Astrophotography – deep sky

Messier 42

Here’s an M42 from earlier this week.

On Monday night, with a very bright moon I took some Ha shots. M42 can be quite a tricky target because there’s such a difference in brightness between the centre and outlying areas, so this is a mix of 1 and 10 min exposures with the Ha filter. Unfortunately the clouds were rolling over quite frequently, and of 15 10 mins shots, only 3 were actually usable- this has given me a very noisy Ha channel to work with.

I had a bit more luck on Thursday night, before the moon came up, capturing 1 and 5 min exposures with the IDAS filter that I use to suppress the bright LED lights. Merging mixed exposure times is a new technique for me, so I’m quite pleased with how it has come out. The trapezium can’t quite be seen, but there’s still a reasonable amount of detail in the bright sections that surround it. The hardest bit was reducing the noise in the final colour image- I’ve lost a bit of detail doing this. Ah well- gives me something to aim for next year…

18/2/19 – Ha – 30x 1 mins, 3x 10 mins

21/2/19 – RGB – 12x1mins, 54x 5mins

IC1333

Inspired by Neil’s image of IC1333, I had a  go myself.

I did my best with the conditions but

I was hampered by a number of things.

  1. The moon was only 15 degrees off the target and 75% full
  2. Only a small amount of data collected. Red 9 x 5 minutes, Green 9 x 5mins, Blue 7 x 5mins.
  3. The camera decided not to function in the cooling mode so all images at ambient temperature  (hence noisy),
  4. Me!

Rosette NB1 filter

I thought id have a crack at the Rosette nebula to test out my new IDAS NB1 filter and I’m very pleased with the result. First thing you’ll will notice with the filter is that due to the higher cut off point and different wavelengths the histogram saturates pretty quickly under a near full moon. The large majority of this is Halpha but its very pleasing to obtain anything under a bright moon especially a part colour image. At this point id say its one of my best astro purchases!

51X2.5min under the moon

M5

Another sleepless night – – –

Did manage to image M5 from the window-sill though. Its a bit tricky to find through the window as it is in an area devoid of bright stars. That is why I tend to use the 80mm with a focal reducer. This is poor optically, but at least it makes the telescope very fast and have a wide field of view, facilitating finding things.

It may be a poor image by Geoff/Damian/Ken/Rob standards, but it beats no image at all!

Compare with the one here with the 8″ SCT from outside;  https://roslistonastronomy.uk/not-many-dso-opportunities-left-this-season

IC 342

More than a month has passed since i had a go at imaging IC 342 and finally this week i had a chance! A very difficult object for me to capture, even a 2.5min exposure only really shows the galactic core. Ive been reading up a bit about this galaxy and it is partially obscured by dusty areas in the milky way which gives it its name “the hidden galaxy”. The ridiculous light pollution of course doesn’t help matters !  This is a total stack of 81×2.5min. It is rather colorful i know but i do like this effect and ive seen some ic 342’s before with a golden look 🙂

 

M35 and NGC2158 from the window-sill

Oddly, I have never imaged the M35/NGC2158 field before, so here is one from the window-sill tonight before it clouded up. It was at the extreme top of the window – not ideal, optically, even by my standards!

Coincidentally, the field of view is similar to Andy’s image intensified view a while ago. See https://roslistonastronomy.uk/image-intensifier-photographs-from-observing-session-17-18-11-2017-home-made-image-intensified-eyepiece-samsung-s7-phone-orion-uk-10-dobsonian-lichfield

This allows us to compare what you would see “live” with an integrating video camera to that with an image intensifier, bearing in mind the intensifier was attached to a 10″ dob and these images are from indoors with an 80mm refractor.

The image above is a processed one from a stack of 40 images at a senseup of 128, ie a 2 1/2 second integration time per image and a total exposure of 100 seconds. ie the view refreshes every 2 1/2 seconds.

If we stack 4 and 8 of these we can see what you will see “live” with a refresh rate of 2 1/2, 10 and 20 seconds, and that is what the following 3 images are, (unprocessed).

 

SH2-252, Monkey Head nebula

This is the RGB version of the Monkey Head nebula (SH2-252) that I have taken over the last few weeks. Those of you who were at the meeting on Friday will have seen this  in the demonstration I did on the night. The nebula sits right at the very top of Orion. Taken with the Takahashi Epsilon 180 @f2.8 and using the Atik 450 camera, this is a total of 4 hours 25 minutes exposures (Ha x 11, O3 x 20, S2 x 22, 5 minute exposures). It’s a good target for imaging, being bright and easy to find.

Geoff