26.8.11

A Russian addition

After acquiring my 200mm Takumar which is giving pleasing results I began looking for a decent cheap 300mm prime lens that might be suited to astro work. Research led me to the Russian Tair-3 which got favourable reports from several users. After seeing some quite impressive examples of photos taken with the lens I decided to visit eBay and found a good example in the Ukraine which I duly purchased and received in 7 days. The lens is built like a tank and is very heavy given its aperture of F 4.5. It has some unusual features including being part of a system that was mounted like a rifle using a gun trigger to fire the shutter....It came complete with the gunlike attachments though I would feel a bit conspicuous using it in that way!.... Keen to try it on the stars I gave it a go under abysmal conditions with continuous patches of cloud and poor transparency. I was only able to obtain half a dozen murky subs of around 5 minutes which have little depth but were sufficient to reveal how well the lens performs. It produces very little CA and is nicely coma free round the edges so I'm looking forward to trying it more seriously. This image is just a random area in Cygnus a bit above Deneb. Details: Tair 3s 300mm F5.6 6 x 5 minutes @ iso1600 (full field) with CLS in DSS, FIV, CS2 & XAT.

22.8.11

A Lacerta planetary

After imaging Collinder 433 the sky remained nicely transparent so I moved on to attempt Abell 80 which is a fairly faint planetary nebula in Lacerta. The rising moon began to affect the later subs but probably not enough to make much difference to the final result. Details: 10" f4.3 Newt. 12 x 10 minutes @ iso1600 with CLS in DSS, FIV, CS2 & XAT.

A Cygnus cluster

With the moon now rising much later a darker sky is available oncemore. I had noticed this attractive faint cluster in Cygnus not far from the North American Nebula. It was difficult to find its ID but I eventually located it on the Collinder list as Collinder 433 / NGC 7044 (Collinder's list can be found here). It seems to contain a high percentage of reddish stars. The transparency was good though it was a bit frustrating waiting for persistent patches of cloud to clear. Details: 10" f4.3 Newt. 14 x 5 minute @ iso1600 with CLS in DSS, FIV, CS2 & XAT.

20.8.11

31 Cygni group

Continuing with the star theme this group in Cygnus is another delight through the eyepiece or binoculars with its contrasting colours. Situated between Deneb & Rukh the brightest components are 30 & 31 Cygni with 31 Cygni dominating. This is itself a spectroscopic binary of type K0 @ 4th magnitude. Details: 10" f4.3 Newt. 20 x various exposures (up to 3 minutes) @ iso1600 with CLS in DSS, FIV, CS2 & XAT.

16.8.11

A famous summer double

While the moonlight dominates I decided to carry on with some star imaging so an obvious target to attempt had to be the colourful double star Albireo in Cygnus. Unfortunately large patches of cloud made obtaining subs a tedious affair and I gave up after obtaining a dozen of various lengths as I had done with the Garnet. I always find Albireo a wonderful sight through an eyepiece with such a spectacular colour contrast between its component stars (spectral types K3 & B8). I was hoping the contrast would be more obvious on the final image which I again have kept flat with no boosting. It does help reveal just how intense the colour of the Garnet Star is. In 1976 it was discovered that the brighter component of Albireo is itself a binary star. Details: 10" f4.3 Newt. 12 x various exposures @ iso800 with CLS in DSS, FIV, CS2 & XAT.

13.8.11

Portrait of a beauty

With a clear opportunity but a bright moon in the sky any serious deep sky imaging wasn't worth considering. However the red star I noted on my recent post of Sh2-104 reminded me that Herschel's famous "Garnet Star" was well placed in my imaging window so I thought it a worthy target in the conditions. I took 20 subs of varying length between 30 seconds & 3 minutes @ iso800 which I hoped would give the strongest colour rendition when stacked together. The final image is flat and hasn't received any saturation boost so the star's amazing colour hasn't been enhanced in any way. Mu Cephei (The Garnet Star) is a red supergiant in Cepheus and is one of the largest and most luminous stars in the Milky Way with the spectral class M21a. ( Wiki states it is 1,650 times the sun's solar radius). Details: 10" f4.3 Newt. 20 x various exposures @ iso800 with CLS in DSS, FIV, CS2 & XAT.

10.8.11

A summer galaxy

The next opportunity found the moon's brightness much more of a problem. Transparency was also quite poor so finding a target worth bothering with under the conditions was a bit difficult. Although galaxies are few in the summer sky compared to the abundance during spring there are some to be found. Close to the Veil Nebula in Cygnus is NGC 7013 which has a fairly bright core so I thought it worth an attempt. The result was much as expected under the conditions with the outer arms not visible and some hard processing required to get much of an image at all. Another one for a better night. Details: 10" f4.3 Newt. 12 x 7minute exposures @ iso1600 with CLS in DSS, FIV, CS2 & XAT.

9.8.11

Another Cygnus Sharpless

Although the moon is now past first quarter its low elevation makes the brightness less of a problem to imaging so with an unexpected clear sky I targeted Sh2-104 which lies in central Cygnus not far from The Crescent Nebula. It is described as "About 450 solar masses of gas forming a shell around the ionising O6V star in this HII region located in the outer galaxy". Of note is the intensely red star to its upper right. With wind blowing throughout much of the session transparency remained good. Details: 10" f4.3 Newt. 17x 8minute exposures @ iso1600 with CLS in DSS, FIV, CS2 & XAT.

8.8.11

Comet 2011 P1 Garradd

With my somewhat limited imaging sky the chances of a bright comet appearing in a good enough position to use my Newtonian are severely reduced. With Comet 2011 P1 Garradd being amenable to my situation it was good to have the opportunity to acquire a fairly high resolution image of this welcome visitor. The first of the 30 x 4minute sub exposures was taken around midnight on 7/8/11 with transparency being quite good throughout the untroubled session. Lying near the Pegasus/Delphinus border the comet is at mag 8.6. Details: 10" f4.3 Newt. 30x 4minute exposures @ iso1600 with CLS in DSS, FIV, CS2 & XAT. (a video of the comet's movement during the exposures can be found below)

4.8.11

Cygnus Central

The next clear evening offered some better transparency so I decided to continue with the Takumar 200mm and try for a fairly deep image of the central Cygnus region. The Crescent Nebula shows well and M 29 looks like a mini Pleiades lower left of centre. A few patches of cloud interfered during the session but the transparency remained quite good throughout. Details: Takumar 200mm @ f5.6 (full field) 16x 8minute exposures @ iso1600 with CLS in DSS, FIV, CS2 & XAT.