M31 and a Couple Rarely Imaged Satellites

[Knight of Clear Skies]

Third light for my WO ZS71, here's my first telescopic image of Andromeda.

Taken with my WO ZS71 ED and 0.8 reducer, giving a focal length of 334mm at f4.7, and my 1600MM Cool. Total integration time is just under 1h lum and 30m for each colour channel, using 30 second unguided subs at -15C and 300 gain.

The mono version, processed separately from from just the lum, shows a little more detail such as hints of dust around the core in M110.

I just managed to catch V1 but seem to have lost in later the processing, I'll have another go at it sometime.

While waiting for full astro dark I had a quick go at a couple of rarely imaged satellites of M31 in Cassiopeia, NGC 185 & 147, as objects of interested rather than in expectation of producing much of an image. Here's the full frame at the same scale as above:

Integration time was about 20 minutes, here's a closer crop:

Both are dwarf spheroidal galaxies and are thought to be a binary pair. NGC 185 is the brighter of the two at the top of this image and shows a hint of dust near the core. They are about half way between M31 and Shedir, which gives some sense of how far M31's gravity reaches.

They are just visible in this reprocessed widefield but can't be distinguished from foreground stars.

Hope you like the images, would welcome any feedback. Think I need to do some tests to see if the scope needs refocusing for each colour channel, and look into processing of starfields again. 

[knobby]

Really nice image, nicely processed too .

[michaelmorris]

There great images.  Thanks for sharing.

[MikeODay]

Wonderful images and a very interesting write-up - a great post!  

Thanks for sharing.

[rl]

Amateur astronomy at its best...

[RobertI]

Lovely images, The colour image is nice but the black and white is superb; tremendous detail and very sharp.

[ultranova]

That's came out very nice indeed,

sharp and detailed, processing is nice and subtle

The lum pic is amazing.

well done

Paul

 

[PatrickGilliland]

Nice subtle version well done, processing is nice.

[Delasaurus]

Nice job

Small is beautiful, who needs big scopes? (I do, coz I always wanted one as a kid

[Knight of Clear Skies]

Thanks everyone. While I'm quite pleased with the colour version, I agree with @RobertI and @ultranova that the mono has come out better with more detail in the dust lanes.

16 hours ago, PatrickGilliland said:

Nice subtle version well done, processing is nice.

Thanks, I tried to hold back on the colour as, while the boldly coloured M31s can look great, it's not a starburst galaxy. I don't make any claims to authenticity though. On the other hand, the stars are lacking in colour.

[Allinthehead]

That's a nice set of images and i enjoyed the blurb about the lesser imaged galaxies. I'm curious as to why you chose such a high gain for the rgb even at 30 seconds you would get better colour at unity or the hdr setting. 

[Knight of Clear Skies]

On 08/10/2017 at 14:34, Allinthehead said:

That's a nice set of images and i enjoyed the blurb about the lesser imaged galaxies. I'm curious as to why you chose such a high gain for the rgb even at 30 seconds you would get better colour at unity or the hdr setting. 

Thanks. The gain setting was a mistake on my part. I wanted to image at above unity gain to minimise read noise, but unity gain is a lot lower than I thought it was (127?). I also need to check the offset I'm using is sensible.