alan4908

14 hours ago, wimvb said:

I use Aladin nowadays. It doesn’t have any scope information or anything, but I just set the fov close to that of my scope and camera. Aladin allows me to explore what will else beside the main target will be in the image and explore the best framing. A 1000 mm fl telescope is a wide field instrument for these small galaxies, and rather than crop, I try to include some extra ”eye candy”. All images from the 2020/2021 season on my astrobin page were planned this way.

https://aladin.u-strasbg.fr/AladinLite/

Yes, I also use Aladin, which I find to be an excellent program but mainly to identify background objects within the field of view. 

Alan

On 06/07/2021 at 17:03, tomato said:

Yes, I only came across it this year when looking for small, photogenic galaxies to image. NGC 3938 is another nice target which doesn’t get imaged very often, I think it looks even more like a mini M101.

Thanks I shall explore that one. 

FYI I normally use CCDNavigator for selecting my targets, I mainly use this since it is also communicates ACP Expert, allowing a new target to be programmed with just a mouse click. 

Alan

On 04/07/2021 at 15:57, peter shah said:

That's beautiful Alan

Thanks Peter 

On 04/07/2021 at 16:15, tomato said:

Great image, plenty of sharp detail and colour.

Thanks - Yes, it definitely is a colourful object, so it is a little surprising that it doesn’t often appear on SGL, perhaps  this is due to it’s small apparent size.

Alan

On 02/07/2021 at 08:41, michael.h.f.wilkinson said:

Really lovely, and not often seen on SGL.

 

Thanks Michael. 
 

On 02/07/2021 at 08:22, wimvb said:

Excellent image of this little gem. I found that it benefits from adding Ha.

https://www.astrobin.com/full/th3p15/B/

Thanks - yes, the Ha filter definitely makes the star forming regions stand out (nice pic by the way) I will have to try this should I ever revisit this target. 

18 hours ago, DaveS said:

My ODK rig runs at a native 0.61"/px though how much of that resolution is actually useable is a moot point.

Yes, given the relatively good UK seeing conditions from my site I did wonder if going below 0.7 arc seconds/pixel would bring any additional resolution to my images, however, I subsequently convinced myself that I was at the limit for my system + site. 

Alan

23 hours ago, DaveS said:

Very nice indeed.

NGC 3184 is a new one on me, but looks well worth imaging

Thanks - yes, it is well worth the effort of imaging but take note that it has a small apparent size. I was at 0.7 arc seconds per pixel and still decided to crop it.

Alan

NGC3184, also known as the Little Pinwheel Galaxy, is located in Ursa Major at the border with Leo Minor and is about 40 million light years distant.  Since it is only 20 degrees inclined from face on, its distinct spiral structure is clearly visible. The yellowish core contains old mature stars, while the spiral arms show star forming HII regions scattered amongst mainly blue stars. A dim gaseous disc surrounds the galaxy which has been found to contain over 1000 compact star clusters.

To the right of the image you can also see a red giant star. A few much more distant galaxies are also visible in the background.

This LRGB image was taken with my Esprit 150 and represents just over 12 hours integration time.

LIGHTS: L:25, R:16, G:17, B:15 x 600s, DARKS:30, BIAS:100, FLATS:40 all at -20C.

Alan

On 17/05/2021 at 12:39, peter shah said:

great to see one of the lesser imaged objects....There so much going on in  Cygnus .....a great shot...

Thanks for the comment Peter 

Alan

Located in Cygnus, I could only find a handful of images of this relatively bright nebula, so it appears quite a neglected target.

What I particularly like are how the blue stars add colour contrast to the deep red of the emission cloud. This close up also reveals the dark structure in the central region.

This LRGB image has an Ha blend into the red channel and represents 23 hours integration time, it was taken with my Esprit 150.

Alan

LIGHTS: L:27, R:21, G:20, B:20 x 600s; Ha: 17 x 1800s. FLATS:40, DARKS:20, BIAS:100 all at -20C.

On 12/04/2021 at 19:49, old_eyes said:

A simple question to other users of the Hitec Astro Weather Deluxe.

I want to close the observatory roof when the weather station reports UNSAFE (clouds or rain), but I want to wait for 5 mins of SAFE before opening up and restarting the sequence. 

I know that the ASCOM drivers for some weather stations allow you to set such delays, but if the Hitec does I can't find it in the manual. I am using Voyager for observatory control and it recognises weather data from AAG or Boltwood, but not from Hitec. So I am using the Safety Monitor facility. This can delay before responding to a change in conditions, but it is symmetrical. The same delay moving from SAFE to UNSAFE as from UNSAFE to SAFE. So a risk of 5 mins rain before the roof closes. 

I have a backup rain sensor I can use for a quicker response, but I just wondered if I am missing something obvious?

I also have the same weather sensor but use it in conjunction with ACP Expert.  The Hitec Astro Weather has  an ASCOM weather service object ID with the name HitecWeather.Weather  - in order to set this up in ACP you simply tell it the ASCOM ID of the weather server and it then knows the state of the weather (Safe or Unsafe).  Although I'm not familiar with Voyager, I'd have thought you be able to perform a similar set up.   

