the bottom of the Tools panel so ASTAP knows the size of field it's trying to solve but it solved your image with my imaging rigs details.

When doing live imaging it's less fiddly because that information is created with the image and sent to ASTAP. 

 

Once solved you can click "show" in Point Craft and it will display the field size and orientation on any supported planetarium you have nominated in APT. Here I have ASTAP's stable mate HNSky as my planetarium, solving the old image above then "show" produces this:

 

Edited October 23, 2021 by Paul M

[Davide Simonetti]

3 hours ago, Paul M said:

APT is actively developed and new features are introduced regularly.

You can test the functionality of plate solving with any images/subs you have to hand.

Just load one into the APT preview pane and then go to Point Craft and either blind solve or enter the approx RA/DEC and click solve. It won't read any fits header [Edit: it seems to now!] but here is your JPEG image, so I just selected that in the Object menu and its coords were input for me. It does help to have the details of the camera sensor and scope entered at the bottom of the Tools panel so ASTAP knows the size of field it's trying to solve but it solved your image with my imaging rigs details.

When doing live imaging it's less fiddly because that information is created with the image and sent to ASTAP. 

 

Once solved you can click "show" in Point Craft and it will display the field size and orientation on any supported planetarium you have nominated in APT. Here I have ASTAP's stable mate HNSky as my planetarium, solving the old image above then "show" produces this:

 

Oh, that looks great...I think I'm going to open APT and have a look. I don't have my kit set up at the moment because it's cloudy and I'm at home but I can still play 😀. Cheers 👍