PHARscape

This is NGC4631 and NGC4656-7 better known as the Whale and Hockey stick galaxies. Imaged over several nights 21-25th April 2022, I managed only a few hours total due to bad weather.

I’ve taken a shot at Messier 51 again. Compared to Messier 51 and first light for my Orion Optics 250mm rebuild from last year it is more successful:

Conditions were much better and my guiding is considerably better with <> 0.6 total rms. With careful processing I am able to extract detail at the limit of the scope and camera performance when seeing is good, as it was last night.

It’s a bad time of year to image as astronomical dark is very short (around 3.5 hrs now), but you can’t turn down the opportunity for a moonless clear night! With 1hr per RGB filter and 30min of Ha squeezed in the result is a detailed but noisy image.

Making the most of my improved guiding I have been using the big 250mm Newt to image some classic galaxies:

This is a combination of several partial sessions that I had to stop for one reason or another. 10hrs split as 4hrs of Red, 2 hrs of Green and Ha, and only 1hr of Blue! I’ve no idea how many frames were rejected – I left that to the WBB scripts. 

I’d like to make the Holmberg IX dwarf galaxy a bit more prominent if I can (I have some Ha there but it’s very faint).

RBG 30s sub @ 0 Gain

For once my guiding was sub 0.5 arc-sec and conditions were great all night (even with gusts of wind) so I was able to capture all the data in one session🥳. This is 3hrs or RGB and 4hrs of Ha. On this occasion I used unity gain for RGB and 200 for Ha, I’ve decided that with so few good nights it makes sense and the noise isn’t excessive. I combined the Red channel as 80%Ha+20% Red to emphasize the disruption. This is probably my best galaxy to date. Only my processing skills limit what my kit can produce.

In comparison here is a wide field image I took last year using my 150mm newt. There’s a lot wrong with the image but it shows the progress I am making.

Broadband imaging is already tricky in the suburbs but I perhaps didn’t help myself by trying to image this lovely galaxy with an almost full moon chasing it across the sky and haze. But still, for 4 hrs of data this RGBHa image is okay. The star field is aggressively clipped to remove the psychedelic rainbow mottling which I think is just pure moonlight.

For the rest of January, I had two more nights where I attempted to capture this target, luckily no moon glow just LP. So here is take 2, this time about 1 hr each of RGB and only 40mins of Ha. But you can easily see the improvement from by the better seeing and lack of moon – more fine details in the galaxy and lots of smaller galaxies sprinkled throughout the image.