FYI - given the variability of the UK weather I use 20 mins before starting things again. 

Alan

22 hours ago, tony210 said:

Great image - you have captured some nice detail here which is the thing that makes galaxy images work I think.

Thanks - I agree with your point on the detail, that's why I went for an imaging set up with the highest resolution I thought was practical for Deep Sky imaging given my local conditions - 0.7 arc seconds per pixel. 

Alan

22 hours ago, tomato said:

Fantastic detail and colour, really sharp. I never realised there was a gap in the tail between it and the galaxy until looking at this close in image.

Thanks for the comment. On the tidal tail - I was expecting this to go all the way to the galaxy but it hit my noise floor quite  a way out. I presume it still exists here but it must be much dimmer in this region.

17 hours ago, geeklee said:

What a cracking image Alan.  Those HII regions - so subtle but so clear.  Lovely colour throughout as well.

As Adam mentioned, having seen a few hours on my own screen (and being largely unimpressed) I know what the aim is for a future version.

Thanks.  Yes, I too really like how those HII regions have come out on the final image. Good luck with your future capture ! 

17 hours ago, peter shah said:

love that...nice and deep

Thanks Peter. 

14 hours ago, simmo39 said:

V nice!

Thanks, I'm glad you liked it ! 

Alan

11 hours ago, Mr Thingy said:

Stunning image. The detail in the dust clouds really add a sense of scale. 

Is that a tail of the galaxy to the left?

Thanks for the comment 

Yes - that faint band of light to the left of the galaxy is the very long tidal tale . It doesn't often appear on images, probably because it is is very faint. As explained above, it was probably created c800 million years ago when M66 passed by and ripped stars and gas out of NGC 3628.

9 hours ago, tooth_dr said:

Really fantastic. You really only appreciate the detail you have managed to capture when you attempt it yourself 

Thanks - yes, I agree - I've often looked at images at this galaxy but never really paid as much attention to the amount of detail before.

Alan

Located in the Leo constellation, NGC 3628 is relatively bright, edge on spiral galaxy about 35 million light years away. Notable features are a broad equatorial dust band, which obscures the central region, and a very faint, 300,000 light years long, tidal tale of stars. It is also known as the Hamburger galaxy.

The neighbourhood also contains two other large galaxies, M65 and M66, which together with NGC 3628 form the Leo triplet.  Gravitational interactions with these galaxies are believed to be responsible for the warped disk and tidal tale. Spectroscopic analysis indicates that the stars in NGC 3628’s disk orbit in the opposite direction to the gas, which was probably caused by a close encounter with M66 800 million years ago, which is also thought to have also created the vast tidal tail.

The LRGB image below was taken with my Esprit 150 and represents 9.5 hours integration time. Apart from the galaxy features described above, if you look closely at the image you can see that I’ve also managed to capture some pinkish/red HII star forming regions in the central region of the galaxy.

Alan

NGC 3628

NGC 3628 (annotated)

LIGHTS: L:17, R:14, G:14, B:12, x 600s; DARKS: 30, FLATS:40, BIAS:100 all at -20C.

23 hours ago, BrendanC said:

Now, I quite like how the galaxy turned out, but the stars leave a lot to be desired. They seem a bit noisy, bloated and ill-defined. I'm not sure what's wrong. Am I overexposing? Is it noise? Have I overdone the processing? If so, which bit? Are my calibration files crap? Or is it just a basic limitation of my kit? Any/all comments/suggestions/recommendations/ideas/thoughts/opinions/insights/questions welcome.

If you zoom in to a high degree on the unbinned (first) image you can see that all the stars suffer a severe elongation. You can also see that the noise is quite high and that the RGB colours and not quite correct. 

I suspect that the non-round stars are due to the fact that your guiding was not working and so the lack of roundness is simply a manifestation of your mounts tracking inaccuracy.  If you look at the binned image, where you have decreased the overall resolution of the image, they appear more round. You can also fix this effect to a large degree in post processing -  I'd suggest Photoshop -  take the image, duplicate the layer. Set the top layer to Darken and then apply the offset filter to the top layer (this moves the top layer by fractions of a pixel with respect to the bottom layer), until you get rounder stars.

To improve your RGB star colours I'd suggest you separate the result into an RGB and a luminescence image and process these separately. This relies on the fact that almost all the detail comes from the luminescence rather than the RGB image. So, take the RGB image and blur it until all the stars look quite blurry. You might also want to increase the colour saturation slightly.  Then recombine if with the lum image. 

On the noise front - I'd make the background less dark - in Photoshop I'd suggest a background level of between 18 and 24, your image is currently around 3 to 5.  I then suggest you look at the image and see where the main sources are, in general I'd always suggest applying any noise reduction scheme in conjunction with an object mask so that it is targeted where it is most needed.

Hope this helps.

Alan

On 14/04/2021 at 22:33, Clarkey said:

Really great image. I like the processing too. Not 'overdone'.

Might put this on my list for next year.

Thanks for the comment - if you do attempt this, then I'd suggest quite long exposures for the outer arms since I found them very faint. 

