stevewanstall

Thank you.  I shall buy some desiccant!

I have just bought a secondhand Newtonian reflector and this item was in the eyepiece  slot of the moonlite focusser. Can someone tell me what it is please?

I have a ZWO ASI1600MM Pro Cooled Monochrome 4/3" CMOS USB 3.0 Deep Sky Imaging Camera. When taking  'darks' this is what appears. It doesn't look like 'hot' pixels. Any ideas?

 The weather  forecast was dry overnight so I had a go at collecting data from around 9pm till 5 am. I collected around 3 hours in L, and an hour each in R, g and B. Lost quite a lot of frames to poor guiding in the early stage, plus  DSS rejected a few too. Subs were 114 s at a gain of 139, all at 1x1, Celestron 9.25, ZWO 1600mm pro

Wikipedia: NGC 4216 is one of the largest and brightest spiral galaxies of the Virgo Cluster, with an absolute magnitude that has been estimated to be −22 (i.e.: brighter than the Andromeda Galaxy), and like most spiral galaxies of this cluster shows a deficiency of neutral hydrogen that's concentrated within the galaxy's optical disk and has a low surface density for a galaxy of its type. This explains why NGC 4216 is considered an anaemic galaxy by some authors, also with a low star formation activity for a galaxy of its type.[5] In fact, the galaxy's disk shows pillar-like structures that may have been caused by interactions with the intracluster medium of Virgo and/or with nearby galaxies.

In NGC 4216's halo, besides a rich system of globular clusters with a number of them estimated in around 700 (nearly five times more than the Milky Way), two stellar streams that are interpreted as two satellite galaxies being disrupted and absorbed by this galaxy are present.

NGC 4216 seems to be in a place of the Virgo cluster where dwarf galaxies are being destroyed/accreted at a high rate, with it suffering many interactions with these type of galaxies.

Thanks for the feedback, I shall have a go!

Bode's Galaxy in Ursa Major

A very crisp and cold night.  I added more luminance data and also collected some RGB for NGC 2841. There is now around 4 hours in L and an hour each in R, G and B. The subs are 114s at a gain of 139. 

Wikipedia:

NGC 2841 is an unbarred spiral galaxy in the northern circumpolar constellation of Ursa Major. A 2001 Hubble Space Telescope survey of the galaxy's Cepheid variables determined its distance to be approximately 14.1 megaparsecs or 46 million light-years. 

This is the prototype for the flocculent spiral galaxy, a type of spiral galaxy whose arms are patchy and discontinuous. The morphological class is SAa, indicating a spiral galaxy with no central bar and very tightly-wound arms. There is no grand design structure visible in the optical band, although some inner spiral arms can be seen in the near infrared. 

The properties of NGC 2841 are similar to those of the Andromeda Galaxy. It is home to a large population of young blue stars, and a few H II regions. The luminosity of the galaxy is 2×1010 M☉ and it has a combined mass of 7×1010 M☉. Its disk of stars can be traced out to a radius of around 228 kly (70 kpc). This disk begins to warp at a radius of around 98 kly (30 kpc), suggesting the perturbing effect of in-falling matter from the surrounding medium.

The rotational behaviour of the galaxy suggests there is a massive nuclear bulge, with a low-ionization nuclear emission-line region  at the core; a type of region that is characterized by spectral line emission from weakly ionized atoms. A prominent molecular ring is orbiting at a radius of 7–20 kly (2–6 kpc), which is providing a star-forming region of gas and dust. The nucleus appears decoupled and there is a counter-rotating element of stars and gas in the outer parts of the nucleus, suggesting a recent interaction with a smaller galaxy.

Equipment: Celestron 9.25 XLT at F10, Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope

With less sharpening. The image is limited by the pixelation though.

12 minutes ago, AbsolutelyN said:

You've got loads of detail here. Perhaps try a little less sharpening and saturation. On sharpening I try to use the pole as a guide - if that's clipping pure white then ease off a bit. 

Ok, thanks for the tip!

Taken with 9.25 Celestron XLT and ZWO ASI1600 in RGB.

Better than my last ! Doesn't really compare with some other images on here though :0).

On 10/09/2020 at 14:27, MarkAR said:

Nice little target, well done.

