NGC4565 - C38 - Needle Galaxy

[Graeme]

Here's my go at the Needle Galaxy in Coma Berenices from last night. I fitted a new dew heater ring on the SCT yesterday and it did a great job. The guide scope was just starting to mist up at the end of the session. The plan was for a 2200 to 0200 four hour session, from just past meridian to sinking in the West. As it turned out I got started at 2250 and finished at 0150 with an HFR rising to 6.8 in the light dome of London.

9.25 SCT CGX ASI294MC Pro, captured with NINA, guided with PHD2 and processed this morning in PixInsight. 42 (from 58) x 180 sec lights, 8 removed for satellite trails, 8 removed for London LP.  -10°C 125 gain. 30 darks (from library), 30 flats, 30 dark flats.

Collimation needs sorting out! Is that what's causing the soft focus?

 

[jacko61]

Do you have a reducer/flattener?  The stars (especially the bigger ones to the right of the galaxy) look a bit eggy which may be contributing to the soft focus look. However, even with a reducer I could never get pin sharp stars with my C8 so I think it's maybe a feature of SCTs in general. 

Graeme 

[Graeme]

I have considered a reducer to open up my field of view but I've not done it yet! I did notice the eggy stars when I was setting up and had a go at tweaking the collimation but it's tricky with the dew shield on. I must get into the habit of collimating first thing and then putting the dew shield on and re-balancing. 

[The Lazy Astronomer]

It may be some tilt in the imaging train as the stars on the right look a bit elongated, but the ones on the left look pretty round to me. 

[Graeme]

10 hours ago, The Lazy Astronomer said:

It may be some tilt in the imaging train as the stars on the right look a bit elongated, but the ones on the left look pretty round to me. 

Good shout! I have always thought the camera in the eye piece holder was a weak link. Perhaps a T Adapter with the camera screwed into the train would help.

[The Lazy Astronomer]

16 hours ago, Graeme said:

Good shout! I have always thought the camera in the eye piece holder was a weak link. Perhaps a T Adapter with the camera screwed into the train would help.

For sure that's your weak link. Threaded connections all the way for astrophotography!

[CCD-Freak]

Seeing is probably the biggest reason for soft and bloated stars. 

 

 

[Graeme]

2 hours ago, CCD-Freak said:

Seeing is probably the biggest reason for soft and bloated stars. 

 

 

Yes, the jet stream is often overhead. Cloud free night skies are rare enough though! Perhaps some of the PI EZ Star Reduction settings could be tweaked.