Alan

20 hours ago, geeklee said:

Another beautiful and rare to see (for me) set of galaxies.  NGC4399 is fascinating with that tantalising bit of detail.  Thanks for the information in the write up too.

Thanks Lee - yes, NGC 4399 is very strange looking - looks a little like a planet made of stars. 

20 hours ago, scotty38 said:

Blimey, another great image. I'd have had to start years ago to get 18hrs of data

Well, given poor UK weather and the fact that I don't have a clear horizon, it does take me rather a long time to get this amount of data. Due to these two factors, I do rely on my automated imaging set up a lot !

20 hours ago, Dave61 said:

What a cracking image that is, very nice.

Thanks !  

NGC 4395 is low surface brightness dwarf galaxy about 14 million light years distant in Canes Venatici.  Although visually dim, the apparent size of the galaxy is quite large, about 13’ x 11’. Unusually, it does not have a central bulge of stars in its central core and is significantly variable in X-Ray emissions with luminosity emissions varying by a factor of two within 300s. Three star forming regions, have separate designations (NGC 4401, 4400, 4399).

Most galaxies contain central black holes and radiation is produced as objects fall into them.  For NGC 4395, the core is extremely dim, so the mass of the associated black hole mass is believed to be extremely small, probably somewhere between 10,000 and 400,000 solar masses, making it one of the smallest black holes found in galaxies.

The LRGB image below has an Ha blend into the red channel and was taken by my Esprit 150 and represents about 18 hours integration time.

Alan

NGC 4395

NGC 4395 (annotated)

LIGHTS: L:32, R:17, G:15, B: 18 x 600s; Ha:8 x 1800s. DARKS:30, FLATS:40, BIAS:100 all at -20C.

On 08/04/2021 at 15:35, scotty38 said:

Yes thanks, I did think it wouldn't harm much if I took off the .8 reducer to give me a whopping 480mm

Good luck with your capture !

On 08/04/2021 at 16:24, ultranova said:

What a cracker, This is a first for me seeing this Galaxy

And what a super job you have done on it.

Judging by the size of it, you need quite an amount of focal length like your

Esprit 150 to get that level of detail.

well done 

Paul

Thanks Paul.  Yes,  a long focal length helps and also small camera pixels.  With my Esprit 150 and my Trius 814 camera set up, I'm at 0.7 arc seconds/pixel which gives me quite a high resolution imaging set up.  

On 08/04/2021 at 16:58, geeklee said:

One of the most unique and beautiful images I've seen on here.  What a great image @alan4908

Thanks for the comment Lee  

On 07/04/2021 at 10:42, Stuf1978 said:

Beautiful image of a target that I've never seen before, great work

Thanks - yes , it doesn't appear very often on SGL, perhaps because  of its small apparent size

22 hours ago, mackiedlm said:

that a beautiful image of a rather unusual target. - One to add to the list.

Thanks - its definitely worthy of more attention that it currently seems to get.

21 hours ago, Paul M said:

Stunning image!

It's a new object for me too.

Thanks for the comment. 

21 hours ago, scotty38 said:

Fantastic image and great write up too. My list of "must try this one too" just keeps getting bigger, I should perhaps write them down....

Thanks - if you are going to attempt this just be aware of its small apparent size.  

20 hours ago, petevasey said:

Beatiful image, Alan.  Fine deep detail and lovely colours.  That tidal tail is very difficult - I know from my own experience!

Cheers,

Peter

Thanks Peter. The tidal tail is very, very faint - even with my quite dark skies and 600s subs its only just above the noise floor . 

Alan

On 05/04/2021 at 09:23, Mr Spock said:

A nice detailed image. The write up is very informative - thank you.

Thanks ! 

Alan

22 hours ago, ramdom said:

Fantastic image, it's a fascinating target as well. 

Yes - a very interesting target - thanks for the comment. 

Alan

On 02/04/2021 at 12:07, Allinthehead said:

Superb image Alan.

Thanks for the comment 

Alan

NGC 4449 is a dwarf galaxy located in Canes Venatici, 20,000 light years across and c12.5 million light years from Earth. Its structure is similar to the Large Magellanic Cloud (LMC), the satellite galaxy to our Milky Way.  Evidence for a very high rate of star formation is indicated by the presence of many young blue stars and pinkish star forming regions.

It was the first dwarf galaxy to have an associated tidal stream identified which is the product of violent interactions with another satellite dwarf galaxy, NGC 4449B. The faint remnants of NGC4449B appear as a dim trail of stars and dust which will eventually merge with NGC 4449.

The observable mass of NGC 4449 is insufficient to explain the interactions with other objects and so the missing mass is called dark matter.  Dark matter is believed to surround all galaxies, including our own. Dwarf galaxies have higher proportions of dark to normal matter and so what appears as a minor amount of observable stellar matter interacting with NGC 4449 may actually represent a large amount of dark matter, which may explain the very high rate of star formation.  

The LRGB image below was taken by my Esprit 150 and represents just over 15 hours integration time.

Alan

NGC 4449

NGC 4449 (annotated)

L:40,R:21, G:10, B:20 x 600s; DARKS:30, BIAS:100, FLATS:40 all at -20C.