John

Before they made telescopes, Takahashi were a specialist sand casting company: http://astrosurf.com/sogorb/takahashi/takahashi.html

Interesting that the internal secondary holder still shows the Celestron Branding in the plastic moulding. Too much trouble to change that I guess, for a marketing experiment.

I guess it's 150mm SCT which Synta have made with the Skywatcher branding on it rather than the Celestron branding. Synta make the SCT's below 11 inches (maybe 14 ?) now as they own Celestron. Whether this means that we will see Skywatcher branded SCT's at some point, who knows ? For a while in the USA you could get Orion (USA) branded SCT's. This is an Orion branded C11: The above OTA is from the era when the C11 was still made in the USA I think.

Having tried for the HH quite often and not got it, I came to the conclusion that the trick was going to be to be able to see / detect the underlying streak of emission nebulosity IC 434 which Barnard 33 (The Horsehead) is set against. To me, when I eventually did manage to see it, the Horsehead looked like a place where an indistinct "bite" of IC 434 was missing I think this is where the H-b filter helps - to tease out this faint HII emission nebula so you can see where it is, and, crucially, the small patch where it isn't. And that is the Horsehead Nebula. A UHC passes both O-III and H-b band widths so can help but the H-b just isolates that one bandwith so is a little more of a helping hand with this task. The O-III bandwidth does not seem to help with this one. As dark and transparent skies as possible are another very important factor as are eyes that have become as dark adapted as they can be. I even stopped using my Rigel finder for a couple of hours when I was doing serious Horsehead searching. No light at all anywhere near my eyes for quite some time. All that to just about visually detect a small patch of blackness against slightly less black, blackness. We must be a little mad

Here are some

I have a Skywatcher ED120 Pro which I love but I have put a Moonlite focuser on the scope and the overall build quality and finish is not as good as my APM, Vixen or Tak refractors. The objective is a very good one though, which is rather important ! I would think that the TS / Altair scopes are a notable step up in all round build quality and quality of fittings such as the focuser, sliding dew shield etc. I had a William Optics 90mm Megrez for a while (it followed a Skywatcher ED100 as it happens) and I would expect the TS / Altair scopes to be similar to the William Optics level of fit and finish. Interestingly, the objectives from the Synta made ED doublet series were used in scopes under other brandings such as William Optics and TS. So we can see where Synta put their effort in with that series. Skywatcher did produce a better finished series with the ED doublets in them called the Equinox series. No longer produced now though:

Very nice report Magnus ! I can't wait to get my 12 inch dob out again You seem to be looking in just the right place for the Horsehead. I've spent quite a lot of time looking at that small patch of sky over the past few winters. Most of the time with no sign of it but when I have managed a glimpse it has been with the H-b filter on the end of the eyepiece. Such a subtle and challenging target - probably about the hardest thing that I've ever observed when I think about it.

You could try a "wanted" advert in the UK Astro Buy & Sell website on on our classifieds section. You never know what might be out there !

Well done Mark

When you star tested, were you getting a reasonably well defined airy disk and diffraction ring / rings when at sharp focus ? Or as the star image quite "hairy" ? I have observed with an 8 inch SCT that was struggling to split Epsilon Lyrae (the "double double") a while back but that did turn out to be out of collimation when we star tested it.

Two things spring to my mind reading your post: cooling and collimation. If you got the scope out at 16:00 hrs then I assume that it had cooled for a decent time before you observed ? Did you star test to check the collimation and, if so, how did the star test look ? The intra and extra images of a star such as Polaris show much about the state of cooling and collimation of a scope. Plus, it's another double star of course ! Your 8 inch SCT should be resolving the double stars you mention, some pretty easily. Mars is whisking away from us now and it's disk is now less than 9 arc seconds but should still be visible as a disk with vague dark markings just about visible. Uranus should show as a grey-green disk, although small, but plainly a disk, at around 200x magnification. I expect you have seen this web page ?: http://www.astrophoto.fr/collim.html

I use the Skytee II which is effectively the same as the TS AZ5. It handles both my 100mm F/9 and 120mm F/7.5 refractors quite easily without the need for a counterweight.

No, telescope or binocular views I think with the moon is projected onto the target object to show the scale of in relative terms. They say that, to the naked eye, the moons disk is about half the size of the nail on your little finger, with your arm outstreched: So I guess that two fingers would cover about the total size of the Veil Nebula complex, as seen with the naked eye (assuming that you could !) ?

I used to think that but I have found both UHC and O-III filters effective with apertures from 80mm and upwards. I used to stick with the "generous" (bandwidth) Baader UHC-S filter with smaller scopes but having tried more regular UHC's and more recently O-III's with such scopes I find them more effective despite the smaller light grasp of the scope. Hopefully Don will see this and explain some more.

From the same source, some graphical representations with the moon for scale: https://calgary.rasc.ca/bigthings.htm#Images

Short and sweet, not to mention noisy ! I guess they will be poring over all the data they got now. I wonder what the local wildlife makes of it ?

I thought I might be in luck tonight as well but the "sucker gaps" in the clouds have progressivly got smaller and smaller so the sucker has given up now and bought the scope back in I got some views of Rigel, Alnitak, Zeta Orionis, Beta Mon in a few favourable cloud gaps but the seeing was rather mediocre so chasing around the sky not that rewarding. 32 Orionis was just about split and 52 elongated. Nothing really at it's best though. Sometimes you just have to beat a retreat !

I came across this list on another forum and thought it might be of interest / use. It is maintained by the RASC Calgary Centre and has information on targets that are as large or larger than the moon in apparent angular size (ie: larger than half a degree). Might be useful in planning observing / imaging ?. Covers N & S hemispheres: https://calgary.rasc.ca/bigthings.htm#Table The biggest couple of targets size is expressed in degrees, the rest in arc minutes.

Big test of Artemis SLS rocket engine due within the hour. Live streaming here: https://www.nasa.gov/multimedia/nasatv/#public

The Sky-90 was a rather unusual scope for Takahashi and there was a fair bit of controversy around it's optical characteristics, maintenance of collimation and handling of CA. From the reading I've done on that model (I have not owned or used one) I suspect much of this was down to misunderstandings though. Roger Vine's review is interesting: http://scopeviews.co.uk/TakSky90.htm

The ED150 would put the AZ-4 under a bit of a strain though ......

Quite a clear split at 225x. It's a 4 arc second gap but quite a large brightness difference between the components - mag 2.6 and mag 7.2, which makes it more of a challenge. The dimmer star can be hard to see if the seeing is wobbly or if the optical system is throwing up some diffraction.

A lot of these scopes are made by the same manufacturer. The Stellamyra is made by Long Perng. I think the TS ones and maybe the Altairs are Kunming United Optics ?

Great to watch - thanks Jeremy So good to see skill, care and pride combining with quality materials and design to produce an exceptional product I feel lucky to own one.

These people in the UK sell Istar achromatic objective lenses: https://www.peak2valleyinstruments.co.uk/page_2238911.html