2 hours ago, AstroNtinos said:

Really nice photo. I can’t believe you could shoot such a little target nicely. Keep up the good work. 

Thanks guys

49 minutes ago, CraigT82 said:

Great start, nice one! Can you really not set the ROI capture size to less than 800x600 on the ASI1600? 

Probably, that was just the lowest I had used. I have not really used SharpCap much or experimented with changing the filed size ROI setting. There is always so much to do/learn!

This is my first ever image of Mars. It was captured using SharpCap, with a ZWO1600M on a Celestron 9.25 XLT. I messed up quite a bit, ruining a lot of frames by have too dim a blue channel. )So, this is based on the poorest resolution camera settings, 800 x 600 pixels. 1000 frames per channel, at around 18 fps, best 25%) However, it is recognisably Mars, so I do have a degree of satisfaction, also I now have a target to improve against.  The ice cap is clearly visible, as are dark and light areas . And its Red!

The image is based on around 40 mins in each R, G, B and L, 118s subs, at a gain of 139. Calibrated with dark flats and flats.

Wikipedia:     NGC 40 (also known as the Bow-Tie Nebula and Caldwell 2) is a planetary nebula discovered by William Herschel on November 25, 1788, and is composed of hot gas around a dying star. The star has ejected its outer layer which has left behind a smaller, hot star with a temperature on the surface of about 50,000 degrees Celsius. Radiation from the star causes the shed outer layer to heat to about 10,000 degrees Celsius, and is about one light-year across. About 30,000 years from now, scientists theorize that NGC 40 will fade away, leaving only a white dwarf star approximately the size of Earth.

Thank you,  a pleasure on a warm summer night.

A warm summers night, nicer outside than insdie a hot house. No nautical night, so I thought I would just browse the heavens, keeping  a single frame as a souvenir of my tour. The colour image is based on single frames of L, R, G, B.  Usual exposure length around 3 mins.

Brocchi's Cluster (part of )

Cave Nebula in Cassiopeia

Dumbbell Nebula

IC 1848 and IC1871

M8 Lagoon Nebula

M11 Wild Duck Cluster

M16 Eagle Nebula

M17 Omega Nebula

M18

M0 Trifid Nebula

M22

M56

M71

M57 Ring Nebula

Part of the Veil Nebula

Equipment: Skywatcher ED80 at F/7.5,  Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope

Thank you

I like the way you have handled the stars. It is something I need to really look at. I have tried imaging this but have ended up with stupendous stars spoiling it ! 

This is based on 114s subs, around 60 mins in L,R, G and B. First time I have used the ZWO camera with the Skywatcher refractor.  From looking at Xiga's image I can now see how deplorable my star sizing is !

Wikipedia:The Pelican Nebula (also known as IC 5070 and IC 5067[1]) is an H II region associated with the North America Nebula in the constellation Cygnus. The gaseous contortions of this emission nebula bear a resemblance to a pelican, giving rise to its name. The Pelican Nebula is located nearby first magnitude star Deneb, and is divided from its more prominent neighbour, the North America Nebula, by a molecular cloud filled with dark dust.

The Pelican is much studied because it has a particularly active mix of star formation and evolving gas clouds. The light from young energetic stars is slowly transforming cold gas to hot and causing an ionization front gradually to advance outward. Particularly dense filaments of cold gas are seen to still remain, and among these are found two jets emitted from the Herbig–Haro object 555. Millions of years from now this nebula might no longer be known as the Pelican, as the balance and placement of stars and gas will leave something that appears completely different.

Equipment: Skywatcher ED80 at F/7.5,  Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope

I shall  Hasta La Vista Green it !

There we go, you are right, a definite improvement!

Subs of 114s, around an hour in each of L,R,G and B. Moon was around 4 days old and not a lot of astronomical night!

Wikipedia:
NGC 6946 (also known as the Fireworks Galaxy or Caldwell 12) is a face-on intermediate spiral galaxy with a small bright nucleus, whose location in the sky straddles the boundary between the northern constellations of Cepheus and Cygnus. Its distance from Earth is about 25.2 million light-years or 7.72 megaparsecs.

