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 The previous night I had collected five hours of data on M106 to find that DSS couldn't find enough stars in the subs!! I think it must be the contrast reducing effect of a full moon. I need to revisit that one to be sure. Anyway, in order to check it wasn't a problem with DSS, I took some more subs of M81 and then combined them with ones I took in April last year. So, around 5 hours of L and 40 mins each of R, G and B. M82 Cigar Galaxy in Ursa Major A beautifully clear, moonless night. Last session I had imaged Bode's Nebula, so I though I would do its companion, M82 tonight. Around 32 mins in RG and B and 102 mins in L, all at 1x1, gain 139. Wikipedia: Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. A member of the M81 Group, it is about five times more luminous than the Milky Way and has a centre one hundred times more luminous. The starburst activity is thought to have been triggered by interaction with neighbouring galaxy M81. As the closest starburst galaxy to Earth, M82 is the prototypical example of this galaxy type. SN 2014J, a type Ia supernova, was discovered in the galaxy on 21 January 2014. In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated M82 X-2.

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.

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).

Thanks guys

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.