Various unusual celestial objects have been observed within NGC 6964. This includes the so-called 'Red Ellipse' along one of the northern arms that looks like a super-bubble or very large supernova remnant, and which may have been formed by an open cluster containing massive stars. There are also two regions of unusual dark lanes of nebulosity, while within the spiral arms several regions appear devoid of stars and gaseous hydrogen, some spanning up to two kiloparsecs across. A third peculiar object, discovered in 1967, is now known as "Hodge's Complex". This was once thought to be a young supergiant cluster, but in 2017 it was conjectured to be an interacting dwarf galaxy superimposed on NGC 6964.

Equipment: Celestron 9.25 XLT at F10,  Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope

I dont think so, it was green before I used a mask to try and 'enhance' it.

This image is based on 114s subs, with around 8 hours  in Red, 4 hours in Blue and Green.  I have an earlier post on here where I asked for help because I was having trouble processing the data (less of it then). Now I have been able to process it more, with using screen invert mask to try and show the outer layer more clearly. What I cannot work out is why it is green !  Other images I have seen show it as red, but I cannot see where the green comes from, though in the histogram in PS, the red channel becomes much broader than the blue and green. Anyway, this is at the limit of my processing skills and is the least weird looking one I can come up with!. I attach the stacked  files if anyone wants a play. I have only calibrated with flats.

Ball.TIF Gall.TIF Rall.TIF

The image is based on 114s subs, around 2 hours in each of L, R , G and B. Processed in DSS, PS and Lightroom. I am guessing it is suffering from not enough data/ no narrowband since it is not as 'full' as other images I have seen.

APOD: NGC 6888, also known as the Crescent Nebula, is a cosmic bubble about 25 light-years across, blown by winds from its central, bright, massive star. This sharp telescopic portrait uses narrow band image data that isolates light from hydrogen and oxygen atoms in the wind-blown nebula. The oxygen atoms produce the blue-green hue that seems to enshroud the detailed folds and filaments. Visible within the nebula, NGC 6888's central star is classified as a Wolf-Rayet star (WR 136). The star is shedding its outer envelope in a strong stellar wind, ejecting the equivalent of the Sun's mass every 10,000 years. The nebula's complex structures are likely the result of this strong wind interacting with material ejected in an earlier phase. Burning fuel at a prodigious rate and near the end of its stellar life this star should ultimately go out with a bang in a spectacular supernova explosion. Found in the nebula rich constellation Cygnus, NGC 6888 is about 5,000 light-years away.

Crescent Nebula in Cygnus, NGC 6888

Equipment: Celestron 9.25 XLT at F10,  Skywatcher EQ6 Pro GEM, ZWO 1600MM Pro, ZWO EFW with ZWO LRGB filters, QHY5IIC guide camera on Skywatcher 9 x 50 finderscope

6 hours ago, ollypenrice said:

You'll need to reprocess from scratch because the original is significantly black clipped:

 

The shiny, jet black sky was an instant give-away but the histogram in Photoshop levels confirms it. There needs to be at least a little flat black line showing before the histogram pedestal starts to rise. Your faintest signal - that which you rightly want to bring into view - has already been discarded. A healthy histogram looks like this:

The peak of the pedestal rises a little to the right so no faint signal has been discarded. You need to watch this like a hawk throughout the processing job and only bring the black point in as the very last operation. (Also not you have two histo peaks which means one of your colour channels is out of alignment.

For the kind of localized faint shell you're trying to reveal I would begin by doing a normal 'stretch and process' job and save that. The outer shell may be hardly visible but don't worry about that till you have a nice basic image.

I would then make a copy layer and make the bottom active and the top invisible. In Curves I would then put a fixing point at the level of the background sky and another below that, then lift the curve just above the background. This should pull out the outer halo. Restore the curve to a straight line just above this so you're only stretching the faint part  you're looking for. There are fancy ways of combining both layers but I like easy, so I'd just use a small softly feathered eraser to take off the top layer where it's blocking the faint stuff underneath. That's how I did the outer halo of the Owl.

Olly

 

 

Thank you for the detailed advice. I shall try and put this into practice over the next couple of days.

6 hours ago, Annehouw said:

What Olly says, plus you might try the Screen, Mask, Invert procedure. 

See here http://www.astronomersdoitinthedark.com/dslr_llrgb_tutorial.php

If you go to the video clip listing, it is the 9th item. The rest of the tutorial is very good as well.

Thank you for the link, again, I shall try this out.

Onwards and upwards!